GB930912A - An electro-erosion machine tool - Google Patents

Abstract

930,912. Automatic control of spark-erosion. A. L. LIVSHITS, M. J. BRISKMAN, A. T. KRAVETS, S. S. PODLAZOV, V. N. SOLOVOV, D. F. YAKHIMOVICH, and N. I. BLITSTEIN. June 24, 1960, No. 22262/60. Class 38 (4). [Also in Group XXII] An electro-erosion machine has its erosion gap EG, Fig. 8, fed by an impulse generator G1 and a control signal derived therefrom regulated by potentiometer R 1 is amplified first by transistors 1T, 2T and then by differential magnetic amplifiers 1MV6, 1MV7, 2MV6, 2MV7 and fed to the armature of tool feed motor 10. The latter has a field OB. Positive feedback is provided in the magnetic amplifier and negative feedback from the armature to the transistors through diode D. In another embodiment, Fig. 9 (not shown), a plurality of spark gap circuits are supplied by a common impulse generator and the gap is controlled by the voltage drop across the circuit carrying the greatest current. In another embodiment, Fig. 10 (not shown), two spark gaps are supplied by separate generators which may operate out of phase with each other. In a further embodiment, Fig. 11, a control signal from the spark gap, limited by shunt circuit D 1 , R 1 is applied to the left-hand grid of valve L 1 , whose cathode resistor R 2 is connected to the right-hand grid of valve L 2 controlling the winding OV 1 of a rotary amplifier EMV supplying the feed motor M. The right-hand half of valve L 1 is meanwhile shut off by a signal from resistor R 2 applied through transferrer Tp and rectifier B. Upon shortcircuit conditions no signal is applied to the lefthand grid of L 1 but its right-hand half conducts and a signal is then passed from R 3 to the lefthand half of valve L 2 which energizes winding OV 1 to cause reversal of the feed motor M and retraction of the tool. Relay P switches the motor M for rapid withdrawal of the tool.