JPS60172420A - Electric discharge machining method - Google Patents

Abstract

PURPOSE:To shorten the time required for machining as well as to improve the accuracy of finishing, by machining a work while giving such feed as leaving the same path as the first one intact to it several times without charging an offset value, and repeating the machining till a working current goes down to the specified value, in case of this electro-discharge machining method. CONSTITUTION:A water working fluid is fed to an opposite gap between a wire electrode 1, traveling between guides 2 and 3, and a work body 4 from a nozzle 9, while discharge is repeated by adding pulse voltage from a power source 11 and thereby electro-discharge machining takes palce. During operation, each of motors 6 and 7 is driven by a numerical control system 8, and feed of the required machining form programed and stored in memory is given to the side of the work body 4 being clamped to a table 5 whereby the work is machined in doing relative feed between the work side and the wire electrode 1. Machining feed in the first cut also is carried out just as the desired machining form, then the machined form is rotated a turn, and first of all, the initial cut takes place, repeating the machining till the working current goes down to the specified value, thus the machining is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an electrical discharge machining method for performing die engraving or wire cutting.

Conventionally, for example, when wire-cutting a die, a finishing allowance is left in advance and the first cut is made, then the offset distance of the same processed shape is gradually reduced, and the cut is made two or three times... The Recand cut method is known to add finishing touches. Furthermore, it is known that when performing die engraving, the electrode and the workpiece are processed in small amounts in a direction perpendicular to the direction in which they face each other.

However, in such fast cutting, if a predetermined (J) is left and the offset amount is changed and machining is performed from 't'K, the amount of electrical discharge machining will vary depending on the location when the workpiece is deformed. This is extremely dangerous as the machining expansion allowance may be partially different.

The machining time after the second time of machining the finishing allowance is also extremely long.

The present invention was proposed in view of these shortcomings, and involves machining while maintaining the same trajectory as the beginning without changing the amount of offset, thereby reducing the machining current or its proportional current to a predetermined value. It is characterized by repeating the kani until the end.

The present invention will be explained below with reference to an embodiment of the drawings.

Figure 1 shows an example of wire cutting, and 1 is wire A.
It has 7 electrodes, is supplied from a reel (not shown), and travels in the direction of the arrow between the lower guides 2 and 3 with a predetermined tension and speed. 4 is a workpiece, which is fixed to a processing table 5, and the table is driven by X-axis and Y-axis motors 6 and 7 to move the shipwreck 1 and 4 relative to the life electrode 1. Send the processed shape! I can do it. 8 will send the processed shape in 19 months! 1 is an NC control device; 9 is a nozzle that supplies machining fluid (ion-exchange treated water) from the top and bottom of the workpiece 4 to the addition section 11; 10 is a nozzle installed coaxially around the nozzle 9;
A jet nozzle that forms a saliva flow curtain, 11 is W~7
This is a machining power source for applying pulsed electricity 11- between the electrode 1 and the workpiece 4 to repeat electric discharge.

At this point, the work rA7 running between guides 2 and 3
A water machining fluid is supplied from a nozzle 9 to the gap between the electrode 1 and the workpiece 4 in the 1 direction, and a pulse voltage is applied from a power source 11 to repeatedly generate electrical discharge for electrical discharge machining. During machining, the motors 6 and 7 are driven by the NC control device 8 (1), and the feed of the required machining shape is determined by 1 gram and stored on the table;
Give it to the side and process it by moving G, 7 relative to the YX7 electrode 1. The machining feed t in the first cut of virgin machining] Required 1!7 J: Feed according to the intended machining shape, rotate the machining shape 1N, and first make the first cut. Next, a second cut is performed with the machining pulse conditions supplied to the machining power supply 11#I being the same and the T energy being decreased by one or more. NC control device 8 at this time
The machining shape feed is set to be equal to the first shape locus, and the machining feed is J. Furthermore, the same shape trajectory was repeated three or four times, and the discharge load was applied without repeating the machining feed. By repeating this process, the machining current gradually decreases, and finally a spark-out state occurs where electric discharge occurs.

Figure 2 shows the above-mentioned [! , 2nd time... This is a graph showing the number of repetitions of machining and the state of decrease in machining current when applying T to the same shape locus. The plate thickness is 10 mm.
The SKD shrine was subjected to a load F using a brass wire with a wire diameter of 0.2 mmφ as an electrode. In the figure, (a) is processed with the power supply voltage constant at 200V each time, and sparks out after 11 times.

Spark out shape accuracy is +0.6μm to -1.1μ
It was m. Also, (mouth) changes the power supply voltage once 11 = 200
v, second time -150V, third time -80V.

4 times [+=60V changed and processed,
The machining accuracy for the fourth time was →-1.2 μm to −1.6 μm.

In the present invention, machining is completed by repeating the machining number of times until the machining current drops to a predetermined value, but of course it is also reasonable to repeat the machining with spark error]~;L in order to improve accuracy.

As described above, in the present invention, the same trajectory of the required target machining shape is repeatedly machined multiple times, and the machining is completed by repeating the machining current dropping to a predetermined value. 1 Ureru J: Sea urchin weight [current is 2nd time compared to 1st time, 3rd time 1-1 current decreases sharply compared to 2nd time [22nd time 3rd time mouth, and further after that] Processing time is short
tits, is this the conventional Afu 1? Compared to the method of making a second cut while changing the cut amount, the processing time is significantly shorter than the method of making a second cut while changing the cut amount.
7. It is possible to reduce the machining current by 1 and avoid completing the machining.

In addition, the present invention is a method in which processing is performed while moving the tape 1f44 other than the wire cutter 1, a method in which the tape 1f44 is processed while moving it to the wire cutter 1, a method in which the tape 1f44 is processed while moving it to the wire cutter 1, and a method in which the tape 1f44 is processed while moving the tape 1f44 other than to the wire cutter 1. A similar effect can be obtained in a method in which machining is performed facing the right-angled XY back surface after Z-axis loading using a machining shape electrode or in a pre-formed machining hole.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an apparatus according to an embodiment of the present invention, and FIG. 2 is a graph diagram of an experiment of the present invention. 1...Wire electrode 2.3...Guide 4...Workpiece 5...Table 6 .7...Motor 8...NG device 9...Machining fluid nozzle 11...Machining power supply Permit applicant 6-

Claims (1)

[Claims] In an electric discharge machining method in which machining is performed by repeatedly applying pulsed discharge while giving a relative machining feed between an electrode and a workpiece, changing the offset amount of the relative machining feed performed between the electrode and the workpiece. An electrical discharge machining method characterized in that the machining current is applied on the same trajectory without any changes, and the machining is repeated a plurality of times until the machining current or its proportional current flowing between the electrode and the workpiece decreases to a predetermined value (if).