Abstract:
Continuous quest for lighter yet stronger materials has led to significant research in the field of composites. Modern-day nanocomposites have found widespread applications in diverse engineering sectors, which often require their machining. In this paper, multi-walled carbon nanotubes (MWCNTs) reinforced composites are subjected to drilling operation under cryogenic condition. To investigate the effects of different drilling parameters, like drill type, feed rate and spindle speed on delamination factors at drill entry and exit, circularity error and surface roughness, a three-level full factorial experimental study consisting of 27 experiments is carried out. To determine the optimal combination of drilling parameters, a recently developed multi-criteria decision making tool in the form of combined compromise solution (CoCoSo) method is employed. Five different objective criteria weight allocation techniques, i.e. mean weight method, standard deviation method, entropy method, criteria importance through intercriteria correlation method and method based on the removal effects of criteria are considered in this paper to avoid subjectivity in the decision making process. The optimal drilling parameters derived using the combined applications of CoCoSo and different criteria weight allocation techniques are also compared. Based on the experimental observations, it can be concluded that a TiCN coated drill with 10 mm/min feed rate and 1500 rpm spindle speed would provide the most desired response values during cryogenic drilling of MWCNTs reinforced composites.