JPS5918174B2 - Electrode positioning device for electrical discharge machining of roll-shaped workpieces - Google Patents

Description

[Detailed description of the invention] This invention relates to a roll-shaped workpiece (hereinafter abbreviated as roll).

) relates to an automatic positioning device for electrodes used in electrical discharge machining. 0 The following explanation will be given by taking as an example the case where the surface of the roll is finished in a matte finish by electric discharge.

Conventionally, for example, when finishing the surface of a steel strip rolling roll, especially a cold rolling roll, with a satin finish, hard metal particles such as shot or grid are projected onto the polished end surface of the roll.
Previously, a method of making impressions on the roll surface was used, but in recent years attempts have been made to perform this type of machining by electric discharge machining.

As is well known, electric discharge machining involves interposing an insulating liquid such as kerosene in the narrow machining gap between the electrode and the workpiece, and periodically applying a pulse waveform voltage between the electrode and the workpiece. by discharging it.

This is a method of processing the surface of a workpiece. By repeating such electrical discharge machining on the roll surface, rotating the roll in the circumferential direction, and at the same time gradually moving the electrode in the direction of the rotation axis of the hole, the roll surface will continuously form a spiral-shaped satin finish. Processed.

The roll surface can be covered with discharge marks. This is: 1-
This method uses electrical discharge machining to uniformly apply a satin finish to the surface of the roll.

The resulting satin surface has a large difference in unevenness compared to mechanical impressions made by metal particle projection, and the shape is much more regular.The shape is not affected by the manufacturing method or hardness of the roll. ．． It also has many advantages, such as the metal structure on the roll surface being hardened by electrical discharge, making it ideal for use as a rolling roll.

However, in this roll electric discharge machining equipment, In order to increase the processing efficiency, a large number of electrodes are attached to an electrode holding device,
This electrode holding device is controlled by a servo control device9, and the servo control device used is one that feeds the electrode in a direction perpendicular to the surface of the machining fluid. The method shown in FIG. 1 has been used to properly position the electrode before electrical discharge machining the roll. That is, FIG. 1 is a schematic configuration diagram for explaining an electrode positioning method in a conventional roll electric discharge machining apparatus. An electrode that generates electrical discharge through the machining fluid. In case of figure 4
Individually equipped. Also. ．． 8 is the plurality of electrodes 7 mentioned above.
an electrode holding device (12) for fixing and holding the electrodes (with screws 23) respectively;
is a bending device that supports the electrode holding device 8. This head device 12 servo-controls the electrode 7 in a direction perpendicular to the machining liquid level. Further, the roll 1 is rotated by a roll rotation drive device (not shown). The head device 12 moves in the direction of the rotational axis of the roll 1 to finish the surface of the roll 1 in a matte finish.

Incidentally, the electrode 7 is fixed at a predetermined location on the electrode holding device 8 before generating an electric discharge between the electrode 7 and the roll 1. Next, this fixing method will be explained.

First, the electrode holding device 8 is brought close to the roll 1 by a drive device (not shown), each electrode 7 is manually pressed against the roll 1, and each electrode 7 is fixed to the electrode holding device 8 with a screw 23.

after that. The electrode holding device 8 is moved in a direction away from the roll 1 by more than the machining gap.

This is the conventional method for positioning the electrodes, but this conventional method mainly involves manual operation. ) Not only is the single electrode positioning operation very complicated, but the time required for electrode positioning is also very long, so it cannot be used in practice for multi-electrode machining. do not have. moreover. This is because it is not possible to compensate for the shortening of the length of the electrode due to wear due to electrical discharge machining. A major drawback is that the electrodes must be replaced very frequently.

This invention was made by focusing on the above drawbacks. Automatically performs electrode positioning operation. Moreover, no matter how much the number of electrodes increases, electrode positioning can be performed in an extremely short time.

Furthermore, even if the electrode is worn out due to machining, the electrode is automatically fed by the amount of the worn length when positioning the electrode, and
By using an electrode that is sufficiently long compared to the length of the electrode that is consumed in one machining process, the frequency of electrode replacement can be greatly reduced.

In addition, by providing the roll diameter inspection device, V) 6 problems caused by the diameter of the roll-shaped workpiece, i.e.,
In order to maintain a constant opposing gap between the roll-shaped workpiece and the electrode, the feeding length of the electrode changes depending on the diameter of the roll-shaped workpiece. This eliminates the problem that vibrations occur, resulting in unstable discharge. A second embodiment of this invention will be described below.
This will be explained in detail using FIG.

Figure 2 is a schematic diagram showing the device of this invention. Figure 3 is an enlarged view of the main parts. In Figure 6, 1 is the roll of the workpiece, 2,
3 is a bearing that supports the roll 1 in a horizontal state; 3 is a shank 14 that chucks the shaft end of the roll 1; 5 is a roll rotation drive device that rotates the roll 1 via the shank 3; A machining tank 7 in which the machining part is immersed in a machining liquid 6 includes a plurality of electrodes that form an electric discharge between the machining part and the machining part of the roll 1. 8 is an electrode holding device for holding the electrode 7. Reference numeral 9 denotes an electrode feeding device that feeds the electrode 7 along the guide portion 10 of the electrode holding device 8. ．． 11 is a device for fixing the electrode 7 to the electrode holding device 8 using the output of a detection device to be described later; 12 is a head device for advancing and retracting the electrode holding device 8; and 13 is a head transverse drive device for rotating the feed screw 14. In particular, the head device 12 is moved in the axial direction of the roll 1. Further, 15 is a power supply device that applies a pulse voltage between each of the electrodes 7 and the roll 1;
Reference numeral 16 denotes a damping device, and this control device 16 includes a detection device 17 that detects the contact state between the electrode 7 and the roll 1, a device 18 that stops the electrode feeding device 9 based on the output of the detection device 17, and a device 18 that stops the electrode feeding device 9 based on the output of the detection device 17. It includes a device 19 for actuating the fixing device 11 with the output of the device 17.

Note that the electrode 3 is held at an inclination angle θ (according to experiments, it has been confirmed that 30 to 40 degrees is appropriate) with respect to the machining liquid level. Further, 20 is a roll diameter snooping device which operates as described later. Reference numeral 21 denotes a drive device for moving the snooping device 20 forward and backward within a predetermined length range, and 22 a device for stopping the advance of the head device 12 when the snooping device 20 and the roll 1 come into contact.

The driving device 21 is composed of, for example, a hydraulic cylinder, and the snooping device 20 is disposed so as to form a predetermined angle (θ in the illustrated embodiment) with the extending direction of the electrode 7. It is configured so that it can come into contact with. This invented device is constructed as described above. Next, the electrode positioning method will be explained.

As shown in FIG. 3, first, the head device 12 is advanced in the direction of the roll 1. In this case, the roll diameter snooping device 2
0 is extended to a certain length (V). The snooping device 20 comes into contact with the surface of the roll 1, and the stop device 22 is actuated to stop the head device 12 from advancing. Thereafter, the electrode 7 is inserted into the guide portion 10 of the electrode holding device 8 (this operation is not necessary if the electrode 7 is already inserted), and the electrode 7 is fed in the direction of the roll 1 by the electrode feeding device 9. The contact between the electrode 7 and the roll 1 is detected by the detection device 17, and based on its output, the electrode feeding device 9 is stopped and the fixing device 6 is activated to fix the electrode 7 to the electrode holding device 8. Then the snooping device 20
At the same time as retreating. The head device 12 is moved backward and the electrode holding device 8 is moved in a direction away from the roll 1. A gap larger than the machining gap is formed between the electrode 7 and the roll 1.

With the above steps, the positioning work of the electrode 7 is completed, and processing can be started at any time. In addition. As shown in FIG. 3, a specific example of the electrode feeding device 9 is as shown in FIG. It may be possible to send them. Further, as a specific example of the fixing device 11, a hydraulic cylinder is operated, and the electrode 7 is fixed to the electrode holding device 8 by the hydraulic pressure.
A device that presses and fixes the guide portion 10 is considered. Furthermore, in the above embodiments, the case in which the apparatus of the present invention is applied to an electric discharge machining apparatus for finishing the outer surface of a roll with a satin finish has been illustrated and described. The present invention is not limited to this, and various design changes are possible. As explained above. According to the apparatus of the present invention, no matter how much the number of electrodes increases (for example, in roll electric discharge machining described as a practical embodiment of the present invention, about 40 electrodes are required).

)゛The operation is not complicated and the electrode positioning work can be completed in an extremely short time. In addition, when positioning 6 electrodes, the length of electrode wear due to 2 electric discharge machining can be automatically corrected, and by using electrodes that are sufficiently long compared to the length of electrode wear due to one machining, the frequency of electrode replacement can be greatly reduced. There are also advantages to being able to do less.

Yet again. By providing the roll diameter inspection device, problem 6 that occurs depending on the diameter of the roll-shaped workpiece, that is, to keep the facing gap between the roll-shaped workpiece and the electrode constant.

The problem is that the feeding length of the electrode changes depending on the diameter of the rolled workpiece, and uneven feeding length causes vibration of the electrode, resulting in unstable discharge. can be solved, and its practical importance is extremely high.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram for explaining a conventional device; FIG. 2 is a schematic diagram for explaining an embodiment of the inventive device; FIG. 3 is a diagram for explaining the main parts of FIG. be. Note that the same reference numerals in the figures indicate the same or corresponding parts, and in the figure, 1 is a roll-shaped workpiece, 5 is a processing tank, and 6 is a processing liquid. 7
is an electrode, and 8 is an electrode holding device. 9 is an electrode feeding device, 11 is a fixing device. ．． 12 is a head device 620 and a roll diameter inspection device 622 is a stop device. 23 is a screw.

Claims (1)

[Claims] 1. An electrode holding device that holds an electrode facing a roll-shaped workpiece immersed in a machining liquid, a head device that advances and retreats the electrode holding device with respect to the roll-shaped workpiece, and a roll-shaped workpiece of the head device. a roll that is attached to the tip end on the side facing the workpiece and is configured to extend to a certain length and come into contact with the roll-like workpiece when the head device advances toward the roll-like workpiece; a diameter snooping device, a device that stops the advance of the head device when the roll diameter snooping device and the roll-shaped workpiece come into contact, and a device that stops the advance of the head device when the roll diameter snooping device and the roll-shaped workpiece come into contact; an electrode feeding device for feeding the electrode, and means for stopping the electrode feeding device and fixing the electrode to the electrode holding device when the electrode comes into contact with the roll-shaped workpiece; When both the diameter snooping devices come into contact with the roll-shaped workpiece, the roll diameter snooping device is moved backward, and the head device is moved in a direction away from the workpiece, thereby removing the electrode and the roll-shaped workpiece. An electrode positioning device for electrical discharge machining of a roll-shaped workpiece, in which a gap larger than the machining gap is formed between the electrodes.