Influence of Punch Profile on Dome-Forming of Thick Sheet.

The purpose of this research is to increase the feasibility of a new lubricant test which is available for the plastic deformation processing of thick sheet. The feasibility of the new test has been already confirmed through a series of experimental procedures in which the friction coefficient could be evaluated from the dome height. In this research, an influence of the punch profile on the neutral point of the compressed material was evaluated by means of the "slab method". At first, the validity of the adoption of slab method was confirmed with the comparison between the result of FEM and the slab method. As a result the variation rate of the neutral point in relation to the friction coefficient in slab method was the same of the result in FEM. Next, the neutral point in the case of a convex profile punch was evaluated with slab method. As a result, the convex profile punch had an excellent performance since the variation rate of the neutral point in relation to the friction coefficient was more remarkable than that of the straight profile punch.