Experimental Investigation Of Ultrasonic Electroplated Diamond Tools

Ultrasonic wave was applied to the fabrication processes of electroplated diamond tools to obtain high quality products. The aim of this study is to improve the diamond tool performance, the bonding strength between substrate and plating, the machining efficiency and tool life. The effect of ultrasonic power on nickel electrodeposits was studied in a typical nickel electroplating solution. Influences of ultrasonic wave on solution and nickel plating performance were analysed. Nickel plating surfaces and section specimens were prepared separately. The surfaces and cross section were observed and microscope hardness were measured. Bonding strength between electrodepositing layer and the tool substrate were measured with thermal shock test and file scratch test. Cathode polarization curves were tested with electrochemistry direct current polarization test system. Grinding experiments were conducted on driller to obtain the grinding ratio of diamond tools.The hardness of nickel layer with ultrasonic wave is bigger than that of without ultrasonic wave. The hardness of nickel layer varies with ultrasonic power. The nickel layer hardness 501 Hv was measured when ultrasonic power was 200 W. The main influencing factors of nickel deposition hardness include fine grain size, machining hardening, compressive stress and dislocation density. When ultrasonic power is 200 W, better bonding strength between electrodepositing layer and the tool substrate is obtained. The corrosion resisting property of nickel layer enhance with the increasing of ultrasonic power. The internal stress of nicel layer become smaller with the increase of ultrasonic power. Cathode polarization trend can be lessened with ultrasonic wave. Diamond tool with dense even-distributed grain can be fabricated when ultrasonic wave was applying 3 min before tick-up operations. In experimental condition, wear-resisting property of diamond tool can enlarge when 100 W ultrasonic power is applied 30 min during last thickening operations. The research results show that ultrasonic wave can lessen cathode polarization degree, increase the hardness of nickel layer, enhance the corrosion resisting property, and increase the bonding strength between electrodeposited layer and substrate. Diamond tools with wear-resisting property was enhanced during thickening operations. However, higher ultrasonic power and early-applying time is not recommended. Diamond tool with good performance was fabricated with experiment parameters in this study.