Elaboration of the Technology of Forming a Conical Product of Sheet Metal

The present work concerns the forming of the sheet metal conical products which, combined with a vulcanized rubber blend form footings for electric power generators. Conical sheet metal elements are most often formed by the following four methods: – multi-operational stamping with stiff tools, – hydro-mechanical stamping, – spinning, – flow turning. In case of stiff tool stamping, traces on the side surfaces after each stamping should be taken into account. Sometimes, they are considered as defects. But in case of a conical insert it could be neglected. For long series production and automatic presses with jaw feeders, this is the most economical technology ever. The hydro-mechanical method is applied up to the drawing coefficient value of 0,38. Moreover, with the material thickness of 3 mm, the method requires very high pressures. When applying this method to flow turning, a different product is obtained – the one with a thick bottom and thin side wall. The large thickness of the initial sheet should also be considered. Since the conical product (Figure 1) is supposed to be 3 mm thick, according to the theory of flow turning (1), the thickness of the initial sheet should be 6,6 mm with the side wall inclination angle of 27° because 1 :