Cutting force, Vibration, and Temperature in Drilling on a Thermoplastic Material of PEEK

Polyetheretherketone (PEEK) is one of the semi-crystalline thermoplastic polymers with excellent machinability and chemical stability applied to precise structural plates and electronic components. This study installed multiple sensors to analyze the machining characteristics in the PEEK drilling. According to the time domain signals, the effects of spindle speed and feed rate on the machining characteristics of cutting force and vibration were investigated. In addition, an infrared thermography was installed to record the temperature variation within the drilling area. The experimental hole was 2-mm diameter with a 4.5-mm depth. Experimental results showed that the effect of the feed rate on thrust force is greater than the spindle speed; drilling by a low-level spindle speed with a low-level feed rate can obtain the smallest cutting force and acceleration amplitude in the spindle axis; the temperature within the drilling area is inverse to the feed rate and a high-level feed rate is helpful for forming regular curl chips. When adequate airflow was applied during the drilling operation, the hole's shrinkage ratio and roundness can be decreased. The data presented in this paper provide valuable references for realizing the drilling of the thermoplastic-PEEK.