Application of a Cryogenic Cooling System on the Grinding Operation of Polyether Ether Ketone Biomaterial (PEEK)

Polyether ether ketone (PEEK) is often used in the biomedical industry because of its remarkable properties, including high-temperature resistance, superior wear and fatigue resistance, and high tensile strength compared to other thermoplastics. The goal of the current study is to study PEEK thermoplastic biomaterial's grinding operation under various cutting situations. PEEK thermoplastic biomaterial's grindability characteristics were assessed in terms of surface roughness, grinding forces, surface hardness, wheel loading, and analysis of surface morphologies. Since the PEEK biomaterial has lower melting point, and poor heat transfer coefficient, it is highly likely to lodge to the pores of wheel surface as well as adhere to ground workpiece, which could result in increased wheel loading and poor ground surface. Here, two auxiliary cooling and cleaning systems, including compressed air jet and cryogenic \({\mathrm{LN}}_{2}\) cooling system as environmentally friendly fluid, have been employed in the grinding process to clean the wheel surface off of the chips. Besides, the effects of input parameters on PEEK grinding were investigated and analyzed as well. The results demonstrate that when utilizing pressured air, the PEEK biomaterial typically exhibits considerably increased surface roughness, the greatest amount of wheel loading, and significant grinding forces; however, when employing a cryogenic cooling system, these characteristics were minimized to a great extent. Besides, images of the wheel surface obtained after grinding have been processed using digital image processing technique in MATLAB platform to determine the proportion of the wheel loading.