Rubber pad forming? 2

[classictrial]

Wonder if there is anywhere that I can find information regarding rubber pad forming small aluminuim parts, using hydraulic press? Here in the UK its very difficult to find any source of info regarding this subject.

Would be particularly interested in what would be possible with a normal 30 ton shop press......depth of draw, size of pad etc?

TIA

Chris

 

[berkshire]

Try obtaining a book from Alcoa aluminium called "Forming Alcoa Aluminum" It has a section on the Geurin trapped rubber process for forming small parts.
B.E.

 

[aerodog]

class,

About 10 years ago I made a small hydro-press using a 6 inch cylinder and a 2,500 psi pump (about 35 U.S. tons).

The forming box was fabricated like a picture frame made from 2 inch channel iron (flanges out) welded to a 1 inch plate. The internal box dimension was 8 x 10 inches.

The forming media was two 1 inch thick rubber pads cut just
slightly larger than the 8 x 10 inch box. The pads were forced into the forming box by extending hydraulic ram.

The press has squeezed a lot of aircraft parts including some that went on the F-16. One Friday afternoon, two of us formed 90 parts in less than one hour.

 

[classictrial]

Wonder if anyone has any experience of the depth of parts that can be formed using rubber, if you were forming 2mm aluminuim sheet?

Chris

 

[aerodog]

classictrial,

Normally, one would not think of depth of part when rubber forming. Think more in terms of flanges on ribs, frames or clips and brackets. The max length of flange would be perhaps 60-70% of the depth of the forming box.

A rubber head can push metal into a female cavity, but the success is dependent on the material, heat treat, severity of form and the tool design.

Rubber head forming works in the aircraft industry because we normally deal with easily formed aluminum in low production quanties. Tooling costs are low as only a male tool made from aluminum is needed, the rubber in the forming box provides a conforming female shape.

In the auto industry, parts are usually steel, production quanties high and matched male/female tooling which necessitates tools made from high strength (tooling) steel.

 

[classictrial]

Thanks Aerodog........we are looking at forming aluminuim fuel tanks for off road motorcycles. Have seen this being done by a local company, but not able to get any useful information, for commercial reasons.

They form using a large 4 post press, forming box, and male tooling made from GRP or epoxy resin system. Looking to make tanks in two halves, weld together the 2 parts, then add bottom and filler and tap fittings.

Previously made tanks using wooden buck, and template cut sheet aluminuim, but rubber pad forming looks as though it would be much faster, and mean a lot less welding.

Chris