super plastic forming

FORMING ME 530 Near-Net Shape Manufacturing Instructor  Dr. Neda Fabris

By Ansul Kumar Singh

What is Super Plastic Forming ? Super Plastic Forming is a process by which complex parts are produced from a single sheet of super plastic material 

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It works upon the theory of Super plasticity

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Super plasticity is the ability of material to undergo extreme elongation allowing for  deep drawing and intricate shapes

Which means materials can elongate more than 150% of its original size

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In fact materials can elongate up to 8000%

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At certain temperature and controlled strain rate

SPF Process A sheet of material is placed into a hot open die and heated up to Super plastic temperature ( Ti – 900 C, Al- 500 C) Inert Gas pressure (Ar) is applied which plastically deforms the sheet into shape of die cavity.

Process Diagram

Types of SPF 1- Vacuum /Stretch FormingGas pressure differential is applied on the super plastic diaphragm causing the material to form into die cavity shape. Applied pressure – 100 Kpa

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2- Blow Forming- Additional pressure is applied from gas reservoir. Max applied pressure is 700Kpa – 3400 Kpa

Super plastic Forming Lab Press Used for SPF of Ti aircraft parts 

TITANIUM SUPERPLASTIC FORMING PRESS COURTESY OF AEROMET INTERNATIONAL1.5M

SPF Alloys 1- Al alloys 5083,7485

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2- Ti alloys TA6V

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3- Inconel 718

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4- Bi-Sn (200% elongation)

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5- Zr-Al

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Advantages 1- Large complex work-pieces in one operation only

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2-Eliminates Springback 

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3- Fine surface finish.

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4- Cost savings ranges up to 30%

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5- Reduces weight by eliminating nuts, bolts and fasteners

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6- Near net complex shapes

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Disadvantages 1- Slow forming rate (Cycle time 2 min to 4 hrs.)

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2-High material cost

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3-Trial and error design

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4-Lack of accurate modeling

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Industries Using SPF 

Aeronautics

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Automotive

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Railways

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Building

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Medical

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Sports

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Application Civil/ Military aircrafts- (Ti, Al alloys)

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Sensor Housing

Fan blade section

  Nose Cover Center

Automotive body panels Window Frames Sheet structures

Closing Shell

Thin Frame Structure

SPF parts in Al Alloy Complex Structures Heat Exchangers

SPF Forming Softwares 

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Used to follow the variation of thickness of the sheets during forming in order to predict the geometry of component after forming.

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ARVIP-3D

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CATIA

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CAM Craft Design

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ABAQUS

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Recent SPF Tool Technology 

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 To control the total price of super plastically formed components, new tools have been developed recently.

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Metallic tools

 Non Metallic tools

Emerging Technologies 

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Quick Plastic Forming It is a hot blow forming process capable of producing Al or  Mg panels at relatively high volumes. The conditions of  deformation are quite close to conditions corresponding to super plastic forming with however strain rates significantly higher than those associated to "pure" super plasticity.

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This technology has been successfully implemented for  automotive lift gates and deck lids with complex shapes for  various car productions.

Project SPLICE 

SPLICE - Super Plastic Laser Induced Component Equipment research at Rolls-Royce, UK.

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Laser will be used for all operations virtually Required to produce SPF component from cutting the initial blank from sheet material to final trimming to hole drilling after forming.

Conceptual LASER SPF manufacturing cell

References 

ASME handbook , Vol. 14 B, Super plastic Forming Process

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E Paul, Black J.T., Materials and Processes in manufacturing, (9th ed.) Wiley

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W.F. Powers, Automotive Materials in the 21st Century, Adv. Mater. Proc., 2001, p 38

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Thank You