JPH0639860Y2 - Wire electric discharge machine - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a wire electric discharge machine, in particular, the centering for determining the center position of an opening made in a workpiece is moved relative to the workpiece and the wire electrode. In this case, it is possible to prevent the upper nozzle, the lower arm, and the like from mechanically interfering with the workpiece by moving beyond the allowable movement range.

"Prior Art" In a wire electric discharge machine, what is called centering is performed by moving a wire electrode and a workpiece relative to each other and detecting contact or proximity between them as described above. 55-31529.

The centering of the aperture through the wire electrode as described above is
A voltage is applied between both electrodes of the wire electrode and the workpiece, an electrical short circuit due to contact between the two is detected, and the opposing positions of the opening in the X-axis direction and the Y-axis direction are measured. The center position of the opening is calculated.

[Problems to be solved by the device] However, some wire electrodes are made of brass wire coated with zinc, and are easily oxidized, and the ultra-thin film formed on the detection surface of the workpiece, jig, gauge, etc. The passivation layer and the oxide film may make it impossible to detect the electrical short circuit and the discharge phenomenon due to the application of a minute voltage. In this case, the relative movement of the wire electrode w and the workpiece c, etc. is continued to cause slot talk over, and as shown in FIG. 8, the upper and lower wire electrode guide portions a and b have a stepped workpiece c or , A jig or a fixture such as a work piece or a gauge is damaged by causing mechanical interference, or when a movable work piece mounting base e is used, the mounting base e and the lower wire electrode guide portion are used. There is a problem that b is mechanically interfered with and damaged.

The present invention has been made for the purpose of solving this problem.

[Means for Solving the Problem] A specific means for achieving the above-mentioned object is to pass a wire electrode stretched by two wire electrode guides sandwiching a workpiece through an opening formed in the workpiece. At the same time, the wire electrode and the workpiece are moved by the relative moving means, and a minute voltage is applied between both electrodes of the wire electrode and the workpiece to detect an electrical short circuit due to contact between them or a discharge phenomenon due to proximity. Then, in the wire electric discharge machine in which the facing position of the opening in the X-axis direction and the Y-axis direction is measured, and the center position of the opening is calculated by the average value thereof, the wire electrode and the workpiece are Area setting means for setting the relative movable permissible area in the area including the opening, deviation detecting means for detecting deviation from the area, and movement stop hand for stopping the relative movement by the detection signal. It is characterized by having a step.

[Operation] According to the specific means, as a permissible region in which the wire electrode and the workpiece can move relative to each other through the hole of the workpiece,
As shown in FIG. 1, the area including the opening is set by the area setting means, and the deviation detecting means for comparing the set value with the moving position of the relative moving means detects the deviation outside the setting area. Then, the movement stopping means that receives the detection signal stops the movement of the relative moving means.

"Embodiment" An embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 2 is a perspective view showing a schematic configuration of a wire electric discharge machine.

The table 2 on which the workpiece 1 is placed and fixed is guided by a guide structure (not shown) and is movable in a horizontal plane. The table 2 is moved relative to the wire electrode 11 by the X-axis servo motor 3 and the Y-axis servo motor 4. The movement position is detected by the X-axis and Y-axis position detectors 5 and 6 mounted on the X-axis and Y-axis servomotors 3 and 4. A rotary encoder is used for the X-axis and Y-axis position detectors 5 and 6.

In addition, the wire electrode 11 is guided by die-shaped wire guides 12 and 13 arranged vertically. Upper wire guide 1
2 is attached to the slider 14. The slider 14 is guided by a guide structure of a slider base 15 and is movable in a horizontal U, V plane, and the movement is performed by a U-axis servomotor 16
And V-axis servomotor 17 controls. The U-axis and V-axis servomotors 16 and 17 are equipped with U-axis and V-axis position detectors 18 and 19 for detecting movement positions in the U-axis and V-axis directions.
The position detectors 18 and 19 use rotary encoders. The lower wire guide 13 is supported by a support arm 20 protruding from a wire electric discharge machine body (not shown). The upper and lower wire guides 12, 13 are integrally provided with nozzles 24, 25 for injecting a working fluid. Upper and lower nozzles 2
4, 25 respectively inject a machining liquid in the axial direction of the wire electrode 11 to create a strong machining liquid flow in the machining gap 7. The power supply 26 is slidably contacted with the wire electrode 11, and a pulsed voltage is applied from a power supply device (not shown). Electric discharge is generated between the wire electrode 11 and the workpiece 1 by this pulsed voltage to perform wire electric discharge machining.

In addition, 27 is an upper guide roller, and 28 is a lower guide roller, which guides the wire electrode 11 fed by applying a constant tension.

The feeding and winding mechanism of the wire electrode 11 is not included in the scope of the present invention, and thus the description thereof is omitted.

FIG. 3 is a schematic block diagram showing the configuration of the present invention.

The processor unit (CPU) 30 has various memories (ROM, R
AM) 31 and 32, a keyboard 33 as an input means for inputting data, setting various detection modes and relative movement allowable areas, and a CRT display 34 as a display means for displaying an undetectable warning and various other displays. Are connected. Further, X-axis and Y-axis drivers 35, 36 for driving the X-axis and Y-axis servomotors 3, 4 for moving the table 2 move the slider 14 via the X-axis, Y-axis controllers 37, 38 and U. The U-axis and V-axis drivers 49 and 50 for driving the axis and V-axis servomotors 16 and 17 are similarly connected to the processor unit 30 via the U-axis and V-axis controllers 51 and 52, respectively. X, Y
The position detectors 5, 6 and 18, 19 for the axes and the U and V axes are connected to the axis controllers 37, 38 and 51, 52 and feed back the respective detection signals. The processor unit
A detection circuit 53 for detecting and controlling the processing reference position or posture of the stretched wire electrode 11 is connected to 30. To the detection circuit 53, the power supply 26 for slidingly contacting the wire electrode 11 to apply a voltage and the workpiece 1 are connected, and an electrical short circuit or a discharge phenomenon during detection control is detected. The processor unit 30, the various memories 31, 32, etc. may be stored in a numerical control device that controls the entire wire electric discharge machine as a whole, or as a single unit with a processor unit on the processing machine side by a data bus or the like. It may be configured to be connected.

Based on the above configuration, the reference hole h drilled in the workpiece 1
The processing procedure of the present invention when performing the centering for obtaining the center position will be described with reference to the flowchart of FIG.

First, in step S101 (the following steps will be omitted), when the program is started, in S102, the centering mode is selected from the detection modes such as centering, end surface positioning, vertical positioning, and guide span calibration.

In S103, the current position of the wire electrode 11 with respect to the table 2, that is, the centering start position is stored as an initial position, and in the subsequent S104, a detectable movement allowable area is input using the keyboard 33 in correspondence with the initial position. Set.

The detectable movement-allowed area is a circular area centered on the initial position ((a) in the figure) as shown in FIG.
It may be a rectangular area surrounding the initial position ((b) in the figure), but in any case, the area includes the reference hole h, and the upper and lower wire guides 12 and 13 and the support arm 20 form the workpiece. Is set within a range that does not cause mechanical interference with a fixture or the like for fixing a jig or the like. The setting is performed by inputting the radius R in the case of a circular area and the X and Y coordinate values in the case of a rectangular area using the keyboard 33.

Subsequently, 1 is set to item i in S105, and the process proceeds to S106, in which the table 2 drives the X-axis or Y-axis servomotors 3 and 4 according to the set value number of item i to start the movement. For example, when i = 1, the direction is the X-axis (+) direction, when i = 2, the direction is the X-axis (−) direction, when i = 3, the direction is the Y-axis (+) direction, and when i = 4, the Y-axis (−) direction. Move in the direction. The moving position of the table 2 is X, which detects the moving amount.
It is detected by Y-axis position detectors 5 and 6. In S107, monitoring of whether or not the movement position of the table 2 is included in the detectable movement allowable region set in S104 based on this detection value is continued until the hole wall of the reference hole h is detected in S108.

When the hole wall of the reference hole h is detected in S108, the movement of the table 2 is stopped (S109), and the stop position P _{1 is set} to the position detector 5,
The detected value of 6 is detected and stored in the memory (RAM) 32 (S110). Then, in S111 and S112, since item i = 1, the process proceeds to S113 to increment item i,
Returning to S106, the steps from S106 onward are repeated as described above. At this time, since item i = 2, the table 2 is moved in the X axis (-) direction from the position P ₁ stopped in S109, and S108 is set.
The detection position P ₂ of the hole wall is stored in each step of to S110. S1
In item 10, since item i = 2, the process proceeds to S114, and the table 2 is returned to the midpoint of the detection positions P ₂ and P ₁ . Below item i
= 3, the table 2 is moved in the Y-axis (+) direction from the midpoint position of P ₂ and P ₁ to detect the hole wall, the detected position P ₃ is stored, and at i = 4, the Y-axis ( -) move in the direction to detect the hole wall stores the detection position P _4, the program proceeds to S114
P _4, returning the table 2 to the midpoint of P _3. Since this movement is performed on a straight line orthogonal to the midpoint in the X-axis direction, the detection position P ₄ ,
By the movement of P _{3 to} the midpoint, the wire electrode 11 is finally positioned at the center position of the reference hole h. The locus of relative movement between the table 2 and the wire electrode 11 is as shown in FIG. In addition, the hole wall detection is performed by a wire electrode to which a minute voltage is applied.
This is performed by detecting an electrical short circuit due to contact between 11 and the hole wall h, or a minute discharge phenomenon due to proximity.

When the boundary of the movement permissible area is detected during the movement of each of the items i = 1 to 4 (NO in S107), the flow proceeds to S115 to stop the movement of the table 2, and subsequently the warning display is performed in S116 with the CRT.
The display 34 is used.

In the description of the above embodiment, the case of centering has been described, but the detectable movement allowable area in the case of performing the end surface setting is performed by a circular area or a rectangular area (FIGS. 7A and 7B). )reference). In any case, it is needless to say that it is necessary to include the workpiece or the detection end face of the gauge in the area and not to cause the above-mentioned mechanical interference in the area.

Especially when performing vertical alignment and calibration of the guide span,
Since it is necessary to fix a pair of gauges g whose detection end faces are vertically aligned correctly to the table 2 and to move not only the table 2 but also the slider 14 to adjust the position of the upper wire guide 12, X, Y Set each movement allowable area of the U-axis and U-axis. In this case, the movement in each axial direction may be monitored by setting the overlapping portion of both areas as the movement permitted area, or the movement in the X, Y axis, U, V axis direction may be monitored for each movement permitted area. .

Note that each detection method is already known, and the warning display when the boundary of the movement-allowed area is detected is the same as in the case of centering in the above-described embodiment, and therefore description thereof will be omitted.

[Advantage of the Invention] As has been clarified in the description of the concrete means and action, the present invention provides the above-mentioned opening as a permissible area in which the wire electrode and the workpiece can move relative to each other through the opening of the workpiece. An area including the hole is set by the area setting means, and when the deviation detecting means for comparing the set value with the moving position of the relative moving means detects the deviation from the outside of the setting area, the movement receiving the detection signal is performed. Since the movement of the relative moving means is stopped by the stopping means, it is possible to avoid damage to the nozzle or the like due to mechanical interference even when an electrical short circuit or a discharge phenomenon is not detected when performing centering. .

[Brief description of drawings]

FIG. 1 is a block diagram showing a functional configuration of the present invention, FIG. 2 is a perspective view showing a schematic configuration of the present invention, FIG. 3 is a block diagram thereof, and FIG. FIG. 7 is a flow chart showing a centering process, FIG. 5 is an explanatory view illustrating a moving region, FIG. 6 is an explanatory view showing a relative movement locus of the table 2 and the wire electrode 11 in the case of centering, and a seventh. FIG. 8 is an explanatory view for explaining the movement allowance region in the case of end face protrusion, vertical protrusion and guide span calibration, and FIG. 8 is a sectional view for explaining the inconvenience of the conventional device. 1 ... Workpiece, 2 ... Table, 3 ... X-axis servo motor, 4 ... Y-axis servo motor, 5 ... X-axis position detector,
6 …… Y-axis position detector, 11 …… Wire electrode, 12,13 ……
Wire guide, 16 ... U-axis servo motor, 17 ... V-axis servo motor, 18 ... U-axis position detector, 19 ... V-axis position detector, 30 ... CPU, 33 ... keyboard.

Claims (1)

[Scope of utility model registration request] 1. A wire electrode stretched by two wire electrode guides sandwiching a work piece is passed through an opening formed in the work piece, and the wire electrode and the work piece are moved by relative movement means. At the same time, a minute voltage is applied between both electrodes of the wire electrode and the workpiece to detect an electrical short circuit due to contact between the two and a discharge phenomenon due to proximity, and the opening is opposed in the X-axis direction and the Y-axis direction. In the wire electric discharge machine which measures the position and calculates the center position of the opening by the average value thereof, the relative movable permissible area between the wire electrode and the workpiece is set to the area including the opening. A wire electric discharge machine comprising: an area setting means for setting, a deviation detecting means for detecting a deviation from the area, and a movement stopping means for stopping the relative movement by a detection signal thereof.