Kirkham University Superplastic Forming Aluminum Coupe Rear Wheel Well

Here at Kirkham University we show you how we superplastic form the rear wheel well of our new Coupe. Superplastic forming is an exceptional method to make complex shapes in aluminum. Special thanks to Glenn Reynolds, author of Army of Davids, for inspiring us to share our knowledge with the world. www.kirkhammotorsports.com

[@deepakjoshua3012]

thank you kirkham university. the video was really useful for understanding the forming process

[@freshkryp69]

This is serious metal work here fellas!

[@KirkhamMotorsports1]

@UsherLinder, Superplastic forming heats the aluminum up to around 900 degrees and then pushes the aluminum onto a form with 100-500 psi nitrogen. Hydroforming (depending upon the process you are referring to) is forming an aluminum part with hydraulic pressure (from water, or oil) as one of the "dies," or using a block of rubber as one of the "dies" over a form. Hydroforming is generally done at room temperature. Superplastic forming is done at 900-950 degrees F.

[@newcomer9747]

@UsherLinder i think your question would be better answered by going down to the crystal formation level when the material is heat to 900c. at that temperature, the material plasticity changes dramatically to allow this process, hence only about 500psi forming pressure required.

[@oOAltoOo]

@newcomer9747 I think it is 900 Fahrenheit not Celsius, given that aluminium (aluminum to yanks ;-)) has a melting point (depending on alloy) of about 660 Celsius. 420 Celsius is not to be scoffed at though, it's enough to give it the malleability, that 500psi is ample pressure.

[@UsherLinder]

I love this series: thanks for posting it!
Questions: What are the differences between Kirkham's superplastic forming and General Motors' hydroforming process? True, both processes form sheet metal; Kirkham uses liquid nitrogen while General Motors uses water to create the pressure, but besides that, are there deeper, more fundamental differences between the two processes which would not be immediately apparent? Thanks! :-)

[@jc8417]

Is there any spring-back with superplastic or hydroforming?

[@KirkhamMotorsports1]

There is no spring back with superplastic forming. There is spring back with hydro forming.

[@Ev4nsk1]

​@@KirkhamMotorsports1 the cooling process after superplastic forming would affect the springback and distortion of the formed sheet after trimming correct? Thank you!

[@KirkhamMotorsports1]

@@Ev4nsk1 There is no spring back after SPF. There is no distortion either, as the metal is formed well into the plastic range. Residual stresses are very minimal, as the material heated well into the plastic range. Trimming doesn't move the formed part very much at all. It is a phenomenal process--it's just really expensive.

[@SirDavidHaddon]

How thick is the Aluminum after Forming it and After Filing parts to get high or low spots out of it???

[@KirkhamMotorsports1]

Probably somewhere around 0.050"