JPH0724645A - Wire electric discharge machining device - Google Patents

Abstract

PURPOSE:To improve machining precision by restraining 'corner sagging' at a corner part of a machining route in a wire electric discharge machining device to improve the machining precision at the corner part in the machining route. CONSTITUTION:By controlling relative positions of a wire electrode 60 and a machined article 100 supplied and controlled by a wire control part 6 by a machining route control part 5 in accordance with a machining route, detecting a corner part in this machining route by a corner detection part 3 and sequentially carrying out correction of tangential movement of a specified distance, movement along a corner of the specified distance and gradual return movement by a machining route correction part 4 concerning this detected corner, 'corner sagging' at the corner part is prevented, and machining precision is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire electric discharge machine for cutting and the like, and more particularly to a wire electric discharge machine for improving machining accuracy in a corner portion in a machining path.

[0002]

2. Description of the Related Art Conventionally, there is a wire electric discharge machining apparatus of this type shown in FIG. FIG. 5 is a block diagram of the conventional device. In the figure, the conventional wire electric discharge machining apparatus includes a memory 1 for storing various programs necessary for machining the workpiece 100, a control arithmetic unit 2 for arithmetically controlling the entire apparatus based on the various programs, and the memory 1 described above.
Machining path control unit 5 for performing arithmetic control of machining path based on the machining program among various programs stored in
And a wire controller 6 for automatically supplying the wire electrode 60 to the processing position of the workpiece 100.
A voltage control unit 7 that applies a predetermined potential difference between the wire electrode 60 and the workpiece 100, and a movable table 90 is controlled to move in the X-axis and Y-axis directions based on the processing route of the processing route control unit 5. And an X-Y motor 9 that operates.

The wire control unit 6, voltage control unit 7 and drive control unit 8 all execute various control operations under the control of the control calculation unit 2. Next, the processing operation of the conventional device based on the above configuration will be described. First, the control calculation unit 2 reads out a program start command and an electrode automatic connection command from the memory 1 and instructs the wire control unit 6 to connect and supply the wire electrode 60. Based on this command, the wire control unit 6 supplies the wire electrode 60 between the pulleys 61 and 62 with a predetermined tension and speed.

The machining program stored in the memory 1 is input to the machining path controller 5 to calculate the machining path, and the drive controller 8 drives the XY motor 9 based on the machining path data to move the movable table 90. To move. This XY
By driving a motor, the relative position of the workpiece 100 to the supplied wire electrode 60 is arbitrarily changed. While moving the movable table 90 on which the workpiece 100 is placed, the voltage control unit 7 applies a predetermined voltage to the wire electrode 60 based on a command from the control calculation unit 2 so that the workpiece 100 has a predetermined shape. Electrical discharge machining.

[0005]

Since the conventional wire electric discharge machining apparatus is constructed as described above, moving the workpiece 100 causes a delay in the wire electrode 60 with respect to the machining direction. However, there is a problem that the corner portion of the processing path cannot be accurately processed. That is, as shown in FIGS. 6A and 6B, the wire electrode 60 is “delayed” with respect to the processing direction. Further, as shown in FIG. 6C, an overcut indicated by S1 occurs inside the corner portion in the machining path of the workpiece 100, and an undercut indicated by S2 occurs outside the corner portion. As a result, L1 and
The "corner sag" of L2 occurs, which deteriorates the machining accuracy.

Various methods shown in FIGS. 7A and 7B are conceivable as a wire electric discharge machining apparatus for preventing such "corner sag". In FIG. 7A, the workpiece 100 is machined so as to pass through the original machining path, return in a loop shape, and return to the original machining path again. However, this machining method complicates the machining program, and
A new problem arises in that the workpiece of the workpiece 100 has to be unnecessarily increased in size. Also, FIG.
In (B), the remaining protrusions in the shaded area are formed, and the processing accuracy cannot be improved.

The present invention has been made to solve the above-mentioned problems, and "corner sag" at the corner portion of the machining path.
It is an object of the present invention to provide a wire electric discharge machining apparatus that suppresses as much as possible to improve machining accuracy.

[0008]

A wire electric discharge machining apparatus according to the present invention includes a wire supply controller for automatically connecting or cutting wire electrodes and supplying the connected wire electrodes to a predetermined position of a workpiece. A machining path control unit that relatively moves the supplied wire electrode with respect to the workpiece based on a preset machining path, and a corner detection unit that detects a course portion in the machining path for the workpiece, When a corner portion of the machining path is detected, it deviates from the machining path of the corner portion and is moved tangentially by a predetermined distance in the tangential direction of the machining path, and after the tangential movement of the predetermined distance, a predetermined distance along the corner portion. Of the machining path is performed, the machining path is corrected to be asymptotic to the machining path after the predetermined travel of the predetermined distance, and the corrected machining path is output to the machining path control unit. It is those with a door.

[0009]

In the present invention, the relative position between the wire electrode controlled by the wire supply controller and the workpiece is controlled by the machining path controller based on the machining path, and the corner portion in this machining path is cornered. The corner is detected by the detection unit, and the machining path correction unit sequentially corrects the tangential movement of the predetermined distance, the forward movement of the predetermined distance, and the asymptotic return movement for the detected corner, thereby eliminating the “corner sag” at the corner. Prevents and improves processing accuracy.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a block diagram of the wire electric discharge machine according to this embodiment. In the figure, the wire electric discharge machining apparatus according to this embodiment includes a memory 1, a control calculation unit 2, a machining path control unit 5, a wire control unit 6, a voltage control unit 7 and a drive control unit 8 as in the conventional device. In addition to this configuration, a corner detection unit 3 for detecting a corner portion in a machining path specified by a machining program stored in the memory 1 and a machining program for the detected corner portion are corrected to perform the machining. This is a configuration including a route correction unit 4 for outputting to the route control unit 5.

The path correction unit 4 includes the corner detection unit 3
When a corner portion in the machining path is detected by, the deviation from the detected machining path of the corner portion is moved in the tangential direction by a slight distance h, and after the movement of the minute h, the corner portion is moved to the machining path. along moved by a minute distance l ₁ and performs a correction of the machining route by returning to the machining path by asymptotic to the machining path after the movement of the minute distance l _1, wherein the machining route controlling machining path after the correction Part 8
It is a configuration for outputting to. Next, the processing operation of the apparatus of this embodiment based on the above configuration will be described with reference to FIGS. 2 is a detailed enlarged view of the correction of the machining path, and FIG. 3 is a flowchart of the machining operation.

First, as a pre-processing, the control operation unit 2 is to mount and fix the workpiece 100 on the movable table 90 and to form an initial hole in the processing start region of the workpiece 100.
Reads the preprocessing program from the memory 1, starts the machining operation based on the read program start command, and instructs the wire control unit 6 to connect the wire electrode 60 by the wire electrode automatic connection command. The wire control unit 6 inserts the wire electrode 60 into the initial hole to connect the wire.
Further, the working liquid is supplied by a working liquid supply unit (not shown), and the voltage control unit 7 applies a voltage to the wire electrode 60.

Further, a machining program is read from the memory 1 from the corner detecting unit 3 and the machining line control unit 5, the machining line control unit 5 calculates a machining route specified by the machining program, and drives based on the machining route. The machining program is executed by driving the XY motor through the control 8 (step 1). In the execution state of this machining program, the corner detection unit 3 detects a corner portion in the machining path specified by the machining program (step 2). Also,
The control calculator 2 determines whether or not the processing of this machining program is executed in the correction mode (step 3). The designation of the correction mode can be separately input by an input device (not shown).

When the corner portion is detected in step 2 and the correction mode is determined in step 3, the control calculation portion 2 determines whether or not this machining program is the first machining (step 4). When it is determined in step 4 that this is the first machining, the corner portion is machined by the rough finishing machining path corrected by the machining path correcting portion 4 shown by the solid line in FIG. 2 (step 5).

In this rough finishing, a new bending point P _{1 is obtained} by extending the bending point O of the original processing program by a distance h.
Bending is performed in the direction from the angle θ. Further, the processing is moved from the new bending point P ₁ to the processing point Q ₁ along the processing path (shown by the chain line) of the original processing program by the distance l ₁ . The machining point Q ₁ is asymptotically approached to the machining path of the original machining program (path shown by the chain line) and returned at the machining point R ₁ , and for subsequent straight line machining, the machining operation is executed by the original machining program.

Table 1 shows the ratio of the on-time to the current value and the off-time in each of a to f during the rough finishing.

[Table 1]

When the rough finishing process is completed, the control calculation unit 2 determines whether or not the preset number of times has been completed. When it is determined that the preset number of times has been completed, the machining operation is completed, while the specified number of times is completed. If it is determined that the determination has not been made, the process returns to step 1 (step 6). If it is determined in step 6 that the specified number of times has not been completed, the process returns to step 1 to execute the next intermediate finishing machining program (step 1). Similar to the case of the first rough finishing, whether or not it corresponds to a corner portion (step 2, correction mode or not (step 3), first time or not (step 4), and second time or not) If it is determined that the second semi-finishing process is performed, the semi-finishing process operation is executed (step 8).

In this semi-finishing process, a bending process is performed by extending the bending point O by a distance h ₂ (h ₂ <h) and bending the new bending point P _{2 in} the direction of the angle θ. Further, the machining is moved by a distance l ₁₂ (l ₁₂ <l ₁ ) from the new bending point P ₂ to the machining point Q ₂ along the machining path (indicated by a chain line) of the original machining program. From this processing point Q ₂ to the processing path of the original processing program (line indicated by the chain line), the processing point R
Return in ₂ to return to the original machining program and continue machining. When this intermediate finishing machining operation is completed, it is judged again whether or not the designated number of times has been reached (step 6), and when it is judged that the designated number of times has not been reached, the finishing machining program is returned to step 1 and executed.

As in the case of each of the first rough finishing and the second intermediate finishing, whether it corresponds to a corner portion (step 2), whether it is in the correction mode (step 3), and whether it is the first time It is determined whether or not (step 4) the second time (step 7), and further whether or not the third time (step 7). When it is determined that the finishing process is the third time, the finishing process operation is executed (step 10). This finishing process requires a further distance h ₃ (h ₃ <h ₃
It is extended by h ₂ ) and bent from a new bending point P _{3 in} the direction of the angle θ. Further, the machining is moved from the new bending point P ₃ by a distance l ₁₃ (l ₁₃ <l ₁₂ ) to the machining point Q ₃ along the machining path (indicated by a chain line) of the original machining program. The machining point Q ₃ is asymptotically approached to the machining path of the original machining program (the line shown by the chain line), the machining point R ₃ is restored, and the original machining program is returned to continue machining.

When this finishing operation is completed, it is again judged whether or not the specified number of times has been reached (step 6), and when it is judged that the specified number of times has been reached, the processing program is completed.
When the control calculation unit 2 determines that the machining program being executed in step 3 is not executed in the correction mode, and when it is determined in step 9 that the machining program is not the final cycle, the machining mode of the corner is normally machined. The operation is executed (step 11).

In the correction of the machining program of the corner portion in the above embodiment, each parameter can be set by distinguishing the distances h, h ₂ and h ₃ from the inside corner and the outside corner. In addition, the distances l ₁ , l ₁₂ , and l ₁₃ are set to the corner angle θ.
It can also be set based on. Furthermore, the distances l ₂ , l ₂₂ , l ₂₃ that make the correction path asymptotic to the original processing path.
Can also be set based on the angle θ of the corner portion.
Further, in the above-mentioned embodiment, the machining programs are three types of rough finishing, intermediate finishing and finishing. However, super finishing etc. can be further added, and the processing can be carried out at an arbitrary number of times.

Further, as shown in FIGS. 4A to 4D, the machining path can be corrected. Same figure (A)
In the case of correction of a corner portion where a straight line and a straight line intersect at an angle θ ₁ , in the same figure (B) is shown in the case of correction of a corner portion where a straight line and a circle (radius R) intersect at an angle θ ₂ . C) is a correction of a corner portion where a circle (radius R) and a straight line intersect at an angle θ ₃ , and in the same figure (D), a circle (radius R) and a circle (radius R) intersect at an angle θ ₄ . It may be corrected. In each of the above figures, processing is performed by extending h from the correction intersection, and further, processing is performed by moving a distance l ′ from a new bending point and then corrected so as to gradually approach the original processing path.

[0023]

As described above, according to the present invention, the relative position between the wire electrode controlled by the wire supply controller and the workpiece is controlled by the machining path controller based on the machining path. The corner detecting section detects the inside corner section, and the machining path correcting section sequentially corrects the tangential movement of a predetermined distance, the forward movement of a predetermined distance, and the asymptotic return movement for the detected corner section. This has the effect of preventing "corner sagging" and improving processing accuracy.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a wire electric discharge machine according to an embodiment of the present invention.

FIG. 2 is an enlarged detailed view of correction of a machining path in the apparatus of the embodiment described in FIG.

FIG. 3 is a flowchart of a processing operation in the apparatus of the embodiment shown in FIG.

FIG. 4 is an enlarged detailed view of correction of a machining path of a wire electric discharge machine according to another embodiment of the present invention.

FIG. 5 is a block configuration diagram of a conventional wire electric discharge machine.

FIG. 6 is a processing state diagram for explaining a problem of the conventional apparatus.

FIG. 7 is an explanatory view of a processing route of a conventional device.

[Explanation of symbols]

 1 Memory 2 Control Calculation Section 3 Corner Detection Section 4 Machining Path Correction Section 5 Machining Path Control Section 6 Wire Control Section 7 Voltage Control Section 8 Drive Control Section 9 XY Motor 60 Wire Electrode 61, 62 Pulley 71, 72 Guide Section 90 Movable table 100 Workpiece

Claims (1)

[Claims] 1. A wire electrode is automatically connected or cut,
A wire supply controller that supplies the connected wire electrode to a predetermined position of the workpiece, and a machining path controller that relatively moves the supplied wire electrode with respect to the workpiece based on a preset machining path. A corner detection unit for detecting a corner portion in the machining path for the workpiece; and a corner portion of the machining path that deviates from the machining path of the corner portion and is predetermined in a tangential direction of the machining path. A tangential movement of a distance, a tangential movement of the predetermined distance, a distant movement of a predetermined distance along the corner portion, and a gradual movement of the predetermined distance after the tangential movement of the predetermined distance to correct the machining path. And a machining path correction unit that outputs the corrected machining path to the machining path control unit.