JP2001353625A - Electric discharge machine, and thermal displacement preventive method of scale for positioning control in electric discharge machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric discharge machine capable of preventing any thermal displacement caused by the local heat in the vicinity of a scale for controlling the positioning, and improving the machining accuracy. SOLUTION: A scale unit 11 for controlling the positioning in the electric discharge machine for implementing the electric discharge machining by circulating a working fluid with the fluid temperature regulated in a table with a work placed thereon comprises fans 1-5 for feeding air inside the scale unit, a temperature regulator 6 for regulating the temperature of the air and feeding the air into the scale unit, and a temperature measuring means 9 for measuring and monitoring the temperature of air. The temperature of the scale unit 11 is consistently maintained at a predetermined value by feeding the temperature-regulated air to the scale unit 11, and the local heat influence in the vicinity thereof is eliminated to prevent the thermal displacement of a scale part. In addition, when the temperature of the air measured by the temperature measuring means 9 is deviated from the predetermined value, the abnormality in temperature is determined to stop the machine via a controller 14 and an NC control panel 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a full closed loop control type electric discharge machine for performing electric discharge machining by circulating a machining liquid whose temperature has been adjusted on a table on which a work is placed, and a positioning control scale in the electric discharge machine. The present invention relates to a method for preventing thermal displacement of a substrate.

[0002]

2. Description of the Related Art Conventionally, in a machine tool, since a change in room temperature adversely affects positioning accuracy and the like, the machine is installed in a constant temperature room with a constant room temperature. There was no problem if the temperature was controlled,
In recent years, machines have become more compact for the purpose of reducing the installation space for machines, etc.Therefore, a drive motor as a heat source and a scale detection amplifier are placed near the scale section for positioning control, The exhaust heat of the oil matic and the NC power supply are also arranged near the scale section, and the scale section for positioning control is easily affected by heat even in a constant temperature room. Under the influence of these local heats, the expansion and contraction of the scale itself is different from the expansion and contraction of the machine body.

FIG. 8 shows test results for examining the influence of the temperature on the (Y-axis) scale in a fully closed loop control type electric discharge machine. In an electric discharge machine installed in a constant temperature room with a room temperature of 27 to 28 ° C., the distance (distance) between two points of a workpiece and a reference origin (table reference point) was measured, and the displacement was measured. The same point was repeatedly measured, and the displacement was measured when a hot air of 40 ° C. was blown around the Y-axis scale portion using a drier. In this test, it was assumed that the hot air of 40 ° C. was used because the exhaust heat of the oilmatic was 40 ° C., which hit the scale. According to the test results, when the room temperature changes at 1 ° C., the (X, Y, Z) displacement amount is a minute displacement of about ± 2 μm, but the 28 ° C. Y-axis scale is blown with hot air at 40 ° C. for 5 minutes. If left later, the displacement of the Y-axis scale is
A displacement (position shift) of 12 μm occurred. This indicates that the scale itself expands due to the thermal expansion of the scale, and it appears that the measured object is displaced, but the measured object itself has not been displaced. As described above, the scale is greatly affected by the temperature, which indicates that the coordinate reading of the machine position cannot be accurately and accurately performed unless the heat source around the machine as described above is excluded. That is, although the local heat has little effect on the expansion and contraction of the entire machine, the scale responds sensitively.

[0004] Even in a cutting machine other than the electric discharge machine, even if the cutting machine is installed in a constant temperature chamber, the temperature is increased by the recent high-speed machining and the heat generated by the spindle head and the driving motor of the column causes heat displacement, thereby causing the machining. There are problems such as adversely affecting accuracy. Therefore, a method of blowing air to the ball screw portion in order to cool the ball screw has been adopted (see Japanese Patent Application Laid-Open No. Sho 60-62438).

[0005]

However, although attempts have been made to suppress the rise in temperature of the heat source itself as described above, it is difficult to eliminate the effects of each of the many heat sources, and this is costly. Becomes
Further, separating the NC control panel, which is a heat source, from the main body of the apparatus is difficult and inefficient in work, requires more space, and loses the meaning of compactness. In addition, at present, the electric discharge machine does not perform high-speed machining as the cutting machine described above,
Although the temperature influence of the heat of rotation of the ball screw is small, in recent years, the influence of the heat of the linear motor as a heat source near the scale described above has been regarded as a problem due to high-speed machining using a linear motor. Therefore, instead of suppressing the temperature around the scale, heat that does not affect the expansion and contraction of the entire apparatus body is left as it is, and a method that eliminates the temperature influence of the scale itself for positioning control and is inexpensive is desired. Was.

In view of the foregoing, the present invention has been made in view of the above-mentioned unsolved problems of the prior art, and is intended to prevent a thermal displacement due to local heat around a positioning control scale and to provide a processing accuracy. It is an object of the present invention to provide an electric discharge machine capable of improving the electric field and a method for preventing thermal displacement of a positioning control scale in the electric discharge machine.

[0007]

In order to achieve the above object, an electric discharge machine according to the present invention is directed to an electric discharge machine for performing electric discharge machining by circulating a machining fluid whose temperature is adjusted on a table on which a work is placed. A blower that supplies air to the inside of the scale unit for positioning control, a temperature controller that adjusts the temperature of the air and sends the air to the inside of the scale unit, and a temperature measurement unit that measures and monitors the temperature of the air is provided. It is characterized by being.

In the electric discharge machine of the present invention, a control means for judging an abnormal temperature when the air temperature deviates from a predetermined temperature and stopping the machine based on the measurement result of the air temperature by the temperature measuring means is provided. Preferably, it is provided.

In the electric discharge machine of the present invention, a liquid temperature measuring means for measuring the temperature of the machining liquid is provided, and the air temperature is controlled so as to be the same as that of the machining liquid. Control means for comparing the measurement result of the working fluid temperature with the measurement result of the air temperature, determining that the temperature is abnormal when the temperature difference between the two deviates from a predetermined temperature difference, and stopping the machine. Is preferred.

[0010] In the electric discharge machine of the present invention, the control means may determine whether the air temperature deviates from a predetermined temperature and / or a temperature difference between the air temperature and the machining fluid temperature deviates from a predetermined temperature difference. In this case, it is preferable to temporarily stop the machine when it is determined that the temperature is abnormal, and to stop the machine if the temperature abnormality does not recover even after the preset time has elapsed.

In the electric discharge machine according to the present invention, it is preferable that a hose for supplying the air to the scale unit and an outer periphery of the scale unit are covered with a heat insulating material.

Further, the method for preventing thermal displacement of a positioning control scale in an electric discharge machine according to the present invention is directed to a positioning method for an electric discharge machine which performs electric discharge machining by circulating a machining liquid whose temperature is adjusted on a table on which a work is placed. It is characterized in that temperature-adjusted air is sent into the inside of the control scale unit, and the temperature of the air is measured and monitored.

A method for preventing thermal displacement of a positioning control scale in an electric discharge machine according to the present invention is directed to a method for electric discharge machining in which a machining fluid whose temperature is adjusted is circulated to a table on which a workpiece is installed to perform electric discharge machining. Sending temperature-adjusted air to the inside of the scale unit, measuring and monitoring the temperature of the air, determining that the temperature is abnormal when the air temperature deviates from a predetermined temperature, and stopping the machine. And

A method for preventing thermal displacement of a positioning control scale in an electric discharge machine according to the present invention is a method for positioning control in an electric discharge machine which performs electric discharge machining by circulating a machining fluid whose temperature is adjusted on a table on which a work is placed. The temperature-controlled air is sent into the scale unit and the temperature of the air is managed to be the same as the working fluid, the temperature of the air and the temperature of the working fluid are monitored, and the air temperature and The method is characterized in that the temperature is compared with the working fluid temperature, and when the temperature difference between the two deviates from a predetermined temperature difference, it is determined that the temperature is abnormal and the machine is stopped.

A method for preventing thermal displacement of a positioning control scale in an electric discharge machine according to the present invention is directed to an electric discharge machine for performing electric discharge machining by circulating a machining fluid whose liquid temperature is adjusted on a table on which a work is placed. The temperature-adjusted air is fed into the scale unit and the temperature of the air is controlled to be the same as the working fluid, and the temperature of the air and the temperature of the working fluid are monitored to adjust the air temperature. When deviating from the prescribed temperature,
Alternatively, the air temperature and the working fluid temperature are compared, and when the temperature difference between the two deviates from a predetermined temperature difference, it is determined that the temperature is abnormal and the machine is stopped.

In the method for preventing thermal displacement of a positioning control scale in an electric discharge machine according to the present invention, when the air temperature deviates from a predetermined temperature and / or the air temperature and the machining fluid temperature are compared. When the temperature difference deviates from the predetermined temperature difference, it is determined that the temperature is abnormal, the machine is temporarily stopped, and the machine is stopped when the temperature abnormality does not recover even after exceeding a preset time. preferable.

[0017]

According to the electric discharge machine and the method for preventing thermal displacement of the positioning control scale according to the present invention, air is supplied so as to keep the temperature of the scale unit constant and is protected by the air, so that the local area around the scale unit can be protected. This can eliminate the influence of excessive heat, reduce or prevent the thermal displacement of the scale portion, and improve the EDM accuracy.

Further, by making the temperature of the processing fluid and the temperature of the scale unit substantially coincide with each other, the temperature of the scale unit can follow the temperature rise of the processing fluid due to the processing heat during processing, and can be immersed in the processing liquid. By setting the temperature to be the same as the temperature of the work, the scale for positioning control can be expanded and contracted in accordance with the expansion and contraction of the work, and the processing accuracy can be further improved. Further, by forming the scale with the same material as the work, the thermal expansion coefficient can be made the same, and the processing accuracy is further improved.

In addition, since the temperature of the air can be automatically monitored in order to cope with an abnormality such as a failure of the air supply device for blowing the air to the scale unit, highly reliable processing can be performed.

In addition, it is possible to prevent the plume of the electric discharge machining from entering the scale unit by the air blown to the scale unit. Occurrence can also be prevented.

[0021]

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

FIG. 1 is a block diagram showing the configuration of an embodiment for implementing a method for preventing thermal displacement of a scale unit in an electric discharge machine according to the present invention.

In FIG. 1, reference numeral 11 denotes a positioning device disposed in a machine body 10 of a fully closed loop control type electric discharge machine for performing electric discharge machining by circulating a machining liquid whose temperature is adjusted on a table on which a work is placed. Linear scale unit for control, X-axis scale unit 11x, Y-axis scale unit 11y, Z-axis scale unit 11z
Consists of Then, in the scale unit 11, one end thereof is connected to the hose 8 (8x, 8x), respectively.
y, 8z) and is substantially sealed so that no other air enters from other than the hose 8, and the other side is provided with an air vent hole 12 (12x, 12y, 12z). 8x, 8y, 8z) passes through the inside of each scale unit 11 (details are not shown), and the temperature-controlled air passes through air vent holes 12 (12x, 12y) provided on the opposite side. , 12z)
Is discharged from

1 is a scale unit 11 (11x, 1
1y, 11z) is an air source of a blower for blowing air into the inside, and the air sent from the air source 1 is supplied to a filter 3, a mist separator 4, and a pressure reducing valve 5 incorporated in an air unit panel 2. After that, it is sent to the temperature controller 6. The filter 3 removes dust from the air, the mist separator 4 adjusts the humidity of the air, and the pressure reducing valve 5 functions to keep the air supply at a constant pressure. The air adjusted in the air unit panel 2 is sent to the temperature controller 6 and is adjusted to a predetermined temperature by a heat exchanger (not shown) in the temperature controller 6. XY through each hose 8 (8x, 8y, 8z)
Each scale unit 11 (11x, 11
y, 11z). 9 is a scale unit 11
Temperature measuring means such as a temperature sensor as a temperature monitoring means for monitoring whether there is any abnormality in the temperature of the air supplied to the hose. In FIG. 1, it is installed on a hose 8x connected to the X-axis scale unit 11x. The temperature of the air supplied to the X-axis scale unit 11x (ie, the temperature of the X-axis scale unit 11x) is measured. Further, the temperature measuring means 9 is electrically connected to the temperature controller 6, and the temperature controller 6 and the temperature measuring means 9 are provided with a predetermined temperature set in advance and an air temperature measured by the temperature measuring means 9. When the air temperature deviates from a predetermined temperature, it is determined that an abnormality has occurred, and means for activating alarm means (not shown) and the like are provided.

In the embodiment constructed as described above, the scale unit 11 (11x, 11x,
11y, 11z) is supplied with air whose temperature has been adjusted to a predetermined temperature by the temperature controller 6, and since the air whose temperature has been adjusted flows through the scale unit 11, the scale units 11 (11x, 11y, 11z) The predetermined temperature is always maintained, and is protected from the nearby heat source without being affected by the nearby heat source. Therefore, the positioning control scale is not affected by local heat in the periphery, can reduce or prevent thermal displacement, and can improve processing accuracy. Furthermore, if each hose 8 and scale unit 11 are covered with a heat insulating material, heat release can be prevented, the temperature can be reliably maintained at a predetermined temperature, and the thermal displacement of the scale can be further reduced.

The scale unit 11 (11x,
11y, 11z), the temperature of the air supplied is constantly measured by the temperature measuring means 9. For example, the air temperature measured by the temperature measuring means 9 is reduced to a predetermined temperature due to a failure of the apparatus or a failure of the piping. Is out of the range, and the temperature controller 6 generates a temperature abnormality such as inability to maintain the air at a predetermined temperature, the temperature controller 6 issues a temperature abnormality signal and issues alarm means (not (Shown) is activated to issue an abnormality alarm to notify the operator of the occurrence of a temperature abnormality. Workers can use this abnormal alarm to
Processing can be stopped by stopping the operation of the device. If the temperature of the air supplied to the scale unit 11 cannot be maintained at a predetermined temperature for some reason, the positioning control scale causes thermal displacement, which adversely affects the processing accuracy. By immediately reporting the temperature abnormality when the temperature abnormality occurs, it is possible to prevent the occurrence of the processing failure.

Next, another embodiment for implementing the method for preventing thermal displacement of the scale unit in the electric discharge machine of the present invention will be described with reference to FIG. In this embodiment, the machine is automatically stopped when a temperature abnormality occurs, and the same members as those in the above-described embodiment are denoted by the same reference numerals.

Also in this embodiment, the air whose temperature has been adjusted to a predetermined temperature by the temperature controller 6 is supplied to the scale unit 11 (11x, 11y, 1
1z) and the scale unit 11 (11x, 1x)
1y, 11z) are always maintained at a predetermined temperature and are protected from nearby heat sources. The temperature measuring means 9 measures the temperature of the air, and monitors the air temperature in the temperature controller 6 by comparing a predetermined temperature set in advance with the air temperature measured by the temperature measuring means 9. In this embodiment, the temperature controller 6 is electrically connected to the controller 14, and the controller 14 is electrically connected to the NC control panel 15 of the electric discharge machine. When a temperature abnormality occurs due to a device failure or a piping failure, the temperature controller 6 sends the temperature abnormality signal to the controller 1 using a communication function.
The controller 14 receives the signal and issues a stop command to the NC control panel 15 of the machine. Upon receiving the stop command, the NC control panel 15 stops the operation of the electric discharge machine and stops machining. In this case, it is also possible to directly send a temperature abnormality signal from the temperature controller 6 to the NC control panel 16.

As described above, in the present embodiment, when an abnormal temperature of the air supplied to the scale unit 11 occurs, the operation of the controller 14 and the NC control panel 15 is performed without the need for the operation of the operator. The operation of the electric discharge machine can be automatically stopped, and machining can be performed with high reliability.

FIG. 3 is a block diagram showing still another embodiment for implementing the method for preventing thermal displacement of a scale unit in an electric discharge machine according to the present invention. It is intended to be used in accordance with the temperature of the working fluid within a certain range.

In this embodiment, as shown in FIG.
A liquid temperature measuring means 18 such as a liquid temperature sensor for measuring the temperature of the processing liquid is provided in the processing liquid tank 17, and the liquid temperature measuring means 18 is electrically connected to the controller 14.
The temperature measuring means 19 such as an air temperature sensor for measuring the temperature of the air sent to the scale unit 11 is connected to the hose 8 (in FIG. 3, the hose 8z communicated with the Z-axis scale unit 11z). Provided in
This temperature measuring means 19 is also electrically connected to the controller 14. The temperature controller 6 in the present embodiment does not particularly require a function of comparing the predetermined temperature with the air temperature and generating a temperature abnormality signal or the like. The other configuration is the same as that of the above-described embodiment, and the same members are denoted by the same reference numerals.

In the present embodiment, the temperature of the air supplied to the scale unit 11 and the temperature of the processing liquid are adjusted to be constant before processing. In this case, the temperature of the air is adjusted by the temperature controller 6 in accordance with the temperature of the working fluid.
Next, the liquid temperature measuring means 18 provided in the processing liquid tank 17
, The temperature of the processing liquid in the processing liquid tank 17 is measured, and the temperature of the air supplied to the scale unit 11 is measured by the temperature measuring means 19.
The data relating to the temperature measured at 19 is sent to the controller 14. In the controller 14, based on the measurement results from the respective measurement means 18 and 19, the processing fluid tank 1
The controller 14 issues a stop command to the NC control panel 15 and detects a difference between the temperature of the working fluid in the nozzle 7 and the temperature of the air supplied to the scale unit 11. , The NC control panel 15 stops the operation of the electric discharge machine. Thereby, the processing can be performed with the processing liquid temperature, the temperature of the scale unit, and the temperature of the work in the same state, and the processing accuracy can be stabilized.

As means for matching the temperature of the air supplied to the scale unit 11 with the temperature of the working fluid, as shown in FIG. In the liquid tank 17, it can be passed while being immersed in the processing liquid. With this configuration, the temperature of the air can be adjusted to the temperature of the working fluid without using the temperature controller (6) as in the embodiment shown in FIG. Can be adjusted to the temperature of the working fluid. Further, in each of the embodiments described above, the temperature is adjusted by circulating the air whose temperature has been adjusted around the scale unit. However, the air may be circulated around the scale unit using a processing liquid.

Next, a method for preventing thermal displacement of the scale unit in the electric discharge machine according to the present invention will be further described with reference to FIG. FIG. 5 is a flowchart showing one embodiment of the temperature control method in the embodiment shown in FIG. 3 or FIG.

First, before processing, the scale unit 11
The temperature of the air to be blown into and the temperature of the working fluid are adjusted to be constant. This allows the operator to set the temperature of the air to be blown by the temperature controller 6 in accordance with the temperature of the working fluid. The processing start (step S1), the temperature T ₁ of the air to be blown into the scale unit 11 are measured by the temperature measuring means 19 (Step S2). At the same time, the temperature T ₂ of the machining fluid in the machining fluid tank 17 is measured by the fluid temperature measuring means 18.
(Step S3). In step S4, the temperature T measured by each of the measuring means 18 and 19, respectively.
_1, T ₂ are compared with the controller 14, T ₁ (the temperature of ie scale unit 11) air temperature for blowing the scale unit 11, when the temperature T ₂ of the machining fluid 1 ℃ or higher {T ₁ -T ₂ ≧ 1 (° C.)}, the controller 14 determines that the temperature is abnormal and the NC control panel 15
To give a machine stop command. This is because when the electric discharge machining starts, machining heat is generated and the machining fluid becomes high.

Here, a description will be given of the temperature change in the working fluid before and during the working. FIG. 7 shows a test graph in which the transition of the working fluid temperature before and during the working is measured. It can be seen that the temperature of the working fluid increases by about 1 ° C. For this reason, even if the temperature of the scale unit (the temperature of the air sent to the scale unit) and the temperature of the processing fluid are matched, the temperature of the processing fluid becomes higher due to the processing. Is set to T
₁ -T ₂ ≧ ₁ (℃) and leave narrow range, if the above temperature difference (T ₁ -T ₂₎ is more than 1 ° C., for a case where the temperature of the scale unit is high, the blowing It can be determined that some abnormality has occurred. That is, when the temperature T _{1 of} the air blown to the scale unit 11 (that is, the temperature of the scale unit 11) is higher than the temperature T _{2 of the} working fluid by 1 ° C. or more, the controller 14 controls the NC control panel 15 A stop command is issued, and the NC control panel 15 stops machining (step S7).

If T ₁ −T ₂ <1 (° C.) (step S 4), in step S 5, the temperatures T ₁ and T ₂ are further compared, and T ₁ −T ₂ <3 (° C.) In the case of, the liquid temperature of the working fluid has risen considerably,
This also means that a temperature abnormality has occurred, and the controller 14 issues a machine stop command to the NC control panel 15,
It is necessary to stop the machine so as to stop the processing (step S7). On the other hand, if the state where T ₁ −T ₂ <3 (° C.) is not maintained, the normal operation is continued (step S6), and thereafter, steps S2 to S6 are repeated, and the temperature of the air blown to the scale unit is increased. The machining is continued while measuring the temperature of the machining fluid and comparing and observing the two temperatures.

As described above, the temperature of the air blown to the scale unit and the temperature of the processing liquid are constantly measured during the processing, and
Machining can proceed while determining whether the operation is normal or abnormal, and high accuracy can be maintained in response to an abnormal state.

Next, another embodiment of the temperature control method in the embodiment shown in FIG. 3 or FIG. 4 will be described with reference to FIG. This method is a method to stop the machine when the temperature difference abnormality occurs several times repeatedly, and once the temperature is once due to some sudden temperature change such as when the connection wiring has a contact failure or when the room temperature changes. Even if an abnormality occurs, if the temperature abnormality can be automatically recovered, this is a convenient method for continuing processing.

In the flowchart shown in FIG. 6, steps S11 to S16 are the same as steps S1 to S6 in the flow shown in FIG. 5 described above, and a detailed description will be omitted.

In step S17, T ₁ −T ₂ ≧ 1
(° C.) (step S14) or T ₁
When −T ₂ <3 (° C.) (step S15),
When it is determined that a temperature abnormality has occurred, processing is temporarily stopped for a certain period of time to be in a waiting state (can be handled by a processing wait time command code). That is, the controller 14
A command to temporarily stop the machine is issued to the C control panel 15, and the NC control panel 15 temporarily suspends the processing of the device. Then, in step S18, after the lapse of a predetermined time, again, to measure the temperature T ₂ of the temperature T ₁ and working fluid blowing air (step S12, step S13), and whether both the temperature difference is restored to the normal state not (Step S14, Step S15), and when the abnormal state is recovered, normal operation is performed (Step S16).
On the other hand, if the recovery has not yet been performed, the processing is further suspended and the time is waited (step S18). The number of waiting times (n) is limited to three (n ≧ 3),
If the temperature abnormality cannot be recovered even after repeating steps S12 to S18 three times, the controller 14 issues a machine stop command to the NC control panel 15,
The NC control panel 15 completely stops machining (step S
19).

As described above, in this embodiment, the conditions for stopping the processing can be made stricter or relaxed, and it is possible to set the temperature difference and the number of recovery waits n according to the processing accuracy. . That is, when the processing accuracy is low, the stop condition is relaxed to give priority to the operation rate, and when the processing accuracy is high, the processing should be performed with emphasis on quality.

FIG. 3 shows the configuration of the embodiment shown in FIG.
Can be configured to combine the configurations of the embodiments shown in FIGS. 2A and 2B so as to view two types of monitoring: abnormality monitoring of the temperature of the air sent to the scale unit, and monitoring of the temperature difference between the working fluid temperature and the air temperature. In that case, it is desirable to prioritize the monitoring of the air temperature shown in FIG. 2 and stop the machine when the temperature of the air to be blown exceeds or falls below a predetermined temperature. As a result, double safety measures can be taken against failure of the temperature measuring means such as the temperature sensor.

In each of the above embodiments, only one temperature measuring means such as a temperature sensor for measuring the temperature of the scale unit is shown. However, a plurality of temperature measuring means may be provided. In addition, the temperature measuring means is not limited to one scale unit, but includes an X axis, a Y axis, and a Z axis.
It goes without saying that the temperature can be simultaneously detected by attaching to all the scale units of the shaft.

Further, according to the present invention, the temperature of the scale unit can be made to follow the temperature rise of the working fluid due to the working heat during working, and is made the same as the temperature of the work immersed in the working fluid. Thus, by forming the scale with the same material as the work, the thermal expansion coefficient can be made the same, and the processing accuracy is further improved. In addition, by blowing the temperature-controlled air to the scale unit, it is possible to prevent machining plumes caused by electric discharge machining from entering the scale unit with the air blown to the scale unit. Is always surrounded by clean air, it is possible to prevent the occurrence of abnormalities due to the contamination of the scale, and it is also possible to maintain good processing accuracy.

[0046]

As described above, according to the present invention,
By keeping the temperature of the scale unit constant and protecting it with air, it is possible to eliminate the influence of local heat in the surroundings, reduce or prevent thermal displacement of the scale unit, and improve the EDM accuracy. Can be improved.

Further, by making the temperature of the working fluid and the temperature of the scale unit substantially coincide with each other, the temperature of the scale unit can follow the temperature rise of the working fluid due to the working heat during the working, and can be immersed in the working fluid. By setting the temperature to be the same as the temperature of the work, the scale for positioning control can be expanded and contracted in accordance with the expansion and contraction of the work, and the processing accuracy can be further improved.

Further, since the temperature of the air can be automatically monitored in response to an abnormality such as a failure of a supply device of the air blown to the scale unit, highly reliable processing can be performed.

Further, it is possible to prevent the plume from being discharged by the electric discharge machining from entering the scale unit by the air blown to the scale unit. Generation can also be prevented, and good processing accuracy can be maintained.

As described above, according to the present invention, instead of suppressing the temperature of the heat sources around the many scale parts, it is possible to eliminate the influence of the temperature of the scale part itself for positioning control by an inexpensive method having high reliability. it can.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment for implementing a method for preventing thermal displacement of a scale unit in an electric discharge machine of the present invention.

FIG. 2 is a block diagram showing a configuration of another embodiment for implementing a method for preventing thermal displacement of a scale unit in the electric discharge machine of the present invention.

FIG. 3 is a block diagram showing a configuration of still another embodiment for implementing a method for preventing thermal displacement of a scale unit in an electric discharge machine of the present invention.

FIG. 4 is a block diagram showing a configuration of still another embodiment for implementing a method for preventing thermal displacement of a scale unit in an electric discharge machine of the present invention.

5 is a flowchart showing one embodiment of a temperature control method in the embodiment shown in FIG.

6 is a flowchart showing another embodiment of the temperature control method in the embodiment shown in FIG.

FIG. 7 is a graph showing measured temperature changes of a machining fluid before and during machining in an electric discharge machine.

FIG. 8 is a graph showing a change in a displacement amount due to a temperature change of a (Y-axis) scale in the electric discharge machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Air source 2 Air unit board 3 Filter 4 Mist separator 5 Pressure reducing valve 6 Temperature controller 7 Distribution unit 8 (x, y, z) Hose 9 Temperature measurement means 10 Machine body 11 (x, y, z) Scale unit 12 ( x, y, z) Air vent hole 14 Controller 15 NC control panel 17 Working fluid tank 18 Liquid temperature measuring means 19 Temperature measuring means

Claims (10)

[Claims] 1. An electric discharge machine for performing electric discharge machining by circulating a machining liquid whose temperature has been adjusted on a table on which a work is placed, and a blowing device for supplying air into a scale unit for positioning control and said air. An electric discharge machine, comprising: a temperature controller for adjusting the temperature and sending the air into the scale unit; and a temperature measuring means for measuring and monitoring the temperature of the air. 2. A control means for judging an abnormal temperature when the air temperature deviates from a predetermined temperature based on a measurement result of the air temperature by the temperature measuring means and stopping the machine. The electric discharge machine according to claim 1. A liquid temperature measuring means for measuring a temperature of the processing liquid, wherein the air temperature is controlled so as to be the same as the processing liquid, and a measurement result of the processing liquid temperature by the liquid temperature measuring means is provided. And control means for stopping the machine by judging an abnormal temperature when the temperature difference between the two deviates from a predetermined temperature difference by comparing the measured temperature of the air with the measurement result of the air temperature. Or the electric discharge machine according to 2. 4. The control means determines that the temperature is abnormal when the air temperature deviates from a predetermined temperature and / or when a temperature difference between the air temperature and the working fluid temperature deviates from a predetermined temperature difference. The electric discharge machine according to claim 2, wherein the machine is temporarily stopped, and the machine is stopped when the temperature abnormality does not recover even after a predetermined time has elapsed. 5. The scale unit according to claim 1, wherein a hose for supplying the air to the scale unit and an outer periphery of the scale unit are covered with a heat insulating material.
The electric discharge machine according to any one of claims 4 to 4. 6. An electric discharge machine for performing electric discharge machining by circulating a machining liquid whose liquid temperature has been adjusted on a table on which a workpiece is placed, wherein the air whose temperature has been adjusted is sent into a scale control unit for positioning. A method for preventing thermal displacement of a positioning control scale in an electric discharge machine, comprising measuring and monitoring the temperature of a workpiece. 7. An electric discharge machine for performing electric discharge machining by circulating a machining liquid whose liquid temperature has been adjusted on a table on which a workpiece is placed, wherein the air whose temperature has been adjusted is sent into a positioning control scale unit. Measuring and monitoring the temperature of the electric discharge machine, and determining that the temperature is abnormal when the air temperature deviates from a predetermined temperature, and stopping the machine. 8. An electric discharge machine for performing electric discharge machining by circulating a machining liquid whose liquid temperature has been adjusted on a table on which a work is placed, wherein the air whose temperature has been adjusted is sent into a scale unit for positioning control and the air is discharged. The temperature of the working fluid is managed to be the same as the working fluid, the temperature of the air and the temperature of the working fluid are monitored, and the air temperature and the working fluid temperature are compared to determine a temperature difference between the two. A method for preventing thermal displacement of a positioning control scale in an electric discharge machine, characterized in that when the temperature deviates from the temperature difference, the temperature is determined to be abnormal and the machine is stopped. 9. An electric discharge machine for performing electric discharge machining by circulating a machining liquid whose liquid temperature has been adjusted on a table on which a work is placed, wherein the air whose temperature has been adjusted is fed into a positioning control scale unit. The temperature of the processing liquid is managed to be the same temperature as the processing liquid, and when the air temperature deviates from a predetermined temperature by monitoring the temperature of the air and the temperature of the processing liquid, or the air temperature and the Prevents thermal displacement of the positioning control scale in an electric discharge machine characterized by comparing with the machining fluid temperature and determining that the temperature is abnormal when the temperature difference between the two deviates from the predetermined temperature difference and stops the machine. Method. 10. When the air temperature deviates from a predetermined temperature and / or when the temperature difference between the air temperature and the working fluid temperature deviates from the predetermined temperature difference, a temperature abnormality is detected. The discharge according to any one of claims 7 to 9, wherein the determination is made, the machine is temporarily stopped, and the machine is stopped if the temperature abnormality is not recovered even after a preset time has elapsed. A method for preventing thermal displacement of a positioning control scale in a processing machine.