Study of the processing properties of a nickel-based diamond film in the development of a miniature circular diamond-blade array

This study presents a hybrid fabrication technique for developing a diamond-blade array used to directly generate a microgroove array onto NAK80 steel. The microgroove array on the NAK80 steel can be used as a biochip mold. The diamond-blade array is made by depositing a nickel-based diamond film onto a disk tool (substrate) through electrochemical co-deposition. The nickel-diamond wheel blank is then cut using RWEDM (Rotary Wire Electrical Discharge Machining) to produce a multi grinding-edge array from the blank. The developed diamond-blade array is then employed in machining a microgroove array on NAK80 steel to produce a biochip mold. The resultant dimensional accuracy, geometric accuracy, and surface finish of the grinding-edge and finished microgroove array are measured and evaluated. The factors influencing formability, thermal machinability, and mechanical properties of the diamond film are discussed in detail. Experimental results indicate that a lower current density and moderate diamond abrasive concentration create a diamond film of high-integrity. Increasing the thickness of the deposited film suppresses thermal fracturing and raises the rigidity of grinding-edges helping to keep the diamond cutting-edge accurate. Nano-metric scale grinding of microgrooves on the NAK80 steel is helpful in maintaining sharpness and slowing the wear rate of the diamond-film grinding-edges.