Multiobjective Optimization in Drilling of Composites

Abstract

Composite laminates such as carbon fiber-reinforced polymer (CFRP) composite, glass fiber-reinforced polymer (GFRP) are attractive for many applications such as aerospace and aircraft structural components due to their superior properties. CNC drilling is the major operation which is performed on CFRP for joining these kinds of materials, due to its poor weldability. But, the major problem associated with CNC drilling of CFRP is the delamination effect which not only degrades the quality of the product but also reduces the fatigue life of the material. However, as delamination effect decreases, the material removal rate also decreases. Therefore, this work deals with the multiobjective optimization of drilling parameters in machining of CFRP considering delamination effect and material removal rate as the responses. In this work, the process parameters considered are speed, feed rate, and diameter of the drill bit. The Taguchi design of experiment was used for obtaining the setting. Out of the entire orthogonal array, L27 orthogonal array was used for the experimental setting. The delamination effect was obtained and calculated by scanning electron microscopy. Further, the fuzzy logic was applied, and the combined effects of both the responses were obtained which is called multiresponse index. The application of fuzzy logic gave an improvement of about 21% in multiresponse index.