GB2236410A

GB2236410A - Numerically controlled machining

Info

Publication number: GB2236410A
Application number: GB9017740A
Authority: GB
Inventors: Yasunori Ono
Original assignee: Amada Wasino Co Ltd
Current assignee: Amada Wasino Co Ltd
Priority date: 1989-08-17
Filing date: 1990-08-14
Publication date: 1991-04-03
Also published as: GB9017740D0; FR2650971A1; IT1242524B; IT9021283A0; JPH0379229A; KR910004284A; DE4026122A1; IT9021283A1; JP3084385B2

Abstract

A numerical control device for a wire electro-discharge machining apparatus comprises a data processing unit 12 for reading and carrying out a numerical control program me which includes a plurality of instructions for a first machining stage and for a second machining stage. The data processing unit carries out the instructions of the control programme in the order that they are written if the automatic wire feeding device 13 of the apparatus is functioning normally. If the wire feeding device 13 malfunctions, data processing unit 12 first carries out the instructions in a first block of the control programme controlling the first machining stage, while performing the machining operation; secondly it carries out these instructions again but in reverse order and without performing the machining operation; thirdly it jumps to the beginning of a second block of instructions for the second machining stage; and fourthly it carries out the instructions relating to the second machining stage. <IMAGE>

Description

TITLE OF THE INVENTION

Numerical control device for a wire electric discharge machine BACKGROUND OF THE INVENTION

Field of the invention

The present invention relates to a numerical control device for a wire electric discharge machine.

Description ofthe Prior Art

In recent years it has become a common practice to restrict the processing energy and change the offset for a wire dimension, and to utilize multiprocessIng methods in which a process Is repeated two or three times, in order to improve the processing precision of a numerical control (NC) wire electric discharge machine. When using an automatic multiprocessing method for an NC wire electric discharge machine with an automatic wire feedIng device, the first process is completed and the wire electrode automatically cut. Then, after returning to the starting point. the wire electrode is automatically fed, and, after the processing conditions and the offset have been automatically changed, the second process is commenced. The subsequent process procedures are also performed in the same manner.

On the other hand, with automatic multiprocessing in an electric discharge machine which Is not equipped with the abovementioned wire feed device, when the first process has been completed, the machine is returned to the starting point. with the electric discharge halted, by retracing the locus of the completed process. Then, After the processing conditions and the offset have been automatically changed the second process is commenced.

Even In an electric discharge machine which is equipped with an automatic wire feed device, In the case where automatic feed of the wire electrode is difficult because the starting hole is small, the wire electrode being used is very fine, the workpiece Is very thick, and the like, and also in the case where the automatic wire feed device breaks down, automatic multiprocessing Is carried out by retracing the locus of the completed process to return to the-starting poit as explained above.

In the type of automatic multiprocessing described in the foregoing explanation. there is a great difference in the way way of moving the wire electrode with respect to a workpiece, according to whether or hot an automatic wire feed device is used. It is therefore necessary for the operator to make modifications on each occasion to ensure that the NC program operates according to the desired procedures. In particular, the drawing up of an NC program which returns to the starting point by retracing the locus of the completed process Is an operation of the same level of difficulty as drawing up a program for the forward direction. This is a heavy load on the person who draws up the program.

SUITMARY OF THE INVENTION An object of the present invention Is to provide, with due consideration to.the drawbacks of such conventional systems, a NC device for the wire electric discharge machine, by which automatic multiprocessing can easily be performed by means of a single numerical control program no matter whether the automatic wire feed device is used or not.

This object is achieved in the present invention by the provisioning of a numerical control device for a wire electro-dischage machining apparatus that Is equipped with an automatic wire feed device, comprising: a data processing unit for reading and carrying out a numerical control program Including a plurality of instruction data for a first stage machining and for a second stage machining; a switch for the automatic wire feed device, which switch Inputs into the data processing unit a signal about whether or not the auto;natic wire feed device is used; and wherein when receiving a signal indicating that the automatic wire feed device is used. the data processing unit read and carry out the Instructions of the numerical control program In the order In which It Is Input thereinto, and when receiving a signal indicating that the automatic wire feed device is not used. the data processing unit read and carry out the Instructions of the control program In a manner such that it first read and carry out the Instructions of the control program from a first block of the control program to a block at the end of the first stage machining, while performing machining operation, it second read and carry out the instructions of the control program from the block at the end of the first stage. machining to a block located substantially at the beginning of the control program, without performing machining operation, third it jumps from the block located substantially at the beginning of the control program to the block at the beginning of instructions for the second machining stage. and forth it read and carry out the Instructions 'of the control program from the begInnIng of the second machining stage to the end thereof.

With such device, when an automatic wl-re feed device is used, each time one process is completed, the wire electrode is cut and connected at the starting point by means of the automatic wire feed device. the offset and processing conditions are set anew, and Multiprocessing is performed. In the case where the automatic wire feed device Is not used. each time one process is completed, the wire electrode is returned to the starting point. retracing the locus of the process which has just been completed, the offset and processing conditions are set, and multiprocessing is performed.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects, features, and advantages of the present invention will become more apparent from the following description of the preferred embodiments taken in conjunction with the accompanying drawings. in which:

Fig. 1 is a block diagram showing an embodiment of a numerical control device In accordance with the present invention.

Fig. 2 is an explanatory drawing showing a path of a wire electrode with respect to a workpiece for.processing a square pattern In the workpiece. Here. SP is the abbreviation for a starting point.

Fi,,, 3 is a flowchart for performing a machining of the pattern shown in rig. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to Fig. 1. an embodiment of the NC device for the wire machining apparatus in accordance with the present Invention, comprises an input unit 11. a data processing unit 12. and a switch for an automatic wire feeding device 13 (referred to as "an automatic wire feeding device switch" hereinafter). The wire machining apparatus is equipped with an automatic wire feeding device (not shown).

The input unit 11 is for inputting a NC program containing a plurality of instructions. An example of the program is as follows:- Block Code Comment Number N001 M64 automatic wire feed N002 G92 X 0 Y 0 creation of coordinate N003 M80 t start of machining N004 G42 D01 + offset of D01 NOOS G01 X 0 Y 5 N006 G01 X 5 Y 0 N007 G01 X 0 Y -10 1,c- deflnir,Lon of primary machinIng pattern NOOS G01 X -10 Y 0 N009 G01 X 0 Y 10 N010 G01 X 5 Y 0 N011 M63 cut of wlre N01-2 M90 mark of multiple machining N013 GOO X 0 Y -5 N014 G40 N015 M66 autoraazic wire feed N016 G92 Y 0 crear-lon of coordinaTe N017 1,1180 srart of machining N018 G4,) D 02' offset of D02 2 N019 G01 X 0 Y 5 N020 GOI X 5 Y 0 N021 G0.1 X 0 Y -10 definition of secondary, machining pattern N022 G01 X -10 Y 0 N023 GOI X 0 Y 10 N024 G01 X 5 Y 0 N025 M63 cut of wire -5 i- mark of multiple N026 M90 machining N027 G01 X 0 Y -5 N028 G40 N029 M68 automatic wire feed N030 G92 X 0 Y 0 creation of coordinate N031 M80 4. start of machining N032 G42 D03 offset of D03 N033 GOI X 0 Y 5 N034 G01 X 5 Y 0 N035 G01 X 0 Y, -10 defining of third machining pattern N036 GOI X -10 Y 0 N 031 7 G01 X 0 Y 10 N038 G01 X 5 Y 0 N039 M03 cut of wire N040 G01 X 0 Y -5 N041 G40 N042 M100 i- end of pattern machinin N043 NO2 + end of program This NC program is for machining a pattern shown in Fig. 2 in three-stage multiple machining method: and the instructions from the block number N001 to L-he blocknumber N011 (the block number being simply re-fered to as "ijk" such as "001" or "Oll" hereinafter) are for a first stage 4 nint_) J_, L-he instructions from machinini- (rouerh mach 121 C 7-15 LjL.i block number 013 to the block number 025 are for a second stage machining (finish machining), and the instructions from the block number 027 to block number 041 are for a third stage machining (further finishing machining).

The automatic wire feeding device switch 13 is for energizing or disenergizing the automatic wire feeding device.

The data processing unit 12 reads and process the NC program input Into the Input unit 11. Specifically, when the wire feeding device switch 13 is turned on, since the wire feeding device is energized, the data processing unit 12 read and process the NC program as it is (i.e. in order of the block number and without any change). on the other hand, when the switch 13 is turned off, since the wire feeding device is disenergized, during the procession of the Instructions of the NC program. once it reaches the M90 code, which is a marking of the multiple machining operation. it stores the block number procession of the instructions and stores the block number 012 where the code M90 is located. Then. it starts to read reversely the instructions jiist read from the block 011 to the block 002 where the code G92 indicating the start of the operations is located. without performing discharginR. When it reaches the block 002 of the code M90, then It jumps to the block 013 next to the block 012 cl, the code 1M90 that has been stored previously. It then performs normal reading and procession of the instructions of the programs. This procedure Is summarized as follows:

NOO1 processing the instructlons in order of the J1 block number from the block N'001 to the biock N002 1X. 0 12 1 N012 N011 processing the instructions in inverse order of the block number from the block 012 to block 002 N002 11 Jump from the block 002 to the bloCk 013 N013 46 N014 processing the instructions in order of the 1 block number Thus, with this embodiment of the present invention, machining operatIon with use of the wire feed device and without use of the wire feed device can be perform by use of a single NC program.

The above mentioned code M90 can be added in the NC program by use of the automatic program preparing device.

Now referring to Fig. 1, this figure is an explanatory flowchart showing the operation of the embodiment of the present invention. This flowchart is used in the case where the offset and operating conditions are set or changed for a square hole in a flat plate. as illustrated in Fig. 2, and a three-stage multiprocess is performed accordin,g to the utilization or nonutilization of an automatic wire feed device.

First. a determination is made In Step 1(hereinafter referred to as S1) as to whether or not an automatic wire feed device is used. If the decision is made thar the automatic wIre feed device is being used, a wire electrode is automatically connected at a starting point, in S-9. If the automatic wire feed device is not being used. the wire elecrrode is connected manually au ihe starting point in S3. In S4, an offset and operating conditions such as power supply and the like are set for a first process, and this first process is performed in the dIrection of the arrows in Fig. 2. The starting point SP is taken as the origin of the X and Y axes.

Mien the first process has been completed a.check Is made in S5 to see whether or not the automatic wire feed device Is being used. If the automatic wire feed device is being used, in SO the wire electrode is cut and the device Is returned to the starting point SP where the wire electrode is automatically reconnected. If the automatic wire feed device is not being used. in S7 the device is returned to the starting point SP, retracing the locus of the completed first process. In 58. the offset and operating conditions such as power supply and the like are set for a second process. and this second process is performed, following the pattern in the same manner as outlined above. - 4 When the second process has been completed a cheek is made In 59 to see whether or not the automatic wire feed device is being used. If the automatic wire feed device is being used, in S10 the wire electrode is cut and the device is returned to the starting point SP where the wire electrode is automatically reconnected. If the automatic wire feed device is not being used, In S11 the device is returned to the starting point SP, retracing the locus of the completed second process. In S12. the offset, and operating conditions such as power supply and the like, are set for a third process, and this third process is performed following the pattern in the same manner as outlined above. When this process has been completed the three-stage multiprocess is terminated.

AS can be clearly understood from the foregoing explanation, a multiprocess can be performed automatically by the method ' of thepresent invention according to specified procedures to cope with the utilization or nonutllization of an automatic wire feed device. Accordingly. modification of the NC program, as performed in conventional methods, Is unnecessary in-the present invention. This reduces the load on the operator, and the problem of errors and the like in changing the program is -g- 1.

1. 1 16 r also reauced.

i

Claims

WHAT IS CLAIMED IS:

1.. A numerical control device for a wire electro-dischage machining apparatus that is equipped with an automatic wire feed device. comprising: a data processing unit for reading and carrying out a numerical control program, which includes a plurality of instruction data for a first stage machining and for a second stage machining; a switch means for inputting into the data processing unit a signal Indicating whether or not the automatic wire feed device is used; and wherein the data processing unit read and carry out the instructions of the numerical control program in the order in which it is input thereinto when receiving a signal indicating that the automatic wire feed device Is used, and when receiving a signal indicating that the automatic wire feed device Is not used, the data processing unit read and carry out the instructions of the control program In a manner such that first It read and carry out the instructions of the control program from the first block of the control program to a block at the end of the first stage machining. while performing machining operation, second It read and carry out the instructions of the control program from the block at the end of the first stage machining to a block located substantially at the beginning of the control program, without performing machining operation. third it jumps from the block located substantially at the,beglnning of the control program to a block at the beginning of instructions for the second machining stage. and forth it read and carry out the instructions of the control program from the beginning of the second machining stage to the end thereof.

2. A numerical control device for a wire electro-dischage machining apparatus, comprising; a data processing unit for reading and carrying out a numerical control program which includes a plurality of instruction data for a first stage machining and for a second stage machining; wherein the data processing unit read and carry out the instructions of the control program in a manner such that first it read and carry out the instructions of the control program from the first block of the control program to a block at the end of the first stage machining, while performing machining operatio. second It read and carry out the instructions of the control program from the block at the end of the first stage machining to a bloclc located substantially at the beginning of the control program. without performing machining operation. third it jumps from the block located substantially at the beginning of the control program to a block at the beginning of instruerions for the second machining stage, and forzh It read and carry out the instructions of the control program, from the be,-,innin,-,, of the second machining stage to the end thereof.

3. A numerical control device, substantially as hereinbefore described with reference to the accompanying drawings.

4. An- novel feature or combination of here-in.

-12 t_ Published 1991 atThe Patent Office. State House. 66171 High Holborn. London WC1R4TP. Further copies may be obtained from Sales Branch. Unit 6, Nine Mile Ploint. Cwmfelinfach. Cross Keys. N. NPI 7HZ. Printed by Multiplex techniques lid. St Mary Cray, Kent.