Microstructural investigation and lubrication study for single point incremental forming of copper

Abstract

Lubrication improves surface finish in Single Point Incremental Forming (SPIF). However the reason behind this improvement needs to be investigated. In this study a polycrystalline Copper sheet was incrementally formed to a truncated conical geometry using different lubrications till fracture. The selection of the tool material for optimal surface finish is also discussed. The effect of lubrication on the surface roughness was studied. To understand the effect of the lubrication from a microstructural point of view, Scanning Electron Microscopy (SEM) analysis of the components was carried out. The SEM images from different lubrication states were compared and found that there is some influence of lubrication on the surface. The surface roughness varied along the depth of the formed truncated conical geometry. It was observed that the marks left by the forming tool and the development of valley like structures along the grain boundaries were the cause for increased surface roughness. Other important observation regarding the microstructure study was that due to high strain deformation the grain shape has elongated in its direction. The lubrication conditions had no significant effect on the formed grain size or shape.