hpdc_en

®

MAGMASOFT Version 4.4 MAGMAhpdc Module

Simulation of the High Pressure Die Casting Process

Manual

2

MAGMAHPDC 4.4 MANUAL

This manual supports MAGMASOFT® 4.4. No part of this document may be reproduced in any form or by any means without prior written consent of MAGMA GmbH. The use of the software described herein is restricted by a license agreement between MAGMA GmbH and the licensee. MAGMA and MAGMASOFT®, MAGMAiron, MAGMAdisa, MAGMAlpdc, MAGMAhpdc and similar names are registered trademarks of MAGMA GmbH. The trademarks of all other products in this document are claimed as the trademarks of their respective owners. The information in this document is subject to change without notice. The information in this publication is believed to be accurate in all aspects; however, MAGMA does not assume responsibility for any consequential damages resulting from its use. The information contained herein is subject to change. Such changes may be incorporated through revisions and / or new editions.

© Copyright 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2005

MAGMA GIESSEREITECHNOLOGIE GMBH KACKERTSTRASSE 11 D-52072 AACHEN GERMANY TEL.: +49 / 241 / 88 90 1- 0 FAX: +49 / 241 / 88 90 1- 60 EMAIL: MAIL@MAGMASOFT.DE INTERNET: WWW.MAGMASOFT.COM

TABLE OF CONTENTS

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Table of Contents 1

MAGMAhpdc ................................................................................................................... 7

2

Introduction..................................................................................................................... 9

3

2.1

The High Pressure Die Casting Process .......................................................... 9

2.2

Simulation Using MAGMAhpdc ...................................................................... 10

2.3

Mold Filling ....................................................................................................... 13

2.4

Solidification..................................................................................................... 15

2.5

Mold Preparation .............................................................................................. 16

How to Use MAGMAhpdc ............................................................................................ 17 3.1

3.2

HPDC Machine Parameters in the Database.................................................. 17 3.1.1

Machine Parameters .............................................................................. 17

3.1.2

Datasets ................................................................................................. 20

Modeling of the Geometry ............................................................................... 21 3.2.1

Special Material Groups......................................................................... 21

3.2.2

Modeling of the HPDC System .............................................................. 22 Complete Modeling ................................................................................ 22 Reduced Modeling ................................................................................. 25

3.3

Defining Simulation Parameters ..................................................................... 26 3.3.1

Overview ................................................................................................ 26

3.3.2

Defining Heat Transfers / 'heat transfer definitions' ............................... 27

3.3.3

Calculating a Shot Profile / 'HPDC calculator'........................................ 28 Overview ................................................................................................ 29 Geometry Data....................................................................................... 31 Machine Data ......................................................................................... 33 Shot Sleeve Data ................................................................................... 35 Process Data.......................................................................................... 37 Optimal Slow Shot Profile ...................................................................... 40 Shot Profile............................................................................................. 42

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PQ2 Diagram.......................................................................................... 44 Shot Characteristics ............................................................................... 45 Venting Options...................................................................................... 46 3.3.4

Window 'cycle definitions'....................................................................... 48

3.3.5

Window 'core open definitions'............................................................... 51 Opening Control by Time ....................................................................... 53 Opening Control by Maximum Temperature .......................................... 54 Opening Control by Local Temperature / Thermocouple ....................... 55

3.3.6

Window 'channel definitions' .................................................................. 56 Cooling Control by Time......................................................................... 60 Cooling Control by Maximum Temperature ........................................... 61 Cooling Control by Local Temperature / Thermocouple ........................ 62

4

3.3.7

Defining Filling Simulation Parameters .................................................. 63

3.3.8

Defining Solidification Simulation Parameters ....................................... 66

3.3.9

Local Squeezing..................................................................................... 67

3.4

HPDC-Specific Entries in the 'protocol listing'.............................................. 69

3.5

Heat Balance..................................................................................................... 70

MAGMAspray ................................................................................................................ 71 4.1

Introduction ...................................................................................................... 71

4.2

The 'spray definitions' Window....................................................................... 73

4.3

The 'spray options' Window ............................................................................ 76

5

MAGMAcoat .................................................................................................................. 79

6

MAGMApressurize........................................................................................................ 83 6.1

Introduction ...................................................................................................... 83

6.2

Defining the Course of Pressure Using a Defined Curve ............................. 85

6.3

6.2.1

Pressure Reduction Control by Time ..................................................... 86

6.2.2

Pressure Reduction Control by Maximum Temperature ........................ 87

6.2.3

Pressure Reduction Control by Local Temperature / Thermocouple ..... 88

Defining the Course of Pressure Using a Free Curve................................... 89

TABLE OF CONTENTS

7

8

5

Stresses in High Pressure Die Casting ...................................................................... 91 7.1

Overview ........................................................................................................... 91

7.2

Simulation ......................................................................................................... 91

7.3

Results .............................................................................................................. 92

Summary – What to Do ................................................................................................ 93 8.1

Project Definition.............................................................................................. 93

8.2

Data for HPDC machines ................................................................................. 93

8.3

Geometry Modeling.......................................................................................... 93

8.4

Simulation Setup .............................................................................................. 93

8.5

Stresses in High Pressure Die Casting .......................................................... 94

8.6

Additional Information ..................................................................................... 94

9

Table of Figures ............................................................................................................ 97

10

Index .............................................................................................................................. 99

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CH. 1: MAGMAHPDC

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1 MAGMAhpdc The add-on module MAGMAhpdc enables you to simulate High Pressure Die Casting (HPDC) processes. All essential thermal and flow boundary conditions are considered. In addition to the functions of standard MAGMASOFT®, you can make use of the following options: •

Simulation of any number of casting cycles.

•

Control of each cooling channel independent from each other as a function of either time, temperature or control thermocouple.

•

Definition of fixed and movable die parts independent from each other. You can assign a different function and control to each part.

•

Die opening either as a function of time, temperature or a control thermocouple.

•

Simulation of cooling effect during die coating.

•

Simulation of cooling effect during die spraying and blowing.

•

Definition of die closing as a function of time or temperature.

•

Definition of the filling conditions by pressure in the shot chamber or at the ingate, as well as by time or volume flow; taking into consideration the particular conditions of HPDC.

•

Definition of different pressures for the separate filling stages.

•

Calculation of mold filling with special boundary conditions.

This manual explains the use of MAGMAhpdc. Please refer to the MAGMASOFT® Manual for an explanation of the basic MAGMASOFT® functions.

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CH. 2: INTRODUCTION

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2 Introduction 2.1 The High Pressure Die Casting Process

Fig. 2-1: Schematic of an HPDC machine

Fig. 2-1 shows a schematic drawing of an HPDC machine. The melt is poured through the pour hole into the shot chamber. During the first phase the plunger presses the melt into the shot chamber, so that the whole cross section of the shot chamber, the runner and gate are filled. Then the plunger is accelerated and presses the melt into the mold (the second phase).

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2.2 Simulation Using MAGMAhpdc A typical simulation cycle of the HPDC process with MAGMAhpdc consists of the simulation of mold filling, solidification, casting removal and mold preparation. You can carry out the mold filling optionally on any of the cycles simulated. Fig. 2-2 shows the general time sequence of a MAGMAhpdc simulation.

Fig. 2-2: Time sequence of the MAGMAhpdc simulation

CH. 2: INTRODUCTION

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Mold filling

Simulation of mold filling starts with the first movement of the piston (first shot phase). Mold filling is described in detail in Ch. 2.3, page 13.

Solidification

Solidification simulation starts when the mold is filled with melt. Solidification simulation is the same as MAGMASOFT® standard. (Please note that with HPDC machines the solidification time starts at the beginning of switching from Phase I to Phase II).

Casting removal

Casting removal starts when the first surfaces start separating from casting and die. Casting removal ends when the last part of the die is removed.

Mold preparation

The mold preparation phase starts when the casting has been ejected from the die. During mold preparation you can spray and blow the die, as well as coat it. Mold preparation ends if the die is closed and the 'wait time' and 'lead time' have elapsed. You can add the wait time individually at the end of each cycle. This enables you to consider e.g. additional mold preparation times that do not occur in every cycle.

A clear understanding of the use of process data during simulation is an absolute must for an effective simulation of the HPDC process. There are differences between the terminology used in the foundry and in simulation, which can easily lead to mistakes. The following diagram (Fig. 2-3) supplies a concise overview of how the real process times are connected to the simulation parameters. It is an extension of the above Fig. 2-2. Near the left margin there is a time indicator that shows the points of time that are characteristic for the HPDC cycle. These times are defined by measures performed in the foundry. Further to the right you find the time spans that you have to define during the HPDC simulation setup. In the right part of the diagram you get an overview of sensible result files.

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Fig. 2-3: Relations between real process times and simulation parameters

CH. 2: INTRODUCTION

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For result interpretation of a simulation, not only filling and solidification results are of interest, but also those process steps during which the environment conditions of the die parts change significantly. These are also called characteristic process times: •

Start of die opening

•

Start of side core removal

•

Start of ejection

•

Start and end of spraying and blowing periods

•

Moment of contact between die halves while die closing

2.3 Mold Filling The mold filling is further divided into four separate time periods as shown in Fig. 2-4:

Fig. 2-4: Filling phase of hpdc process

Shot chamber dwell time

The initial filling of the shot chamber is instantaneous in MAGMAhpdc. The shot chamber dwell time starts at shot chamber pouring and ends with the beginning of the first (slow) shot phase.

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The cooling of the melt during this dwell time is not considered in MAGMAhpdc. Therefore you must consider the temperature of the melt in the chamber during the shot at simulation. First shot phase

Velocity during the first shot phase should prevent a wave on the free surface, in order to avoid any air entrapments in the melt. Therefore the piston moves slowly forward until the shot chamber is 100% filled.

Plunger acceleration

The first phase ends at the beginning of filling the running and gating system, and the plunger is accelerated up to the velocity of the second phase.

Filling of the casting cavity

The plunger's velocity reaches its highest level in the second phase, as the metal enters the die cavity, i.e. the melt is positioned at the ingate everywhere (theoretical approach) These high velocities result in the thin wall sections of the casting being completely filled.

You can calculated the so-called "shot profile" using the MAGMAhpdc 'high pressure die casting calculator', using the geometry data entered in the preprocessor and the parameters defined by you in the calculator. The various stages of filling are shown in Fig. 2-5. The solid lines represent a non-accelerated shot profile, the dashed lines stand for an accelerated shot profile. The accelerated shot profile is sometimes called a "parashot". It simply represents an acceleration of the plunger through the first shot phase as opposed to a constant velocity for the non-accelerated case. You can select both options in the MAGMAhpdc module.

CH. 2: INTRODUCTION

15

Fig. 2-5: Plunger position and velocity as function of time

2.4 Solidification Solidification simulation is the same as in MAGMASOFT®. The temperature distribution at the end of the mold filling simulation is automatically transferred to the solidification simulation. You have to enter the various times and periods of the result distributions in different windows explained in Ch. 3.3.1, page 26. You must note carefully to which time point (the beginning of the cycle, the end of filling or end of casting removal) each entry refers. Please note that with HPDC machines the solidification time starts at the beginning of switching from Phase I to Phase II.

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2.5 Mold Preparation After casting removal you can prepare the mold for the next casting cycle by spraying and/or coating. See Ch. 4, page 71 and Ch. 5, page 79 for further information.

CH. 3: HOW TO USE MAGMAHPDC

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3 How to Use MAGMAhpdc If you create a new project or a new version of an existing project, using the 'create project' or 'create version' functions, you must choose the 'High Pressure Die Casting' entry in the list 'Project Mode'.

3.1 HPDC Machine Parameters in the Database 3.1.1

Machine Parameters

The 'HPDC-Machine' datasets serve to administrate the parameters of high pressure die casting machines. You can define an individual dataset for each machine type. In the database, datasets for all commonly used machines by several producers are stored. Hoever, the data can only be regarded as standard values, as the machines are normally modified before delivery. Please refer also to Ch. 3.1.2, page 20. Fig. 3-1 shows the parameters that must be defined in the database in order to access the HPDC machines for the simulation with MAGMAhpdc.

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database 'Database' menu Select database 'Dataset' menu 'HPDC - Machine' 'Edit' 'Edit' menu 'Machine Parameters'

Fig. 3-1: Defining machine parameters

The entries mean the following: 'Machine type'

Machine type and machine name

'Max length of shot chamber'

Maximum length of shot chamber (mm)


19

'Min. piston diameter'

Minimum piston diameter (mm)

'Max piston diameter'

Maximum piston diameter (mm)

'Max. piston speed'

Maximum piston speed without melt in empty shot for machine demo picture (m/s)

'Max. piston acceleration'

Maximum piston acceleration (m/s2). We highly recommend to adapt the acceleration values for the maximum piston acceleration in the database to the conditions found in your foundry. You can define the parameter 'Max. piston acceleration' using recorded pouring curves as follows:

α = ∆v ------∆t

Equation 3-1

α = Maximum piston acceleration ∆v = Velocity difference phase 2 – phase 1 ∆t = Time difference between end of acceleration (phase 2) minus begin of acceleration (phase 1) 'Locking force'

Nominal locking force (kN)

'Distance between tie bars'

Distance between tie bars (mm)

'Input of hydraulic parameters' 'yes' 'no' 'Max. injection (hydraulic) pressure'

Input of hydraulic parameters is activated (see the three following entries). Input of hydraulic parameters is deactivated.

Maximum injection pressure (piston-type accumulator) (bar)

'Diameter of hydraulic cylinder' Diameter of hydraulic cylinder (mm) 'Calculate injection force'

If you activate this button, MAGMAhpdc calculates the dynamic injection force and the maximum final pressure from the hydraulic parameters (see the two next entries). You must activate the 'yes' button under 'Input of hydraulic parameters', if you want to calculate this.

'Max. dynamic injection force'

Maximum dynamic injection force (kN)

'Max. multi injection force'

Relation of translation, multiplied with this force (kN) (=maximum final pressure)

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3.1.2

Datasets

The following list contains the HPDC machines of the 'MAGMA' database. Please note the following: •

We recommend to use a demo machine if you want to create datasets to your needs.

•

The data in the 'MAGMA' database cannot be used immediately, but must be imported to at least one of the 'User', 'Global' or 'Project' databases and maybe corrected there. The 'Ready to use' function is deactivated in all datasets of the 'MAGMA' database.

•

You can perform user specific modifications of the HPDC machines. Please check, however, that the data correspond exactly to your respective machine parameters.

•

The datasets for HPDC machines from MAGMAhpdc Release 3.x are not compatible to those of Release 4.4. Please take care to modify or complete the data accordingly.

Demo HPDC machines: Demo_100

Demo_250

Demo_4000

Demo_1000

Demo_3000

Demo_700

Demo_1500

Demo_400

Müller-Weingarten HPDC machines: GDK1000

GDK2500

GDK520

GDK1200

GDK2800

GDK630

GDK1350

GDK320

GDK750

GDK1600

GDK3500

GDK850

GDK2000

GDK400

GDK2200

GDK4100

Bühler HPDC machines: SC_D105

SC_F105

SC_N105

SC_D105L

SC_F105L

SC_N105L

SC_D140

SC_F140

SC_N140

SC_D140L

SC_F140L

SC_N140L

SC_D180

SC_F180

SC_N180

SC_D180L

SC_F180L

SC_N180L

SC_D220

SC_F220

SC_N220

SC_D220L

SC_F220L

SC_N220L


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SC_D26

SC_F26

SC_N26

SC_D270

SC_F270

SC_N270

SC_D270L

SC_F270L

SC_N270L

SC_D320

SC_F320

SC_N320

SC_D320L

SC_F320L

SC_N320L

SC_D34

SC_F34

SC_N34

SC_D42

SC_F42

SC_N42

SC_D53

SC_F53

SC_N53

SC_D66

SC_F66

SC_N66

SC_D84

SC_F84

SC_N84

SC_D84L

SC_F84L

SC_N84L

IP1100_SC

IP2700_SC

IP4100_SC

IP1350_SC

IP300_SC

IP550_SC

IP1650_SC

IP3300_SC

IP750_SC

IP200_SC

IP3700_SC

IP900_SC

IP2150_SC

IP400_SC

Italpresse HPDC machines:

3.2 Modeling of the Geometry For the modeling of the geometry in the MAGMASOFT® preprocessor you can use all standard functions. Please refer to the MAGMASOFT® Manual for further information.

3.2.1

Special Material Groups

In addition to the normal material groups in MAGMASOFT®, MAGMAhpdc also contains the following special material groups, which you use to describe the system elements of a die casting process. The names in brackets correspond to those used in the preprocessor: No.

Material group

21

Movable part of the die (Side core / 'SIDEC')

22

Movable part of the die (Ejector die / 'EJECTOR')

22


23

Fixed part of the die (Cover die / 'COVER')

25

Biscuit (without Inlet) ('BISCUIT')

32

Squeeze stamp ('STAMP')

33

Squeeze reservoir ('RESVR')

The piston is modelled with the material group 23. For the process definition, the piston diameter is determined by the diameter of the biscuit. This is why you should define the biscuit as a cylinder (SET CYL x1 y1 z1 x2 y2 z2 R1 R2). Relevant here is the diameter defined for the first point. All die parts apart from the fixed half of the die are movable. Generally the movable half of the die, the casting and the side cores go up together first, then the side cores are moved back, and finally the casting is ejected. The definition of the die opening process is described in Ch. 3.3.5, page 51. If you want to simulate local squeezing with the 'local squeezing' function, the material groups 32 and 33 are available. You can construct several squeezing systems; make sure, however, that you always allocate unambigous, separate MAT IDs. A squeeze reservoir together with a squeeze stamp always form one squeezing system, in which the contact area determines the squeezing direction. This is because you must always define both material groups! Make also sure that you use the MAT IDs correctly and consistently, because the MAT IDs are used for the following activation of the squeeze reservoirs in the simulation setup. Please refer to Ch. 3.3.9, page 67 for details on this.

3.2.2

Modeling of the HPDC System

Complete Modeling When you model the casting, running and gating geometry in the preprocessor, you must take care to use the material groups according to their functions in the HPDC process. A complete model contains the volumes as displayed in Fig. 3-3, which means that biscuit and runners are included in the model. The complete model is quite clear since it represents the casting as it is produced by the machine, but requires more calculation time than the reduced modeling does (Î page 25). You should use the following material groups (the names in brackets correspond to Fig. 3-2): ¾

Inlet (In)

¾

Biscuit (S)


¾

Gating (G)

¾

Ingate (Ig)

¾

Cast (C)

23

Note the following: •

You must model the overflows and the casting as material group 1 ('Cast Alloy'). If these are modeled as material group 'Gating' or 'Ingate', the calculation of the shot profile will be done incorrectly.

•

The total volume of the material groups 'Inlet' and 'Biscuit' (modeled biscuit) should be equal to the volume of the biscuit of the actual casting. This ensures that the thermal history of the die in the region of the biscuit is correctly modeled. If the combined 'Inlet' plus 'Biscuit' volume is bigger than the volume of the shot sleeve at the end of the first shot phase (i.e.shot sleeve is 100% filled), the filling simulation will not start.

•

The enmeshment of the 'Inlet' and 'Biscuit' should result in a minimum of 2 layers of elements along the length of the 'Inlet' and 3 layers along the length of the 'Biscuit'. This ensures that the filling simulation is carried out correctly.

The general usage of the material groups are shown in Fig. 3-3 and Fig. 3-4. Normally the material groups shown in Fig. 3-3 are used, thus taking the biscuit into consideration.

!

If the HPDC calculator is used for determining a pouring rate (shot curve), the volume of the material group 'Biscuit', that is, of the whole biscuit, must correspond to the biscuit minus the 'Inlet' volume (Fig. 3-2):

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Fig. 3-2: Layout of material groups

Fig. 3-3: Shot profile depending on the selected material groups with complete modeling


25

Reduced Modeling The reduced modeling of the HPDC system as shown in Fig. 3-4 is used if you have to focus simulation of the casting on special parts of the system and not on the casting as a whole. You can also apply it if simulation of the complete model would exceed the available computer capacity. Note that for calculation of parameters and starting points, MAGMASOFT® always uses the complete model according (Î page 22), which represents the casting as it is produced by the machine. For example, in a reduced model you can neglect parts of the gating or parts of a sophisticated vacuum system. If you are interested only in the early stages of filling dependent on the gating system selected, it is also possible to neglect the rest of the casting.

!

If a reduced model is used, MAGMASOFT® is not able to correctly calculate the weights and volumes of the material groups involved from the preprocessor. You have to correct the values accordingly in this case. You can define the correct values of the volumes using the fields 'biscuit', ' runners' and 'cavity+overflows'.

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Fig. 3-4: Shot profile depending on the selected material groups with reduced modeling

3.3 Defining Simulation Parameters 3.3.1

Overview

After geometry modeling and enmeshment you can enter the parameters for simulation as follows:

Ö

Open the menu 'simulation'.

Ö

The window 'high pressure die casting' appears. Choose the type of simulation you want to carry out.

Ö

The window 'material definitions' opens. This window corresponds to MAGMASOFT® standard. Note that in MAGMAhpdc you have to define three additional material groups (Î Ch. 3.2.1, page 21).


27

Ö

The window 'heat transfer definitions' opens. Define the heat transfers between the different material groups of your casting system as used from MAGMASOFT® standard (Î Ch. 3.3.2, page 27).

Ö

The window 'high pressure die casting' appears. Starting from this window, you can calculate a flow rate for mold filling (Î Ch. 3.3.3, page 28). You can skip this window in case of redefinition using the 'skip' command.

Ö

The window 'cycle definitions' opens. Define the number of casting cycles to be calculated and if mold filling is to be taken into account (Î Ch. 3.3.4, page 48).

Ö

The window 'core open definitions' appears, where you define the opening of the die and side cores after solidification of the casting (Î Ch. 3.3.5, page 51).

Ö

The window 'channel definitions' opens. Here you define the control of cooling channels in case you have modeled cooling channels in the preprocessor (Î Ch. 3.3.6, page 56).

Ö

The window 'options' appears, where you can define simulation of coating of the die as well as pressurized solidification. These options are described in Ch. 5, page 79 and Ch. 6, page 83.

Ö

The window 'filling definitions' appears. Here you define the parameters for the simulation of mold filling (Î Ch. 3.3.7, page 63).

Ö

The window 'solidification definitions' opens, where you define the parameters for the simulation of solidification (Î Ch. 3.3.8, page 66; note the information on feeding given there). Here you can also define the simulation of a spraying process (Î Ch. 4, page 71) and the settings for local squeezing (Î Ch. 3.3.9, page 67).

Ö

The window 'online job simulation control' appears. Start and control the calculation from this window as usual.

3.3.2

Defining Heat Transfers / 'heat transfer definitions'

After the material definitions, define the heat transfer in the 'heat transfer definitions' window as used from MAGMASOFT®. There is a constant heat transfer coefficient available in the 'MAGMA' database, which is called 'MERGEMATERIALS'. You can use it to define an ideal heat transfer between two volumes, which have the same material group but different MAT IDs. This is useful with materials that are not physically separated in reality (this is why 'MERGEMATERIALS' is very high), but for which you

28


want to simulate different boundary conditions. Example: Materials that are sprayed or coated when the die opens. If you use the 'core open definitions' function (Î Ch. 3.3.5, page 51) to open the parts of the die, take care to perform the same definitions for the neighboring geometry elements for which you use 'MERGEMATERIALS'.

3.3.3

Calculating a Shot Profile / 'HPDC calculator'

Starting with this window, you can calculate the flow rate for mold filling:

Fig. 3-5: Available options when starting the HPDC calculator

The following options are available: 'ok'

MAGMASOFT® offers a shot profile (boundary condition for filling simulation) based on the data determined by MAGMAhpdc and a given HPDC machine whose machine specific data are taken into account. The shot profile offered by the program can be modified. Please refer to the following paragraphs for details.

'skip'

No new shot profile is determined. A shot profile that you have already defined in this project version is kept. This can be advantageous, e.g. when you want to restart a filling simulation with 'restart'. Please refer to Ch. 3.3.7, page 63 for further information.

'cancel'

By selecting 'cancel' you abort the entire input of simulation parameters and return to the main user interface of MAGMASOFT®.

If you confirm with 'ok', the windows described below appear. Here you define the parameters needed for the HPDC process. The parameters are used to calculate the shot profile, i.e. the progress of the poured metal volume in dependence on time.


29

Overview Navigation through the windows At the bottom of each main window of the HPDC calculator there are the following buttons: 'cancel'

'cancel' aborts the parameter input and leads you back to the initial window of the HPDC calculator, 'high pressure die casting'.

'
'
'next>'

'next>' leads you to the respective next window. This button is deactivated in the last window. By selecting the buttons '' you can switch at random between all main windows of the HPDC calculator.

'ok'

By selecting 'ok' you terminate the parameter definition (assuming that you have passed through all of the input dialogues) and get to the window 'cycle definitions'.

Data Fields The data fields of the main windows are divided into two columns. The fields of the first (left) column are colored white and cannot be edited, they are display only fields. Here you find the data that MAGMAhpdc takes from geometry modeling and enmeshment. If the resulting values are exceeding sensible ranges or theoretical knowledge respectively, the data field is colored red. In the second (right) column you find light gray colored fields. Here you can modify the data given by the program. The corresponding units for the values to be input are listed as well. As default, the values of the first column appear here; i.e. where fields exist in both columns, the values are identical. Proceed as follows to edit input fields:

Ö

Move the mouse pointer to the field you want to edit and press the left mouse button. The field activated for input is colored blue now. Alternatively, you can move from one field to another by pressing the TAB key.

Ö

Enter the desired value and press the RETURN key. Now the old value is replaced by the new one.

Ö

By clicking with the mouse on the arrow-shaped buttons next to the input fields, you can invoke a list in which several user-defined values for the corresponding function are saved and may be invoked again (history). By clicking again on the wanted value you take it over into the field, and the list is closed. This, however, works only within one calculator session. If you

30


leave the calculator and enter it again, or if you use '
Ö

Often there are several sensible input possibilities that have been stored by the program. By clicking with the left mouse button on the arrow buttons next to the input fields you can invoke a list containing the corresponding values. By clicking on the desired value you take it to the field. The list closes at the same time.

The editing of the input fields is optional; you can but do not have to edit the fields. If you enter values that are beyond the limit values stored in the database, the data field changes its color to yellow.

!

In this case, the calculations are neither carried out nor updated!

Sometimes there are white display only fields also in the second column, e.g. in Fig. 3-6. In these fields, values that are derived from values in input fields are calculated. When you change values in input fields, these display fields automatically change correspondingly.


31

Geometry Data

Fig. 3-6: Defining geometry data

Volumes: 'biscuit'

Volume of the biscuit The biscuit is the melt volume that stays and solidifies in the shot chamber after the plunger movement (plunger end position). During geometry modeling, this biscuit consists of the volumes assigned to the material groups 'Biscuit' and 'Inlet'. The volume is calculated from preprocessor data.

'runners'

Volume of the running and gating system The volume of the running and gating system is the sum of the volumes assigned to the material groups 'Gating' and 'ingate'. The calculation is based on preprocessor data.

'cavity+overflows'

Volume of casting and overflows

32


This field displays the sum of all volumes assigned to the material group 'Cast 'Alloy' (1). These are the volumes of the casting and the overflows. The calculation is based on preprocessor values. 'molten metal ladled'

Total melt volume Sum of all metal volumes needed for the casting process (= sum of the values in the fields 'biscuit', 'runners' and 'cavity+overflows'). Please note that you may have to correct the volume if the reduced model (Fig. 3-4) has been used for geometry modeling.

'ingate area'

Cross section area of the ingate This cross section area is calculated using preprocessor data. Please note that, depending on the spatial position of the ingate cross section, the calculation of the cross section area from geometry data may be inaccurate. If the ingate cross section is parallel to the coordinate system, the area is calculated accurately. In addition, it is required that the ingate is cut off by the casting exactly at the transition to the casting. Deviations from this position can lead to inaccuracies. Please be careful with overlapping cross sections as well. As the ingate cross section is a crucial initial value for the calculation of the shot profile and also an orientation value for the foundryman, this value always has to be checked and replaced by the actual value if necessary.

'projected area'

!

Projected area Projected casting area in the die parting plane. In the list next to the input field there are also the projected areas of the other principal planes. As default, the projected areas are active towards the inlet. The projected areas for possible side cores / sliders are not taken into account. You must correct them manually (see the explanations of Fig. 3-7).

You can only determine a flow rate that corresponds to practice if you have modeled the volumes in the way described above. In the case of a reduced model (Î page 25), you have to correct the volumes as described above to make them correspond to the volumes of the entire casting system.


'characteristic wall thickness'

33

Characteristic wall thickness of the casting This value is not taken from preprocessor data but has to be defined by you.

'quality'

Quality requirement Choose 'standard', 'technical' or 'high' (pressure-tight). The choice of quality requirement serves the selection of the specific final pressure ('required specific pressure') in the following window.

Machine Data

Fig. 3-7: Defining HPDC machine data

The list on the left of the window shows the datasets of all HPDC machines that exist in the MAGMASOFT® databases and lie within the values defined at 'closing force'. By clicking on the register cards 'database', 'filename' and 'closing force', you can sort the datasets by the database, the file name of the dataset or the level of closing force. Using the three parameters listed on the right side of the window below 'closing force', you can filter datasets concertedly from the list (for explanations see below at 'security factor' and 'lower/upper limit').

34


Please refer also to Ch. 3.1, page 17. In the following, the entries of the 'machine data' window are explained: 'required specific pressure'

Specific casting pressure This value depends on the selected alloy and quality requirement for the casting. You have to define the quality in the window 'geometry data' at 'quality' (Î Fig. 3-6, page 31).

'selected specific pressure'

Specific casting pressure Valid values lie within the interval of 'required specific pressure'. The value that you define here is used as default for the 'working pressure' value within the MAGMApressurize option (Î Ch. 6.2, page 85).

'min. required closing force'

!

Minimum required closing force Product value of 'projected area' and 'selected specific pressure'

The minimum required closing force is only valid for a die without side cores. If you use dies with side cores, the minimum required closing force can be much higher due to the additional locking forces of the side cores! You should carry out the calculation of the effective projected area of the side cores following the usual procedure in your foundry. You must add the determined additional area in the field 'projected area' of the window 'geometry data' (Î Fig. 3-6, page 31).

'security factor'

Security factor The closing force of the machine must be higher than the explosive force ('min. required closing force'). If you use molds with side cores, a further increase is necessary.

'lower/upper limit'

Lower or upper limit for the displayed machines

Tab. 3-1: Specific casting pressures [bar] Aluminium

Zinc

Magnesium

Brass

Standard

200-400

100-200

200-400

300-400

Technical

400-600

200-300

400-600

400-500

Pressure-tight

800-1000

250-400

800-1000

800-1000


35

Shot Sleeve Data

Fig. 3-8: Defining shot sleeve data

'die casting machine'

Machine type and denomination

'diameter of plunger'

Diameter of the plunger When you open the HPDC calculator, the value that you have defined in the preprocessor appears first. The plunger diameter should correspond to the biscuit diameter in case you have modeled the biscuit using the material group 'Biscuit'.

'active length of shot sleeve'

Length of the shot sleeve or maximum active plunger stroke up to the end position on the ejector side. Please keep the limitation due to the machine type when entering this value ('Max. length of shot sleeve').

'shot sleeve filling'

Filling degree of the shot sleeve in percent. This value is automatically calculated from the length of the shot sleeve and the plunger diameter, and is given here as information. The field cannot be edited.

36


When the values lie below 10% or above 100%, an error message appears. 'area of plunger'

Plunger area

'volume of shot sleeve'

Volume of the shot sleeve up to plunger end position

'accelerated first phase'

'on'

MAGMAhpdc calculates an accelerated shot profile ('filling phase', Î Ch. 2.3, page 13). In this case, the button 'opt. slow shot' is deactivated.

'off'

MAGMAhpdc calculates a non-accelerated shot profile.

'opt. slow shot'

Optimization of the shot profile for cold chamber HPDC machines in the first (slow) phase. Please refer also to page 40.

'shot profile'

You can use this option to invoke a graph of the calculated shot profile. Displayed is the pouring rate (i.e. position of the piston), dependent on time. The user-defined pouring rate is displayed in relation to the curve proposed by the HPDC calculator. You gain a visual control that displays too big differences between the two curves. Please refer also to page 42.

'PQ2'

Display of the PQ2 diagram A picture is invoked that shows the melt flow situation for the liquid metal within the casting system up to the runners and gating. It shows the connection between metal pressure P and the metal volume flow Q, or piston velocity, dependent on the gating's cross section and the density of the chosen alloy (Î Fig. 3-15, page 44).


37

Process Data

Fig. 3-9: Defining process data

'die casting machine'

Machine type and machine name

'slow shot velocity'

Velocity of the plunger during the first phase, vI = constant. If the options 'accelerated first phase' or 'opt. slow shot...' (see below) are active, the maximum velocity during the first phase is shown.

'theoretical cavity filling time'

Theoretical time for filling (from ingate) This value is calculated from the 'characteristic wall thickness' value and the chosen alloy.

'fast shot velocity'

Velocity of the plunger during the second phase, vII = constant.

'cavity filling time'

Filling time that is calculated again in case parameters have been changed (Î Tab. 3-2, page 38)

'velocity at the ingate'

Velocity at the ingate (Î Tab. 3-3, page 39)

38


For the values' display of the last two functions, please note the following: If you define too high velocities and too long times, these are hightlighted red. If you define too slow velocities and too short times, these are highlighted blue. 'accelerated first phase'

'yes'

MAGMAhpdc calculates an accelerated shot profile (Î Fig. 3-13, page 43).

'no'

MAGMAhpdc calculates a non-accelerated shot profile.

'opt. slow shot'

Optimization of the shot curve in the first (slow) phase for cold chamber machines (Î Fig. 3-10, page 40).

'shot profile'

You can invoke a graph of the calculated shot profile using this option (Î Fig. 3-12, page 42).

'PQ2'

Display of the PQ2 diagram A picture is invoked that shows the melt flow situation for the liquid metal within the casting system up to the runners and gating. It shows the connection between metal pressure P and the metal volume flow Q, or piston velocity, dependent on the gating's cross section and the density of the chosen alloy (Î Fig. 3-15, page 44).

Tab. 3-2: Standard values for filling (according to F.C.Bennett) Wall thickness [mm]

Filling time [ms]

1,5

10-30

1,8

20-40

2,0

20-60

2,3

30-70

2,5

40-90

3,0

50-100

3,8

50-120

5,0

60-200

6,4

80-300


39

You should choose big values for aluminium, medium values for zinc and small values for magnesium.

Tab. 3-3: Standard values for velocities at ingate [m/s] (according to F.C. Bennett) Alloy

Velocity at ingate

Aluminium

20-60

Zinc

30-50

Magnesium

40-90

Brass

20-50

40


Optimal Slow Shot Profile

Fig. 3-10: Optimizing the slow shot wave profile ('best')

You can invoke the window for optimizing the shot profile using the 'opt. slow shot...' buttons of the windows 'shot sleeve data' and 'process data'. The default setting is 'best' (Fig. 3-10). Here you can control shot profile optimization during the first (slow) phase for cold chamber machines.


Fig. 3-11: Optimizing the slow shot wave profile ('optimal')

'level'

Level of optimization

Arrow buttons for animation

•

Single arrow to right: start animation

•

Square: stop animation

•

Double arrow to right: jump to end of animation

•

Arrow to right pointing on surface: fast forward run

•

Arrow to left pointing on surface: fast backward run

'ok'

The calculated values are taken, and the window closes.

'apply'

The calculated values are taken, and the window remains open.

'cancel'

Optimization is deactivated, and the window closes.

The calculations are based on the following study:

41

42


Marilyn C. Thome, and Dr. Jerald R. Brevick, "Optimal Slow Shot Profiles in Cold Chamber Die Casting", Report No. ERC/NSM-C-95-14, The Ohio State University, March 1995 Shot Profile You can invoke the graph of the calculated shot profile using the 'shot profile' buttons of the windows 'shot sleeve data' and 'process data'. The pouring rate (piston position) is shown dependent on time (Fig. 3-12, Fig. 3-13 and Fig. 3-14). The user-defined pouring rate is displayed in relation to the curve proposed by the HPDC calculator. You gain a visual control that displays too big differences between the two curves. Use 'dismiss' to return to the respective window of the HPDC calculator.

Fig. 3-12: Shot profile (constant velocity, first phase)


Fig. 3-13: Shot profile (accelerated first phase)

Fig. 3-14: Shot profile ('opt. slow shot' activated)

43

44


PQ2 Diagram

Fig. 3-15: Defining the operating point

!

Depending on your geometry and the selected HPDC machine, the velocity in the first phase (slow shot) may be higher than the velocity in the second phase (fast shot) – due to settings for calculation. This leads to unsensible results in the 'shot profile' window. This error is not handled by the program in the moment. Please modify your geometry (e.g. piston diameter) or change the velocity in the second phase.

Using the 'PQ2...' button of the windows 'shot sleeve data' and 'process data' you can invoke a picture that shows the melt flow situation for the liquid metal within the casting system up to the runners and gating. It shows the connection between metal pressure P and the metal volume flow


45

Q, or piston velocity, dependent on the gating's cross section and the density of the chosen alloy (Fig. 3-15). Use the 'dismiss' button to return to the respective window of the HPDC calculator. The lines show the situation at 1) maximum theoretical filling time 2) maximum velocity at the ingate 3) minimum velocity at the ingate Shot Characteristics

Fig. 3-16: Defining the switching point

'switch over stage 1-2'

Start of acceleration phase (switching point) Up to this plunger position, the die is filled with the velocity of the first phase ('slow shot velocity'). If the plunger in the shot chamber has reached this position, it is accelerated up to the velocity of the second phase ('fast shot velocity').

'plunger, start of stage 2'

Position of the plunger if the second phase is reached.

46


'plunger, runner full position'

Position of the plunger if the running system is filled (metal at ingate)

'slow shot velocity'

Velocity of the plunger in the first phase, vI = constant

'fast shot velocity'

Velocity of the plunger in the second phase, vII = constant

'cavity filling time'

Filling time, counted from ingate

'optimal ingate area'

Optimal cross section area of the ingate, proposed by the HPDC calculator This cross section area is calculated based on the data. It does not necessarily reflect the real area.

'velocity at the ingate'

Velocity of the melt if it enters the ingate

For the values' display of the two functions 'cavity filling time' and 'velocity at the ingate', please note the following: If you define too high velocities and too long times, these are hightlighted red. If you define too slow velocities and too short times, these are highlighted blue. Venting Options The options available under 'vents' in the 'venting options' windos (Fig. 3-17) have the following meaning:


47

Fig. 3-17: 'vacuum' option for venting

'no vents defined'

No vents have been defined. The window is empty. No venting model is being simulated.

'vents: off'

Vents have been defined, but they are not active. No venting model is being simulated.

'vents: on'

In the mold cavity there is atmospheric pressure. If filling proceeds, this pressure increases. The resulting high pressure can be partially released by vents. Defined vents are taken into consideration during simulation.

'vents: vaccum'

The entries shown in Fig. 3-17 appear. You can define a time dependent low pressure curve at the outer point of the vent by entering value pairs in the 'new value pair' field ((blank)). The pressure field corresponds to the pressure field at the tank side of the vacuum valve. •

Use 'insert' to insert value pairs into the list in the left part of the window.

48


•

Use 'delete' to delete a value pair, which has been marked in the list before.

•

Use 'delete all' to delete all value pairs from the list.

•

Use 'undo' to undo the last action made (e.g. deleting a value pair).

•

If you choose 'default', the programm calculates a pressure curve. Based on the presently active shot profile, the mold cavity is completely ventilated before the melt reaches the ingate.

If you choose 'on' or 'vacuum', there will be additional results of the 'AirPressure' type in the MAGMAhpdc postprocessor, which will show the air pressure as absolute pressure ('Results' tab, following the filling results). Please refer to the MAGMAventing documentation within the MAGMASOFT® 4.4 Manual for details (on page 6-17 pp there, the 'AirPressure' results are explained, too). Please note that the access to this option in MAGMAhpdc differs from standard MAGMASOFT®. The former uses the HPDC calculator, while you have to go to the 'options' window in the latter.

3.3.4

Window 'cycle definitions'

In addition to the calculation of individual castings MAGMASOFT® enables you to simulate multicycle casting in permanent molds. During subsequent cycles a temperature profile results as it exists in real casting. So if mold filling is calculated in the last cycle, a realistic temperature profile of the mold is used for simulation. If enough cycles are calculated, the temperature profile is nearly steady. You must set the parameters defining this multi-cycle process in the following window:


49

Fig. 3-18: Defining casting cycles

The separate fields in this window have the following meaning: 'number of cycles'

Number of cycles that you want to simulate.

'cycle number'

This number identifies the cycle.

'do filling'

Simulation of mold filling is optional during each cycle. If mold filling is calculated ('yes'), the calculated temperature field at the end of mold filling is used to start solidification simulation. As long as no other filling simulation is calculated ('no'), the temperature field for cast alloy is used for all further solidification simulations.

50


'fill results'

'fill results' defines if the results of filling simulation are stored ('yes') or not ('no'). In the postprocessor you can only view results that you have stored. Use the left mouse button to switch between 'yes' and 'no'.

'solid results'

'solid results' defines if the results of solidification simulation are stored ('yes') or not ('no'). In the postprocessor you can only view results that you have stored.

'consider casting'

'yes'

After casting ejection in this cycle, the casting as well as the mold is included in simulation.

'no'

After casting ejection in this cycle, only the mold is included in simulation. Use this option to save computing time, if you are interested in casting results only for later cycles, e.g. steady state conditions.

If the mold is closed, simulation is always carried out with the casting and the mold. Just perform a mouse click on the respective field if you want to change between 'yes' and 'no' in the last four columns. 'wait time'

'wait time' is an additional time (idle time) that you can define at the end of each cycle. You can use 'wait time' to simulate the effects of production stops or of additional preparation of the next cycle. During the 'wait time' the mold is open. The closing of the die as defined in the field 'die closing' is displaced according to 'wait time'. The default setting is '0.00'. This unit is seconds. If you want to define a different wait time, click on the field of the respective cycle. A small window opens, which is called 'wait time defines'. Enter the wanted wait time and confirm with 'ok'. The window closes, and the defined time appears in the 'wait time' column.

'die opening'

This parameter is not used here. You have to define die opening using the window 'core open definitions' (Î Ch. 3.3.5, page 51).

'opening parameter'

This parameter is not used here. In MAGMAhpdc you have to define parameters for die opening using the window 'core open definitions' (Î Ch. 3.3.5, page 51).


51

'die closing'

'die closing' specifies the parameter for closing the die. The die can be closed depending on time or temperature. You must define the corresponding time / temperature in the field 'closing parameter'.

'closing parameter'

Parameter that determines the closing of the die: If die closing depends on time (option 'time' in the field 'die closing'), enter the time when the die is closed. Keep in mind that this time is counted from the time of ejection. If die closing depends on temperature (option 'temperature' in field 'die closing'), enter the temperature of the mold core in [°C]: If the maximum temperature of the die pieces falls below this temperature, the die will be closed. If 'wait time' is not equal '0' for any cycle, closing of the die is delayed for this cycle corresponding to 'wait time'.

'lead time'

3.3.5

This parameter defines the time in [s] that the process needs from die closing up to the beginning of the next shot (Î Fig. 2-2, page 10 and Î Fig. 2-4, page 13).

Window 'core open definitions'

Use this function to define the times after which the different die parts are opened during the HPDC process. You can do this in three ways: 'time'

A time, measured from the beginning of mold filling, controls opening.

'temperature'

A temperature as a criterion for opening. If the calculated maximum temperature in the specified material group is below this temperature, the mold opens.

'thermocouple'

When the temperature at a control point falls below the predefined value, the die opens. Note that you must define the control points in the preprocessor (Î Ch. 3.10, page 3-98 of the MAGMASOFT® 4.4 Manual).

52


Fig. 3-19: Defining mold opening

On the left side of the window all die parts (material groups) that require a definition of opening times are shown. Mark the corresponding line, if you want to see or define movable die half ('SideCore') or fixed die half ('Cover-Die'). If you have already defined any parameters, the corresponding data are shown in the area above. 'core identifier'

This field shows the part of the system for which you have defined the opening time (e.g. 'Side Core, 2').

'controlled by'

The type of control is shown. This may be time, temperature or thermocouple.

'control value (open)'

The first parameter which controls the opening is shown. The parameter depends on the type of control: 'time'

time[sec]

'temperature'

temperature[°C]

'thermocouple'

temperature [°C]


'control parameter'

53

The second parameter that controls the opening is shown. As before, the parameter depends on the type of control: 'time'

not used

'temperature'

material group / MAT ID, in which the maximum temperature is used

'thermocouple'

coordinates and number of the control point / thermocouple

Proceed as follows if you want to enter new data or change data:

Ö

Select the die part ('Side-Core' (movable die half), 'Cover-Die' (fixed die half)) in the list that requires new or changed data for die opening by clicking the left mouse button in the corresponding line.

Ö

Click on the 'options' button or press the middle mouse button to open a new window 'open options'. This enables you to define control parameters for opening the die part.

Ö

A second window 'open options' appears. Choose 'controlled by'. The possible types for control appear ('time', 'temperature', 'thermocouple'). Choose one of these with the left mouse button.

Ö

Depending on your choice for opening control ('time', 'temperature' or 'thermocouple') carry out the steps described in the following three chapters.

Opening Control by Time

Ö

Choose 'controlled by' and the option 'time'.

Ö

Enter the time for opening of the specified core in the field 'control value (on)'.

54


Fig. 3-20: Controlling mold opening by time

Ö

Confirm your choice with 'ok'. The new parameters are saved for the selected mold.

Opening Control by Maximum Temperature

Ö

Choose 'controlled by' and the option 'temperature'.

Ö

First enter the temperature limit in the field 'control value (open)' that will control opening.

Ö

Select a material group in the list below by clicking the left mouse button in the corresponding line. The material group is then shown in the field 'control parameter'.

Ö

If the calculated maximum temperature in this material group falls below the temperature limit entered in the field 'control value (open)', the selected die part opens.


55

Fig. 3-21: Controlling mold opening by maximum temperature

Ö

Confirm your choice with 'ok'. The new parameters are saved for the selected die part.

Opening Control by Local Temperature / Thermocouple

Ö

Choose 'controlled by' and the option 'thermocouple'.

Ö

First enter the temperature limit in the field 'control value (open)' that will control opening.

Ö

Select a control point in the list below by clicking the left mouse button in the corresponding line (The coordinates of the control point are shown). Your choice is shown in the field 'control parameter'.

Ö

If the calculated temperature at the selected point (thermocouple) falls below the temperature limit defined as 'control value (open)', the selected die part opens.

56


Fig. 3-22: Controlling mold opening by local temperature

Ö

Confirm your choice with 'ok'. The new parameters are saved for the selected die part.

3.3.6

Window 'channel definitions'

In this window you can define the control of the cooling channels in the die. If, during modeling of the geometry, you have defined parts of your geometry as material group 'Cooling', you will now find these cooling channels listed at the bottom of this window on the left hand side. There are three types of control for the cooling channels, each of which you must define via the 'options' button: 'time'

You can directly enter a point of time for the beginning and for the end of the contol (cooling or heating). The times refer to the beginning of the cycle.

'temperature'

You can define temperature limits as the criterion for control. You have two options, cooling and heating:


57

Cooling: If the calculated maximum temperature in the specified material group reaches the temperature 'control value on', cooling starts. If the calculated maximum temperature in the specified material group falls below another defined temperature limit ('control value (off)'), cooling is stopped in the specified cooling channel. The temperature that you define for 'control value on' must be higher than the one defined for 'control value (off)'. The start temperature within the chosen material group must lie below the temperature value for 'control value on'. Only then the cooling will be activated if the 'control value on' temperature value is reached. Heating: If the calculated minimum temperature in the specified material group falls belowe the temperature 'control value on', heating starts. If the calculated maximum temperature in the specified material group reaches another defined temperature limit ('control value (off)'), heating is stopped in the specified cooling channel. The temperature that you define for 'control value on' must be lower than the one defined for 'control value (off)'. The start temperature within the chosen material group must lie above the temperature value for 'control value on'. Only then the heating will be activated if the temperature falls below the 'control value on' value. 'thermocouple'

You can define a temperature limit at specific points (control points, thermocouples) for controlling. Here, too, you can choose cooling and heating. This works the same way as 'temperature', however, the chosen control points are considered as the medium, not the material group(s). Note that you must define control points in the preprocessor (Î Ch. 3.10, page 3-98 of the MAGMASOFT® 4.4 Manual). Here, too, the values for the control points must lie out of the range of the "'control value (on)' to 'control value (off)'" interval, as explained for 'temperature' above.

58


Fig. 3-23: The window 'channel definitions'

All geometry elements that you have modeled as cooling channels (labelled here as 'channel') are listed at the bottom left of the window (Fig. 3-23). If required, click on 'expand' to make sure that you can view all channels. Besides each channel, its MAT ID, the defined control parameter and the way of controling ('cooling' or 'heating'; if you choose the 'time' parameter, the last column for this channel is empty) are listed. Mark its line if you want to view or define the control of a specific cooling channel. The corresponding data are shown in the upper part of the window. 'channel'

This field identifies the cooling channel with its MAT ID.

'control type'

The type of control is shown. This may be 'time', 'temperature' or 'thermocouple'.

'control value (on)'

The first parameter for cooling control is shown. The parameter depends on the type of control that you have defined with 'options': 'time'

time [sec]

'temperature'

temperature limit 'on' [°C]


'thermocouple' 'control value (off)'

'control parameter'

59

temperature limit 'on' [°C]

The second parameter is shown that controls cooling. As before, the parameter depends on the type of control: 'time'

not in use

'temperature'

temperature for cooling 'off' [°C]

'thermocouple'

temperature for cooling 'off' [°C]

The third parameter that controls cooling is shown in this field. As before, the parameter depends on the type of control: 'time'

not in use

'temperature'

material group / MAT ID in which the criterion 'temperature' is used. The temperature must lie out of the range of the "'control value (on)' to 'control value (off)'" interval, as explained above.

'thermocouple'

coordinates and number of the control point / thermocouple. The thermocouple must lie out of the range of the "'control value (on)' to 'control value (off)'" interval, as explained above. The start temperature of the thermocouple must be smaller (in case of heating) or bigger (in case of cooling) than the respective limit value of the control interval.

Proceed as follows if you want to enter new data or change parameters:

Ö

Select the cooling channel in the list that requires new or changed control data. Select the corresponding line with the left mouse button. If you have defined several cooling channels, you must choose 'expand' in order to edit each individual channel (the 'expand' button is thereupon deactivated, as in Fig. 3-23). If you want to assign the same control to all cooling channels, you can choose 'hide'. In this case you need to define the parameters (as explained later) only once; the definitions are then automatically assigned to all channels.

Ö

Click on the 'options' button to change or enter new data.

Ö

Choose 'controlled by' in the window that appears now, 'channel options'. The possible types for the control appear ('time', 'temperature', 'thermocouple'). Choose one of these.

Ö

Depending on your choice for control ('time', 'temperature' or 'thermocouple') proceed as described in the next three chapters.

60


Ö

Confirm with 'ok' in the 'channel definitions' window. This leads you to the next window of the simulation setup.

Example of a definition: In Fig. 3-23, the following control has been defined for the marked cooling channel: The cooling channel with MAT ID 5 starts heating the die if the minimum calculated temperature in the 'Cast Alloy' material group, MAT ID 1, falls below 100 °C. The heating stops if the minimum calculated temperature in this material group reaches again 250 °C. Remarks: •

Although a control in both directions – cooling and heating – is possible, the terms "cooling channel" and "Cooling" (material) are always applied.

•

There are several datasets in the 'MAGMA' database that have been adapted to the special requirements on cooling channels ('Cooling' material group). You should always select one of these datasets when assigning the materials with 'material definitions'. Take also care to select the dataset for the wanted control under consideration of the defined temperatures. Please refer to Ch. 8.2.7, page 8-47 of the MAGMASOFT® 4.4 Manual.

•

For the temperature of the cooling medium (heat balance) please refer also to Ch. 3.5, page 70.

Cooling Control by Time

Ö

Choose 'controlled by' in the 'channel options' window and the option 'time'.

Ö

Enter the time after beginning of each cycle when the control is to start in the field 'control value (on)'.

Ö

Enter the time after beginning of each cycle when the control is to stop in the field 'control value (off)'.


61

Fig. 3-24: Cooling channel control by time

Ö

Confirm your choice with 'ok'. The parameters for the chosen cooling channel are stored, and you return to the 'channel definitions' window.

Cooling Control by Maximum Temperature

Ö

Choose 'controlled by' in the 'channel options' window and the option 'temperature'.

Ö

Enter the first temperature limit in the field 'control value (on)'. If the maximum calculated temperature in a specified material group (selected in the list below) exceeds or falls below this value, cooling or heating will start.

Ö

Enter the second temperature limit in the field 'control value (off)'. If the maximum calculated temperature in the specified material group falls below or exceeds this value, cooling or heating will stop. For a control as cooling, the first temperature limit must be higher than the second one. On the other hand, for a control as heating, the first temperature limit must be lower than the second one (as in Fig. 3-25).

62


Ö

In the list in the lower part of the window, select the material group whose temperature is to be considered for control. The material group is shown in the field 'control parameter'. For a better control of the temperatures, its initial temperature is listed behind each material group.

Fig. 3-25: Cooling channel control by maximum temperature

Ö


Cooling Control by Local Temperature / Thermocouple

Ö

Choose 'controlled by' in the 'channel options' window and the option 'thermocouple'.

Ö

Enter the first temperature limit in the field 'control value (on)'. If the maximum calculated temperature in a specified thermocouple (selected in the list below) exceeds or falls below this value, cooling or heating will start.

Ö

Enter the second temperature limit in the field 'control value (off)'. If the maximum calculated temperature in the specified thermocouple falls below or exceeds this value, cooling or heating will stop.


63

For a control as cooling, the first temperature limit must be higher than the second one (as in Fig. 3-26). On the other hand, for a control as heating, the first temperature limit must be lower than the second one.

Ö

Select the control point (thermocouple) in the list below, whose calculated temperature is to be considered for control. The point's coordinates are then shown in the field 'control parameter'.

Fig. 3-26: Cooling channel control by local temperature

Ö


3.3.7

Ö

Defining Filling Simulation Parameters

In MAGMAhpdc, the function 'filling depends on' in the 'filling definitions' window offers three additional options (Fig. 3-27). Please take care not to choose 'pressure' here.

64


Fig. 3-27: Defining filling parameters in MAGMAhpdc

'HPDC calculated flow rate'

The pouring rate calculated in the HPDC calculator is shown in this window. Please refer also to Ch. 3.3.3, page 28. Note that you are not able to modify the pouring rate here.

'HPDC user1 flow rate'

With this option you also reach a window that shows the pouring rate calculated in the HPDC calculator. Here, however, you can edit the pouring rate. At first import the calculated pouring rate using the 'import data' button (Fig. 3-28). For more information refer to the MAGMASOFT® 4.4 Manual, Ch. 5.2.5, page 5-21.

'HPDC user2 flow rate'

If you have not used the HPDC calculator (Î 'skip' button in the window 'high pressure die casting'), you can manually edit a pouring rate at this point. This can be useful for example to enter data directly measured at your HPDC machine. The window is empty if invoked for the first time. You can now •

enter a self-defined curve using value pairs or


65

•

!

import the values from 'HPDC user1 flow rate', if you have used the HPDC calculator before. Choose again the 'import' button to do so.

Take care not to mistake the terms 'user1' and 'user2' appearing here for the identical material descriptions used in the preprocessor.

Fig. 3-28: Editing the pouring rate under 'filling depends on'

!

There is a vital difference between the pouring rates with and without HPDC module. If the HPDC module is not active, melt flow starts at 0.0 seconds. The inlet is filled first, then the gating system and the ingate. The point of time 0.0 corresponds to the moment when the first drops of melt flow into the inlet. The standard option 'pouring rate' for 'filling depends on' exactly corresponds to this pouring rate curve without HPDC module. The last defined coordinate of the pouring rate curves of the three above-mentioned HPDC specific options corresponds to the point of time when the whole geometry is filled. Thereupon, the program specifies the starting point of the simulation by means of backward integration. The starting point (not the time 0.0 as without the HPDC module!) corresponds to the time when the melt starts filling the inlet. For the HPDC module, the time 0.0 corresponds to the moment when the plunger starts to move into the shot sleeve (after the lead time).

66


Ö

You should always have a look on the mold erosion criterion in the postprocessor, due to the high flow velocities in the HPDC process (Î Ch. 4.4.2, page 59 of the Postprocessor on Geometry 4.4 Manual). In the window 'filling definitions', activate the function 'calculate erosion' (Î 'yes') in order to activate the calculation of this criterion.

3.3.8

Defining Solidification Simulation Parameters

Define the parameters in the 'solidification definitions' window as used from MAGMASOFT®. Please note the following: •

If you want to display the 'FEEDING' criterion in the postprocessor, you must calculate the final pressure (for pressurized solidification), using the MAGMApressurize option (Î Ch. 6, page 83).

•

In this case, you have to activate the calculation of feeding ('calculate feeding' Î 'yes') and choose a 'feeding effectivity' value of about 90 %. A value like this indicates that pressurized solidification will take place as long as there is an "open" connection to the inlet. If the ingate is frozen off, the program will consider the 'feeding effectivity' value from the database. Only if you perform these steps you will receive realistic 'FEEDING' results.

Fig. 3-29: Warning message regarding feeding

If you have indeed activated 'calculate feeding', but not the MAGMApressurize option, a warning message appears (Fig. 3-29) after confirming with 'ok' in the 'solidification definitions' win-


67

dow. Choose 'no', return to the 'options' window and activate the calculation of final pressure with MAGMApressurize. In case you have changed material definitions via the databases within the 'Cast Alloy' material class in the 'material definitions' window, another warning message appears. It says that you must check and maybe change the criteria temperatures and the value for the feeding effectivity. For details, please refer to page 5-59 of the MAGMASOFT® 4.4 Manual. If both scenarios occur, both warning messages appear together in one window. •

If you want to simulate the spraying and blowing of the die, you must activate the MAGMAspray option via 'spray process' Î 'yes'. Please refer to Ch. 4, page 71 for details.

•

If you want to simulate local squeezing, you must choose 'local squeezing' Î 'yes'. Please refer to Ch. 3.3.9, page 67 for details.

•

If you simulate stresses with MAGMAstress, the selected solidification simulation results serve as the basis for the stress calculation. Please refer to Ch. 7, page 91 for details.

3.3.9

Local Squeezing

You can use the function 'local squeezing' to simulate local squeezing via defined melt reservoirs. To do so you must have correctly defined and positioned corresponding volumes of the material group 32 (squeeze stamp) and 33 (squeeze reservoir) including the corresponding MAT IDs (Î Ch. 3.2.1, page 21). A reservoir together with a stamp form a squeezing system each. For each reservoir – i.e. for each MAT ID of all volumes of the group 33 – you must define the starting time for the squeezing process (calculated from the end of filling), the duration of the squeezing process and the corresponding pressure. Proceed as follows:

Ö

Invoke the 'solidification definitions' window (see also Ch. 3.3.8, page 66).

Ö

Choose 'local squeezing' Î 'yes'. The window 'local squeezing definitions' appears (Fig. 3-30).

68


Fig. 3-30 Defining local squeezing

Ö

If you want to view or define the control of a particular squeeze reservoir, mark its line first of all. The corrresponding data will be shown in the upper part of the window: 'squeezer'

This field shows the squeeze reservoir including its MAT ID.

'squeeze start'

Start of the squeezing process in s (after the end of filling)

'squeeze duration'

Duration of the squeezing process

'squeeze pressure'

Pressure during the squeezing process in bar

If you want to enter new data or change parameters, proceed as follows:

Ö

Select the squeeze reservoir from the list for which you want to enter new data or data that must be changed. Mark the corresponding line with the left mouse button for doing so. If you have defined several squeeze reservoirs, you must choose 'expand' in order to being able to edit each individual reservoir (the 'expand' button will then be deactivated). If you want to assign the same control to all squeeze reservoirs, you can choose 'hide'. In this case you


69

need to define the parameters only once as described in the following; the definitions will then be valid for all squeeze reservoirs automatically.

Ö

Choose 'options' to enter new data or to edit existing data. The window 'local squeezing options' appears (Fig. 3-31).

Fig. 3-31: Defining parameters for local squeezing

Ö

Enter the described values for start, duration and pressure of the squeezing process and press the RETURN key.

Ö

Confirm with 'ok'. This leads you back to the 'local squeezing definitions' window. The new or edited parameters for the processed squeeze reservoir(s) appear in the fields and the list of this window.

Ö

Confirm with 'ok' there. This leads you back to the 'solidification definitions' window.

The squeezing process is definitely terminated when the die is opened for the first time.

3.4 HPDC-Specific Entries in the 'protocol listing' If you are performing a simulation with MAGMAhpdc, some additional information regarding the HPDC process appears in the 'protocol listing' window (Î main MAGMASOFT® interface Î 'info' menu). Choose the 'Hpdc definitions' entry in this window. Thereupon all HPDC-specific data will appear in the list in a convenient manner, as there are: •

'geometry data'

•

'machine data'

70


•

'shot sleeve data'

•

'shot profile'

•

'process data'

•

'shot characteristics'

•

'venting process'

•

'cycle definitions'

•

'core open definitions'

•

'cooling channel definitions'

The window 'protocol listing' is explained in detail in Ch. 9.9, page 9-19 of the MAGMASOFT® 4.4 Manual.

3.5 Heat Balance You can display the heat flux of materials and defined partial processes, e.g. spraying of the die, as well as of cooling channels. You can access the corresponding output of the program via three functions of the 'info' menu. These are described in Ch. 9.8, page 9-14 of the MAGMASOFT® 4.4 Manual.

CH. 4: MAGMASPRAY

71

4 MAGMAspray 4.1 Introduction In batch production processes, especially HPDC processes, you can apply parting compounds on the die by spraying and subsequent blowing between the individual casting cycles (Fig. 4-1). Depending on the used media and the time, a significant amount of heat is taken from the die, which can lead to a shortening of process cycles.

Fig. 4-1: Die cooling by spraying

The MAGMASOFT® option MAGMAspray simulates cooling of the die caused by spraying and blowing. "Spraying" simulates the application of common water-solutant parting compounds, "blowing" simulates the subsequent drying of the die by compressed air. Cooling is considered for all areas of the mold that have contact to the material groups 'Cast Alloy', 'Core', 'Feeder', 'Feederneck', 'Gating', 'Filter' and 'Ingate'. Contact surfaces of the mold to the material groups 'Inlet',

72


'Stalk' and 'Biscuit' are not cooled. Tab. 4-1 shows the available material groups for the mold, depending on the used MAGMASOFT® modules. Module

Material group in the preprocessor

Standard MAGMASOFT®

Permanent Mold 'PERMM' / 6

High pressure die casting (MAGMAhpdc)

Permanent Mold 'PERMM' / 6 Side core 'SIDEC' / 21 Movable die half, 'EJECTOR' / 22 Fixed die half, 'COVER' / 23

Low pressure die casting (MAGMAlpdc)

Permanent Mold 'PERMM' / 6 Side core 'SIDEC' / 21 Top core 'TOPC' / 22 Bottom core 'BOTTC' / 23

Wheel casting (MAGMAwheel)


Tab. 4-1: Available die parts in MAGMASOFT® and various modules To start MAGMAspray, proceed as follows:

Ö

Enter the simulation parameters as usual.

Ö

In the 'solidification definitions' window, there is a 'spray process' entry. If you activate the button at the right of 'spray process', a small submenu containing the entries 'yes' and 'no' appears. Activate 'yes'. If the entry is 'yes' already, you have to activate it again.

Ö

The 'spray definitions' window appears (Fig. 4-2).

CH. 4: MAGMASPRAY

73

4.2 The 'spray definitions' Window

Fig. 4-2: Defining the spraying process

To use MAGMAspray, define the individual process steps as described in the following. Please note that the fields in the 'spray definitions' window are displays only. If you want to edit their contents, choose the buttons 'options', 'insert', 'add' or 'delete'. These buttons are described at the end of this chapter. You can define as many process steps as you like for the spraying process, which are all displayed in the 'step list'. To activate a process step, select the corresponding line in the list with the left mouse button. The information given in the part of the window that is headlined with 'selection'

74


and lies above the list always refers to the process step that is currently active. This information means the following: 'step'

Serial number of the process step

'action'

Type of the process step:

'controlled by'

'control value'

'control parameter'

'materials'

•

spraying (spray)

•

blowing (blow)

•

waiting (wait)

Parameter for controlling the process step (how long the process step is to last): •

time (time)

•

temperature (temperature)

•

temperature at thermocouple (thermocouple)

Value for controlling the process step (depending on the choice made under 'controlled by'): •

time (time)

•

temperature (temperature)

•

temperature at thermocouple (thermocouple)

Unit for controlling the process step (depending on the choice made under 'controlled by'): •

(empty)

•

controlling material group with MAT ID

•

control point with coordinates

Die materials groups that are involved in the process step

For details on these functions please refer to Ch. 4.3, page 76. When you open the window for the first time during simulation definition, a process step has already been defined by default, which you must edit first. Proceed as follows to delete, edit or add process steps:

Ö

Mark the respective step in the list 'step list'.

Ö

If you want to delete a complete step with all entries, choose 'delete'.

Ö

If you want to edit the first step set by default or steps that have been defined later, choose 'options'. As an alternative, you can mark the step and press the middle mouse button.

CH. 4: MAGMASPRAY

Ö

If you want to insert a step after an already defined step, choose 'add'.

Ö

If you want to insert a step before an already defined step, choose 'insert'.

75

Each of the last three actions leads you to the 'spray options' window (Fig. 4-3).

!

If you want to start the spraying process not immediately after the separation of the last die part from the casting (ejection), you must define 'wait' as the first process step, including the corresponding time. If e.g. you want to start spraying 4 seconds after separation of the last die part, you must define 'wait' as the 'action' option, 'time' as the 'controlled by' option and '4' as the 'control value'.

76


4.3 The 'spray options' Window

Fig. 4-3: Editing process steps

Ö

Here you can edit the values displayed in the 'spray definitions' window. The first entry, 'step', cannot be changed. It shows the process step that is currently active and to which all of the following information refers:

'action'

'spray':

Spraying of the die parts (material groups) defined under 'materials' is defined as process step.

CH. 4: MAGMASPRAY

'controlled by'

77

'blow':

Blowing of the die parts (material groups) defined under 'materials' is defined as process step.

'wait':

Waiting for the next step (spraying or blowing) is defined as process step.

'time':

The process step lasts for seconds.

'temperature'

The process step ends when the temperature of the selected material group (see 'control parameter' and 'parameter list') falls below the given value.

'thermocouple'

The process step ends when the temperature at the selected control point (type 'THERMO') falls below the given value. Please refer also to Ch. 3.10, page 3-98 of the MAGMASOFT® 4.4 Manual regarding control points.

'control value' 'control parameter'

'[s]'

if you have chosen 'time'

'[°C]'

if you have chosen 'temperature' or 'thermocouple'

(empty)

if you have chosen 'time'

controlling materi- if you have chosen 'temperature'. The list of availal group able material groups is displayed at 'parameter list'. control point coor- if you have chosen 'thermocouple'. The list of availdinates (x,y,z) able thermocouples is displayed at 'parameter list'. 'parameter list'

(empty)

If you have chosen 'time', the list is deactivated.

material group list If you have chosen 'temperature', all material groups appear here, including their MAT IDs (if defined). At the right of each group, its initial temperature is listed (as in Fig. 4-3). Choose one entry. control point coor- If you have chosen 'thermocouple', all control point dinates (x,y,z) coordinates defined in the preprocessor appear here. Choose one entry. 'material list'

Here you define the die material groups that are to be available for the selected process step. If you want to select several material groups, keep the SHIFT key pressed while clicking with the left mouse button. The selection depends on the module that is currently active (please refer also to the table above).

78


Ö

Choose 'ok' to confirm your input. This leads you back to the 'spray definitions' window. All entries that are new or modified are displayed in the 'step list'. If you choose 'cancel', your input is not saved. This leads you also back to the 'spray definitions' window.

Ö

In the 'spray definitions' window, choose 'ok' to save and terminate your MAGMAspray definitions. If you choose 'cancel', you abort the input without saving. In both cases you get back to the 'solidification definitions' window.

In the two windows described in Ch. 4.2 and 4.3, the following has been defined: •

Four process steps (chronological order: waiting, die spraying, waiting, die blowing).

•

The first process step, 'wait', is defined because spraying is to start only 4 seconds after separation of the last die part.

•

The second process step, die spraying ('spray'), is ended when the temperature of the material group 'Permanent Mold', MAT ID 1, falls below 350 °C.

•

The duration of the third and the fourth process step (waiting and die blowing) is defined by the 'controlled by'-parameter 'time'.

!

If you have defined a spraying process and subsequently added new or changed material groups, you must (re)define the corresponding parameters if necessary, if you rerun the simulation setup. In case of both adding and removing material groups, you must open the 'spray definitions' window and leave it again with 'ok', even if you do not perform any changes there. Otherwise, the simulation setup does not accept the changes.

CH. 5: MAGMACOAT

79

5 MAGMAcoat In permanent mold processes you can apply a coating to prepare the mold surface for the next casting. This coating helps to produce castings with optimized surfaces. Coating is performed at the end of a production cycle when the casting has been removed from the mold and the mold itself is open (Fig. 5-1).

Fig. 5-1: Coating in permanent mold casting

The coating of the mold surfaces has a cooling effect and influences the thermal behavior. This effect is taken into account by the module MAGMAcoat. With MAGMAcoat you can simulate the cooling effect of coating. This cooling is taken into account for all surfaces of the mold that have contact with the material groups 'Cast Alloy', 'Feeder', 'Feederneck', 'Gating', 'Filter' and 'Ingate' during solidification. Contact surfaces between 'Inlet', 'Stalk', 'Biscuit' and the mold are not cooled.

80


Tab. 5-1 shows the available mold material groups for MAGMAhpdc, MAGMAlpdc and MAGMAwheel. Module

Material group in the preprocessor

Standard MAGMASOFT®

Permanent Mold 'PERMM' / 6

High pressure die casting (MAGMAhpdc)

Permanent Mold 'PERMM' / 6 Side core 'SIDEC' / 21 Movable die half, 'EJECTOR' / 22 Fixed die half, 'COVER' / 23

Low pressure die casting (MAGMAlpdc)


Wheel casting (MAGMAwheel)


Tab. 5-1: Die parts available in MAGMASOFT® and various modules

Proceed as follows to calculate the cooling effect of coating during simulation:

Ö

Enter your simulation parameters as used from standard MAGMASOFT®.

Ö

Before you define the parameters for mold filling and solidification, the window 'options' appears (Fig. 5-2). (Note: If more than one option is installed, the other options are also displayed here). Choose the 'yes' setting for 'Die Coating'.

CH. 5: MAGMACOAT

81

Fig. 5-2: Selecting 'Die Coating' option

Ö

In the window 'options' choose 'parameters' to set the times for coating. The window 'coating parameters' appears (Fig. 5-3).

Fig. 5-3: Defining coating times

!

Use 'reset' to redefine the settings in the 'coating parameters' window to the original values.

'start coating at'

Start time for coating [s] This time is counted from the casting removal from the last part of the die to the beginning of coating. For example, if coating is to be started 60 seconds after the last part of the die has been removed, enter the value '60'.

'stop coating at'

Stop time for coating [s]

82


This time is counted from the casting removal from the last part of the die to the end of coating. For example, if coating is started 60 seconds after the casting removal and will be active for 30 seconds, enter the value '90'. The changed heat transfer rate due to coating is simulated in MAGMASOFT® using the dataset 'default.coat' (MAGMAdata Î data type 'Boundary'). Note that the cooling effect of coating is taken into account in each cycle, if you simulate more than one cycle.

CH. 6: MAGMAPRESSURIZE

83

6 MAGMApressurize 6.1 Introduction During solidification the volume of the melt is reduced. In most casting processes this volume shrinkage is compensated by gravity driven feeding. In high pressure die casting processes, a final pressure is admitted on the piston to enable feeding (Fig. 6-1). The melt is pressurized during solidification.

Fig. 6-1: Pressurized solidification

With the option MAGMApressurize you can simulate the effect of pressurized solidification in MAGMASOFT®. Proceed as follows:

84


Ö

Enter the simulation parameters as used from MAGMASOFT® Standard.

Ö

Before you define the parameters for mold filling and solidification, the window 'options' appears (Fig. 6-2). (If other options have been installed, they are also displayed in this window.)

Fig. 6-2: Activating the 'Pressurize' option

Ö

Select 'yes' to activate the option 'Pressurize'. The creation of the final pressure will then be taken into account during simulation.

Ö

Select 'parameters' to define the parameters for the admitted pressure. The window 'pressurize parameters' appears.

Ö

Define the pattern of the pressure as a function of time.


85

Fig. 6-3: Defining pressurized solidification using defined points

There are two possibilities: •

You can define the pattern of pressure using a curve with defined points and parameters. In this case, select the 'Ramp' option at 'definition type' (Fig. 6-3; this is also the default setting). Thereupon the same notations as in Fig. 6-1 appear in the window 'pressurize parameters'. This is described in detail in Ch. 6.2, page 85.

•

You can also define the pattern of pressure using a free curve for which you must define the coordinates yourself. In this case you have to select the 'Curve' option at 'definition type'. This is described in detail in Ch. 6.3, page 89.

In both cases, you have to select 'ok' in the window 'pressurize parameters' to return to the 'options' window.

6.2 Defining the Course of Pressure Using a Defined Curve If you select the 'Ramp' option at 'definition type' in the window 'pressurize parameters', you can define the course of pressure using the parameters illustrated in Fig. 6-3. Proceed as follows:

86


Ö

The pressure increases from the 'starting pressure' up to the 'working pressure' within the 'pressure setup time'. Enter the corresponding values.

Ö

The 'working pressure' remains constant until a condition defined by you is reached. You must define this condition in the field 'reduction controlled by'. You can control the pressure reduction by time, by a maximum temperature within a material group or by a local temperature ('thermocouple'). These options are described in the following three subchapters.

Ö

After you have defined the control of pressure reduction, you have to enter the period of pressure reduction in the field 'pressure reduction time' (Fig. 6-1).

Ö

Confirm your input with 'ok'. This leads you back to the 'options' window.

6.2.1

Pressure Reduction Control by Time

Ö

Position the mouse pointer on the field 'reduction controlled by' and press the left mouse button. Choose the option 'Time' from the menu that appears now (Fig. 6-4).

Ö

Enter the start time for pressure reduction in the field 'start reduction after'. Note that this time is counted from the end of the 'pressure setup time' (Î Fig. 6-1, page 83).

Fig. 6-4: Pressure reduction control by time


Ö

87

Confirm your choice with 'ok'.

6.2.2

Pressure Reduction Control by Maximum Temperature

Ö

Position the mouse pointer on the field 'reduction controlled by' and press the left mouse button. Choose the option 'temperature' from the menu that appears now (Fig. 6-5).

Ö

Click on the button on the right of 'controlling material'. Select the material group for control of pressure reduction in the window that appears now. Confirm your choice with 'ok'.

Ö

Enter the temperature limit which will control the start of pressure reduction in the field 'threshold temperature'.

Fig. 6-5: Pressure reduction control by maximum temperature

Ö

If the calculated maximum temperature in the material group selected in the 'controlling material' field falls below the temperature limit entered in the field 'threshold temperature', pressure reduction starts.

Ö


88


6.2.3

Pressure Reduction Control by Local Temperature / Thermocouple

Ö

Move the mouse pointer to the 'reduction controlled by' field and press the left mouse button. Choose the option 'Thermocouple' from the menu that appears now (Fig. 6-6).

Ö

Click on the button on the right of 'controlling thermocouple'. Select the desired control point for control of pressure reduction in the window that appears now. Confirm your selection with 'ok'. Please note that you have to define the control points for control already in the preprocessor. Please refer to Ch. 3.10, page 3-98 of the MAGMASOFT® 4.4 Manual for further information.

Ö

Enter the temperature limit for the control of pressure reduction in the field 'threshold temperature'.

Fig. 6-6: Pressure reduction control by local temperature

Ö

Pressure reduction begins when the temperature at the control point selected at 'controlling thermocouple' falls below the 'threshold temperature'.

Ö



89

6.3 Defining the Course of Pressure Using a Free Curve If you select the option 'Curve' at 'definition type' in the window 'pressurize parameters', you can freely define the course of pressure using your own curve. In this case, the parameters described in Ch. 6.2, page 85 are of no importance. The following window appears (Fig. 6-7).

Fig. 6-7: Defining pressurized solidification as a free curve

Proceed as follows:

Ö

Select 'edit'. A window appears, in which you can define the individual coordinates of the curve as value pairs (Fig. 6-8).

90


Fig. 6-8: Defining value pairs for a free curve

Ö

Enter the value pairs of the curve at 'New value pair' (pressure in mbar / time in s). Separate the two values by a blank and then select 'insert'. Thereupon the value pair appears in the list at the top right of the window, and the coordinate appears in the diagram on the left.

Ö

If you want to delete a value pair, mark it in the list and choose 'delete'. Select 'delete all' if you want to delete all value pairs.

Confirm with 'ok'. This leads you back to the window 'pressurize parameters'. Now select 'ok' to get back to the 'options' window.

CH. 7: STRESSES IN HIGH PRESSURE DIE CASTING

91

7 Stresses in High Pressure Die Casting 7.1 Overview You can simulate stresses and strains during the solidification of HPDC parts, using the MAGMAstress module. A simulation like this is based on the temperature distribution, which is being calculated during the solidification simulation (time-dependent). What is more, you can simulate stress the build-up within HPDC dies. In the following, you find some information on HPDC-relevant functions of MAGMAstress.

7.2 Simulation •

The stress simulation is based on the result files of the solidification simulation. Perform the solidification simulation as usual, including several cycles.

•

In order to simulate the stress distribution within HPDC dies, choose the normal result files from a cyclic calculation. If you are to calculate stresses and strains in an HPDC part, please note the following: In high pressure die casting processes you can start the stress calculation at the temperature at which the die is opened. With standard settings the software automatically starts to calculate at pouring temperature, even though the temperature interval between pouring temperature and die opening temperature is of no interest. If you want to use this function, you must choose the result file 'DieOpen' in the window 'stress input / output' in the simulation setup of MAGMAstress. Furthermore you must take care that all other result files that you select are calculated after the 'DieOpen' result. So when you start simulation, MAGMASOFT® calculates the stresses from the time of die opening and writes the results according to the files you have selected in addition to 'DieOpen'. If you have not chosen any other result but 'DieOpen', the program calculates residual stresses and deformations after ejection (cooling from ejection temperature to ambient temperature) and residual stresses at ambient temperature for high pressure die casting.

Please refer to the simulation chapter of the MAGMAstress 4.4 Manual regarding details on the result files.

92


7.3 Results Please refer also to the postprocessor chapter of the MAGMAstress 4.4 Manual, where HPDC stress results are analyzed in the postprocessor.

!

Please read the MAGMAstress Manual and the training material completely if you want to simulate stresses.

CH. 8: SUMMARY – WHAT TO DO

93

8 Summary – What to Do 8.1 Project Definition •

MAGMAhpdc projects must be created as 'High Pressure Die Casting' in the project administration.

8.2 Data for HPDC machines •

Select or create a data set for an HPDC machine in the MAGMASOFT® databases. Modify the machine parameters if necessary. These must be exactly the same as the corresponding parameters in reality.

8.3 Geometry Modeling •

The side cores, the die parts and the biscuit must be modelled with the material groups that are designed for this purpose. The plunger is modelled with the material group 23 ('COVER'). For the plunger, please refer also to Ch. 3.2.1, page 21.

•

The other parts of the casting system, too, must be defined according to their function in the HPDC process.

•

You can model a complete or a reduced HPDC system. Please note, however, that the simulation represents the casting as it is produced by the machine only if you use the complete model (refer also to Ch. 3.2.2, page 22).

8.4 Simulation Setup •

Use the heat transfer coefficient 'MERGEMATERIALS' to define an ideal heat transfer between two volumes that are not physically separated in reality, but for which you want to simulate different boundary conditions (refer also to Ch. 3.3.2, page 27).

•

By using the integrated HPDC calculator you must define a a flow rate for mold filling.

94


•

Use the last window of the HPDC calculator to simulate venting of the die (refer also to page 46).

•

Define the opening of the different die parts during the HPDC process via 'core open definitions' (not via 'cycle definitions').

•

Define the control of the cooling channels in the die via 'channel definitions', provided you have defined cooling channels in the geometry ('COOLING' material group).

•

For the filling simulation, three additional options are available under 'filling definitions' Î 'filling depends on'. You can use them to define a flow rate.

•

As high flow velocities occur in HPDC, you should always view the mold erosion criterion in the postprocessor. Activate its calculation under 'filling definitions' (Î 'calculate erosion' Î 'yes').

•

If necessary, simulate die cooling by applying a parting compound on the die surface with the MAGMAcoat option ('options' Î 'Die Coating').

•

If necessary, simulate die cooling by spraying and blowing with the MAGMAspray option ('solidification definitions' Î 'spray process').

•

If necessary, simulate local squeezing ('solidification definitions' Î 'local squeezing').

•

If you want to view feeding results in the postprocessor, you must calculate pressurized solidification with the MAGMApressurize option ('options' Î 'Pressurize'). Then, after having activated the calculation of feeding, you must choose a value of about 90% under 'solidification definitions' Î 'feeding effectivity'.

8.5 Stresses in High Pressure Die Casting •

If necessary, perform stress calculations in the casting and in the HPDC die.

8.6 Additional Information •

Use the 'info' menu to list all HPDC-specific data clearly ('protocol listing' Î 'Hpdc definitions').

CH. 8: SUMMARY – WHAT TO DO

•

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Use the 'info' menu if necessary to list the heat balance of materials and defined partial processes as well as of cooling channels via three functions of the 'info' menu (Î Ch. 9.8, page 9-14 of the MAGMASOFT® 4.4 Manual).

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CH. 9: TABLE OF FIGURES

97

9 Table of Figures Fig. 2-1: Schematic of an HPDC machine .................................................................................... 9 Fig. 2-2: Time sequence of the MAGMAhpdc simulation............................................................ 10 Fig. 2-3: Relations between real process times and simulation parameters............................... 12 Fig. 2-4: Filling phase of hpdc process ....................................................................................... 13 Fig. 2-5: Plunger position and velocity as function of time.......................................................... 15 Fig. 3-1: Defining machine parameters....................................................................................... 18 Fig. 3-2: Layout of material groups ............................................................................................. 24 Fig. 3-3: Shot profile depending on the selected material groups with complete modeling ........ 24 Fig. 3-4: Shot profile depending on the selected material groups with reduced modeling.......... 26 Fig. 3-5: Available options when starting the HPDC calculator................................................... 28 Fig. 3-6: Defining geometry data................................................................................................. 31 Fig. 3-7: Defining HPDC machine data....................................................................................... 33 Fig. 3-8: Defining shot sleeve data ............................................................................................. 35 Fig. 3-9: Defining process data ................................................................................................... 37 Fig. 3-10: Optimizing the slow shot wave profile ('best') ............................................................. 40 Fig. 3-11: Optimizing the slow shot wave profile ('optimal') ........................................................ 41 Fig. 3-12: Shot profile (constant velocity, first phase) ................................................................. 42 Fig. 3-13: Shot profile (accelerated first phase) .......................................................................... 43 Fig. 3-14: Shot profile ('opt. slow shot' activated) ....................................................................... 43 Fig. 3-15: Defining the operating point........................................................................................ 44 Fig. 3-16: Defining the switching point ........................................................................................ 45 Fig. 3-17: 'vacuum' option for venting ......................................................................................... 47 Fig. 3-18: Defining casting cycles ............................................................................................... 49 Fig. 3-19: Defining mold opening ................................................................................................ 52 Fig. 3-20: Controlling mold opening by time ............................................................................... 54 Fig. 3-21: Controlling mold opening by maximum temperature .................................................. 55 Fig. 3-22: Controlling mold opening by local temperature .......................................................... 56

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Fig. 3-23: The window 'channel definitions' ................................................................................ 58 Fig. 3-24: Cooling channel control by time.................................................................................. 61 Fig. 3-25: Cooling channel control by maximum temperature .................................................... 62 Fig. 3-26: Cooling channel control by local temperature............................................................. 63 Fig. 3-27: Defining filling parameters in MAGMAhpdc ................................................................ 64 Fig. 3-28: Editing the pouring rate under 'filling depends on' ...................................................... 65 Fig. 3-29: Warning message regarding feeding.......................................................................... 66 Fig. 3-30 Defining local squeezing.............................................................................................. 68 Fig. 3-31: Defining parameters for local squeezing .................................................................... 69 Fig. 4-1: Die cooling by spraying................................................................................................. 71 Fig. 4-2: Defining the spraying process ...................................................................................... 73 Fig. 4-3: Editing process steps.................................................................................................... 76 Fig. 5-1: Coating in permanent mold casting .............................................................................. 79 Fig. 5-2: Selecting 'Die Coating' option ....................................................................................... 81 Fig. 5-3: Defining coating times .................................................................................................. 81 Fig. 6-1: Pressurized solidification .............................................................................................. 83 Fig. 6-2: Activating the 'Pressurize' option .................................................................................. 84 Fig. 6-3: Defining pressurized solidification using defined points ............................................... 85 Fig. 6-4: Pressure reduction control by time ............................................................................... 86 Fig. 6-5: Pressure reduction control by maximum temperature .................................................. 87 Fig. 6-6: Pressure reduction control by local temperature .......................................................... 88 Fig. 6-7: Defining pressurized solidification as a free curve........................................................ 89 Fig. 6-8: Defining value pairs for a free curve ............................................................................. 90

CH. 10: INDEX

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10 Index

A

closing force 33, 34

air entrapments 14

coating of the die (see also "MAGMAcoat") 7, 16, 27, 28, 79 pp

'AirPressure' 48 ambient temperature 91

B biscuit 22, 23, 31, 35, 93 blowing of the die (see also "MAGMAspray") 7, 11, 13, 67, 71, 74, 77, 78, 94 'Boundary' (data type) 82 boundary conditions 7, 28, 93

'coating parameters' 81 computer capacity 25 computing time 50 control points 51, 57, 74, 77, 88 cooling 14, 91 'cooling channel definitions' 70 cooling channels 7, 27, 56, 58, 59, 60, 70, 94, 95 cooling of the die (see also "spraying of the die") 7, 56–63, 71, 79, 80, 82, 94

C 'calculate erosion' 66, 94 'calculate feeding' 66 casting cycles 7, 10, 27, 48, 49, 50, 71, 91 casting pressure 34 casting removal 10, 11, 15, 16, 81, 82 'channel definitions' 27, 56, 58, 60, 61, 62, 63, 94

'core open definitions' 27, 28, 50, 51, 70, 94 cores 51, 53 bottom core 72, 80 side core 13, 21, 22, 27, 32, 34, 72, 80, 93 top core 72, 80 cover die 22 'create project' 17

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'create version' 17

filling conditions 7

criteria temperatures 67

'filling definitions' 27, 63, 66, 94

'cycle definitions' 27, 29, 48, 70, 94

filling degree 35 'filling depends on' 63, 65, 94

D database 17, 19, 20, 30, 33, 66, 67, 93 'MAGMA' 20, 27, 60

filling simulation 10, 11, 15, 23, 27, 28, 49, 50, 63, 94 filling stages 7

density 36, 38, 45

filling time 37, 38, 45, 46

die closing 7, 13, 50, 51

final pressure (see also "MAGMApressurize") 19, 33, 66, 67, 83 pp

'Die Coating' 80, 81, 94 die opening 7, 13, 22, 27, 28, 50, 53, 91 die parts 7, 11, 13, 21, 22, 32, 51, 52, 53, 54, 55, 56, 72, 75, 76, 77, 78, 80, 81, 82, 93, 94

flow rate (see also "pouring rate") 27, 28, 32, 64, 65, 93, 94 flow velocities 66, 94

G E ejection 13, 50, 51, 75, 91 ejector die 21 enmeshment 23, 26, 29

F feeding 27, 66, 67, 83, 94 'FEEDING' (criterion result) 66 'feeding effectivity' 66, 94

gating system 14, 22, 23, 25, 31, 36, 38, 44, 45, 65 geometry data 14, 31, 32, 34, 69 geometry elements 28, 58 geometry modeling 14, 21, 22, 25, 26, 27, 29, 31, 32, 33, 35, 51, 56, 57, 65, 72, 77, 80, 88, 93

H heat balance 60, 70, 95

CH. 10: INDEX

heat transfer 27, 82, 93

101

inlet 22, 23, 31, 32, 65, 66, 71, 79

'heat transfer definitions' 27 heating of the die 56–63 'High Pressure Die Casting' (project mode) 17, 93 'HPDC calculated flow rate' 64

L lead time 11, 51, 65 'local squeezing' 22, 67, 94 local squeezing 22, 27, 67, 68, 69, 94

HPDC calculator 23, 28, 29, 30, 35, 36, 42, 45, 46, 48, 64, 65, 93, 94

squeeze reservoir 22, 67, 68, 69

'Hpdc definitions' ('protocol listing') 69, 94

squeezing system 22, 67

HPDC machines 11, 15, 17, 20, 30, 33, 36, 93 HPDC system 22, 25 'HPDC user1 flow rate' 64, 65 'HPDC user2 flow rate' 64 'HPDC-Machine' (database) 17, 18 hydraulic parameters 19

squeeze stamp 22, 67

'local squeezing definitions' 67, 69 'local squeezing options' 69 locking force 19, 34

M machine data 33, 34, 69 machine parameters 17, 18, 20, 93 'Machine Parameters' (database) 18

I 'info' menu 69, 70, 94, 95 ingate 7, 14, 23, 31, 32, 37, 46, 48, 65, 66

machine type 17, 18, 35, 37 'MAGMA' database 20, 27, 60

ingate cross section 32, 46

MAGMAcoat 79 pp, 94

velocity at the ingate 37, 39, 45, 46

MAGMApressurize 34, 66, 67, 83 pp, 94

initial temperature 77

MAGMAspray 67, 71 pp, 94

injection force 19

MAGMAstress 67, 91, 92

102

MAGMAventing 48 MAT IDs 22, 27, 53, 58, 59, 60, 67, 68, 74, 77, 78 'material definitions' 26, 60, 67 material definitions 27, 67 material groups 21, 22, 23, 24, 25, 26, 27, 31, 32, 35, 51, 52, 53, 54, 56, 57, 59, 60, 61, 62, 67, 71, 72, 74, 76, 77, 78, 79, 80, 86, 87, 93, 94 materials 27, 28, 60, 70, 95 melt volume 31, 32 'MERGEMATERIALS' 27, 28, 93 metal pressure 36, 38, 44 mold erosion 66, 94 mold preparation 10, 11, 16


plunger 9, 11, 14, 22, 31, 35, 36, 65, 93 acceleration 9, 14, 19 diameter 19, 22, 35, 44 position 15, 31, 42, 45, 46 velocity 14, 15, 19, 36, 37, 38, 45, 46 postprocessor 48, 50, 66, 92, 94 pouring rate (see also "flow rate") 23, 36, 42, 64, 65 pouring temperature 91 PQ2 diagram 36, 38, 44 preprocessor see "geometry modeling" pressure casting pressure 34 metal pressure 36, 38, 44 pressure curve 47, 48 pressure field 47

O operating point 44 'options' 80, 81, 84, 85, 86, 90, 94 overflows 23, 31, 32

P

pressure reduction 86, 87, 88 'Pressurize' 84, 94 'pressurize parameters' 84, 85, 89, 90 pressurized solidification (see also "MAGMApressurize") 27, 66, 83 pp, 94 process data 11, 37, 40, 42, 44, 70 process times 11, 12, 13

permanent mold (see also "die ...") 48, 72, 78, 79, 80

project version 17, 28

piston see "plunger..."

projected area 32, 34

CH. 10: INDEX

'protocol listing' 69, 70, 94

103

solidification simulation 10, 11, 15, 27, 49, 50, 66, 67, 91 solidification time 11, 15

Q quality requirement 33, 34

'spray definitions' 72, 73, 76, 78 'spray options' 75, 76

R

'spray process' 67, 72, 94

'Ready to use' 20

spraying of the die (see also "MAGMAspray") 7, 11, 13, 16, 27, 28, 67, 70, 71 pp, 94

result files 11, 91

squeeze reservoir 22, 67, 68, 69

S

squeeze stamp 22, 67

security factor 33, 34

squeezing system 22, 67

shot chamber 7, 9, 13, 14, 18, 31, 45

'start coating at' 81

shot characteristics 45, 70

'stop coating at' 81

shot curve (see also "pouring rate") 23, 38

stress calculation 67, 91, 94

shot phase 11, 13, 14, 23 shot profile 14, 23, 24, 26, 28, 32, 36, 38, 40, 42, 43, 44, 48, 70 shot sleeve 23, 35, 36, 65 shot sleeve data 35, 40, 42, 44, 70 simulation parameters 11, 12, 26, 28, 63, 66, 72, 80, 84 simulation setup 11, 22, 60, 78, 91, 93 'solidification definitions' 27, 66, 67, 69, 72, 78, 94

T temperature distribution 15, 91 temperature field 49 temperature profile 48 thermocouples 7, 51, 52, 53, 55, 57, 58, 59, 62, 63, 74, 77, 86, 88 thin wall sections 14

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V venting 46, 47, 70, 94 vents 46, 47

W wait time 11, 50, 51 wall thickness 33, 37, 38


NOTES

Notes

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Notes


NOTES

Notes

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hpdc_en

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