A hybrid process of raining co-deposition and rotary wire spark erosion in the development of a custom CBN tool for making a biochip injection mold

This study examines a hybrid process combining raining co-deposition and rotary wire spark erosion with one-off grinding to generate an array of microgrooves in the fabrication of biochip injection molds on NAK80 steel. A precision composite electroforming device that can create a rain like co-deposition effect to uniformly grow a Ni-based Cubic Boron Nitride (CBN) abrasive layer onto a wheel-blank substrate is proposed and employed. Slicing and dressing are conducted by using rotary wire spark erosion to make the co-deposited wheel-blank into a thin CBN wheel-tool with a grinding edge array that alternates between coarse and detailed. A multiple microgroove array on NAK80 steel is one-off generated by using the developed CBN wheel-tool array, swiftly creating a superior surface finish for biochip injection molding. A comprehensive examination of the quantitative and qualitative properties of the CBN wheel-tool was undertaken. Experimental results have been evaluated in terms of CBN grit content, accuracy of co-shaft machining, influence of grinding depth, shape of microgroove and tool wear as well as an estimation criterion for the CBN wheel-tool array.