GB1352351A - Automatically operating on a workpiece with a cutting or forming tool - Google Patents

Abstract

1352351 Machine tool control SIEMENS AG 19 April 1971 [26 March 1970] 9981/71 Heading B3B [Also in Division G3] A contour 3 is produced from a blank 4 on a lathe 1 by a programmed numerical control system employing a DDA-interpolator 9 energizing stepping motors 7, 8 positioning a carriage 6 for a cutting-tool 5. An adaptive logic unit 10, in the line to motor 8, controls the depth of cut in dependence on the torque on the spindle of the lathe. The motor pulses are blocked with an increase in torque above a preset value and fed to an overrun counter 11; for a further increase of torque, pulses are fed to the motor 8 to reduce the depth of cut. When the preset torque value is not attained, the depth of cut is increased until the preset torque is attained, or the contour reached. The DDA interpolator comprises integrators 92-94 and a pulse generator 91 connected to a logic unit 95 providing pulse trains #X and #Z to the motors whereby a circularly or linearly interpolated path element is traversed in time #t. The end of the interpolation is established when the set values are attained in stores 13, 14. When the path deviates from the programmed contour, the tool path velocity is kept constant by modifying the effective path length, stored in the integrator 93, in dependence on a comparison, by a device 12, of the deviation held in the overrun counter 11 and the final path value held in the store 13.