JP4047175B2 - Abrasive fluid jet system - Google Patents

Abstract

The invention provides an abrasive jet system having a high-pressure fluid supply (10) means supplying fluid to a vessel (11) which includes a layer of abrasive slurry and a top layer that contains substantially of fluid over the layer of abrasive slurry. The system also includes a first conduit (14) which leads from the fluid supply means to the top layer of fluid in the vessel and as high-pressure fluid is fed into the vessel, causes displacement of abrasive slurry from a discharge conduit (16). The system further includes a second conduit (21) which connects at different points to the first conduit and the discharge conduit, and including a fluid valve (13) between the operative connection to the first conduit and the discharge conduit, that controls the fluid flow within the second conduit. The fluid valve is closed once the system is pressurised to displace abrasive slurry through the discharge conduit (16) and is opened upon de-pressurization of the system to allow fluid flow from the first conduit (14) to the second conduit and to stop discharge of the abrasive slurry.

Description

【Technical field】
[0001]
The present invention relates to an abrasive fluid jet cutting system, and in particular, but not limited to, a pressurized abrasive slurry is supplied from a pressurized abrasive slurry container to an abrasive fluid jet nozzle to perform cutting operations, etc. The present invention relates to a system that enables a machining operation with an abrasive fluid jet that can be implemented.
[0002]
[Background]
Abrasive fluid jet systems in the art are used in a variety of applications where precision cutting is required. An example of the use is cutting of a substrate. As one type of polishing jet system, there is a type in which an abrasive that is contained and discharged from a pressure vessel under pressure is mixed with a driving liquid just before forming a polishing slurry by a nozzle and used for forming a polishing slurry. Such mixing is realized by the Venturi effect. The slurry is then typically accelerated through a nozzle to form a polishing fluid jet tool for substrate cutting.
[0003]
When a multi-nozzle cutter is used in such an existing system, it is necessary to feed the abrasive individually to each of the nozzles. Thus, in order to feed the abrasive for each individual nozzle, individual control is required, and there is an increased possibility that one or more nozzles of the multi-nozzle cutter operate in a condition that is not ideal.
[0004]
An alternative to existing systems for mixing abrasive with fluid is described, for example, in International Publication No. WO 95/29792. In this system, a pressure vessel is provided, and after the abrasive and the fluid under pressure are mixed in the pressure vessel, the pressure vessel is sent to a nozzle through a conduit.
[0005]
In addition, the pamphlet of International Publication No. WO 00/52679 comprises high-pressure fluid supply means (31, 32) for supplying a fluid under pressure to the accompanying container (1) through the inlet (6). A fluid supply system is described in which fluid can absorb other components, such as abrasive material, within the container. The outlet (51) from the container leads to a nozzle (54). The jet pump (61) has an outlet (64) which is connected via a valve (65) to a connection point between the container discharge pipe (51) and the system outlet (54). When the valve (65) is closed, the pressurized fluid supplied to the high pressure inlet (62) of the jet pump (61) passes through the lower pressure inlet (63) of the jet pump to the container (1). It goes to the inlet (6), passes through the container accompanied by the abrasive material, and then flows to the nozzle (54) through the container discharge pipe (51). Valve (65) is opened so that isolation valve (52) is flushed or closed to stop the flow to the nozzle. With this configuration, the amount of abrasive discharge is not diluted by inducing a dilute liquid flow near the lower end of the discharge pipe, and when the abrasive discharge is stopped, this dilution flow is reduced. The container discharge pipe (51) cannot be washed away.
DISCLOSURE OF THE INVENTION
[Problems to be solved by the invention]
[0006]
As higher pressure liquids are used to improve the cutting force, the compressibility of the liquid becomes an important factor. When it is necessary to stop the discharge of the polishing slurry and depressurize the polishing slurry pressure vessel in order to pause the operation process or to facilitate re-feeding of the abrasive, the resulting high pressure results in compression. A large amount of the fluid left inside the pressure vessel. In the conventional state of the art system, when a large volume of compressed fluid is depressurized, the only escape path for the fluid is a discharge conduit having an inlet in the slurry confinement. Therefore, since a large amount of slurry is continuously discharged, the problem of nozzle clogging occurs. Such nozzle clogging is caused by the fact that the pressure of the discharged slurry is lower than the normal operating pressure, and sufficient momentum that can avoid clogging of the delivery pipe and the nozzle cannot be obtained.
[0007]
Such unnecessary discharge may occur, for example, when a slurry storage pressure vessel pressurizing pump fails. The slurry inside the pressure vessel is under high pressure and is compressed by the pump, so if the pump fails, the compressed slurry expands and is sent through the delivery tube for at least a short period. As a result, the polishing slurry continues to be discharged from the nozzle.
[0008]
When designing a solution, it is important to avoid problems such as high wear rates and high reliability concerns caused by high pressure and the processing medium itself including the abrasive.
[0009]
The object of the present invention is to alleviate the above mentioned problems and to avoid nozzle blockage or to give the public a practical option.
[0010]
[Means for Solving the Problems]
In a first aspect, the invention generally includes a container for containing a polishing slurry in a lower layer and a substantially abrasive-free fluid in an upper layer, a first end connected to the container, and a high pressure fluid. A pressurized supply conduit having a second end for connection to a source and for delivering a high pressure fluid to the container; a slurry suction end disposed in a lower layer of the container; and an abrasive outlet A first end connected to an upper layer of the container; and a slurry suction and delivery conduit for sending slurry to the slurry outlet simultaneously with discharge by the high-pressure fluid conveyed to the container. And a second end connected to the pressure release port, the pressure release conduit further comprising a valve for controlling fluid flow through the pressure release conduit; First end connected to pressure supply conduit And a second supply conduit having a second end connected to the slurry wicking delivery conduit, wherein the second tip of the second supply conduit is near the slurry wicking end. It can be said that it is a fluid supply system for sending polishing slurry, characterized in that it is connected to a suction and delivery conduit.
[0011]
Preferably, the second end of the pressure release conduit is connected to the slurry wicking delivery conduit, and the pressure release port is provided by the abrasive outlet.
Also preferably, the first end of the pressurized supply conduit is located in the upper layer of the container. The first end of the pressure release conduit may be connected to the pressurized supply conduit, such that it connects to the upper layer of the container via the first end of the pressurized supply conduit. It is good also as a structure.
Alternatively, the first end of the pressurized supply conduit may be located in the lower layer of the container.
The first end of the pressure release conduit may be directly connected to the upper layer of the container. Furthermore, a flow control valve may be provided in the pressurized supply conduit.
[0012]
In a second aspect, the present invention generally provides a process for supplying a high pressure fluid to a container containing a polishing slurry in a lower layer and a substantially abrasive-free fluid in an upper layer, and located in the lower layer of the container. A process of sending a high-pressure fluid connected to the conduit to the slurry suction and delivery conduit in the vicinity of the slurry suction end to be discharged, and discharging the polishing slurry through the slurry suction and delivery conduit by the supplied high-pressure fluid Diluting the polishing slurry discharged through the slurry wicking and delivery conduit with a fluid sent to the conduit via the connection in the vicinity of the slurry wicking end, and the discharged dilution. Discharging the generated slurry from the abrasive outlet, and opening a valve in a pressure release conduit connected to the container to release the pressure in the container and closing the valve Therefore to restore the pressure in the container, it can be said that the delivery method of polishing slurry containing the steps of opening and closing the valve of the discharge and for ejecting the stop or start the said slurry.
[0013]
Preferably, the pressure in the container is relieved via the slurry wicking and delivery conduit and outlet.
Preferably, the high-pressure fluid supplied to the container is guided to the upper layer of the container.
Alternatively, the high-pressure fluid supplied to the container is guided to the lower layer of the container.
The pressure may be released through a conduit for supplying the high-pressure fluid to the container.
The pressure may be released through a conduit directly connected to the upper layer of the container.
[0014]
Preferably, when initially supplying high pressure fluid to the vessel and delivering high pressure fluid to the slurry wicking delivery conduit, the valve causes fluid to flow through the pressure release conduit to pressurize the system. The valve is then closed to discharge the slurry and discharge it from the abrasive discharge conduit.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention takes advantage of the natural tendency of fluids to travel through a path of least resistance so that the compressed fluid is discharged into a discharge conduit that is configured to be discharged without abrasives. enable.
[0016]
FIG. 1 is a diagram illustrating a first embodiment according to the present invention. In the figure, a pressure vessel 11 having a compartment for containing a polishing slurry is provided. An abrasive slurry is a mixture of an abrasive material in a fluid such as water or a liquid composition containing water. The pressure vessel 11 contains the polishing slurry 2. A layer of liquid 4 is provided above the polishing slurry 2 inside the pressure vessel 11. This liquid 4 is similar to the liquid used to generate slurry by entraining abrasive particles, but is located at a position higher than a predetermined level “L” in the pressure vessel 11 and the abrasive is mixed therein. Not.
[0017]
A pressurized fluid supply 10 incorporating a pressure pump supplies fluid to the pressure vessel 11 via delivery conduits 14 and 15. A conduit 15 is provided for delivering fluid to the wicking delivery conduit 16 so that the slurry is discharged through the opening 30 and is appropriately diluted. This dilution may be necessary to avoid blockage of the wicking delivery conduit.
[0018]
The delivery conduit 14 is the primary supply and vessel pressurization conduit. In the configuration shown in FIG. 1 of the present invention, the conduit 14 has an outlet opening 24 by means of the outlet opening 24 in the fluid only region (ie, the region above the level L) in the pressure vessel 11. 1 opening is formed.
[0019]
The hopper 17 supplies the polishing slurry 2 to the pressure vessel 11 through a conduit 19.
The pressure release conduit 21 is provided for fluid communication of the content in the container, and is in fluid contact with a fluid that does not contain abrasive. In the configuration of FIG. 1, the fluid contact is provided through a portion of the delivery conduit 14. The fluid valve 13 controls the flow of fluid through the pressure control conduit 21.
[0020]
During normal operation of the system, the pump system delivers pressurized fluid to the pressure vessel. As a result, the polishing slurry 2 is discharged to the nozzle 12 through the inlet opening 30 of the slurry suction and delivery conduit 16. The inlet opening 30 is preferably located below the level L and close to the bottom of the pressure vessel 11.
[0021]
The pressure release conduit 21 can also be regarded as a bypass conduit that bypasses the internal volume flow in the pressure vessel containing the abrasive. The bypass conduit is controlled by a liquid flow control valve capable of blocking the flow in the conduit 21.
[0022]
In the configuration of FIG. 1, the conduit 14 is connected to the upper surface of the pressure vessel 11 where no polishing slurry 2 is present. During decompression (e.g., when the fluid supply 10 has failed, is turned off, or is about to be turned off), the conduit 21 is connected to the delivery conduit 14 outside the pressure vessel. The fluid valve 13 is opened. The volume of the contents inside the pressure vessel 11 remains compressed but tends to expand. Two openings are available at this time, but such expansion tends to discharge through the conduit 21 instead of the opening 30 in the conduit 16. This is because in the expansion of the volume due to the discharge of the slurry flow through the opening 30 of the conduit 16, a higher flow resistance is generated by the inner diameter and length of the conduit 16 and mainly by the density and viscosity of the slurry layer 2. is there.
[0023]
During startup and pressurization of the system, the fluid valve 13 is first opened. Fluid flows from the source 10 through the conduit 14 into the pressure vessel 11. Some fluid flow enters the conduit 21 with the fluid valve 13 open. Pressurization of the pressure vessel also occurs, but is thus reduced by partial branching of the flow. In a preferred form in which the pressure release conduit 21 is connected to the upstream portion of the second opening 30 of the slurry wicking delivery conduit 16 (and preferably outside the pressure vessel), the flow resistance of the slurry rising through the opening 30 is shown. In combination with the fact that the flow through conduit 21 to the suction delivery conduit 16 creates back pressure in that portion of suction delivery conduit 16 toward opening 30, the slurry will not move to the nozzle.
When the valve 13 is closed, a sufficient amount flows into the slurry pressure vessel 11, so that the abrasive is discharged into the inlet opening 30 of the supply pipe 16. When the valve 13 is closed, the fluid flow from the source 10 enters the pressure vessel 11 via the conduit 14, thereby discharging the polishing slurry to the inlet opening 30 of the wicking delivery conduit 16. . In the wicking delivery conduit 16, the abrasive slurry mixes with the main stream from the supply tube 15 and is transported through the wicking delivery conduit 16 to the nozzle 12.
[0024]
The abrasive flow can also be stopped at any time by opening the valve 13. During decompression, the fluid valve 13 is opened, providing an alternative suitable route for the compressed fluid to pass through the conduit 21. When the content inside the pressure vessel expands, the expanded content passes through the pressure release conduit 21. The conduit 14 has its own opening at a position above the level L inside the pressure vessel, which is a position where the polishing slurry can reliably reach the fluid valve 13. Therefore, the fluid that passes through the valve 13 is usually clean water that does not contain an abrasive. And since it operates with a minimum pressure differential, its service life will generally be longer than in other cases. Furthermore, the inner diameter of the conduit 21 should be sufficiently large so that the speed of the fluid entering the valve 13 is considerably lower than the settling speed of the polishing slurry 2 to be used. This prevents any abrasive particles entering above the level L in the pressure vessel from entering or moving along the supply tube 14 and from entering the conduit 21 through the fluid valve 13. Will be further separated.
[0025]
FIG. 2 is a diagram illustrating a second embodiment of the present invention, in which a separate release conduit 21 is provided. Unlike the first embodiment shown in FIG. 1, the conduit 21 is not connected to the conduit 14 and is used only as a compressed volume escape path inside the container 11.
The fluid that passes through the second fluid valve 23 is always a fluid that does not contain abrasives, and the fluid valve 13 operates less frequently, that is, only in the pressurization and decompression phases. As a result, the wear rate of the valve 13 is reduced. In addition, although it is preferable to provide the 2nd fluid valve | bulb 23, it is not essential.
[0026]
In the event that the flow needs to be diverged due to a failure in pressurization of the pump relative to the source 10, a drop in pressure in the conduit 14 or in the pump is detected by the pressure sensor, thereby automatically 13 may be opened, and the pressure in the pressure vessel may be released through the conduit 21. If the pumping of the supply source 10 continues even though it is necessary to stop the flow of the polishing slurry, the fluid can be passed through the supply pipes 14 and 15 by simply opening the valve 13 (if Although it may be allowed to continue to flow into the pressure vessel 11 (if it is not closed alone), the path through which the pressurized material in the pressure vessel can pass with minimal resistance is the conduit 21, so that water enters and levels Since it comes out only above L, only water will surely be discharged to the nozzle 12 via the conduit 21. This flow continues as long as pump pressurization at the fluid source 10 is in operation and the pressure balance of the compressed fluid is not reached, so the valve 13 remains open.
[0027]
The diaphragm pump 18 is used to draw the fluid 4 through the conduit 20, and draws the polishing slurry 2 from the hopper 17 into the pressure vessel 11 by using the pressure drop inside the pressure vessel 11 generated thereby. In the specific embodiment shown in FIG. 2, with the fluid valve 13 and the second fluid valve 23 closed, the diaphragm pump 18 is used to remove fluid from the pressure vessel via the conduit 20 and is contained in the pressure vessel. The polishing slurry 2 is drawn from the hopper 17 through the conduit 19 by the vacuum generated in the above.
[0028]
It will be appreciated that the system avoids fluid compressibility problems that lead to unnecessary ejection of abrasive material into the nozzle in the pressurized and decompressed states of the system. By providing an alternative route of less resistance to escape the expansion of the compressed fluid volume from the interior of the pressure vessel from a location where the abrasive is not carried to the nozzle, the present invention avoids nozzle clogging. Useful.
[0029]
Referring to FIG. 3, another alternative configuration is shown. In the figure, the delivery conduit is positioned such that the first opening is submerged in the slurry. In this configuration, the separate opening provided by the pressure release conduit needs to be above level L. The reason why the first opening 24 is disposed near the second opening 30 is that the closer to the second opening, the better the mixing of the abrasive and water for forming the slurry is realized.
[0030]
FIG. 4 shows yet another alternative arrangement in which the pressure release conduit discharges to a different location than the slurry wicking delivery conduit. The pressure from the fluid in the conduit 21 cannot be used to apply back pressure to the fluid in the slurry wicking and delivery conduit 16, so that some slurry (while the volume of the pressure vessel content is expanding). ) This is a lower priority option than the other configurations described above in that it may be carried through the opening to the slurry wicking delivery conduit.
[0031]
It should be noted that the present invention described herein can be modified, modified, and / or added other than those specifically described above. In addition, all such changes, modifications, and / or additions that fall within the spirit and scope of the above are to be understood as being included in the present invention.
[Brief description of the drawings]
[0032]
FIG. 1 is a system diagram showing a first embodiment according to the present invention.
FIG. 2 is a system diagram showing a second embodiment according to the present invention.
FIG. 3 is a system diagram showing a third embodiment according to the present invention.
FIG. 4 is a system diagram showing a fourth embodiment according to the present invention.

Claims (14)

A container (11) for containing a polishing slurry (2) in the lower layer and a fluid (4) substantially free of abrasive in the upper layer;
A pressurized supply conduit (14) for delivering high pressure fluid to the vessel, having a first end connected to the vessel and a second end for connection to a high pressure fluid supply (10); ,
A slurry suction end (30) disposed in a lower layer of the container and a delivery end connected to an abrasive discharge port (12), and the slurry is discharged simultaneously with discharge by the high-pressure fluid carried to the container. A slurry suction and delivery conduit (16) for delivery to the outlet;
A pressure release conduit (21) having a first end connected to the upper layer of the container and a second end connected to a pressure release port, for controlling liquid flow through the pressure release conduit. Said pressure release conduit (21) further comprising a valve (13) for
A second supply conduit (15) having a first end connected to the pressurized supply conduit (14) and a second end connected to the slurry wicking and delivery conduit (16);
For sending a polishing slurry, characterized in that the second end of the second supply conduit (15) is connected to the slurry wicking delivery conduit (16) in the vicinity of a slurry wicking end (30) Fluid supply system.   The second end of the pressure release conduit (21) is connected to the slurry wicking and delivery conduit (16), the pressure release port being provided by the abrasive outlet (12). 2. The fluid supply system according to 1.   The fluid supply system according to claim 1 or 2, wherein the first end of the pressurized supply conduit (14) is located in the upper layer of the container.   The fluid supply system of claim 2, wherein the first end of the pressurized supply conduit (14) is located in a lower layer of the container.   The first end of the pressure release conduit (21) is connected to the pressurized supply conduit (14) by connecting to the upper layer of the container via the first end of the pressurized supply conduit. The fluid supply system according to claim 3, wherein the fluid supply system is connected.   5. Fluid supply system according to claim 3 or 4, characterized in that the first end of the pressure release conduit (21) is directly connected to the upper layer of the container.   The fluid supply system of claim 6, wherein the pressurized supply conduit (14) includes a flow control valve (23). Supplying a high pressure fluid to a container (11) containing a polishing slurry (2) in the lower layer and a fluid (4) substantially free of abrasive in the upper layer;
In the vicinity of the slurry wicking end (30) of said container said slurry wicking delivery conduit located below layer (11) (16), a step of sending to said high pressure fluid slurry wicking delivery conduit (16),
Discharging the polishing slurry (2) via the slurry suction and delivery conduit (16) by the supplied high pressure fluid;
Diluting the abrasive slurry discharged through the slurry wicking and delivery conduit (16) with a fluid sent to the slurry wicking and delivery conduit (16) through the slurry wicking end (30 ) ;
Discharging the discharged diluted slurry from an abrasive outlet (12);
The valve (13) in the pressure release conduit (21) connected to the container (11) is opened to release the pressure in the container, the pressure in the container is restored by closing the valve, and the slurry A polishing slurry delivery method comprising: (2) discharging and opening and closing the valve (13) for stopping or starting the discharge. 9. The method for delivering a polishing slurry according to claim 8, wherein the pressure in the container (11) is released through the slurry suction and delivery conduit (16) and the abrasive outlet (12).   10. The method for feeding polishing slurry according to claim 8 or 9, wherein the high-pressure fluid supplied to the container (11) is guided to the upper layer of the container.   10. The method of claim 9, wherein the high pressure fluid supplied to the container (11) is guided to the lower layer of the container. 11. The polishing slurry delivery method according to claim 10, wherein the pressure is released through a pressurized supply conduit (14) for supplying the high-pressure fluid to the container (11). 12. The method of claim 10, wherein the pressure is released via the pressure release conduit (21) directly connected to the upper layer of the container (11). When initially supplying high pressure fluid to the vessel and delivering high pressure fluid to the slurry suction and delivery conduit (16), the valve (13) causes the pressure release conduit (21) to be pressurized to pressurize the system. 14. The system of claims 8-13, wherein the valve (13) is closed to allow fluid to flow therethrough, after which the valve (13) is closed to discharge the slurry and discharge from the abrasive outlet (12) . The polishing slurry delivery method according to any one of the above.

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