EFFECTS OF COLD AIR SUPPLY ON CUTTING CHARACTERISTICS IN SMALL HOLE DRILLING OF PEEK

A polyetheretherketone (PEEK) is one of the thermoplastic resins. The material is superior in mechanical strength, heat resistance and chemical resistance. Therefore, it is suitable for industrial components such as automotive parts, machine parts, electrical and electronics parts. Particularly, it is used for an inspection socket of a connector and the semiconductor package in the field of electronic components. Consequently, a demand of the high efficiency machining in small drilling for the PEEK increases with a miniaturization and diversification of the industrial equipment. However, PEEK, which is a thermoplastic resin, has a problem that the hole accuracy is lowered due to the cutting heat. The objective of this study is to achieve high precision and high efficiency machining process for industrial components of the PEEK such as an inspection socket of a connector or the semiconductor package. In order to solve these problems, this study carries out cooling workpiece by cold air supply. This paper describes the investigation result of the effect of cold air cooling on hole accuracy and cutting state in the small hole machining of PEEK. As a result, it was found that cooling the workpiece is effective to suppressing the cutting heat and improve hole accuracy. Within the experimental conditions, the combination of non-step drilling and cooling enables high-precision drilling with approximately the same accuracy as step drilling. Keywords: Small drilling, PEEK, Cutting heat, Air cooling