JPH05177448A - Electric discharge machining device - Google Patents

Abstract

PURPOSE:To highly precisely perform a three-dimensional form electric discharge machining using a slender shaft-like electrode such as a wire. CONSTITUTION:During working, an electrode is raised at a determined time interval by devices 8, 23, and the top end length of the rising electrode is measured by a device 24. Feeding devices 9, 10 for feeding the electrode 1 on the basis of the measurement and correcting it to a determined length are provided, and the relative three-dimensional form working feed of the corrected electrode and a body 2 to be machined is controlled by a NC 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric discharge machine.

[0002]

2. Description of the Related Art Conventionally, when performing electric discharge machining with a full-scale electrode, it is extremely difficult to manufacture the full-scale electrode, and because the electrodes are consumed, a large number of electrodes of the same shape must be produced and used in exchange. There was a drawback that the cost etc. increased. For this reason, a method has been attempted in which a rod-shaped simple electrode is used to give a machining feed of a three-dimensional shape by NC control, but in this case, a thin wire diameter consumes a lot of length, and particularly a water-machining liquid is used. When used, the consumption ratio becomes extremely large, and there is a drawback that the consumption correction is troublesome.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate such drawbacks and to improve three-dimensional electric discharge machining using a wire or rod-shaped electrode so that the electric discharge machining can be performed with high accuracy.

[0004]

A rising control device for controlling the rising of the electrode at a predetermined time interval during the electric discharge machining, a measuring device for measuring the tip length of the electrode rising by the device, and the device. A feed device for feeding the electrode on the basis of the measurement and correcting it to a predetermined length; a feed control device for giving a feed of a three-dimensional shape between the electrode corrected by the device and the workpiece; The present invention is characterized in that the electrode provided with the processing feed and the processing power supply for supplying the processing energy are provided between the workpieces.

[0005]

In the present invention, as described above, the thin wire or the rod-shaped electrode is used to perform the electric discharge machining of the three-dimensional shape while correcting the wear, so that it is possible to perform the high precision die machining. The correction of the electrode is based on a rise control device that controls the rise of the electrode at a predetermined time interval during the electric discharge machining, a measuring device that measures the tip length of the electrode that is raised by the device, and a measurement of the device. The electrode length is automatically corrected at a predetermined time interval, and therefore the electrode processing device is always provided at any position. It is corrected to a fixed length, and it is possible to perform extremely precise electric discharge machining even if an electrode such as a thin wire is used. Moreover, measurement is performed almost instantaneously by using a laser in the measuring device, and each step of resuming machining by raising, correcting, and lowering the electrode is continuously performed as a reciprocating motion, which is repeated at predetermined time intervals. As a result, the effect of removing machining chips and the like existing in the machining gap is enhanced, and stable high-speed machining can be achieved. Further, since the machining feed is carried out by an electrode whose length is constantly corrected by multi-axis control of three or more axes, it is possible to carry out highly precise machining of electric discharge machining of any complicated shape. Further, by shortening the time interval for length correction by the above-mentioned electrode lift control, even when using a water solution that consumes a large amount of electrode as a working fluid, it is possible to easily perform precision machining and improve the machining speed. it can.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment of the drawings. In FIG. 1, 1 is a short electrode like a pencil lead,
A rod-shaped electrode having a length of 30 to 100 mm, a diameter of about 0.1 to several mm, and often about 0.5 to 1 mmφ is used. Reference numeral 2 is a work piece, for example, when an artificial tooth or bridge is connected to an implant or a natural tooth base, a metal ring is inserted to secure the fitting between the two. Intended for processing. Reference numeral 4 denotes a storage pipe for the short and long rod-shaped electrode 1 provided in the electrode supporting main shaft 3, and a plurality of electrodes 1 are constantly stored, and the storage electrode 1 is fed into a guide pipe 6 fixed to the center by a taper member 5. .. 7 is a spring for pushing up the pipe 6 together with the member 5, 8 is the pipe 6
With the claw nozzle that holds the tip of the rod electrode 1 extruded from, the claw spreads when the tip of the pipe 6 is pushed in, and when pulled out, the claw is closed and the rod electrode 1 is held and fixed. A knock cam 9 pushes up the upper end of the pipe 4 intermittently, and is driven by a motor 10. By this intermittent drive, the tip of the rod electrode 1 is pushed out from the claw nozzle 8 to step 7 by a minute length. Reference numeral 11 is a motor for rotating the main shaft 3, 12 is a head for supporting the whole main shaft, etc., and an air jet nozzle surrounding the rod electrode 1 is provided at the tip. A fixing device 14 fixes the workpiece 2 on the processing table 15. The XY table 15 gives a machining feed to the fixed workpiece. Also, an R-axis (C-axis) for rotation can be attached here. 16 and 17 are the drive motors, 18 is the head 1
A drive motor for giving Z-axis feed to 2 and a U-V axis table 19 give tilt feed to the head shaft via a member 20 fixed to the table. 21 and 22 are U and V axis drive motors,
Reference numeral 23 denotes an NC control device that program-controls each axis motor,
Reference numeral 24 is a device for irradiating light such as a laser and receiving reflected light for measuring the electrode tip length, and measuring while controlling the motor 25 up and down, and feeding back this detection signal to the NC device 23. The correction control of the electrode tip length is performed. Reference numeral 26 is a processing tank for storing a processing liquid, and 27 is a processing power supply for supplying a processing pulse between the electrode 1 and the workpiece 2.

In the electric discharge machining, electric discharge is performed by a supply pulse from a machining power supply 27 between the rod electrode 1 whose tip projection length is adjusted to a predetermined value and the workpiece 2 immersed in the tank 26. It discharges, but the X-, Y-, and Z-axis motors 16 are added to the machining shape programmed by the NC controller 23 during machining.
17 and 18 are controlled, and a three-dimensional shape feed is given to perform processing. The Z-axis drive motor 18 also functions as a controller for raising the electrode 1, and controls the raising of the electrode 1 by a signal supplied from the NC controller 23 at predetermined time intervals, and measures the electrode tip length each time. An air jet is jetted from a nozzle 13 to the tip of the electrode 1 whose rising is controlled to blow off the adhering machining liquid, and light is irradiated by a device 24 in a removed state, and a reflected light is received while moving up and down by driving a motor 25. Measure the electrode tip length. The measurement signal is fed back to the NC controller 23, the motor 10 is driven to correct the length, and the cam 9 knocks the upper end of the pipe 4 to control the delivery of the electrode 1. Knock the rod electrode 1
When the pipe 6 to be inserted into is pressed downward by pressing the spring 7, the tip of the pipe 6 widens the claw nozzle 8 to project the rod electrode 1 at the core, and when the cam 9 rotates, the pipe 6 is now rotated by the spring 7. Is pushed up, but at this time, the claw nozzle 8 is closed to grab the electrode 1 and maintain the protruding state. By repeating such knock feeding, the tip of the rod electrode 1 is pushed out stepwise. When it is confirmed by the measuring device 24 that the tip of the rod electrode 1 has been corrected to a predetermined length, the Z-axis motor 18 feeds to maintain a small gap between the workpiece and the workpiece, and continue electrical discharge machining. The measurement of the electrode length and the correction control based on it are minute times of only a few seconds, and the machining can be continued almost continuously. The time interval of this electrode rise length measurement and the correction control by it must be changed depending on the processing conditions, the wire diameter of the electrode, the degree of electrode wear due to the material, etc. Normally, NC control is repeated at intervals of about 1 min. Set in the device 23.

Further, the measurement of the rise of the electrode 1 is carried out on the table 1
5 It is repeated from any position during machining by feeding at set time intervals, the electrode length is corrected, and machining by three-dimensional control is always performed with an electrode having a constant protrusion length,
It is possible to perform extremely precise patterning. Further, by controlling the raising of the electrodes at this time interval, machining scraps are eliminated, short-circuiting and the like can be forcibly released, extremely stable machining can be performed, and machining speed is improved. It should be noted that the removal of the machining waste can be performed by pressurizing and jetting by providing a machining liquid jet nozzle along the rod electrode 1, and by controlling the rotation of the electrode 1 by the rotation of the main shaft of the motor 11, stable machining can be performed. Stable processing can be performed by uniform wear of the entire tip. Each time the rod electrode 1 cut into a predetermined length is consumed, other electrode rods 1 in the storage pipe 4 are sequentially supplied from the taper member 5 to the pipe 6, and new electrodes are continuously replenished. Even if the short and long electrodes are used, machining can be continued continuously without interruption of replenishment, and efficient electric discharge machining can be performed.

FIG. 2 is a partial view of an embodiment in which a continuous wire 29 wound around a reel is used as an electrode. Reference numeral 30 is a nozzle for guiding the tip of the wire electrode, 31 is a projecting feed roller, and 32 is a roller drive motor. In this embodiment as well, although not shown, the protruding length of the wire electrode 29 from the nozzle 30 is measured, the motor 32 is driven based on the measurement, and the wire 29 is fed by the roller 31 to keep the protruding length constant. Is corrected so that this operation is repeated at a predetermined time interval during processing so that the wire electrode controlled to have a constant length is always processed.

In FIG. 1, the work material head 12 is not limited to being set vertically to the work table 15,
There are cases where precision machining of slopes etc. is performed by controlling the inclination of a predetermined angle. At this time, the NC controller 23 drives the U and V axis motors 21 and 22 by applying a signal, and the cross table 19 drives the member 20. This allows the head 12
The upper end of the head moves to the left, right, front and back of the U and V axes.
Is supported by a fulcrum 28 in the middle between the upper and lower sides, and the upper and lower ends are swingably supported. Therefore, even if the lower end swings and tilts by the movement control of the upper end, the tip of the electrode 1 is tilted at a predetermined angle with respect to the processing table 15. You can The tilt angle is U
The motors 21 and 22 of the -V table can be controlled arbitrarily, and the inclined surface and the like of the workpiece 2 can be precisely machined by facing the electrodes from the direction inclined at a predetermined angle.

As described above, according to the present invention, the processing of the three-dimensional shaped part by the wire or the rod-shaped electrode has been described. In addition to this processing, the composite processing such as the combination of the wire cut electric discharge machining and the grinder polishing can be performed. This makes it possible to easily and accurately perform any shape processing. Although the present invention has been described above with reference to one embodiment, a mechanism for feeding out a wire or rod-shaped electrode, a measuring device for measuring the tip length of the electrode, a three-dimensional machining feeding device, etc. have the same functions other than those shown in the drawings. The mechanical device can be arbitrarily used. Further, it is possible to apply a servo control to the electrodes by using a device that gives vibration in addition to rotation, or by using the voltage and current of the machining gap as signals in the machining feed.

[0012]

As described above, according to the present invention, the thin wire or the rod-shaped electrode is used to perform the electric discharge machining of the three-dimensional shape while correcting the wear. Therefore, it is possible to easily perform the high precision die machining. .. Then, the correction is a control device that raises the electrode at a predetermined time interval during electric discharge machining, a measuring device that measures the tip length of the raised electrode, and the electrode is extruded based on this measurement to a predetermined length. A correction feeding device is provided, and the electrode length is automatically corrected at a predetermined time interval.Therefore, regardless of the position of the electrode machining device, machining is always performed with a fixed length of electrode tip. It is possible to perform extremely precise electric discharge machining by using a thin electrode.

Further, by using a laser or the like as the measuring device, the measurement can be performed in a very short time by performing non-contact measurement, and the length can be corrected, and the machining can be restarted by raising, measuring, correcting or lowering the electrode. Each step is continuously performed as a reciprocating motion, and three-dimensional shape processing can be continuously and efficiently performed.
Further, since the measurement can be performed by providing a device for injecting an air jet to the elevated electrode to remove the adhering machining liquid, the precise measurement and the correction due to the precision measurement can be performed, and thus, the high precision machining can be performed. Further, by the electrode rising control, this is repeated at a predetermined time interval, so that the effect of eliminating machining chips is good, and the effect of increasing the machining speed by stable discharge is obtained. Further, since the machining feed is carried out by the electrode whose length is constantly corrected by the multi-axis control of three or more axes, the three-dimensional machining of an arbitrary complicated shape can be machined with high precision.

[Brief description of drawings]

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

FIG. 2 is a partial configuration diagram of another embodiment.

[Explanation of symbols]

 1 Rod Electrode 2 Workpiece 3 Main Spindle 4 Electrode Storage Pipe 5 Tapered Member 6 Electrode Guide Pipe 7 Spring 8 Claw Nozzle 9 Knock Cam 11 Spindle Rotation Motor 12 Head 13 Air Nozzle 15 X, Y Table 18 Z Axis Motor 19 U, V Table 23 NC control device 24 Measuring device 27 Processing power supply

Claims (3)

[Claims] 1. An electric discharge machining apparatus for performing three-dimensional electric discharge machining using a wire, rod-shaped, or pipe-shaped electrode while continuously feeding at a constant speed as a function of the machining electrode during the electric discharge machining, or While intermittently feeding, a raising control device that raises and controls the electrode at a predetermined time interval, a measuring device that measures the tip length of the electrode that is raised by the device, and sends out the electrode based on the measurement of the device. A feeding device for correcting to a predetermined length, a machining feed control device for imparting a machining feed of a three-dimensional shape between the electrode and the workpiece to be compensated by the device, the electrode to which the machining feed is given by the device, and the workpiece. An electric discharge machine comprising: a machining power supply for supplying machining energy between the bodies. 2. The measuring device is provided with an air jet nozzle to remove contaminants such as liquid droplets at the tip of the electrode, and then measure the length.
The electric discharge machine according to the item. 3. The electric discharge machining apparatus according to claim 1, wherein the three-dimensional machining feed control device is provided with a multi-axis feed control device having three or more axes.