GB1323439A - Automatically operating on a workpiece with a cutting or forming tool - Google Patents

Abstract

1323439 Lathes SIEMENS AG 22 Sept 1970 [1 Oct 1969] 45173/70 Addition to 1242760 Heading B3B [Also in Division G3] In a lathe the tool traverse and/or the depth of cut are reduced for as long as the spindle torque, which is dependent on the machining performance, exceeds an upper threshold, infeed up to a maximum of the programmed profile is carried out as long as the torque exceeds a lower threshold, and during each machining cycle at the end of a section of the workpiece, the departure from the programmed profile is compared with the profile programmed for the next machining phase and in dependence on the comparison the next phase is by-passed or corrected. In the turning of a step on a shaft W, Fig. la, F is the final profile, and R is the unmachined stock. One of the first cuts will lie on line a, in which case the value XÁ corresponding to the deviation in the X direction between the programmed profile F and the actual profile will be larger during machining in phase S1 than in phase S2. Phase S2 can therefore be by-passed, and the cut can be made from phase S1 to phase S3. At the start of phase S3 deviation XÁ is reduced by the value Xe. When subsequently machining along line b, XÁ is smaller than the contour change in phase S2 and therefore this phase cannot be by-passed, but instead the value supplied to the control in this phase must be reduced by the amount of deviation XÁ. In the same way the deviation must be taken into account when machining a taper, Fig. 1b (not shown), or a circular arc, Fig. 1c (not shown). Fig. 2 illustrates a computer circuit for executing the requisite calculations. In the overflow store 1 of the series type the value XÁ is stored, which corresponds to the deviation between the programmed and the actual profiles. In a terminal value store 2 the value Xe corresponding to the increase in the co-ordinate in the X direction in the next stage is stored. Each of these stores is preceded by an adder 5, 6, respectively. Both stores are connected to a comparison computer circuit 4, and to a computer logic system 3. If the interpolation of phase S1 has been completed, a comparison is carried out between deviation XÁ at the end of the first phase and co-ordinate change Xe in phase S2. Depending upon whether XÁ is smaller or larger than Xe commands are issued by the logic system. Considering the broken line in Figs. 1a and 2, XÁ is larger than Xe, Xe in store 2 is subtracted from XÁ in store 1, and the value in store 2 reduced to zero. Several phases may be by-passed, or a check on the phases may be carried out only after several phases have been carried out.