GB1247910A - Cleaning method and means for electro-chemical grinder - Google Patents

Abstract

1,247,910. Spark-erosion. HAMMOND MACHINERY BUILDERS Inc. 27 Nov., 1968 [4 Dec., 1967], No. 56335/68. Heading B3V. [Also in Division C7] In an electrochemical grinding machine, a sensing electrode and associated circuitry control energization of a cleaning electrode so as to remove waste material which accumulates on the surface of a grinding device comprising non- electrically conductive abrasive grains protruding from an electrically conductive matrix. The grinding device may be a wheel, disc or belt. The removal of waste may be by electrolysis or by spark discharge. The current supplied to the cleaning electrode may be fluctuating or intermittent and may be of constant or alternating polarity. Fig. 3 shows a rotating electrochemical grinding wheel 11, workpiece W, cleaning electrode 22 and sensing electrode 29. A control C measures the resistance between the sensing electrode 29 and the matrix of the grinding wheel and automatically controls energization of the cleaning electrode by controlling a switch 26. When the workpiece is retracted, a microswitch 25 opens the circuit containing the cleaning electrode. The wheel, in addition to being rotated, may be oscillated relative to the cleaning electrode. Alternatively, the cleaning electrode may be oscillated. There may be a common supply of electrolyte, e.g. from the wheel centre, for the workpiece, cleaning and sensing electrodes or each may be supplied separately. Using spark erosion, the cleaning may be by successive bursts of pulsed discharges with the wheel connected either as cathode or anode. Working of a WC workpiece using a metal bonded diamond wheel and an aqueous solution of NaNO 3 is referred to.