JP2000271869A - Working fluid feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a working fluid feeder capable of verifying the replacement timing of an impeller in advance. SOLUTION: During cutting of a work 12 with a wire saw, the flow rate of slurry flowing through a supply pipeline 15 is detected by a flow meter 33. The flow meter 33 is disposed on a downstream side from a heat exchanger 20 in the supply pipeline 15. The flow rate of slurry detected by the flow meter 33 is converted into a voltage value and fed to an inverter 34 serving as a speed controller. The voltage value is processed by the inverter 34, and its frequency is converted to control the impeller speed of a feed pump 19. A display 35 is connected to the inverter 34 and warningly-displays the degree of wear to the impeller if the frequency of the inverter 34, as an input, exceeds a warning value determined in advance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a machining fluid supply device for supplying a machining fluid such as a slurry to a machining section of a machine tool or the like by driving a pump.

[0002]

2. Description of the Related Art Generally, in a wire saw configured to cut a workpiece made of ingot into a wafer,
While the wire is running, an aqueous or oily slurry containing loose abrasive grains is supplied onto the wire. In this state, the work is pressed against the wire and is brought into contact with the wire to cut the work. At this time, the slurry is supplied by a pump, and loose abrasive grains contained in the slurry wear the impeller of the pump. If the impeller wear progresses to a certain degree or more, even if the impeller rotation speed is increased,
Predetermined slurry flow rate cannot be maintained.

[0003]

On the other hand, the pump is controlled by an inverter so that the slurry flow rate is constant.
It is also conceivable that the speed is adjusted automatically. However, in such a case, since the slurry flow rate is kept constant, the degree of impeller wear is not apparent. As the impeller wear progresses, there is a possibility that the slurry flow rate suddenly decreases. In such a case, for example, in a wire saw,
The processing accuracy before and after the change in the slurry flow rate will be different, and a defective product may even be formed.
In order to avoid this, regular inspection of the impeller part is indispensable, but since the impeller part is arranged in the slurry flow path, inspection work involving disassembly of the pump is troublesome. Met.

[0004] The present invention has been made by focusing on such problems existing in the prior art. It is an object of the present invention to provide a working fluid supply device capable of confirming the impeller replacement time in advance without disassembling the pump.

[0005]

In order to achieve the above object, the invention according to claim 1 comprises a detecting means for detecting a change in load acting on a pump and a degree of wear of an impeller of the pump accordingly. And a display means for indicating the above.

Accordingly, the load acting on the pump fluctuates according to the degree of wear of the impeller, and the fluctuation is detected by the detecting means. Then, the degree of wear of the impeller can be easily and always confirmed by the display means according to the detection result.

According to a second aspect of the present invention, in the first aspect, a control means for controlling the supply flow rate to be constant is provided. Therefore, in order to maintain uniform processing accuracy, the supply flow rate of the processing liquid can be kept constant.

According to a third aspect of the present invention, in the second aspect of the present invention, the detecting means detects the flow rate of the machining fluid, and the pump rotational speed is controlled in accordance with the detection result from the detecting section. A speed control device for controlling is provided, and the degree of wear of the impeller is displayed according to a frequency change of the speed control device.

Therefore, the degree of wear of the impeller can be confirmed by detecting the supply flow rate of the working fluid. According to a fourth aspect of the present invention, in the third aspect, the gist is that the speed control device constitutes the control means.

Therefore, since the speed control device also serves as the control means, the structure of the working fluid supply device can be simplified.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a slurry supply apparatus will be described below in detail with reference to the drawings.

As shown in FIG. 1, in a wire saw in which a workpiece 12 is cut into a wafer, a slurry as a working fluid is supplied from a slurry supply pipe 13 onto the wire 11 while the wire 11 is running. You. In this state, the work 12 is pressed into contact with the wire 11, and the work 12 is cut into a slice. The slurry is a mixture of an oily or aqueous dispersion and abrasive grains.

The slurry storage tank 14 stores slurry therein. The slurry storage tank 14 and the slurry supply pipe 13 are connected by a supply pipe 15. The slurry collection tank 16 is disposed below the wire 11, and the slurry collection tank 16 and the slurry storage tank 14 are connected by a collection pipe 17. The recovery pump 18 is disposed in the recovery pipe line 17, and the slurry dropped from the wire 11 into the slurry recovery tank 16 is moved to the slurry storage tank 14 via the recovery pipe line 17 by the operation of the recovery pump 18. Will be returned. In this way, the slurry is supplied in the slurry supply device in the direction of the arrow in the figure.

The supply pump 19 is connected to the slurry storage tank 14.
The slurry in the slurry supply tank 14, which is disposed in the nearby supply pipe 15 and is operated by the supply pump 19,
The slurry is supplied from the slurry supply pipe 13 to the wire 11 of the wire saw via the supply pipe 15.

The heat exchanger 20 is arranged downstream of the supply pump 19. And the slurry is heat exchanger 2
Cooled by 0 and maintained at a constant temperature. The slurry return mechanism 22 is arranged at the highest position in the slurry supply device as shown in FIG. 2 and is connected to the supply pipe line 15 via a branch pipe 21 via a cylinder valve 23. The cylinder case 23 of the cylinder valve 23 is provided with a cylindrical cylinder chamber 25 opened downward. A port 26 is connected to the cylinder chamber 25 so as to communicate with the lower end of the cylinder chamber 25. A piston-like valve body 27 is provided in the cylinder chamber 25, and the valve body 27 faces a valve seat 28 and opens and closes a port 26.

On the side surface of the valve case 24, two ports 29, 30 are vertically arranged with a valve body 27 interposed therebetween so as to communicate with the cylinder chamber 25. The two ports 29 and 30 are connected to the air supply source 31 by the switching valve 3.
2, respectively.

In the slurry return mechanism 22, when the wire saw is operated, the switching valve 32 is at one of the switching positions, compressed air is being sent from the air supply source 31 to the port 29, and the valve seat 28 is shown in FIG. Port 26 is closed at the position where As a result, the slurry is supplied to the supply piping 15
The slurry is sent out inside the slurry supply pipe 13 without flowing into the slurry return mechanism 22.

On the other hand, when the slurry staying in the supply pipe line 15 is returned to the slurry storage tank 14 or the slurry recovery tank 16 when the wire saw is not operated, the switching valve 32 is switched to the other position, and By sending compressed air from the air supply source 31, the valve seat 2
8 is moved upward from the position shown in FIG. 2 and port 26 is opened. As a result, the compressed air is sent into the supply pipes 15 on both sides through the branch pipe 21, and the compressed air is supplied into the supply pipes 15 and the heat exchanger 20.
The slurry staying inside the tank is returned to the slurry storage tank 14 or the slurry recovery tank 16, and the slurry is prevented from staying in the supply pipe 15 and the heat exchanger 20.

A flow meter 33 as a detection unit is disposed downstream of the heat exchanger 20 in the supply pipe line 15, and the flow rate of the slurry flowing through the supply pipe line 15 is detected by the flow meter 33. The detected slurry flow rate is converted into a voltage value and sent to an inverter 34 as a speed control device. After this voltage value is processed by the inverter 34, the frequency is converted and output to a motor (not shown) of the supply pump 19, so that the impeller rotation speed of the supply pump 19 is controlled. Thus, the slurry flow rate detected by the flow meter 33 is fed back to the supply pump 19 via the inverter 34, and the slurry supply pipe 1
The amount of slurry supplied from 3 is kept at a predetermined amount.

A display 35 as a display means is connected to the inverter 34. And the inverter 34
Is input, and if the frequency exceeds a predetermined warning value, a warning indicating the degree of impeller wear is displayed.

Next, the operation of the slurry supply device configured as described above will be described. As shown in FIG. 1, when cutting the work 12 with a wire saw, a slurry is supplied to the wire 11 from a slurry supply pipe 13. At this time, the slurry is sucked up from the slurry storage tank 14 by the supply pump 19 and sent out to the heat exchanger 20. Heat exchanger 2
The slurry sent to 0 is cooled to a predetermined temperature in the heat exchanger 20, and then supplied to the wire 11 from the slurry supply pipe 13 through the supply pipe 15, the flow meter 33, and the slurry supply pipe 13. The slurry supplied from the slurry supply pipe 13 is once collected in a slurry collection tank 16 and collected by a collection pump 18.
Is returned to the slurry storage tank 14.

After the cutting of the work 12 is completed, the recovery pump 18 and the supply pump 19 are stopped, and the air supply source 31 switches the switching valve 32 from the air supply source 31 to the cylinder chamber 25 of the slurry return mechanism 22 shown in FIG. In operation, compressed air is delivered to the port 30. The compressed air is sent from the port 26 through the branch pipe 21 into the supply pipe 15, and the slurry retained in the supply pipe 15 is returned to the slurry storage tank 14 or the slurry recovery tank 16. .

During the circulation of the slurry such as the cutting of the work 12, the flow rate of the slurry flowing through the supply pipe 15 is detected by the flow meter 33. Then, using the detected value as an input, the impeller rotation speed of the supply pump 19 is controlled by the inverter 34, and the slurry flow rate is maintained at a predetermined amount.

By monitoring the frequency change of the inverter 34, the degree of wear of the impeller in the supply pump 19 can be confirmed. That is, for example, 1 per minute
When the slurry of 00 liters is supplied from the supply pipe 13, the frequency of the inverter 34 with respect to the load acting on the supply pump 19 at the start of use of the impeller indicates 40 Hz. The time when the frequency exceeds 60 Hz is defined as the impeller replacement time. When the degree of wear of the impeller of the supply pump 19 progresses, and the frequency of the inverter 34 necessary for the quantitative supply of slurry gradually increases to increase the rotation speed of the supply pump 19, and exceeds 60 Hz. Then, a signal is output to the display 35, and the warning display is performed.

Here, the effects exerted by the first embodiment will be described. (1) In the present embodiment, the display 35 is provided as a display unit for indicating the degree of wear of the impeller.
The degree of impeller wear can be constantly checked without requiring any inspection work such as disassembling the supply pump 19. Therefore, it is not necessary to check the degree of impeller wear, and it is possible to avoid an unexpected situation in which the slurry flow rate changes and the machining accuracy differs.

(2) In this embodiment, by detecting the slurry supply flow rate by the flow meter 33, the control of the supply pump 19 and the confirmation of the impeller wear degree can be performed at the same time via the inverter 34.

(3) In the present embodiment, a slurry return mechanism 22 is provided. Therefore, when the cutting process is completed, the slurry staying in the supply pipe 15 and the heat exchanger 20 can be easily returned to the slurry tanks 14 and 16 in a short time. Therefore, it is possible to prevent the slurry from accumulating in the supply pipe 15 and the heat exchanger 20.

(4) In the present embodiment, since the inverter 34 as the speed control device also serves as the control means for the slurry flow rate, the structure of the working fluid supply device can be simplified.

The above-described embodiment can be modified as follows. In the above embodiment, as shown in FIG. 3, a slurry supply system passing through the work processing portion and a slurry supply system passing through the heat exchanger 20 are separately provided. In this case, the slurry return mechanism 22 is also provided separately for each system.

In the above embodiment, the display 35
Is configured to operate using the frequency of the inverter 34 as an input. This may be changed so that the value obtained by converting the slurry flow rate detected by the flow meter 33 into a voltage value is input.

Even when changed as described above, the same effects as the effects of the above embodiment can be obtained.

[0032]

Since the present invention is configured as described above, it has the following effects. According to the first aspect of the present invention, the display means for indicating the degree of wear of the impeller is provided, so that the degree of wear of the impeller can always be easily checked.

According to the invention described in claim 2, according to claim 1
In addition to the effects described above, the supply flow rate of the processing liquid can be kept constant in order to maintain uniform processing accuracy. According to the third aspect of the invention, in addition to the effect of the second aspect, the degree of wear of the impeller can be confirmed also by detecting the supply flow rate of the working fluid.

According to the invention described in claim 4, according to claim 3,
In addition to the effects described above, the configuration of the working fluid supply device can be simplified since the speed control device also serves as the control means.

[Brief description of the drawings]

FIG. 1 is a diagram showing a slurry supply device according to an embodiment.

FIG. 2 is a sectional view showing a slurry return mechanism.

FIG. 3 is a diagram showing a slurry supply device according to another embodiment.

[Explanation of symbols]

19, 42: slurry supply pump, 22: slurry return mechanism, 33: flow meter, 34: inverter, 35: display.

 ──────────────────────────────────────────────────の Continued on the front page F term (reference) 3C047 FF11 GG19 3H020 AA01 AA03 AA07 BA00 BA06 BA11 BA18 BA21 CA04 CA08 DA04 EA16 EA17 3H045 AA06 AA09 AA12 AA14 AA21 AA31 BA00 BA19 BA28 BA31 BA41 CA49 CA21 EA50

Claims (4)

[Claims] In a working fluid supply device in which a working fluid is supplied to a working portion by driving a pump, a detecting means for detecting a change in a load acting on the pump and a degree of wear of an impeller of the pump in response thereto. A processing fluid supply device provided with a display means for indicating. 2. The processing liquid supply device according to claim 1, further comprising control means for controlling the supply flow rate to be constant. 3. The apparatus according to claim 2, wherein the detecting means includes a detecting unit for detecting a flow rate of the working fluid, and a speed control device for controlling a pump rotation speed according to a detection result from the detecting unit. A machining fluid supply device that displays the degree of impeller wear based on a frequency change of the speed control device. 4. The machining fluid supply device according to claim 3, wherein the speed control device constitutes a control unit.