DIGITALLY CONTROLLED ELECTROEROSION MACHINE

• US 3,581,045 A
• Filed: 11/07/1968
• Issued: 05/25/1971
• Est. Priority Date: 11/14/1967
• Status: Expired due to Term

• Current Assignee: Panschow Rudolf, Russbuelt Herbert, Suhr Volker, Werner Ullmann
• Original Assignee: Panschow Rudolf, Russbuelt Herbert, Suhr Volker, Werner Ullmann
• Inventors: PANSCHOW RUDOLF, RUSSBUELT HERBERT, SUHR VOLKER, Ullmann, Werner
• Application Number:
  US04/774,080
• Time in Patent Office: 929 Days
• US Class Current: 219/69.16
• CPC Class Codes: B23H 7/065 Electric circuits specially adapted therefor

Abstract

A program-controlled electroerosion machine is described having a novel numerical control arrangement incorporating a computer interconnected with novel supporting and controlling apparatus. The subject inventive control arrangement operates so as to detect from an information-recording medium a desired travel path of relative movement between the electrode and workpiece and, from such detected information, digital pulses are produced and applied to incremental drive means such as stepping motors to effect the relative movement. The subject invention incorporates the provision of a reverse storage means incorporated to receive the digital drive pulses and store the same in a sequential manner. In the event of a short circuit or other disturbance at the work gap, the novel reverse storage means causes relative movement to be effected in a reverse fashion to retrace the desired path of movement until the disturbance is eliminated. Subsequent thereto, normal forward operation of the control apparatus proceeds.

Claims

1. A program controlled electroerosion machine comprising, in combination:

electrode means;

workpiece means;

incremental drive means for producing a relative movement between said electrode means and said workpiece means in at least one plane; and

means for controlling said incremental drive means including;

an information-recording medium having at least one data block thereon containing information representative of the desired travel path of said relative movement;

reading means for reading said information-recording medium;

computer means;

control means for said computer means, said control means being coupled with said reading means and operating said computer means such that digital drive pulses for said incremental drive means are generated in accordance with said information representative of said desired travel path of said relative movement;

adjustable feed generator means coupled with said control means for varying the frequency of said digital drive pulses, whereby the speed of said relative movement can be regulated;

reverse storage means coupled between said computer means and said incremental drive means for continuously and repetitiously storing a predetermined number of said digital drive pulses in sequential arrangement, said reverse storage means normally passing said digital drive pulses to said incremental drive means in a forward sequential manner, whereby said desired travel path of said relative movement is produced; and

, monitor means responsive to the presence of predetermined conditions at said electrode and workpiece and coupled to said control means and said reverse storage Means for causing said computer means to cease generating said digital drive pulses and for causing said reverse storage means to operate in a reverse direction, said stored digital pulses in said reverse storage means being passed to said incremental drive means in a reverse sequential manner to retrace, in a reverse direction, said desired travel path of said relative movement to eliminate the presence of said predetermined conditions.

2. An electroerosion machine as defined in claim 1, further including means associated with said computer means for causing said computer means to adjust said digital drive pulses as a function of the thickness of said machining electrode and the work gap between said electrode and said workpiece.

3. An electroerosion machine as defined in claim 1, wherein said control means comprises a main control means for receiving information from said reading means relative to the linear characteristic of said desired travel path of relative movement of said electrode and said workpiece, said main control means having two outputs, a first and second secondary control means for curvilinear and linear interpolation respectively, a controllable switching element, one of said outputs of said main control means being directly coupled with said switching element, the other of said outputs of said main control means being connected through said first secondary control means with said switching element, said second secondary control means being connected with said switching element.

4. An electroerosion machine as defined in claim 3, wherein said reading means comprises a buffer storage means for delivering to said computer means information from said information-recording medium relative to the coordinates of said relative movement, an intermediate storage means, and wherein said computer means in association with said control means uncodes said coordinates and delivers said uncoded coordinates into said intermediate storage means.

5. An electroerosion machine as defined in claim 4, wherein said second secondary control means is coupled through said controllable switching means to said adjustable feed generator means and further is coupled to said first secondary control means, said second secondary control means being operably coupled with said computer means for linear interpolation of the coordinates of said desired travel path of relative movement, said second secondary control means carrying out continuous subtraction operations of said coordinates stored in said intermediate storage means.

6. An electroerosion machine as defined in claim 4 further including a fixed-value storage means for storing coordinate values of chords of a unit curvilinear section, said first secondary control means provided for curvilinear interpolation, said main control means, said intermediate storage means, and said fixed-value storage means cooperating to cause said computer means to calculate the coordinates of the curve section of said desired path of travel.

7. An electroerosion machine as defined in claim 6 wherein said first secondary control means is operative to actuate said controllable switching element thereby causing pulses generated by said feed generator means to be coupled with said second secondary control means, said second secondary control means in association with said computer means then converting said coordinates stored in said intermediate storage means by cyclic interpolation into said digital drive pulses applied to said reverse storage means.

8. An electroerosion machine as defined in claim 3, further including circuit means for continuously correcting rounding-off errors of the individual curve sections as occurring in said computer means.

9. An electroerosion machine as defined in claim 3, wherein said reverse storage means is coupled to said adjustable feed generator means, said adjustable feed generator means upon the occurrence of a disturbance at the work gap between said electrode and said workpiece marking a last-writTen storage location in said reverse storage means.

10. An electroerosion machine as defined in claim 9, further including a separate timing clock generator means for delivering pulses to said reverse storage means for controlling the reverse running of said reverse storage means during its return movement from said marked location.

11. An electroerosion machine as defined in claim 10, wherein said separate timing clock generator means has an adjustable clock frequency for the delivered pulses.

12. An electroerosion machine as defined in claim 1, wherein said reverse storage means comprises a ring storage device having a plurality of registers therein, said ring storage device reading out said digital drive pulses stored therein in a reverse sequential manner until either the storage capacity of said ring storage device is reached or until said predetermined conditions at said electrode and said workpiece no longer exist.