Electro-erosion machine tool and a pulse generator for use in such a machine tool
AssigneeAG Fur Industrielle Elektronik
InventorsWerner Ullmann, Ernst Buhler
Life of this patent
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Abstract
A pulse generator for use in forming the erosion pulses of an electro-erosion machine tool comprises means for forming two envelope curve signals representing upper and lower limit levels for the instant level of the output pulse, a comparing device for comparing the actual current level of the output pulse with the envelope curve signals, and a current supply for forming the pulse under the control of a switch which is turned on and off by the comparing means in such a way as to maintain the output pulse current level in the region represented by the space between the envelope curves.
Claims17
A pulse generator for forming electrical pulses which are to be passed across a working gap between a workpiece and a tool electrode in an electro-erosion machine tool so as to machine the workpiece by eroding it, the pulse generator comprising:
- envelope signal forming means (1) for forming respective signals having waveforms which define an upper and lower envelope curve (16 and 17) having shapes corresponding to the envelope shape of the pulse to be generated;
- current supply means for supplying electrical current to said working gap, the supply means including a switch (4) for turning the supply current on and off;
- gap current representative signal forming means (7) for forming a signal representative of the gap current passing across said gap;
- comparing means (2) which is connected to said envelope signal forming means (1) and said gap current representative signal forming means (7) and is operable for comparing the gap current representative signal with each envelope signal;
- control means (3) which is connected to be responsive to the output of the comparator means and to control said switch for turning said supply current on and off in dependence upon the comparison;
- and
- diode means (6) connected to said supply means to form a circuit (via 6, 7, 8a and 8b) which includes the said work gap when the generator is in use and in which residual current can flow when said supply current is turned off by said switch (4).
Dependencies are inferred from the claim text.