Influence of the chemical composition of Polyurethane block on the surface roughness in machining

The polyurethane block also known as PB is widely use in the automotive industry to manufacture checking fixtures. This material has a high machinability and a low hardness that can range from 37 to 84 at the shore D hardness. To acquire the appropriate milling parameter for this material has always been a challenge for the manufacturing industry, especially when comes to achieving a certain degree of surface quality as this material is highly porous. In this paper, the most significant milling parameter that affects the surface roughness was studied using DoE. Surface roughness tester was used to evaluate the surface finish. The morphology and composition of the PB were determined by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX). It was found that the most significant factor among the milling parameter was the stepover and that the surface quality was heavily dependent on the amount of weight percentage of silicon.