Hey all, I am an engineering student studying towards a BEng degree. As part of my design course I am required to design a draw bench that is able to draw tapered brass tubes for french horns. The maximum diametre of the tube is 20mm. For the drawing I wanna construct a slider with two lead screws and a stepper motor at the end of the slider. For the tube I want to insert a tapered mandrel inside and I want to move the mandrel with the tube through steel die washers. The mandrel should be attached to a carriage moving with the lead screws. I have problems with selecting materials for the die washer, calculating thr draw force and therefore selecting the appropriate lead screws and motor. If I take the yield stress of brass, assuming that the drawing process requires a plastic deformation, I get draw forces around 10kN. This seems unreasonable since on a couple of youtube videos people were able to draw the tube by hand. I am really worried now since I cant start working on my project. Any help would be appreciated. Thank you! Sam
assumptions You may want to check your wall thickness, temperature (they may have pre-heated the brass) and maybe leverage.
