Recently, lightweight materials centered on the future mobility industry are used in various parts such as battery housings and EV platform frames to improve fuel efficiency of automobile engines. Polycrystalline Diamond (PCD) tools are in demand by parts processing companies to improve productivity for machining lightweight parts. PCD drills have excellent cutting performance and wear resistance in high-speed machining. They are expected to grow in the global cutting tool market in the future. Research is needed to improve their performance. In this study, PCD gun drill and twist drill were respectively manufactured using brazing technology. Comparative machining experiments were then conducted. The PCD gun drill is a straight-shaped tool with a PCD tip brazed to a tool body groove for the tip to enter the cutting edge. The PCD twist drill is a spiral-shaped tool with a PCD drill blank brazed to a V-shaped butt joint with the tool body and an internal groove. Both PCD drills were successfully manufactured and evaluated for dimensional accuracy and surface quality by machining aluminum alloy materials with MCT equipment. In the future, we will evaluate not only aluminum materials, but also various machining materials.

The worsening environmental pollution has increased the interest in developing eco-friendly technologies. The purpose of this study is to develop an aero-heat exchanger to reduce the emission of environmental pollutants. The operating conditions of an aircraft are extremely harsh, leading to challenges with the determination of appropriate materials and structures that can withstand the severe conditions. In addition, since the tubes brazed to the tube-sheet are structurally fragile, it is essential to assess the structural integrity of tubes. In this study, the overall structural integrity of the tubular heat exchanger under development was evaluated. An appraisal of the junctions between tubes and tube-sheet, which are the most critical parts, was conducted. A finite element (FE) analysis was employed for the assessment of structural integrity. FE analysis was used to evaluate the brazed joint of tubes using a model in which specific tubes were designed to withstand the high temperature of the tube-sheet. The evaluation was carried out compared with the fatigue strength of Inconel 625, the material constituting the heat exchanger.