In Reply to: Re: Cold draw forming posted by Lloyd Goodwin on 04/04/01 at 11:25 PM:
Sorry for the delayed reply, I appreaciate the response, I've put placed this project the back-burner, and chances are it will stay there. It is a VERY undocumented process, and very rare and precise science.
Forgive me if I misunderstand the process you discribed but I don't think its quite what i'm looking for. The problem with your method is that by initially stretching the material your applying another form of forming/shaping that induces internal stresses that are not consistant throughout the specimen and comprimises the end result of the drawing process. In drawing or extrusion the only constraints are applied the end of untreated specimen and it is pulled through the die (of specific geometry). This in theoy causes a uniform deformation of the material under controlled conditions (ie: rate of force being applied) and limits the fatigue areas of the final product.
The geometry of the die, the location of the clamping or securing device, the force and the rate at which it is applied are the critical factors for the process. The most difficult problem is finding materials/assembly that has the shear strenght to withstand the tremendous amount of force required in the process. Another source of error is accurately predicting bend.