JPS6047049B2 - Machining fluid injection device for electrical discharge machining equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric discharge machining apparatus, and more particularly to a machining fluid injection device for supplying machining fluid to a machining gap between a machining electrode and a workpiece.

In electrical discharge machining, in order to apply a pulse current to the minute machining gap between the machining electrode and the workpiece to perform normal machining, it is necessary to expel machining debris or gas generated during machining from the machining gap to the outside. Therefore, clean machining fluid is always supplied to the machining gap.

This machining fluid supply has conventionally been carried out by providing a hole in the machining electrode for supplying the machining fluid, but depending on the machining conditions, such as in general machining, the machining fluid supply hole may be provided in the machining electrode. There are many cases where it is undesirable or impossible to provide, and in such cases, it is necessary to
Machining liquid is supplied from the outside of the machining electrode using a spray nozzle or the like. In this case, it was extremely difficult to determine the best direction for the injection nozzle, and it was difficult to continue machining under normal machining conditions. In order to improve these drawbacks, devices shown in FIGS. 1 to 3 have been proposed.

In Figs. 1 and 2, 1 is the workpiece, 2 is the processing electrode,
Reference numeral 8 denotes a rotatable machining liquid spray nozzle of the machining electrode 2, and its jet stream is always directed toward the machining gap C. 4 is a motor for rotating the nozzle, and 5 is a device for detecting the voltage between the electrodes, which rotates and stops the motor 4 or controls the rotation speed according to the potential difference between the voltage between the electrodes and the reference voltage.

For example, when there is no longer a difference between the voltage of the machining gap C detected by the voltage detection device 5 and the reference voltage, this is regarded as a stable machining state, and control is performed to stop the rotation of the injection nozzle 3 by the motor 4. Let's do it. Further, FIG. 3 shows a plurality of jet nozzles 6a facing the machining gap C around the machining electrode 2.
~6d are fixedly installed, and the supply of machining fluid to each nozzle is controlled by a rotation control valve 7. The valve body 8 of the rotation control valve 7 is connected to the motor 4 as in FIG. and is rotated by the voltage detection device 5.

Therefore, depending on the rotational position of the valve body 8, the notch 1 of the central passage h communicates with any of the through holes a to d of the casing 9, and the nozzle that can perform the most stable processing among the nozzles 6a to 6d is connected to the notch 1 of the central passage h. The machining fluid is injected. When such conventional devices only provide relative feed between the workpiece and the machining electrode in the direction in which they approach each other, a constant flow rate is required to automatically set the preferred supply direction of the machining fluid. The above effects can be obtained.

However, when applying an auxiliary displacement between the workpiece and the machining electrode that has an element in a direction perpendicular to the direction in which they approach each other, the position of the machining surface changes with this auxiliary displacement, resulting in a new machining process. Unable to maintain proper machining fluid supply to the surface. In other words, the machining fluid may not be sprayed onto the newly machined surface, resulting in an unstable machining condition.
For this reason, the motor 4 rotates to change the machining fluid injection direction, but it is impossible to instantly return the machining surface to a stable state once it has become unstable, and the machining surface shifts to a more stable state. If an auxiliary displacement in a different direction is given before the auxiliary displacement is applied, the control of the injection direction becomes more complicated and it takes a long time to resolve the unstable state, and in the end it becomes impossible to perform stable machining with the auxiliary displacement. . The purpose of the present invention is to eliminate the drawbacks of such conventional devices and to make it possible to spray machining fluid from an appropriate direction for auxiliary displacement. A plurality of injection nozzles are arranged, and machining liquid is selectively supplied to these injection nozzles in synchronization with the direction of auxiliary displacement, thereby giving a certain relationship between the direction of auxiliary displacement and the injection direction of machining liquid. This makes it possible to obtain stable machining conditions. The invention will now be described with reference to the illustrated embodiments.

In FIG. 4, 10a to 10d are injection nozzles installed toward the machining gap between the workpiece 1 and the machining electrode 2;
The liquid supply pipes 11a to 11d for these injection nozzles 10a to 10d are provided corresponding to each side of the machining electrode 2 having a square cross section.
It is connected to the second ejection pipes 13a to 13d. 14a~
Reference numeral 14d indicates electromagnetic valves inserted between the ejection pipes 13a to 13d and the supply passage 15, and the opening/closing control of these electromagnetic valves is performed by a numerical control device 17 that receives signals from the tape 16 containing data regarding auxiliary displacement. .

Note that n is a signal for raising and lowering the processing electrode 2. That is, in this device having the above configuration, the direction of the auxiliary displacement that changes every moment is given by the information from the tape 16, and based on this signal, the numerical control device 17 controls the solenoid valve 14a of the injection direction switching device 12.
~14d is controlled to open and close.

For example, when the relative traveling direction between the machining electrode 2 and the workpiece 1 is in the direction of arrow A, the solenoid valve 14a is configured so that the machining fluid is injected from the injection nozzle 10a at the front in the machining direction.
Similarly, in the direction of arrow B, the solenoid valve 14d is opened.
is opened to inject machining fluid from the injection nozzle 10d. The above examples regarding the direction of the auxiliary displacement and the injection direction of the machining fluid are not absolute, and in the case of the A direction and the B direction, the injection nozzles 10c and 10b at the rear in the machining progress direction are opposite to each other.
There may also be cases where machining fluid is injected from. In short, the direction of the machining liquid jetting direction corresponding to the direction of the auxiliary displacement may be determined in consideration of the direction of the auxiliary displacement and other machining conditions so as to obtain the most preferable machining state experimentally and empirically. The changeover switch 18 of the injection direction switching device 12 is used to switch the injection direction of the machining liquid to the opposite direction with respect to the machining electrode 2 . That is, for example, the injection state from the injection nozzle 10a is instantaneously switched to the injection from the injection nozzle 10c. Of course, it is possible to inject from multiple injection nozzles in the direction of a specific auxiliary displacement, and the voltage value between the machining electrode 2 and the workpiece 1 detected by the inter-electrode voltage detection device Based on this, it is also possible to change the jetting force of the machining liquid mound. Fifth
The figure shows an example of installing the injection nozzles when the cross-sectional shape of the processing electrode 2 is rectangular, and two injection nozzles 10 are arranged on each long side of the processing electrode 2.

In this way, the number of injection nozzles is determined as appropriate depending on the shape of the machining electrode, and by controlling the injection of machining fluid from these injection nozzles in the same manner as described above, it is possible to obtain a preferable machining fluid jet direction for the auxiliary displacement. Ru. As described above, the present invention changes the injection direction of the machining fluid in synchronization with the direction of the auxiliary displacement, so the machining fluid can be efficiently applied to new machining surfaces and other machining surfaces due to the auxiliary displacement. Therefore, it is possible to obtain the effect that high-precision machining is possible due to stable machining conditions.

[Brief explanation of the drawing]

Figure 1 is a connection diagram showing an example of a conventional machining fluid injection device;
The figure is a plan view of the main parts showing the rotating state of the injection nozzle of the apparatus shown in Fig. 1, Fig. 3 is a connection diagram of the main parts showing another conventional processing injection device, and Fig. 4 is the processing according to the present invention. FIG. 5 is a perspective view showing an embodiment of the liquid injection device; FIG. 5 is a perspective view of main parts showing another embodiment of the present invention. 1: Workpiece, 2: Processing electrode, 10a to 10d, 10:
Injection nozzle, 12: injection direction switching device.

Claims (1)

[Claims] 1 A main feed in a direction in which the two relatively approach each other, and an auxiliary displacement having an element in a direction orthogonal to this main feed are applied between the processing electrode and the workpiece, and the processing electrode and the workpiece are In an electric discharge machining device that processes a workpiece by causing electrical discharge while supplying machining fluid to a machining gap between the two, the machining fluid is injected from different directions around the machining electrode toward the machining gap. Machining fluid injection of an electric discharge machining apparatus, characterized in that a plurality of injection nozzles are arranged and an injection direction switching device is provided for selectively supplying machining fluid to these injection nozzles in synchronization with the direction of the auxiliary displacement. Device.