Practical application of EN ISO 13849-1 for machine tools - Eberhard Beck

“Safety related control systems for machinery“

EU-Symposium

“Safety related control systems for machinery”

Brussels, 9th September 2010

“Practical application of EN ISO 13849-1 for machine tools”

INDEX Werke GmbH & Co. KG Hahn & Tessky Eberhard Beck Head of control techniques INDEX-Werke

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Overview

Structure for the Presentation

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General Introduction

The company of INDEX

1

Practical application of EN 13849 to Machine Tool

Workpiece clamping device as EN 13849 safety function Requirements according EN 12415 // EN ISO 23125 Requirements applying EN ISO 13849 risk analysis Conclusion

2

Further experiences out of the EN ISO 13849 application

Translation problems “How to get EN ISO 13849 diagrams”? Multiple safety functions for EN ISO 13849 requirements

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out of the EN ISO 13849 application


1914 Founded by Hermann Hahn

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History of INDEX-Werke From the beginning …

1914

1954

1970

Begin with the production of turret screw machines

20.000 INDEX machines sold

1985

1990

1992

1997

First CNC-controlled multi spindle machine with hollow shaft motor

The Eugen und Irmgard Hahn foundation becomes shareholder with 85% after the death of Eugen Hahn

Introduction of the modular building block system with the RatioLine and VerticalLine

Merger with TRAUB-Drehmaschinen GmbH

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First NC machine


History of INDEX-Werke … to the past 10 years

2000

2002

Introduction of flexible high performance turn mill centers

Integration of various technologies in serial production

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2005 First provider of a Virtual Machine for the PC

2009 Introduction of 5-axisturn mill centers of the newest generation


Customer segments and industries … typical cycle times and part numbers

Cycle times Medical Industry

from ≥ 1 second up to > 2,5 hours typical 30 to 240 s

Air- / Spacecraft Technology

Fittings / Fluidics

Electronics

Automotive Number of parts Optics / Precision Mechanics

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from single part production up to > 10 Mio parts/year


INDEX-Werke GmbH & Co. KG

… in figures, locations and subsidiaries

Turnover (2008) Number of Employees (2008) Number of Machines (2008) Export rate

510 Mio € ca. 1950 ca. 1200 ca. 40 %

Locations and subsidiaries 09.09.10

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Agents


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Typical parts machined by INDEX machine tools (examples for bar machining)


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Working zone of INDEX machines (example)


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Machining inside INDEX machines (video example)


Overview


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Workpiece clamping device as safety function (based on EN ISO 23125 + EN ISO 13849 requirements )


Workpiece clamping safety function “state of the art” safety equipment (sensors) are monitored by PLC Monitoring pressure cylinder A Monitoring pressure cylinder B Monitoring jaw position

Sensor for jaw position Sensors for clamping pressure

PLC control + PLC software

Main spindle with chuck 24V/I

nonreturn valves

A

Clamping/ unclamping valves

Hydraulic pipes

B

Hydraulic power supply

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Monitoring hydraulic pressure

24V/O

Pressure cylinder A

24V/O

Pressure cylinder B

24V/O

Cylinder stop

24V/O

Enabling cylinder movement


Overview


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EN 12415 Cat. “1” EN954-1

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“C-Standards” for machine tools in relation to “accidents at machine tools”

Improvement of accidents in Germany since 1993 Meldepflichtige Unfälle an Werkzeugmaschinen 50000

45000

Anzahl

40000

35000

30000

25000 Maschinenrichtlinie (und Typ C Normen) 20000 1992

1994

1996

1998

2000 Jahr

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2002

2004

2006

2008


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EN 23125 PL “b” EN13849

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EN ISO 23125 workpiece clamping function “state of the art” EN ISO 13849 safety calculation

Institute of employers„ liability insurance association (BGIA)

safety function “workpiece clamping”

evaluation according to DIN EN ISO 13849:2007

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VDW-Project

Functional safety for machine tools

More than 100 experts: 60 designers, 30 suppliers, 16 Safety Experts, …have - 20 typical safety functions for machine tools defined - 10 safety functions have been calculated in more than 1,5 years - over 40 meetings have been hold and more than 200.000 € have been spent

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Definition of safety functions workpiece clamping device “state of the art”

Standstill of the spindle Clamping of the workpiece Diagnosis clamping state and door

Clamping at

Run up of the spindle Diagnosis clamping pressure and position Machining of the workpiece Run down of the spindle Opening of the clamping device

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Clamping at


Definition of safety functions workpiece clamping device “state of the art”

safety function

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safely limited speed

d

SF2

workpiece clamping without speed (= 0)

b

SF3

Monitoring workpiece clamping with speed (> 0)

b


Safety block diagram + SISTEMA “PL result” workpiece clamping safety function “state of the art” EN ISO 23125

SISTEMA PL “b” EN23125

EN ISO 23125

SISTEMA PL “c” EN23125

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Overview


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EN ISO 13849 result / requirements workpiece clamping safety function “new safety status?”

?

PLrequired PL “d” EN13849

Selection of performance levels, a - e

Figure A.1 – risk graph to define the performance level for each safety function

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EN ISO 13849 requirements Comparison workpiece clamping safety function against remaining residual risks in practice

In spite of PLr (EN 13849) “d” – in practice there is no significant increasing of real safety at the machine Because the following remaining residual risks in practice also have to be considered:

- The risk of a collision between moving tools, tool carriers and the workpiece or the workpiece clamping device

- The risk for a lack of clamping force based on a bad maintenance condition of the clamping devices

- The risk of an insufficient hydraulic clamping pressure in relation to the machining operations - The risk for a not suitable maximum spindle speed for the clamping device and / or the workpiece 09.09.10

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EN ISO 13849 requirements Evaluation EN ISO 13849 requirements against experts experience in practice

Without having PLr based on experts experience out of “Type C” standard, the found high end PLr” of EN 13849 can be misleading

-

The safety status only can be seemingly increased. In practice, seldom a real safety improvement at the real machine can be achieved

- The “high end PLr” requires high efforts in realization. Remaining risks outside the scope of the safety related control system could stay unnoticed -

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The “high end PLr” often is very difficult to realize. This can cause to further problems in operation of the machine and lead to the manipulation of safety devices -26-


Overview


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Conclusion

Conclusion:

The big differences between new EN ISO 13849 PLr safety requirements and EN 954-1 safety categories based on “type C” safety standards leads to great trouble and uncertainty among the applicants of the EN ISO 13849 standard

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Overview


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Difficulties in application of EN ISO 13849 Safety function based on EN 954-1 has been a

Technical layout (Mechanic, Hydraulik. Hard-/ Software)

Translation from Technical layout to Logical structures of EN 954-1 categories “relative easy” for technicians

Logical structure of safety functions according EN 954-1 09.09.10

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1:1 relationship


Difficulties in application of EN ISO 13849 From the point of view of a machine tool (MT) builder … How to translate safety function into EN 13849?

Technical layout (Mechanic, Hydraulik. Hard-/ Software)

How to translate from Technical layout to

?

EN 13489 safety block-diagrams?

Structure of EN 13849 functions safety block-diagrams 09.09.10

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Overview


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Difficulties in application of EN ISO 13849 Safety functions based on EN 13849 have a

1:n relationship

SF2: Werkstückspannen im Stillstand (Anlauf verhindern bei falschem Spannzustand) K2

S1

K1 + T1

Standard SPS Blatt KR5701.51371 (Seite 515)

Spannwegkontrolle

M

NCU S840D + SINAMICS Blatt KR5701.51371 (Seite 515)

SF3: Werkstückspannen unter Drehzahl (lösen verhindern) K1 + T1

G1 Motorgeber Werkstückspindel

K2

Spannmechanik

Standard SPS Blatt NCU S840D KR5701.51371 (Seite 515) + SINAMICS Blatt KR5701.51371 (Seite 515)

SF4: Spindel stillsetzen bei Druckverlust Spannmechanik

S2 Drucküberwachung

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K2 Standard SPS Blatt KR5701.51371 (Seite 515)

K1 + T1 NCU S840D + SINAMICS Blatt KR5701.51371 (Seite 515)

M


Difficulties in application of EN ISO 13849 Safety functions based on EN 13849 have a

1:n relationship

SF5: Druckänderung verhindern unter Drehzahl G1

K2

K1 + T1

Motorgeber Werkstückspindel

NCU S840D + SINAMICS Blatt KR5701.51371 (Seite 515)

Standard SPS Blatt KR5701.51371 (Seite 515)

K1 + T1 Sicherheitssteuerung Spannungsversorgung für Ventilsteuerung wird über PROFISAFE geschaltet

SF2 und SF4 sind bei BGIA Betrachtung nicht abgebildet. Kein Induktivgeber in SF2 bei BGIA. PLr c weil bei Fräsmaschinen d zum Einsatz kommt.

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Gesteuertes Druckventil


Overview


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Summary - out of the EN ISO 13849 application

1.

For EN ISO 13849 application there is no description or guideline how to “translate” technical structures into EN ISO 13849 based safety block structures for EN ISO 13849 evaluation and calculation.

2.

EN ISO 13849 beginners are not able to understand and apply EN ISO13849 standard without (foreign) introduction and practical training.

3.

The need to specify and define multiple EN ISO 13849 safety functions for the evaluation of one physical technical safety structure requires great efforts which SME seldom are able to spend.

4.

Different level of safety requirements inside EN 954-1 based Cstandards in comparison to EN ISO 13849 based risk analysis lead to great uncertainty and trouble among EN ISO 13849 applicants.

5.

The “high end PLr” of EN ISO 13849 based risk analysis often is much beyond the technical “state of the art”. It's realization is difficult, very expensive and causes most further problems in machine operation.

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Recommendation - out of the experience of the EN ISO 13849 application

1.

There should be a written guideline how to “translate” technical structures into EN ISO 13849 based safety block structures in general

2.

There should also be a guideline how to apply EN ISO 13849 calculation for EN ISO 13849 based safety block structures in general

3.

The EN ISO 13849-1 and ISO 14121 risk assessment should be synchronized and harmonized!

4.

The safety requirements in C-Standards – based on experts experience – have to be the leading value in EN ISO 13849 “translation” of these standards!

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EU-Symposium

“Safety related control systems for machinery”

Thank you for your attention!

Questions?

Eberhard Beck Head of control techniques INDEX-Werke 09.09.10

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Practical application of EN ISO 13849-1 for machine tools - Eberhard Beck

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