Patent GB-1182749-A (GB)
Title: Improvements in or relating to Electro-Erosion
IPC: B23H7/06
Filed: 1968-02-09
Abstract: 1,182,749. Programmed control. INDUSTRIELLE ELEKTRONIK AGIE LOSONE BEI LOCARNO, A. G. FUR. Feb.9, 1968 [NOV. 14, 1967], No.6670/68. Heading G3N. An electro-erosion machine of the spark or electrolytic type is programme controlled by a digital system comprising a main programme unit 23 and subroutine stores 24, 29 the latter being coupled by a gate 28 with a backward store 30 for receiving feed advance pulses formed in co-operation with a computer 26 and the main unit 23 and at least one substore 24, 29, backward store 30 being connected to stepping motors 33 for the relative displacement between at least one electrode holder and a work-table in coordinate planes, and a feed advance generator 27 connected to the gate 28 and backward store 30 having an adjustable timing frequency regulating the speed of the electrode displacement. A device 34 corrects relative movement in dependence upon the thickness of the electrode and or work gap. The programme control circuit is activated by push button on a panel 20 causing a first block of information to be run into a reading device 21 which information may be recorded on punched tape, punched card, magnetic tape, photographic film, or derived from a teleprinter system and include symbols indicating the form of curves required. When the first block had been received a programme start push button is operated and the first block is transferred into a buffer store 21a. At the same time a pulse generator 22 is started, and main unit 23 is released which receives symbols from store 21a which also transmits co-ordinate data to a computer 26 which recodes this in machine language which is forwarded to an intermediate store 26a. At this point main unit 23 reactivates the reading device 21 to accept the next block of information. If the symbol is of one type main unit 23 opens gate 28 which also receives pulses from generator 27 the frequency of which may be varied by a potentiometer P or a supervisory device 32 responsive to an error signal dependent on say electrode current or voltage. The output pulses from gate 28 pass through a substore 29 which are transmitted to the computer 26 which calculates the method of interpolation and passes information in through a backward store 30 to the stepping motors 33. When the intermediate store 26a is exhausted, a signal through a conductor 261 and main unit 23 closes gate 28 and activates buffer store 21a so that the next block of information is passed forward. The backward store 30 is a ring counter and if for example a blockage should occur in the work gap or for other reason the electrode is required to be reversed in direction, either by a signal from device 32 or from a push button, store 30 runs backwards under the control of a generator 31 until the information stored at 30 is exhausted, the start and finish of such backward movement being recorded, and the electrode will be tracked along the same path as traversed in its forward movement. Closure of another push button switch moves the electrode forward again to its previously stopped position. Store 30 is arranged so that when it has reached its capacity the locations first occupied can be erased. The substore 29 may be used for example for linear co-ordinate movement and substore 24 for parabolas or other curved paths, stores 24, 29 being activated as appropriate by store 23. The arrangement may control a number of machines performing identical tasks or a number of machines performing different tasks parts of the control arrangement being used on a time division basis. Each machine may have one or more electrodes of the same or differing diameters and one or more workpieces. A trace may also be made for example on paper of the relative electrode movement through say a pantagraph coupled with the electrode or work-table or a drawing machine which receives the same signals as the stepping motors 33. Methods of interpolation and for deriving corresponding co-ordinates are given in the Specification. Information may be fed into the system by means of a keyboard teleprinter a microphone, character reader, or contact reading device, or by picture scanning by means of a Braun tube.