JPS58186528A - Wire cut electric discharge machining method - Google Patents

Abstract

PURPOSE:To leave a connection part of machined articles between external male and internal female sides and prevent a drop of the article in the external male side further prevent damage of a machined surface at cutting of said connection part, when a material is cut to a shape of closed contour. CONSTITUTION:A machining start hole PO is provided to one side 1 not used as the product of materials between external male and internal female sides, and a wire is moved from the hole PO to a machining start point A of a closed contour line. Successively, machining is performed along the closed contour line to leave an unmachined distance DELTAS at an end point B, and the wire is moved curving to a machining end point C and then the machining is stopped. In consequence, the distance DELTAS can be correctly held to prevent a drop of the external male side due to an excessive cut, further a sag or the like of the wire at restarting of machining in a connection part is not influenced to a machined surface.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wire cut electric discharge machining method, and more particularly to a wire cut electric discharge machining method in which a material is cut into a closed contour shape based on a cannibal program number and the male side or female side is a machined product. This is related to the processing method.

Traditionally, machining of materials using wire-cut electric discharge machining method is
Most of this is done to cut the material into a closed profile shape and produce a male or female product. However, since the material is cut into a closed contour shape, the male workpiece falls at the same time as processing is completed, and the lower wire guide device may be damaged by the falling workpiece, or even if the lower wire guide device is not damaged, its mounting position may be changed. There was a problem with the shift. Furthermore, the fallen male workpiece itself comes into contact with the wire electrode and becomes of the same polarity as the wire electrode (cathode), causing electrical discharge machining to occur between it and the male workpiece (anode), damaging the machined surface. There was a problem.

In order to avoid problems caused by the male workpiece falling, cut along the closed contour of the material, leaving a distance that allows the male and female workpieces to be connected, and then stop the process and move the male side A jig is installed to prevent the workpiece from falling and the remaining portion is cut. However, when temporarily stopping machining, the S side and slI! What value should be set for the distance ΔS that can maintain the connection of the processed parts of l? It is difficult to stop the machining at the set value, and in some cases, the machining progresses beyond the set value, causing the male workpiece to fall.

Furthermore, when starting reworking the remaining portion, there is a problem in that the width of the cutting groove at the starting point of reworking increases due to slack in the wire or the like. Furthermore, there is a practical problem in that a repetition definition program cannot be used by stopping at a point separated by .DELTA.S on the surface leading to the machining start point.

The object of the present invention is to process the male side and female side along the closed contour shadow line in a wire cut electric discharge machining method in which a material is cut into a closed contour shape based on a cannibal program and the male side or *ii is the machined product. It is possible to perform cutting while leaving the shortest distance that can maintain the connection between the male and female parts, and there is no risk of the male part of the workpiece falling off. To provide a wire-cut electrical discharge machining method that can easily machine a surface that matches the machining surface of the previous stage when cutting a connection maintenance part of a workpiece, and can repeatedly use a defined program until the end.

The wire-cut electric discharge machining method according to the present invention is a wire-cut electric discharge machining method in which a material is cut into a closed contour shape and the male side or female side is a processed product, and a machining start hole is drilled on the side that is not processed into a product by machining the material. and inserting a wire into the pattern hole to start electrical discharge machining, moving the wire from the hole to a processing start point on the closed contour line, and moving the wire from the starting point along the closed contour line,
Before reaching the start point again, connect the machining start hole and the machining start point to the workpiece side where the machining start hole is located, leaving a distance between the start point and the male side and the female workpiece that can maintain the connection. This method is characterized in that the machining is stopped after the refracted movement so as not to approach the machining locus in between.

Hereinafter, the method of the present invention will be explained based on the drawings. FIG. 1 shows an example of a material processed by the method of the present invention. The material is cut into rectangular closed profile shapes into a male workpiece 1 and a female workpiece 2. In addition, the female side processed product 2 is used as a product. Therefore, a machining start hole PO is drilled in the ill that will not be made into a product by machining the material, a wire is inserted into the machining start hole PO to start electrical discharge machining, and the wire is first passed from the hole PO to the machining start point A of the closed contour line. Moving. The material is then cut by moving along the closed contour line. The trajectory of the wire has a width of 2. A groove with a width of u is formed. The wire moves along the closed contour line, leaving an unprocessed distance ΔS at the end point B before reaching the starting point A, and bends the wire regularly toward the male workpiece L side where the processing start hole PO is located, and the processing ends. After moving to point C, processing is stopped. The distance ΔS is the male side processed product 1 and the female side processed product 2
The connection can be maintained over short distances. That is, ΔS
is a short distance that prevents the male workpiece 1 from being cut at a distance of ΔS and falling naturally before the fall prevention means is installed during and after processing.

For a material with a thickness of 20 m, it is sufficient to set ΔS between 0.03 and 0.06 m. Further, the rail after bending from the end point B is made not to approach the machining trajectory between the machining start hole PO and the machining start point person by a distance of 68 or more.

Such wire-cut electrical discharge machining is generally automated based on a cannibal program.

In this way, since the closed contour line is bent without being stopped leaving a distance of ΔS,
The distance ΔS can be maintained accurately. In addition, even if machining is completed during an unattended period such as at night and the machine is left unattended for a long time, the distance ΔS required to maintain the connection between the male and female workpieces is maintained accurately. There is no possibility that the male side workpiece will fall.

In order to cut 68 parts, the required fall prevention treatment is performed between the male and female workpieces, and then the processing is started. Since the wire is moved after being energized at the position of the four wire points C, even if the machining width becomes large at the start of machining due to slack in the wire, there is no problem because it is not within the closed contour line. In addition, since the actual processing distance ΔS is a short distance, for example, 0.03 to 0.06 tomth, this reprocessing can be carried out in a short time.

Next, the principle of the method of the present invention will be explained with reference to FIG. The method of the present invention involves a wire-cut electrical discharge machining method in which a material is cut into a closed contour shape and the male side or female side is processed.
A machining start hole PO is provided on the side that will not be made into a product by machining the material, enters the closed contour line from that point, matches the start point P1 of the machining trajectory of the closed contour shape with the end point, and connects the machining start hole PO and the start point @ Direction with angle θ with respect to Ll (*
L2) is characterized by letting the machining trajectory escape, and during actual machining,
By setting the machining trajectory offset to the west by the length Δl, which is half the wire diameter plus the one-sided discharge gap, the starting point and ending point are offset to points A and B, and the starting point A and ending point B are offset to the west. Gap between machined grooves (distance ΔS)
In this method, the male workpiece is supported and the connection between the male workpiece and the female workpiece is maintained at that point to prevent the male workpiece from falling.

ΔS is roughly expressed by the following formula.

Δd=s−Δl=Δ"11"l) However, S is the distance between the end point B and the line L1, the wire diameter is 0.25 m, and the one-sided discharge gap is Q.
, 935m, Δl =0.125 +0.03
5: 0.16m. As mentioned above, it is possible to maintain the connection between the male side workpiece and the female side workpiece at a distance of ΔS using a material with a thickness of 20 m, that is, the distance is short enough to prevent the male side workpiece from falling. is 0.03 to 0.061111, so from the above formula, ΔS is 0.03 to 0.061111.
In order to do so, θ=36 to 40 degrees.

By setting the offset amount Ml and the angle θ as described above, it is possible to form a gap of the required distance ΔS between the machining start point A and the machining end point B, and to stop the machining. There is no risk of the male workpiece falling after processing is stopped.
Even when the device is reworked with fall prevention means, the remaining connection portion can be quickly cut off without damaging the processed surface of the closed contour portion.

In addition, when processing a material along a closed contour line of a cross-shaped dodecagon as shown in Fig. 3, the processing shape trajectory from point P1 to point P2 is repeated four times, and then point P3 is reached! By shifting this trajectory, the shape repetition definition can be used four times. In the conventional method, it was necessary to stop at point P4 for the fourth and final time after repeating three times to prevent the male workpiece from falling, but it was difficult to perform this stop accurately and it was necessary to rework. There was a problem in that the machined surface near the point P4 was damaged.

The method of the present invention is configured as described above, so that the cutting of the closed contour shape is performed while leaving the minimum distance that can maintain the connection between the male side and the #s@workpiece accurately as designed, and then the machining is stopped. This prevents the male workpiece from falling during and after machining, and there is no damage or damage to the workpiece or the lower wire guide device.In addition, the remaining connection part after taking measures to prevent falling is prevented. Machining K @ allows rapid machining without damaging the machining surface of the closed contour shape part.Furthermore, when method 1 of the present invention is used, it is possible to repeatedly define the shape (macro definition) in the program. ) can be used effectively to the end.

[Brief explanation of drawings]

Fig. 1 is a plan view of an example of a material processed by the method of the present invention, Fig. 2 is an explanatory diagram for calculating the principle of the method of the present invention,
FIG. 3 is an explanatory diagram of an example of a closed contour shape suitable for applying the method of the present invention. 1...Jl & side processed product, 2...Female side processed product, PO・
... Machining start hole, A... Machining start point (on the closed contour line),
B... Machining end point (on the closed contour line), C... Machining end point ΔS... Distance that can maintain the connection between the male and female side workpieces.

Claims (1)

[Claims] In the wire-cut electric discharge machining method in which the material is cut into a closed contour shape and the male side or S* is the processed product, a machining start hole is drilled on the side that is not processed into a product from the machining number of the material, and a wire is inserted into the hole. Start electrical discharge machining, move the wire from the hole to the machining start point of the closed contour line, move the wire from the starting point along the closed contour line, and before reaching the cough start point again, insert a male wire between it and the mirror start point. After machining, the workpiece side with the machining start hole is moved by bending so as not to approach the machining trajectory between the machining start hole and the machining start point, leaving a distance that can maintain the connection between the side and female side workpieces. Wire-cut electrical discharge machining method with a % image of stopping.