JPH01216725A - Method for controlling wire electric discharge machine - Google Patents

Abstract

PURPOSE:To reduce the breakage of a wire electrode and stably carry out electric discharge machining with high accuracy by calculating the optimum machining condition from the signal of an in-process board thickness detecting means and outputting a signal corresponding to this calculated optimum machining condition to each control portion of a wire electric discharge machine. CONSTITUTION:The absolute positions of wire supporting mechanisms 5, 9 placed in the vicinities of the upper/lower faces of a workpiece 1 are detected by encoders 8, 12 and the relative values between these wire supporting mechanisms 5, 9 are processed by a CPU 15 to calculate the board thickness of the workpiece 1. The CPU 15 reads the optimum machining conditions such as the calculated board thickness signal, the electric conditions of the optimum discharging voltage and current, etc., and a machining feeding speed, etc., suited to the material of the workpiece inputted by an input means 17 from a memory device 16. A signal corresponding to this optimum machining condition is outputted to each control portion of a wire electric discharge machine, to reduce the breakage of a wire electrode and carry out a stable electric discharge machining with high speed and high accuracy.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is applicable to the shape of a workpiece in a wire electrical discharge machine for efficiently and highly accurate machining of workpieces with changes in thickness. It concerns an adaptive control method.

(Prior Art) Conventionally, as a technique for machining workpieces with changes in plate thickness using a wire electrical discharge machine, there is Japanese Patent Application Laid-Open No. 62-10920. Child table 2
A workpiece 51 was fixed to the holder, and a nozzle 53 was attached to the tip. The sensor tip 5 is attached to the wire support device 54 on the Z axis.
A height sensor 55 with 6 is installed.

In the above configuration, the XY child table is moved by an XY control program, and the Z coordinate value for the XYu mark is input to the control device and stored.

(At this time, fix the Z axis so that it does not move.) Next, remove the sensor 55, stretch a wire between the upper and lower nozzles, and execute the xY control program. Corresponding to the position of Z
It outputs to the shaft and is controlled so that the gap between the workpiece 51 and the nozzle 53 is always kept constant.

(Problems to be Solved by the Invention) In the conventional technique, the XY@ control program is executed before wire electrical discharge machining work is performed.

It requires man-hours to memorize the Z coordinate values corresponding to the XY coordinates in the control device, and a separate device is required for that purpose, which not only reduces machining efficiency but also increases costs. .

Furthermore, if the Z coordinate value stored in the control device is used as is, the edge of the nozzle, etc., which has a different area from the measuring tip, may interfere with the slope of the workpiece.

Therefore, it is necessary to make corrections based on the three-dimensional information of the workpiece stored in the control device so that the nozzle does not interfere with the workpiece. As a result, the control becomes complicated, and it becomes difficult to replace the nozzle with a different diameter, resulting in a reduction in operability and maintainability.

(Means for Solving the Problems) The present invention has been made to solve the problems in the conventional technology, and involves machining by generating electrical discharge between the wire electrode 23 and the workpiece 1. In wire electrical discharge machine,
In-process plate thickness detection means, comprising means for detecting the positions of the upper and lower surfaces of the workpiece l during processing, and means for calculating the plate thickness from signals from the means for detecting each position; The present invention is characterized by comprising means for calculating optimal machining conditions based on a signal from the in-process plate thickness detection means, and outputting a signal corresponding to the calculated optimal machining conditions to each control section of the wire electric discharge machine. The present invention relates to a method of controlling a wire electrical discharge machine.

(Function) In the above configuration, the in-process plate thickness detection means detects the upper and lower surface positions of the workpiece during processing and calculates the relative distance between the upper and lower surface positions to detect the plate thickness. The thickness of the workpiece to be machined is immediately detected during machining, and the optimum machining conditions such as electrical conditions such as discharge voltage and current, and machining feed rate are calculated according to the thickness signal. The signals generated by the wire are output to each control section of the wire electrical discharge machine, allowing high-precision machining at high machining speeds and stable machining with less wire electrode breakage.
This can be achieved with extremely simple operations.

(Example) Hereinafter, an example of the present invention will be described in detail based on FIGS. 1 to 4.

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention.

A work l is fixed on a table 2 by a known method.

A wire 23 passes through the processing portion of the workpiece 1, and the wire 23 is fed by a wire 23 supply/winding device 24.
A new wire 23 is always discharged between it and the workpiece 1.

In addition, the upper and lower surfaces of the wall 1 (are respectively
22597, the second
There are wire support mechanisms 5 and 9 shown in the figure, and the machining fluid supplied from the machining fluid supply port 27 is sprayed onto the machining part of the workpiece 1 from the nozzle parts 5a and 9a, as shown in FIG. It has become.

Further, the nozzle parts 5a and 9a have contact detection contacts 5b and 9b as shown in FIG.
-122597, exactly as detailed in
For the reason shown in FIG. 4, the tips of the nozzles 5a and 9a are controlled so that they are always located near the upper and lower surfaces of the work l.

The absolute positions of the wire support mechanisms 5 and 9 are detected by encoders 8 and 12 shown in FIG.

The thickness of the workpiece is calculated by processing the relative values between the wire support mechanisms in the CPU 15.

The CPU 15 receives the plate thickness signal and the material input means 1 in advance.
Using the material of the workpiece input from 7 as a key, the optimal machining voltage value corresponding to the workpiece thickness and material is obtained from the storage device 16 in which the optimal machining voltage function for each workpiece material and workpiece thickness is stored. The optimum machining voltage signal is read out and further outputted to the machining power source 18, and the machining power source 18 is set to the optimal machining voltage.

Further, the amount of machining fluid ejected also corresponds to the material information separately input into the storage device 16, as described above. Since the function of the optimal machining fluid amount for the plate thickness is stored, once the plate thickness information is calculated.

The corresponding optimum machining fluid volume signal is sent to solenoid 19.
21, the proportional solenoid valves 20 and 22 may be controlled to eject an optimum amount of machining fluid corresponding to the thickness of the workpiece for each material.

Note that 7 and 11 are tachogenerators that detect the speed of the drive motor 6°10 in the Z-axis direction, and the speed signal in the Z-axis direction is fed back to the amplifier 13.14, and the nozzle 5a is
, 9a are controlled by speed feedback.

Further, the CPU 15 uses the board thickness calculated from the signals from the encoders 8 and 12 of the wire support mechanisms 5 and 9 and the material input from the input device 17 as keys, and uses the material and board similarly stored in the storage device as described above. The optimum machining speed V is read from the machining speed table for each thickness, and the CPU 15 calculates the optimal machining in the X-axis and Y-axis directions based on the XY two-dimensional machining path information separately stored in the storage device 16 and the machining speed V. Calculate the velocities v, l and vv.

The signals are sent to the X-axis drive motor 3 and the Y-axis drive motor 4, and the processing speeds in the X-axis and Y-axis directions are controlled to be the optimum machining speeds v, l, and 7, and the workpiece 1 is processed at the combined machining speed V-Vx''+
It can be processed with V.

Alternatively, the voltage between the workpiece and the wire electrode according to the material and thickness of the workpiece is stored in the memory device 16, and the optimum voltage between the electrodes corresponding to the thickness calculated during machining is set to the machining power supply. The birch machining speed vlI is set to , and this voltage is kept constant.
It is also possible to increase or decrease vv.

(Effects of the Invention) As described above, in the present invention, the thickness information of the workpiece can be detected accurately and instantaneously in-process, so wire electrical discharge machining can be performed under the optimum machining conditions for the thickness of the workpiece at each processing point. machine can be controlled.

Therefore, machining can be performed at maximum machining speed.

Not only can productivity be greatly improved, but also stable machining with less wire electrode breakage and high precision machining can be achieved.

In addition, everything is automatically controlled, and the machining path information prepared by the operator only needs to be two-dimensional (XY), and machining can be done with a simple scratching operation.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of a workpiece shape adaptive control method for a wire electrical discharge machine according to an embodiment of the present invention, FIG. 2 is a known wire support mechanism used in this embodiment, and FIG. An enlarged view of part m in FIG. 2. FIG. 4 is an explanatory diagram of the operation control of the wire support mechanism. FIG. 5 is a diagram showing a conventional technique. 1...Workpiece 2...Table 3...X
Axis drive motor 4...Y-axis drive motor 5...Upper wire support mechanism 5a...Upper nozzle 5b...Upper contact detection contact 6...Upper 2-axis drive motor 7...Upper tachogenerator 8 ...Top encoder 9.
...Lower wire support mechanism 9'a...Lower nozzle 9b...Lower contact detection contact lO...Lower two-axis drive motor 11...Lower tachogenerator 12...Lower encoders 13, 14... Amplifier 15...CPU16.
...Storage device 17...Material input device 18...
・Processing power supply 19.21... Solenoid 20,
22... Proportional solenoid valve 23... Wire 24...
Wire supply/winding device 25... Power supply 26... Voltmeter for contact detection 27... Machining fluid supply port Patent applicant
Komatsu Manufacturing Co., Ltd. Representative (patent attorney) Oka 1) Wa Ki Diagram 2 and > Diagram 4 / Y Diagram 5 Procedural Amendment (Voluntary) In November 1986, L. was requested by Japan and China? a? ``Unonote 2''Sale' C-J-L Role 1, Indication of the case Patent Application No. 42905 of 1988 2, Title of the invention Control method for wire electric discharge machine 3, Relationship with the person making the amendment Case Patent applicant Telephone (03) 584-7111 (Main) 4. Date of amendment order (shipping address) Voluntary 5. Specification subject to amendment 6. Contents of amendment i--' 6j Also as below. 7 and 11 are in J (2) Page 7 11100 [Speed signal is amplifier]
(3) Page 7, line 12, r9a
The position of r9a is corrected to the position and speed J, respectively.

Claims (1)

[Claims] In a wire electrical discharge machine that performs machining by generating an electric discharge between the wire electrode 23 and the workpiece 1, means for detecting the positions of the upper surface and the lower surface of the workpiece 1 during machining; an in-process plate thickness detecting means comprising means for calculating plate thickness from a signal from a means for detecting the position of the in-process plate thickness, a means for calculating optimum processing conditions based on a signal from the in-process plate thickness detecting means, and A method for controlling a wire electrical discharge machine, the method comprising: outputting a signal corresponding to the optimum machining conditions determined to each control section of the wire electrical discharge machine.