Tailored ZrO₂ based tool for minimizing thermal damages in bone machining

Thermal damage to bone after orthopaedic surgery can cause osteonecrosis, delayed bone healing, lower bone strength, implant failure, and infection concerns. Thermal osteonecrosis can be avoided by using adequate tool selection, ideal cutting parameters, intermittent cuttings, temperature monitoring, personalised surgical plans, etc. This research showcases previous bone-cutting temperatures (T_max) recorded through milling (44 °C -70 °C). Also, it introduces an innovative method by employing a novel ZrO₂-based cutting tool against SS316L-based surgical cutting tools. Bone machining experiments were carried out with customised SS316L and bio-ceramic ZrO₂ milling inserts to investigate thermal damages. Feed f = 0.03 mm/tooth, 0.05 mm/tooth, and speed s = 900 rpm and 1000 rpm were used for four cutting conditions. Fourth-generation SCADA systems leverage IoT frameworks to process in-situ temperature data from bone workpieces through k-type thermocouples. Bone machining is processed by milling; maximum (T_max)and mean (T_mean) temperatures are measured. T_mean is essential since it determines the temperature generated when the tool is in contact with the bone for a more extended period. The experiments showed that SS316L-based incisions generated a T_max of 36.25 °C to 39 °C and ZrO₂-based incisions recorded 35 °C to 39.25 °C. Incisions made with ZrO₂ tools had minimal T_mean temperatures at f = 0.03 mm/tooth & s = 900 rpm. All ZrO_2-based T_mean from the other three cutting parameters are lower than SS316L. Since generated T_max and T_mean from ZrO₂-based surgical cuttings are lower than surgical SS316L-based cuttings and also lower than temperatures from previous studies, ZrO₂-based tools can be the alternative to presently exercised metal-based cutting tools.