INFLUENCE OF FRICTION CONDITIONS ONSHEET HYDROFORMING USED IN AUTOMOBILE INDUSTRIES

Abstract

Sheet hydroforming (SHF) or hydro-mechanical deep drawing (HDD) has been emerged as one of the desirable manufacturing processes particularly in automobile industries. This importance is appeared due to its capability of producing complex mechanical components in few steps. It also presents further advantages such as improved structural strength, stiffness, and more efficient material usage. The SHF depends directly on many factors, and the most important one is a friction. The friction plays an important role in SHF operation processes; therefore, different values of coefficient of friction between the die and sheet were considered in the present paper. These values were varied from 0.01 up to 0.35, and hence the obtained results showed that higher values of coefficient of friction led to a low expansion capabilities and more thickness alteration. This means that the friction between die walls and the employed sheet was increased when a bead force is created a bead force and it is dependent directly on the contacted surfaces and expanded plastic zone. Finally, some preliminary results on the effect of friction on this type of high pressure forming and choosing best working conditions, as well as effect on sheet thickness are presented with some experimental results.