JPH0227094B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to the improvement of electric discharge machining equipment, and in particular, to prevent the processing machine body from being deformed due to the thermal influence of machining energy, in order to enable precision machining. The present invention relates to an electrical discharge machining device.

[Prior art]

As a conventional electrical discharge machining apparatus of this type, the one shown in FIG. 1 is known. FIG. 1 is a schematic diagram showing the configuration and operating mode of a conventional electrical discharge machining device. In the figure, 2 is the machining fluid, 1 is the machining fluid 2
Machining tank that stores and performs electrical discharge machining inside the tank, 3
is an electrode; 4 is a main shaft for processing and feeding the electrode 3;
5 is a workpiece; 6 is the processing tank 1 and the workpiece 5;
This is a table for attaching the holder, and is movable in the direction of the arrow X in FIG. 7 is a saddle, which moves the table 6 along the arrow Y in FIG.
direction. 8 is a head attached to guide the main shaft 4; 9 is a column that supports the head 8; 9a is an inner surface of the column; 9b is an outer surface of the column; 10 is a bed on which the column 9 is attached and supports it; is a cooling fan attached to the top of the column 9.

Next, the operation of this conventional electric discharge machining apparatus will be explained. Electric discharge is generated by supplying discharge energy from a power source (not shown) between the electrode 3 and the workpiece 5 in the machining liquid 2 stored in the machining tank 1, and the workpiece 5 is heated. It performs electrical discharge machining. At this time, the temperature of the machining fluid 2 rises due to the discharge energy, and the machining bath 1 and the table 6 are heated by this fluid temperature.
The temperature of the table 6 rises higher than the temperature around the electric discharge machine main body, and this temperature rise gradually increases depending on the amount of machining energy from the start of machining, and becomes the largest heat source in the electric discharge machine main body. The upper surface of the machining fluid 2 whose temperature has increased, the machining tank 1 and the table 6
Radiant heat 11 shown by the arrow in Fig. 1 is generated from
This radiant heat 11 heats the inner surface 9a of the column facing the heat source, raising the temperature of these surfaces. Furthermore, the temperature distribution in each part of the processing machine changes due to changes in the atmosphere such as room temperature.

Since the conventional electric discharge machining apparatus is configured as described above, as the workpiece 5 is subjected to electric discharge machining, the surface temperature of the main body of the machine, that is, the column 9, the bed 10, etc. facing the heat generation source increases. When the surface temperature of the part increases compared to the surface temperature of the part, the column inner surface 9a and the main shaft 4 undergo thermal deformation, as shown by the two-dot chain line in FIG. A positional shift shown by ε in the figure occurs. For this reason, there was a drawback that the processing accuracy of the workpiece 5 deteriorated. In addition, similar positional deviations occur due to changes in room temperature, etc., and processing accuracy deteriorates. As a countermeasure for this, conventional electrical discharge machines have a cooling fan 12 installed at the top of the column 9 or at the rear of the bed 10.
Although the main body of the processing machine was cooled by blowing in outside air, the ventilation inside the processing machine was insufficient because the ventilation path was not clear. FIG. 2 shows the state of ventilation inside the processing machine, and the length of the arrow indicates the wind speed. Furthermore, FIG. 3 shows the actual measurement results of the temperature distribution and displacement of the processing machine when the room temperature changes when ventilation inside the processing machine is insufficient. Also,
FIG. 4 shows a relative change over time that occurs between the electrode 3 and the workpiece 5 due to a change in room temperature.

[Summary of the invention]

The present invention has been made in order to eliminate the drawbacks of the conventional ones as described above, and it provides smooth ventilation to the inside of the main structure by installing a suitable ventilation plate inside the electric discharge machining equipment, that is, inside the column. By making the temperature distribution uniform throughout the main structure, it is possible to reduce machining errors caused by relative positional deviation between the electrode and the workpiece due to thermal deformation of the main structure, making it possible to perform highly accurate machining. The purpose is to provide electrical discharge machining equipment.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The electrical discharge machining apparatus of the present invention will be explained below based on an embodiment shown in the drawings. FIG. 5 is a vertical cross-sectional view of the electric discharge machining apparatus of the present invention, with parts of the same configuration as the conventional apparatus omitted, showing the configuration in which a ventilation plate is installed inside the processing machine, which is a feature of the present invention, and its operating mode. It is. In the figure, reference numeral 9 is a column, 10 is a bed, 12 is a cooling fan installed on the top of the column 9, 13 is a ventilation plate installed inside the column 9, and 14 is the column 9 and the ventilation plate. This is an upper lid installed so that ventilation is provided to the space between 13 and 13. FIG. 6 is a cross-sectional view showing how the ventilation plate 13 is attached to the column 9 in this embodiment. 15 is a reinforcing rib provided on the column 9, and 16 is an installation groove provided in the reinforcing rib.

Next, the operation of the embodiment shown in FIGS. 5 and 6 will be explained. Although illustration is omitted, in the same way as already explained in FIG. When performing electric discharge machining in step 5, the radiant heat 11 radiated from the heat generating sources such as the machining fluid 2, the machining tank 1, and the table 6 heats the inner surface 9a of the column 9 and the bed 10, but the ventilation plate 13 is not heated inside the column 9. Since the outside air supplied by the cooling fan 12 always flows into the space between the ventilation plate 13 and the column 9 in contact with the inner surface of the column 9, the inner surface of the column 9 is always cooled. Therefore, the temperature distribution in the column 9 is kept uniform, and as a result, the temperature distribution in the column 9 due to the increase in the temperature of the machining fluid 2
No thermal deformation occurs. Further, the same effect can be obtained with respect to environmental temperature changes such as room temperature and sunlight, and therefore the workpiece 5 can be subjected to electric discharge machining with extremely high precision.

FIG. 7 shows another embodiment of the present invention, in which the position of the reinforcing rib 15 for attaching the ventilation plate 13 to the column 9 is different from that of the embodiment shown in FIGS. In each of these embodiments, the ventilation plate 13 is installed inside the column 9, but even if it is installed inside the bed 10, almost the same effect can be obtained. 16 in the figure is an installation groove.

〔Effect of the invention〕

As described above, according to the electrical discharge machining apparatus according to the present invention, heat radiation from heat sources such as machining fluid, a machining tank storing this machining fluid, a table on which this machining tank and a workpiece are attached, room temperature, sunlight, etc. In response to changes in environmental temperature, a ventilation plate is installed inside the processing machine to guide the outside air blown from the cooling device into the ventilation path downward along the inner wall of the column, and then into the bed through the ventilation hole to cool the column and bed. By applying ventilation cooling to the main structure, we have made the temperature distribution uniform throughout the main structure, so we can minimize the thermal influence from the heat generation source on the machine structure. - Since relative positional deviation between the workpieces can be eliminated, it is possible to perform electrical discharge machining of the workpieces with extremely high precision.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing the configuration of a conventional electrical discharge machining device and its operating mode, Fig. 2 is a vertical cross-sectional view showing the ventilation condition inside a conventional electrical discharge machine, and Fig. 3 is a diagram showing insufficient ventilation inside the processing machine. Figure 4 is a cross-sectional view showing the actual measurement results of the processing machine temperature distribution and displacement amount when the room temperature changes. The diagram shown,
FIG. 5 is a vertical cross-sectional view showing the internal structure and internal ventilation state of the electric discharge machining apparatus of the present invention, FIG. 6 is a cross-sectional view showing the installation state of the ventilation plate on the column in the embodiment of FIG. 5, and FIG. The figure is a cross-sectional view showing how a ventilation plate is installed on a column in another embodiment of the present invention. In the figure, 1...processing tank, 2...processing liquid, 3
...Electrode, 4...Spindle, 5...Workpiece, 6...
Table, 7...Saddle, 8...Head, 9...
Column, 9a...Column inner surface, 9b...Column outer surface, 10...Bed, 11...Radiant heat, 12
...Cooling fan, 13...Ventilation plate, 14...
... Upper lid, 15 ... Reinforcement rib, 16 ... Installation groove. Note that in FIGS. 2 and 5, arrows indicate flow velocity vectors, and the length of the arrow corresponds to the flow velocity. Also, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. In an electrical discharge machining device that processes a workpiece by generating electrical discharge between electrodes and a workpiece that are arranged opposite to each other, a ventilation hole is provided in the ceiling of a column of the electrical discharge machining device. A reinforcing rib is provided protruding from the inner wall of the column while being connected to a cooling device, and a ventilation plate is provided between each of the adjacent reinforcing ribs, and the upper part of each of these ventilation plates is closed in the vicinity of the ventilation hole. and a lower end thereof is fixed to the bottom plate of the column to form a ventilation passage between the ventilation plate and the inner wall of the column, and a ventilation passage is provided in the bottom plate of the column through the ventilation passage and the bed of the electrical discharge machining apparatus. A hole is provided to guide outside air blown from the cooling device into the ventilation passage downward along the inner wall of the column,
An electric discharge machining apparatus characterized in that the electric discharge machining apparatus is configured to be guided into the bed from the ventilation hole. 2. The electric discharge machining apparatus according to claim 1, wherein the reinforcing rib is provided with an installation groove in which the ventilation plate is installed.