General end-mill is considered and chosen by kinds and properties of material before machining, but in case of orthopedic surgery, cutting performance of orthopedic end-mill must be always best because bone condition is checked after operative preparation including skin incision. Generally hard metal end-mill is used for high cutting performance in industrial fields. To apply hard metal end-mill to robotic orthopedic surgery, prototypes with STS are manufactured and tested for determining proper number of flutes and helix angle, additionally proper overhang length of end-mill from sleeve end was determined by checking deflection under cutting load and critical speed using FEM program. As a result helix angle, blade number and overhang length are determined as 45∘, 3, 7cm respectively.

In this paper, experimental studies of the regrinding of tungsten carbide (WC-Co) tools for high-speed machining were conducted. Regrinding and a subsequent evaluation test were carried out for a flat endmill tool with diameters of 10 mm and 3 mm using a CNC five-axis tool grinder and a CNC three-axis machining center. Tool wear on the two types of endmill tools increased as the cutting length increased, and the tool wear was not influenced by the regrinding state. In case of the micro endmill with a tool diameter of 3 mm, the effective regrinding time was determined for a flank wear threshold of 0.3 mm considering the tool life according to cutting length. The tool lives of the 10 mm and 3 mm endmill tools were increased by 80% and 72%, respectively. This conclusion proves the Feasibility of the recycling of tungsten carbide materials in the high-speed machining of high-hardened materials for industrial applications.