Investigation of frictional behaviour in incremental sheet forming of grade one titanium sheet

Incremental Sheet Forming (ISF) is a flexible sheet forming process. Its interfacial friction between the ISF tool and the blank sheet has a significant effect to the forming forces, deformation, fracture, and surface finish. This study reports an experimental investigation into the frictional behaviour in ISF processing of Grade 1 commercial pure Titanium (Grade 1 CP Ti) using a rigid hemispheric and a roller ball tool. Straight groove tests of reciprocating sliding were conducted to measure the forming forces in both vertical and horizontal directions with and without imposing deformation under different lubrication conditions. The results showed that the friction indicator increased with the increased passes and the friction coefficients maintained a constant value. It was found that the horizontal force component due to plastic deformation were constant using different tools and under different conditions and could be quantified by comparing data from testing with and without plastic deformation.