SUPERPLASTIC FORMING

ME 530Near-Net Shape Manufacturing

InstructorDr. 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

It works upon the theory of Super plasticity

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

In fact materials can elongate up to 8000%

At certain temperature and controlled strain rate

SPF ProcessA 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 Forming- Gas pressure differential is applied on the

super plastic diaphragm causing the material to form into die cavity shape.

Applied pressure – 100 Kpa

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

CAPABLE OF 910 C, 500 TON CLAMPING LOAD AND 2M X PLATEN SIZE⁰

SPF Alloys

1- Al alloys 5083,7485

2- Ti alloys TA6V

3- Inconel 718

4- Bi-Sn (200% elongation)

5- Zr-Al

Advantages1- Large complex work-pieces in one operation only

2-Eliminates Springback

3- Fine surface finish.

4- Cost savings ranges up to 30%

5- Reduces weight by eliminating nuts, bolts and fasteners

6- Near net complex shapes

Disadvantages1- Slow forming rate (Cycle time 2 min to 4 hrs.)

2-High material cost

3-Trial and error design

4-Lack of accurate modeling

Industries Using SPF Aeronautics

Automotive

Railways Building

Medical

Sports

ApplicationCivil/ Military aircrafts- (Ti, Al alloys)

Sensor Housing Fan blade section

Nose Cover Center Automotive body panels

Window Frames

Sheet structures

Closing ShellThin Frame Structure

Complex StructuresHeat Exchangers

SPF parts in Al Alloy

SPF Forming Softwares Used to follow the variation of thickness of the

sheets during forming in order to predict the geometry of component after forming.

ARVIP-3D

CATIA

CAM Craft Design

ABAQUS

Recent SPF Tool Technology

To control the total price of super plastically formed

components, new tools have been developed recently.

Metallic tools Non Metallic tools

Emerging Technologies

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.

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.

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 manufacturingcell

References

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

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

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

Thank You