JPH0585289B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to the improvement of electric discharge machining equipment, and in particular, to enable precision machining, the workpiece and the electrode are separated by the influence of machining energy or changes in the environment. This invention relates to an electric discharge machining apparatus that prevents positional deviations occurring during the process.

[Prior art]

Conventionally, there has been a device of this type as shown in FIG. In the figure, 1 is a machining tank, 2 is a machining liquid,
3 is an electrode, 4 is a main shaft that feeds the electrode 3 in the vertical direction, 5 is a workpiece, and 6 is a table to which the processing tank 1 and workpiece 5 are attached, and can be moved in the X direction shown by the arrow in the figure. It's becoming like that. Reference numeral 7 denotes a saddle, which is adapted to move the table 6 in the Y direction indicated by the arrow in the figure. 8 is a head on which the main shaft 4 is held slidably up and down, 9 is a column that supports this head 8, 9a is the front surface of the column, 9b
10 is a bed to which the column 9 is attached and supports it; 12 is a ventilation blower attached to the upper part of the column 9.

Next, the operation will be explained. When a voltage serving as discharge energy is applied from a power source (not shown) between the electrode 3 and the workpiece 5 in the machining fluid 2 of the machining tank 1, an electric discharge occurs, and the workpiece 5 is machined. . In this case, the temperature of the machining fluid 2 increases due to the discharge energy, and the temperature of the machining bath 1 and the table 6, which are heated by this increase in fluid temperature, increases. 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 electrical discharge machine main body. Radiant heat 11 shown by the arrow in the figure is generated from the upper surface of the machining fluid 2, the machining tank 1, and the table 6 whose temperature has increased, and the column front face 9a facing the heat source is heated by this radiant heat 11. and their surface temperature increases. Furthermore, the temperature distribution of each part of the electrical discharge machining apparatus changes due to the influence of the surroundings of the electrical discharge machining apparatus, such as room temperature.

Since the conventional electric discharge machining apparatus is configured as described above, as the workpiece is machined, when the surface temperature of the mechanical structure facing the heat generation source increases compared to other surface temperatures, For example, as shown by the two-dot chain line in the figure, the column front face 9a and the main shaft 4 are thermally deformed, and the position of the electrode 3 is ε in the figure compared to the initial stage of machining.
Due to the positional deviation shown in Figure 2, there were disadvantages such as a decrease in the machining accuracy of the workpiece. Furthermore, temperature unevenness occurs due to differences in the heat capacities of individual structural members of the processing machine due to changes in room temperature, etc., resulting in positional deviations similar to those described above. As a countermeasure to the above, conventional electrical discharge machining equipment installed a cooling fan 12 at the top of the column or at the rear of the bed to bring in outside air to equalize the temperature of each part of the equipment, but the ventilation path was not clear. Another drawback was that ventilation was only allowed inside the structure.

Figure 6 is a perspective view showing 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, and Figure 7 shows the electrode 3 and the workpiece due to room temperature changes. FIG. 5 is a diagram showing temporal changes in relative position occurring between FIG.

[Summary of the invention]

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and it installs a cover that tightly adheres to the outer surface of the main structural members of the processing machine, so that the outside air sent into the processing machine from the ventilation blower can be used for processing. After being circulated inside the machine, it is circulated through the space formed by the cover and the outer surface of the main structural members of the processing machine through ventilation holes provided in the main structural members of the processing machine, and then exhausted to the outside. Ventilation is carried out on both the inner and outer surfaces of the machine's main structural members, and as a result, machining errors caused by relative positional deviations between electrodes and workpieces due to thermal deformation of the machine structural members are reduced, resulting in extremely high-precision machining. The present invention provides an electrical discharge machining device that can perform the following tasks.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described based on the drawings. In Figure 1, 8 is the head, 9 is the column,
10 is a bed, 12 is a ventilation blower installed in front of the bed, and 13 is a ventilation cover installed on the column 9 and the bed 10, which covers the front, rear, and sides of the column 9 and the side of the bed 10. 1
4 is a gasket attached to improve the airtightness of the ventilation cover attachment part, 15a is a ventilation hole provided in the upper part of column 9, and 15b is a seal between column 9 and bed 10.
16 is an exhaust port provided at the front of the ventilation cover 13 attached to the bed 10.

Next, the operation shown in FIG. 1 will be explained. As explained in FIG. 5, when electric discharge is generated between the electrode 3 and the workpiece 5 in the machining liquid 2 stored in the machining tank 1, and the workpiece 5 is subjected to electric discharge machining, , the radiant heat radiated from the heat generating sources such as the processing liquid 2, the processing tank 1, and the table 6 heats the column 9, the bed 10, and the like. On the other hand, the ventilation blower
The outside air supplied inside passes through the inside of the bed 10, passes through the inside of the column 9 through the ventilation hole 15b, and is sent out into the space formed by the outer surface of the column 9 and the ventilation cover 13 through the ventilation hole 15a.
The outside air sent into the ventilation cover 13 is sent to the column 9.
After passing through the front, side and rear of the bed 1
The air is discharged to the outside from the exhaust port 16 via the side surface of the air conditioner. In the above process, the column 9 and bed 10, which are the main structural members of the processing machine, are cooled from the inside and outside by the outside air supplied by the ventilation blower 12, so that the temperature distribution of the column 9 and bed 10 approaches the outside temperature. Equalized. As a result, the relative positional shift caused by thermal deformation of the processing machine body due to the heat source mentioned earlier is suppressed, and the temperature of each part of the processing machine is evened out even against environmental changes such as room temperature and sunlight. , the relative positional deviation decreases as above.

FIG. 2 shows another embodiment in which a ventilation blower 12 is installed at the top of the column 9, and an exhaust port 16 is provided at the top of the ventilation cover to perform air intake and exhaust at the top of the column 9. FIG. 3 shows another embodiment in which a ventilation blower 12 is installed on a ventilation cover 13 to ventilate the outer surfaces of the column 9 and the bed 10, and then ventilate the inner surfaces. In FIG. 4, a second exhaust port 16b is provided in the part of the ventilation cover 13 facing the table 6 and the saddle 7,
This is another embodiment in which part of the exhaust air cools the table 6 and the saddle 7. Further, in this embodiment, the ventilation blower 12 is directly fixed to the bed 10, but outside air may be supplied from outside using a ventilation hose, duct, or the like. Moreover, even greater effects can be obtained by installing a plurality of ventilation blowers 12.

〔Effect of the invention〕

As described above, according to the electric discharge machining apparatus of the present invention, heat radiation from heat sources such as machining fluid, a machining tank that stores this machining fluid, a table on which this machining tank and a workpiece are attached, and room temperature, sunlight, etc. In response to changes in the environment, a ventilation cover is installed outside the processing machine.
The outside air supplied by the ventilation blower smoothly passes through the inner and outer surfaces of the processing machine, making the temperature of each part of the processing machine uniform, thereby minimizing the thermal influence on the machine structure from the heat source. Therefore, relative positional deviation between the electrode and the workpiece caused by the difference in the amount of thermal deformation of the mechanical structure can be eliminated. Furthermore, even if there is a sudden change in the room temperature or a temperature difference in the vertical direction, the temperature of the processing machine is quickly equalized and the same effect can be obtained, allowing extremely accurate electrical discharge machining of workpieces. be effective.

[Brief explanation of drawings]

1A and 1B are schematic diagrams showing the configuration and operating mode of one embodiment of the present invention, each of FIGS. 2 to 4 is a schematic diagram of another embodiment of the present invention, and FIG. The figure is a schematic diagram showing the configuration of a conventional electric discharge machining device and its operating mode. Figure 6 shows the temperature distribution of the machine when the room temperature changes when there is insufficient ventilation inside the machine.
FIG. 7 is a perspective view showing actual measurement results of the amount of displacement, and is a diagram showing temporal changes in relative displacement occurring between the electrode 3 and the workpiece 5 due to changes in room temperature in the X, Y, and Z directions. 1... Processing tank, 2... Processing liquid, 3... Electrode, 4... Spindle, 5... Workpiece, 6... Table, 7... Saddle, 8
...Head, 9...Column, 9a...Column front, 9b
...Column rear surface, 10...Bed, 11...Radiant heat, 1
2... Ventilation blower, 13... Ventilation cover, 14... Packaging, 15a... Ventilation port, 15b... Ventilation port, 16
a, 16b...Exhaust port. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. In an electric discharge machining device that performs machining by generating electric discharge between opposing electrodes and a workpiece,
A cover having an exhaust port at at least one location is attached to the outer surface of a main structural member of the processing machine such as a column or a head, and a ventilation port is provided at at least one location on the part of the main structural member of the processing machine to which the cover is attached, An electric discharge machining device characterized in that a ventilation blower for feeding outside air into the inside of the processing machine is installed in the bed or column, and forced air cooling by the ventilation blower is also performed outside the processing machine. 2. The electric discharge machining apparatus according to claim 1, wherein the ventilation blower and the processing machine main body are connected by a ventilation hose or a duct. 3. The electrical discharge machining apparatus according to claim 1 or 2, characterized in that a plurality of ventilation blowers are installed. 4 Claim 1 characterized in that a packing is installed between the cover and the main structural part of the processing machine
The electric discharge machining apparatus according to item 1 or 2.