JPH0230813B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to the improvement of electrical discharge machining equipment, and in particular, to prevent the processing machine body from deforming 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, numeral 2 denotes a machining fluid, 1 a machining tank that stores the machining fluid 2 and performs electrical discharge machining therein;
3 is an electrode, 4 is a main shaft for processing and feeding the electrode 3, 5 is a workpiece, and 6 is a table for attaching the processing tank 1 and the workpiece 5, which are arranged in the direction of the arrow X in FIG. It is made movable. 7
is a saddle that can move the table 6 in the direction of arrow Y in FIG. 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 were drawbacks such as deterioration in the processing accuracy of the workpiece 5. 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 had a cooling fan 12 installed at the top of the column 9 or at the rear of the bed 10 to cool the machine body by blowing in outside air, but the ventilation path was not clear. Ventilation inside the processing machine was insufficient. 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 processing machine temperature distribution and the amount of displacement when the room temperature changes when ventilation inside the processing machine is insufficient.
Further, FIG. 4 shows a temporal change in the relative displacement occurring between the electrode 3 and the workpiece 5 due to a change in room temperature.

[Summary of the invention]

The present invention was made in order to eliminate the drawbacks of the conventional products as described above.
By installing an appropriate ventilation guide inside the main structure to provide smooth ventilation inside the main structure and making the temperature distribution uniform throughout the main structure, the electrode 3 and workpiece 5 due to thermal deformation of the main structure can be prevented. It is an object of the present invention to provide an electric discharge machining apparatus that can reduce machining errors caused by relative positional deviation between the two and perform highly accurate machining.

[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-section 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 guide is installed inside the processing machine, which is a feature of the present invention, and its operating mode. FIG. 6 and FIG. 7 each show an embodiment in which the external shape of the ventilation guide is different, and in each figure, A is a front view, and FIG. 7 is a longitudinal sectional view. In the figure, reference numeral 9 is a column, 10 is a bed, 13 is a ventilation guide installed inside these processing machine structures, and 13' is a flange for attachment.
In FIG. 5, by installing the ventilation guide 13 inside the processing machine, the ventilation is concentrated on the inner surface of the processing machine, so that the amount of heat exchange increases. Therefore, the temperature distribution of the processing machine remains uniform even when the environment changes.
Deformation due to local temperature rise of the processing machine is reduced. Note that the length of the arrow in the figure is drawn in proportion to the wind speed.

Next, the operation shown in FIG. 5 will be explained. Although not shown in the drawing, as already explained in FIG.
When performing electric discharge machining on the workpiece 5 by generating an electric discharge between the
and radiant heat 1 dissipated from a heat source such as a table 6
1 heats the front of column 9, but ventilation guide 13
By installing the inside of the column 9, the ventilation guide 13
Since outside air is supplied to the ventilation fan 12 into the space between the column 9 and the column 9, the column 9 is cooled. Therefore, the temperature distribution of the column 9 is kept uniform, and as a result, thermal deformation of the column 9 due to an increase in the temperature of the machining fluid 2 does not occur. Furthermore, the same effect can be obtained against environmental changes such as room temperature and sunlight, and therefore the workpiece 5 can be subjected to electric discharge machining with extremely high accuracy.

FIG. 8 shows another embodiment of the invention. Reference numeral 14 in the figure is a ventilation duct, which is installed inside the bed 10, and the ventilation introduced by the cooling fan 12 is directed from the tip of the ventilation duct 14 to the bed 10 as shown by the arrow in the figure. After flowing along the inner wall and cooling it, a space is formed inside the column 9 between the outside of the ventilation guide 13 and the inner wall of the column, the head of which is oriented in a direction opposite to that of the embodiment shown in FIG. and flows out of the processing machine. At this time, since the inner wall of the column 9 is used, the same effect as in the embodiment shown in FIG. 5 can be obtained.

〔Effect of the invention〕

As described above, according to the electric discharge machining apparatus according to the present invention, radiant heat from heat sources such as the machining fluid, the machining tank that stores the machining fluid, and the table on which the machining tank and the workpiece are attached, room temperature, sunlight, etc. In response to changes in environmental temperature, a ventilation guide is installed inside the processing machine and the column and bed are ventilated and cooled by outside air blown from the cooling device, thereby making the temperature distribution uniform throughout the main structure. Therefore, the thermal influence from the heat generation source on the mechanical structure can be reduced as much as possible, thereby eliminating relative positional deviation between the electrode and the workpiece due to thermal deformation of the processing machine body.
Therefore, it is possible to perform electrical discharge machining of a workpiece with high accuracy.

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing the configuration and operating mode of a conventional electrical discharge machine, Figure 2 is a sectional view showing the ventilation inside the conventional electrical discharge machine, and Figure 3 is a diagram showing the ventilation inside the machine. Figure 4 is a perspective view of the device showing the actual measurement results of the temperature distribution and displacement amount of the processing machine when the room temperature changes. , a diagram shown in each Z direction, FIG. 5 is a vertical cross-sectional view showing the internal structure and internal ventilation state of an electrical discharge machining apparatus which is an embodiment of the present invention, and FIGS. 6 and 7 are respectively shown in FIG. An example of the shape of the ventilation guide in the embodiment is shown, and in each figure, A is a plan view, B is a side view, and FIG. 8 is a longitudinal sectional view showing 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 guide, 13' ... mounting flange, 14 ... ventilation duct. Note that in FIG. 2, FIG. 5, and FIG. 6, arrows indicate flow velocity vectors, and the length of the arrow corresponds to the flow velocity. In addition, the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. In an electric discharge machining device that processes a workpiece by generating electric 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 electric discharge machining device for cooling. In addition to connecting the devices, a cylindrical ventilation guide having a substantially conical upper part is disposed within the column, and the upper part of the ventilation guide and the ventilation hole are connected to each other, and the ventilation guide and the inner wall of the column are connected to each other. A ventilation passage is formed between the columns, and a ventilation hole is provided in the bottom plate of the column to communicate the ventilation passage and the bed of the electric discharge machining apparatus, and outside air blown from the cooling device to the ventilation passage is passed through the column. An electrical discharge machining apparatus characterized in that the electric discharge machining apparatus is configured to be guided downward along an inner wall and into the bed through the ventilation hole. 2. In an electrical discharge machining device that processes a workpiece by generating an electric discharge between electrodes and a workpiece that are arranged opposite to each other, an electric discharge machining device is installed in a column of the electrical discharge machining device, and the upper part is fixed to the ceiling of the column. a cylindrical ventilation guide with a substantially conical lower part; disposed within the bed of the electrical discharge machining apparatus, one end fixed to a side wall of the bed and connected to a cooling device provided outside the machine; a ventilation duct whose other end opens near the side wall of the bed facing the side wall, the column and the bed are communicated through a ventilation hole, and an exhaust hole is provided on the outer periphery of the ventilation guide on the ceiling of the column. outside air blown from the cooling device to the ventilation duct is sent into the bed from the opening of the ventilation duct, turned around, guided in the opposite direction along the inner wall of the bed, and then passed through the ventilation hole to the column. An electric discharge machining apparatus characterized in that an air passage is formed which is guided along an inner wall of the machine and discharged from the exhaust hole to the outside of the machine.