Investigation of the performance of recycled copper swarf tool electrode processed through bound powder extrusion for micromachining

This experimental study used recycled copper chips as a base material for electrode manufacturing through the additive manufacturing route utilizing the bound powder extrusion (BPE) process. Initially, the copper chips were collected from a conventional machining centre. Then, the chip size was reduced by the two-step milling process (ball-to-powder ratio, 2:1) to attain the micro-sized fine particles around 44 μm, which is the prerequisite for preparing the base material for the BPE process. Subsequently, the input parameters were optimized to a layer thickness of 0.125 mm, nozzle diameter of 1 mm, and printing speed of 20 mm/s by the Box-Behnken design approach and attained a maximum relative density of 98.57%. Finally, the BPE-recycled copper tool electrode was manufactured in 0° and 90° orientations. Further, the electrical conductivity of the tool, material removal rate, tool wear rate, and surface roughness of the machined surface of manufactured components were evaluated and compared for BPE-90°, BPE-0°, and conventional tools. The result shows that the BPE-90° tool electrode performs better than BPE-0° and conventional tools.