JPH0227095B2 - - 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, in order to enable precision machining, the relative relationship between the workpiece and the electrode is reduced due to machining energy or environmental changes. The present invention relates to an electric discharge machining apparatus that can prevent positional deviation from occurring.

[Prior art]

As a conventional electric discharge machining apparatus of this type, the one shown in FIG. 4 is known.

FIG. 4 is a schematic diagram showing the configuration and operating mode of a conventional electrical discharge machining device. In the same figure,
2 is a machining fluid, 1 is a machining tank in which the machining fluid 2 is stored and electrical discharge machining is performed therein, 3 is an electrode, 4 is a spindle that feeds the electrode 3 in the vertical direction, 5 is a workpiece, and 6 is a machining tank 1 and the workpiece 5 are mounted on a table that is guided so as to be movable in the direction of the arrow X in FIG. Reference numeral 7 denotes a saddle, which is guided so that the table 6 can be moved in the direction of arrow Y in FIG. 8 is a head that guides and attaches the main shaft 4; 9
9a is the column that supports the head 8, 9a is the front of the column, 9b is the rear of the column, 10 is the bed to which the column 9 is attached and supports it, 12 is the ventilation blower attached to the top of the column 9, and 13 is the machining fluid 1.
A fan cooler 14 is used to suppress the rise in liquid temperature due to machining energy and synchronize the liquid temperature with room temperature. 14 is a machining liquid tank that stores the machining liquid 2 to be supplied to the machining tank 1.

The electric discharge machining apparatus generates electric discharge between an electrode 3 and a workpiece 5 in a machining fluid 2 stored in a machining tank 1 by supplying electric discharge energy from another power source (not shown). This is to perform electrical discharge machining of object 5.

At this time, the temperature of the machining fluid 2 rises due to the discharge energy, and the machining tank 1 and table 6 are heated by the rise in fluid temperature. Its temperature rises above the surrounding air temperature. 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 machining apparatus main body. In order to suppress the temperature rise of the machining fluid 2, the machining fluid inside the machining fluid tank 14 is cooled by the fan cooler 13, but the temperature of the machining fluid 2 still rises by about 4 to 5° C. under maximum machining conditions. Therefore, radiant heat 1 shown by the arrow in FIG.
1 is generated, and this radiant heat 11 heats the column front surface 9a facing the heat generation source, the surface temperature of these increases, and the processing heat temperature distribution becomes non-uniform. On the other hand, it has become clear that changes in the environment such as room temperature can cause the temperature distribution to become uneven due to differences in the heat capacity of each part of the processing equipment.
It should be noted that the cause of the change in local temperature distribution such as in the column 9 due to an increase in the temperature of the machining fluid 2 during machining and the change in the temperature distribution of the entire machining equipment due to environmental changes such as room temperature are different. Therefore, they can occur independently.

Therefore, in conventional electrical discharge machining equipment,
When electrical discharge machining of the workpiece 5 is continued, the surface temperature of the mechanical structure facing the heat source increases compared to other surface temperatures, and as a result, for example, as shown by the two-dot chain line in FIG. 9a, the main spindle 4 was thermally deformed, and the position of the electrode 3 was shifted from the position indicated by ε in FIG. 4 compared to the initial stage of machining, which resulted in drawbacks such as deterioration of machining accuracy of the workpiece 5. Furthermore, even if the machining fluid 2 is cooled by the fan cooler 13, depending on the capacity of the fan cooler 13, the
Since the liquid temperature increased by ~5°C, processing accuracy deteriorated. On the other hand, as mentioned earlier, changes in room temperature will cause temperature unevenness due to differences in heat capacity of each part of the processing equipment, and if the temperature difference in the vertical direction of the outside air is particularly large, processing accuracy will also deteriorate. was. FIG. 5 shows the actual measurement results of the temperature distribution and displacement amount of the processing equipment when the room temperature changes. Furthermore, FIG. 6 shows temporal changes in relative displacement occurring between the electrode 3 and the workpiece 5 due to changes in room temperature. Even if the processing machine is cooled by installing the ventilation blower 12 at the top of the column or at the rear of the bed and blowing in outside air, the temperature of the processing fluid 2 increases during processing, so the workpiece 5 facing the processing fluid 2 A temperature difference occurs between the table 6, saddle 7, etc. and the column 9, bed 10, etc. that are cooled by the ventilation blower 12, which upsets the temperature balance of the entire processing device and degrades processing accuracy. In other words, during actual machining, the part facing machining fluid 2 has a temperature close to the machining fluid temperature, and the other parts have a temperature close to room temperature, so a difference in thermal expansion occurs between these parts, and this causes the relative position This is the biggest cause of misalignment. Conventional electric discharge machining apparatuses have insufficient countermeasures against this point, and therefore have the disadvantage of causing deterioration in machining accuracy.

[Summary of the invention]

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and by providing a device that performs ventilation cooling of the main body of the processing device using the exhaust of the cooling means for processing fluid, the mechanical structure can be improved. To provide an electric discharge machining device capable of performing extremely highly accurate machining by preventing relative positional deviation between an electrode and a workpiece due to thermal deformation and reducing machining errors caused by the relative positional deviation. The purpose is to

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

In Fig. 1, 1 is a machining tank, 2 is a machining liquid, and 3 is a machining tank.
4 is an electrode, 4 is a main shaft that supports the electrode 3 and feeds it in the vertical direction, 5 is a workpiece, 6 is a table that fixes the workpiece 5 and the processing tank 1 and feeds it in the X direction, 7
is a saddle that feeds in the Y direction (perpendicular to the drawing), 8 is a head that guides the main shaft, 9 is a column that holds the main shaft, 10 is a bed that fixes the column,
13 is a cooling means such as a fan cooler for cooling the machining fluid 2 (hereinafter referred to as a fan cooler); 14 is a machining fluid tank; 15 is an air intake to the fan cooler 13;
16 is an exhaust from the fan cooler 13, 17 is a fan cooler exhaust duct, 18 is a ventilation guide installed inside the bed 10, 19 is an exhaust port provided at the top of the column, and 20 is a machining fluid supply pump.

Next, the operation of the embodiment shown in FIG. 1 will be explained.

When electric discharge is generated between the electrode 3 and the workpiece 5 in the machining fluid 2 stored in the machining tank 1, and the workpiece 5 is discharge-machined, the machining fluid 2 in the machining tank 1 is The machining fluid is collected in the machining fluid tank 14 in a state where the temperature has increased. While the machining fluid is being supplied from the machining fluid tank 14 to the machining tank 1 by the machining fluid supply pump 20, the high temperature machining fluid is cooled by the fan cooler 13 and supplied to the machining tank 1. The thermal energy of the machining fluid 2 carried away by the fan cooler intake air 15 warms the fan cooler intake air 15 itself, so the fan cooler exhaust air 16 passes through the fan cooler exhaust duct 17 to the bed 10 in a form whose temperature has increased by the amount of heat exchanged compared to the intake air 15. It passes through the inside of the column 9 and is discharged from the exhaust port 19 to the top of the column 9 and the front of the bed 10.

Therefore, the machining fluid 2 cooled in the machining tank 1
is supplied, it is possible to suppress the temperature rise of the machining fluid 2 in the machining tank 1 even though a large amount of machining energy is generated. By suppressing the temperature rise of the machining fluid 2, the temperature rise of the electrode 3, spindle 4, workpiece 5, table 6, saddle 7, and head 8, which are affected by heat radiation from the machining tank 1, can be reduced compared to when the fan cooler 13 is not installed. can be significantly suppressed compared to

However, even if the temperature rise of the electrode 3 and the like is suppressed, there is a slight rise in temperature, for example, 2 to 5°C.

However, since the fan cooler exhaust 16 is passed through the column 9 and the head 10, the electrode 3, spindle 4, workpiece 5, table 6, saddle 7
The temperature difference between the column 9 and the head 10 can be reduced to a negligible extent, and the temperature distribution of the entire electric discharge machining apparatus can be made more uniform.

FIG. 2 shows another embodiment in which the fan cooler 13 is installed directly on the bed 10.

Further, in this embodiment, the fan cooler 13 is connected in series between the machining tank 1 and the machining liquid tank 14, but the same effect can be obtained even when the fan cooler 13 is connected in parallel as shown in FIG. Furthermore, fan cooler 13 is 1
It is also possible to use a plurality of fan coolers 13 instead of one fan cooler 13, thereby making it possible to further equalize the temperature of the entire electrical discharge machining apparatus.

Although the embodiments of this invention have been described in detail above, this invention is not limited to the above embodiments.
It goes without saying that the invention can be modified and implemented as appropriate within the scope of the gist of the invention.

〔Effect of the invention〕

As described above, according to the electrical discharge machining apparatus according to the present invention, the exhaust from the fan cooler for cooling the machining fluid is used to ventilate the parts that are not easily affected by the temperature rise of the machining fluid. Compared to the case where the machining fluid is directly used for ventilation, the temperature difference between the parts that are affected by the temperature rise of the machining fluid and the parts that are less affected is smaller, and the temperature balance of the entire electrical discharge machining equipment can be maintained. Since it is possible to eliminate the relative positional deviation between the electrode and the workpiece caused by the difference in the amount of thermal deformation of each part of the structure, it is possible to perform electrical discharge machining of the workpiece with extremely high precision. Furthermore, since it functions as both a ventilation blower and a fan cooler, it has the effect of reducing the cost and noise of the entire device.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram showing the configuration and operating mode of one embodiment of the present invention, FIGS. 2 and 3 are schematic explanatory diagrams showing other embodiments of the invention, and FIG.
The figure is a schematic explanatory diagram showing the configuration of a conventional electric discharge machining device and its operating mode. Figure 5 is a perspective view showing the actual measurement results of the temperature distribution and displacement amount in the electric discharge machine when room temperature changes. Figure 6 is a diagram showing the temperature change in room temperature. The temporal change in relative displacement that occurs between the electrode and the workpiece due to
It is a characteristic diagram shown separately in Y and Z directions. 2... Processing fluid, 3... Electrode, 5... Workpiece, 9
... Column, 10 ... Bed, 13 ... Fan cooler, 14 ... Processing liquid tank, 16 ... Fan cooler exhaust, 17 ... Fan cooler exhaust duct, 1
8...Ventilation guide. Note that the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] 1. In an electric discharge machining apparatus that processes a workpiece by generating electric discharge between the workpiece and an electrode placed opposite to the workpiece, at least the workpiece and a bed for placing a machining tank containing a machining fluid in which the electrode is immersed, and a column for supporting the electrode;
a machining fluid tank for storing machining fluid to be supplied to the machining tank; a cooling means for cooling the machining fluid stored in the machining fluid tank or the machining fluid to be supplied to the machining tank; and a cooling means provided in the bed. An electric discharge machining apparatus characterized in that it is equipped with an exhaust gas supply means consisting of an exhaust intake port through which cooler exhaust gas is taken in, and a ventilation guide that communicates the inside of the bed and the inside of the column. 2. The electric discharge machining apparatus according to claim 1, wherein the cooling means is a fan cooler.