Effects of high speed in the drilling of glass whisker-reinforced polyamide composites (PA66 GF30): statistical analysis of the roughness parameters

Abstract

Glass fiber-reinforced polyamides are promising materials especially for automotive applications, exhibiting high mechanical strength and stiffness. In order to achieve the required tolerances and surface quality, these materials must be subjected to machining operations. Drilling is one of the machining processes most widely applied to composite materials and, for this reason, this article is focused on the machinability of polyamide reinforced with glass whiskers for high speed drilling operation. A full factorial experimental design was carried out in order to identify the main effects and interaction between the factors feed speed, spindle speed and drill point angle on surface roughness (R a) and normalized peak count (Pc) responses. The work material (PA66-GF30 polyamide reinforced with 30% glass whiskers) was drilled using tungsten carbide (ISO grade K10) drills. The results indicated that the interaction between feed speed, spindle speed, and drill point angle presented a significant effect on the Ra response. In addition to that, the factor feed speed and the interaction between spindle speed and drill point angle significantly affected the peak count response.