Experimental investigation of the effect of different cooling methods on drill‐induced damage in pultruded composites

Pultruded (nonlaminated) composites find application in construction of bridges, prefabricated walkways and platforms, ballistic applications, and so forth. However, literature on the drilling of nonlaminated composites is scarce. In addition, many researchers have also proposed that standard twist drill is not suitable for making quality holes in composites under dry conditions. Hence, this study is to analyze the influence of external and internal cooling methods on drill‐induced damage factor while drilling glass fiber‐reinforced epoxy pultruded composites and thereby to find the suitability of widely available twist drill. The drilling experiments using TiN/TiAlN‐coated tungsten carbide twist drills of diameter of 10 mm were conducted using response surface methodology. From this investigation, it is evident that the internal cooling method is significant for obtaining high hole quality followed by external cooling method, and thereby suitability of twist drill has been proved. POLYM. COMPOS., 37:2855–2859, 2016. © 2015 Society of Plastics Engineers