Influence of lubricants and lubricating methods on surface roughness in the two-point incremental sheet forming process

The selection of lubricants depends on the deformation mechanism of each process which significantly affects the surface roughness. In the incremental sheet forming process, there has been little attention on this aspect. This study investigates the influence of lubricants and lubricating methods on the surface quality and geometric accuracy during the two-point incremental forming process (TPIF). By using five different lubricants and two lubricating methods, the experiments were conducted to deform the 45°-cone parts with an aluminum sheet. Then, the formed parts were analyzed in terms of surface roughness and geometric accuracy. The morphology of the formed surfaces was also observed by using the scanning electronic microscope (SEM). The experimental results showed that the mixed lubricant (graphite powder + MSo2 + machine oil) greatly improved the surface quality and geometric accuracy. Using vegetable oil as an alternative lubricant for the TPIF process induced low cost and environmental effects but provided the surface quality similar to machine oil.