A machinability study of GFRP pipes using statistical techniques

Nowadays, glass fiber reinforced plastics (GFRP) play a vital role in many engineering applications as an alternative to various heavy exotic materials. In GFRP polymeric composites, the matrix of polymer (resin) is reinforced with glass fibers. Such composite pipes are finding applications not only in construction industries, but also in the transportation of corrosive fluid. These pipes are manufactured through hand lay-up or filament winding processes. Though the technology of composite manufacturing is advanced, near-net-shaped components with the required surface finish quality can be achieved only by machining. This paper mainly focuses on the evaluation of the surface finish of the machined surface of GFRP pipes and associated studies. Experiments were conducted through the established Taguchi’s design method. In this work, the machining characteristics are investigated based on surface roughness and tool wear. The machining parameters are also optimized by employing statistical techniques, using the technique of analysis of variance (ANOVA) obtained from regression analysis. Both simple regression and cross product regression methods were employed and their suitability was also studied. An empirical model is also developed to determine the percentage of improvement in tool wear and surface finish. The machined surface exhibited a better surface finish of 4 to 8 microns, whereas the surface roughness of the unmachined surface was observed to be around 80 to 100 microns.