CONTROL SYSTEM FOR AN ELECTRO-EROSION MACHINE TOOL

1536127 Control of electro-erosion FUR INDUSTRIELLE ELEKTRONIK AGIE LOSONE BEI LOCARNO AG 4 Dec 1975 [20 Feb 1975] 49902/75 Heading G3N An electro-erosion process is automatically controlled by adjustment of such process conditions as flow of flushing medium and mark/space ratio of working discharge pulses in dependence on signals 101, 201 respectively representing the rate of wear of the tool electrode 1 and of the workpiece electrode 2. A detector 6 of conditions in the working gap 3 establishes, with respect to a desired value input 15, an error input 42 to a unit 100 which computes squared integrated error as described in Specification 1454088. The rate-oftool-wear output 101 is derived from this computation. Unit 200 compares the number of actual discharges across gap 3 with the total number of applied pulses (some of which do not produce discharges) and this comparison provides the rateof-workpiece-wear signal 201. The relative effects of the signals 101, 201 may be time variable, e.g. the workpiece erosion rate may be relatively high initially and lower during a later fine finishing stage.