APPARATUS AND METHOD FOR ABRASIVE WATER JET MACHINING
To provide an abrasive water jet machining apparatus in which the machining accuracy and machining efficiency is improved by improving the flowability of an abrasive through a nozzle. An abrasive water jet machining apparatus performs machining by directing an abrasive water jet at a workpiece, the abrasive water jet being composed of a mixture of a high-pressure processing fluid with an abrasive. The machining apparatus includes: a nozzle that directs the abrasive water jet; a high-pressure water supply device that supplies the processing fluid to the nozzle; and an abrasive supply device that supplies the abrasive to the processing fluid. The abrasive is composed of a coated abrasive, the coated abrasive being produced by coating a surface of an abrasive material composed of abrasive grains with a water-repellent material or flow promoting material. The abrasive supply device 8 supplies the coated abrasive to the nozzle.
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1. Technical Field
The present invention relates to an apparatus and method for abrasive water jet machining, in which machining is performed by directing an abrasive water jet at a workpiece, the abrasive water jet being composed of a mixture of a high-pressure processing fluid with an abrasive.
2. Related Art
As a machining apparatus for performing cutting on hard-to-machine workpieces of glass, stones, synthetic resin, composite materials such as carbon fiber reinforced plastic (CFRP), or the like, there is known an abrasive water jet machining apparatus in which a general abrasive (abrasive material), such as garnet, is mixed into high-pressure water.
A related art technology in which an abrasive (abrasive material) is improved in materials, surface shape, grain diameter, grain diameter distribution or the like in order to efficiently realize suitable cutting is disclosed, for example, in Japanese Unexamined Patent Application Publication No. H8-1515 (see paragraphs [0004] to [0008] and FIG. 1) and Japanese Patent No. 4653962 (see paragraphs [0041] to [0044] and FIG. 3).
The Japanese Unexamined Patent Application Publication No. H8-1515 discloses an abrasive (abrasive material) of ceramic fine grains each having an edge portion, each of the grains having a size in the range of 0.2 to 3 mm. The Japanese Patent No. 4653962 discloses an abrasive jet machining method using spherical zircon beads with a grain diameter in the range of 10 to 800 μm, the grain having a nearly truly spherical shape.
However, the Japanese Unexamined Patent Application Publication No. H8-1515 and Japanese Patent No. 4653962 do not disclose an effective technology for preventing the abrasive from clogging a nozzle. Especially in recent years, in order to perform accurate cutting of workpieces of different materials, shapes, and thicknesses, it is necessary to perform a machining with the optimum jet diameter as appropriate on the workpieces different in final cutting width. Unfortunately, when the nozzle diameter is reduced in order to make the jet diameter smaller, the nozzle diameter is brought close to the grain diameter of the abrasive, causing a clogging of the nozzle with the abrasive more likely to occur.
Furthermore, if the abrasive is non-water-repellent (non-hydrophobic), an abrasive material adheres to a wall surface of an abrasive material passage with water adhering thereto as a contact body, and further, the subsequent abrasive material adheres to the abrasive material with the water as a contact body, leading to chained agglomeration of the abrasive materials, thereby causing the problems of a reduction in the inner diameter (airway) of the abrasive material passage and a decrease in flowability.
In this case, the problem is that the abrasive materials adhering to an inner wall of the abrasive material passage cause a blockage in a flow passage and cut off the air pulled in by a jet, resulting in feed failure of the abrasive materials.
SUMMARYAccordingly, the present invention has been made under such circumstances, and an object of the present invention is to provide an apparatus and method for abrasive water jet machining, in which the machining accuracy and machining efficiency is improved by improving the flowability of an abrasive through a nozzle.
In order to address the above-mentioned problems, a first aspect of the present invention provides an abrasive water jet machining apparatus that performs machining by directing an abrasive water jet at a workpiece, the abrasive water jet being composed of a mixture of a high-pressure processing fluid with an abrasive. The abrasive water jet machining apparatus includes: a nozzle that directs the abrasive water jet; a processing fluid supply portion that supplies the processing fluid to the nozzle; and an abrasive supply portion that supplies the abrasive to the processing fluid. The abrasive is composed of a coated abrasive, the coated abrasive being produced by coating a surface of an abrasive material composed of abrasive grains with a water-repellent material or flow promoting material. The abrasive supply portion supplies the coated abrasive to the nozzle.
With this construction, the abrasive supply portion for supplying the abrasive to the processing fluid supplies the coated abrasive produced by coating the surface of the abrasive material composed of abrasive grains with the water-repellent material or flow promoting material. Thus, the coated abrasive repels the processing fluid or promotes flowability by surface tension acting on the processing fluid existing among the grains of the coated abrasive, thereby preventing the abrasive material from adhering to a wall surface of an abrasive material passage and always establishing an open airway that allows air to flow. Consequently, the flowability of the abrasive through the nozzle can be improved.
Thus, in the abrasive water jet machining apparatus, the abrasive in the processing fluid at the time of machining the workpiece with the abrasive water jet is uniformly dispersed and smoothly flows without agglomeration. Therefore, during a machining work, interruption of the work due to clogging of the nozzle, etc. with the abrasive can be prevented.
Furthermore, because the coated abrasive is less likely to cause clogging and has excellent fluidity, the amount of the abrasive in the abrasive water jet can be increased so as to improve machinability. It is therefore possible to shorten cutting time and speed up the processing, and, at the time of machining, provide smooth finishing of the machining surface as compared with the machining with the related art abrasive material.
Also, preferably, the coated abrasive has a property of floating in the processing fluid.
With this construction, because the coated abrasive has a property of floating, the sinking and deposition of the abrasive grains of the coated abrasive in the nozzle can be reduced, thereby it is possible to prevent the coated abrasive from clogging the nozzle.
Furthermore, preferably, the abrasive supply portion includes: an abrasive material supply portion that supplies the abrasive material to the processing fluid; a coated abrasive supply portion that supplies the coated abrasive to the processing fluid; and switching unit for selectively supplying the abrasive material supplied from the abrasive material supply portion or the coated abrasive supplied from the coated abrasive supply portion.
With this construction, the abrasive to be supplied into the nozzle can be selectively changed between the abrasive material and the coated abrasive by switching the switching unit. Therefore, the abrasive water jet machining apparatus can machine the workpiece by effectively utilizing the property of the abrasive material that is more excellent in machinability and the property of the coated abrasive that is more excellent in non-agglomerating property or flowability.
A second aspect of the present invention provides an abrasive water jet machining apparatus that performs machining by directing an abrasive water jet at a workpiece, the abrasive water jet being composed of a mixture of a high-pressure processing fluid with an abrasive. The abrasive water jet machining apparatus includes: a nozzle that directs the abrasive water jet; a processing fluid supply portion that supplies the processing fluid to the nozzle; an abrasive supply portion that supplies the abrasive to the processing fluid; and a liquid supply portion that supplies a water-repellent material or flow promoting material to the processing fluid or the abrasive.
With this construction, because the liquid supply portion supplies the water-repellent material or flow promoting material to the processing fluid or abrasive, the water-repellent material having surface tension or the flow promoting material having the function of promoting the flowability is mixed into the processing fluid or abrasive, thereby improving the flowability of the processing fluid or the abrasive. Consequently, a trouble due to deterioration in flowability can be avoided.
Moreover, preferably, the water-repellent material or flow promoting material is composed of any one of a fluorine-based material, silicon-based material, a coating material composed of a mixture of a fluorine-based material or a silicon-based material and an oily raw material, paraffin, and fats.
With this construction, because the water-repellent material or flow promoting material is composed of any one of a fluorine-based material, silicon-based material, a coating material composed of a mixture of a fluorine-based material or a silicon-based material and an oily raw material, paraffin, and fats, each of the abrasive grains has the function of promoting the water repellency or flowability. Therefore, the grains of the coated abrasive coated with the water-repellent material have the hydrophobic property of repelling the processing fluid with one another, and thus repel the processing fluid with one another in a state of being mixed in the water jet, thereby allowing preventing agglomeration and eliminating a clogging of the nozzle. Furthermore, the grains of the coated abrasive coated with the flow promoting material are reduced in flow resistance during flowing, thereby allowing preventing agglomeration and eliminating a clogging of the nozzle.
It should be noted that the water-repellent material or flow promoting material may include any material other than the above if it has water repellency or flowability, and is not limited to the above-described coating material.
Also, preferably, the abrasive water jet machining apparatus further includes: a catcher tank that filled with liquid that receive and absorb water jet and its energy for machining the workpiece under the liquid; and a discharge port that discharges the liquid stored in the catcher tank. The coated abrasive floating in the liquid is discharged and recovered from the discharge port.
With this construction, the coated abrasive floating in the liquid stored in the catcher tank is discharged and recovered from the discharge port, thereby enabling recycled use thereof. Furthermore, the non-water-repellent abrasive material sinks to an inner bottom of the catcher tank in the liquid and therefore can be recovered separately from the floating coated abrasive.
Preferably, the abrasive water jet machining apparatus further includes a liquid level adjusting device that adjusts a liquid level of the liquid by adjusting a height of the discharge port.
With this construction, by raising the height of the discharge port with the liquid level adjusting device, the liquid level inside the catcher tank can be raised. Also, by lowering the height of the discharge port with the liquid level adjusting device, the liquid level inside the catcher tank can be lowered and adjusted as appropriate according to the thickness of the workpiece.
In addition, a third aspect of the present invention provides an abrasive water jet machining method in which machining is performed by directing an abrasive water jet at a workpiece, the abrasive water jet being composed of a mixture of a high-pressure processing fluid with an abrasive. The method includes producing a coated abrasive as the abrasive by coating a surface of an abrasive material composed of abrasive grains with a water-repellent material or flow promoting material.
With this construction, the coated abrasive produced by coating the surface of the abrasive material composed of abrasive grains with the water-repellent material or flow promoting material is supplied to the processing fluid. Thus, in the case of the coated abrasive coated with the water-repellent material, the coated abrasives repel the processing fluid with one another by surface tension acting on the processing fluid existing among the abrasive grains. Furthermore, in the case of the coated abrasive coated with the flow promoting material, each of the abrasive grains is improved in flowability. Therefore, with the coated abrasive coated with the water-repellent material or flow promoting material, agglomeration in the nozzle or the like or clogging can be eliminated. As a result, the abrasive water jet machining method allows uniform dispersion and smooth flow of the grains of the coated abrasive in the water jet at the time of abrasive water jet machining.
Also, a fourth aspect of the present invention provides an abrasive water jet machining method in which machining is performed by directing an abrasive water jet at a workpiece, the abrasive water jet being composed of a mixture of a high-pressure processing fluid with an abrasive. The method includes supplying a water-repellent material or flow promoting material to the processing fluid or the abrasive.
With this construction, by using the coated abrasive having a property of floating, the sinking and deposition of the grains of the coated abrasive in the nozzle can be reduced, thereby allowing preventing the coated abrasive from clogging the nozzle.
According to the present invention, the present invention is to provide an apparatus and method for abrasive water jet machining, in which the machining accuracy and machining efficiency is improved by improving the flowability of an abrasive through a nozzle.
Embodiments of the present invention will be described in detail based on the following drawings, in which:
Hereinafter, an apparatus and method for abrasive water jet machining according to an embodiment of the present invention will be described with reference to the accompanying drawings. Before an explanation of an abrasive water jet machining apparatus 100, a workpiece W to be used therein will be explained.
<Construction of Workpiece>Although the material and shape of the workpiece W is not particularly limited, a hard-to-machine material, such as glass, stones, synthetic resin, or composite materials including carbon fiber reinforced plastic (CFRP), is most suitable as the workpiece W to be used in the abrasive water jet machining apparatus 100. Hereinafter, a description will be given using a generally elongated, substantially planar thick plate as an example of the workpiece W.
<Construction of Abrasive Water Jet Machining Apparatus>As shown in
As shown in
It should be noted that although in this embodiment
As shown in
Referring mainly to
As shown in
The water-repellent material or flow promoting material G2 is a coating material for coating the abrasive material G1 to cause it to have the function of promoting water repellency or flowability, and composed of, for example, a fluorine-based material, silicon-based material, a coating material composed of a mixture of a fluorine-based material or silicon-based material and an oily raw material, paraffin, Teflon (R), or an oily raw material. It should be noted that, more specifically, the fluorine-based material or silicon-based material includes a common material, such as fluorine, silicon, and silica, or a compound of a material, such as fluorine, silicon, and silica, and silane or a silane derivative. Furthermore, the oily raw material includes alcohol, ethanol, and various kinds of wax.
In the experiments shown in
Furthermore, in an experiment conducted by actually using the coated abrasive G3 (water-repellent abrasive) in the nozzle 1 as shown in
As shown in
It should be noted that examples of the method for producing the coated abrasive G3 include, but are not particularly limited to, a method in which the coated abrasive G3 is produced by putting the abrasive material G1 and the coating material (water-repellent material (G2)) into a general mixer, agitating and then drying them, and a method in which the coated abrasive G3 is produced by spraying the coating material (water-repellent material (G2)) on the abrasive material G1 and then drying it. Examples of other methods for producing the coated abrasive G3 include a method for producing a metal composite body in which a silica layer made of silica serving as the water-repellent material (G2) is formed on surfaces of abrasive grains (metal grains) of the abrasive material G1 or the like, as disclosed in Japanese Patent Nos. 3906137 and 3906138.
<Construction of Nozzle>As shown in
It should be noted that in
The nozzle body 10 is a member that is composed of an upper body 11 and a lower body 12 and designed to position with high accuracy and dispose the components including the water nozzle 14. The mixing chamber 13 is formed in a central portion of the nozzle body 10. It should be noted that although in this embodiment, the nozzle body 10 has a structure separated into the upper body 11 and the lower body 12, the upper body 11 and the lower body 12 may be integrated.
The mixing chamber 13 forms a space of a nearly columnar shape. In a central portion of the mixing chamber 13, the water jet WJ ejected from the water nozzle 14 passes through the inside of the mixing chamber 13 to be introduced into the abrasive nozzle 15.
The mixing chamber 13 includes a supply port 13a allowing the abrasive G (the abrasive material G1 or the coated abrasive G3) to be introduced therein. The abrasive G discharged from the abrasive supply device 8 (see
Within the mixing chamber 13, the supply port 13a is disposed toward the introducing port 14a of the water nozzle 14 with respect to an upper end of the abrasive nozzle 15. That is, the supply port 13a prevents the abrasive G from entering the water jet WJ and clogging an upstream opening end of the abrasive nozzle 15 within the mixing chamber 13.
In this manner, when the water jet WJ ejected from the water nozzle 14 passes through the inside of the mixing chamber 13, an appropriate amount of the abrasive G (the abrasive material G1 or the coated abrasive G3) is suitably sucked together with air from the supply port 13a by a negative pressure generated by the high speed water jet WJ. Therefore, clogging with the abrasive G near the supply port 13a can be effectively avoided. Furthermore, the abrasive G sucked from the supply port 13a is drawn and mixed into the water jet WJ within the mixing chamber 13 while floating together with an air current and accumulating to produce the water jet AW mixed with an appropriate amount of the abrasive material G1 or the coated abrasive G3.
As shown in
As shown in
Furthermore, the hole diameter D2 of the abrasive nozzle 15 is set, for example, in the range of about 0.2 to 0.7 mm and, preferably, set larger than the hole diameter D1 of the water nozzle 14.
That is, an advantageous effect of preventing clogging of the abrasive nozzle 15 with the abrasive G can be expected by setting the hole diameter D2 of the abrasive nozzle 15 to be larger than the hole diameter D1 of the water nozzle 14.
<Construction of Abrasive Supply Device>As shown in
The first abrasive supply device 8A for supplying the non-coated abrasive material G1 and the second abrasive supply device 8B for supplying the coated abrasive G3 have the same structure. Therefore, the first abrasive supply device 8A will be mainly described and description of the other device will not be given accordingly.
The first abrasive supply device 8A (second abrasive supply device 8B) includes: an abrasive material supply pipe 80a (coated abrasive supply pipe 80b) that supplies the abrasive material G1 (coated abrasive G3) stored in an abrasive material supply tank (not shown); a storage portion 81 that stores the abrasive material G1 (coated abrasive G3); an outlet hole 82 that is disposed at a lower portion of the storage portion 81; a carrier rotor 83 that is disposed below the outlet hole 82 with a predetermined gap δ (see
As shown in
With this construction, the carrier rotor 83 is designed to hold the abrasive material G1 (coated abrasive G3) flowing from the outlet hole 82 so as to prevent it from being scattered, and carry a required amount of the abrasive material G1 (coated abrasive G3) to the receiving portion 85 with proper timing.
It should be noted that although in this embodiment, the projection portion 83b is provided at the outer peripheral portion of the carrier rotor 83, the projection portion 83b is not particularly limited if it has a shape that allows a predetermined amount of the abrasive material G1 (coated abrasive G3) to accumulate therein for a predetermined time, but may include a recessed portion or may be composed of a recessed portion and a projecting portion, or may be formed without such recessed and projecting portions.
As shown in
As shown in
On the other hand, when the carrier rotor 83 is rotated, the first abrasive supply device 8A (second abrasive supply device 8B) carries the abrasive material G1 (coated abrasive G3) accumulated in the gap 8 along an outer peripheral surface of the carrier rotor 83 to thereby cause the subsequent abrasive material G1 (coated abrasive G3) to flow again into the gap 8 from the outlet hole 82 (see
The switching unit 88 is a switching valve having two input ports and a single output port, and the input ports may be switched manually or automatically by electromagnetic force.
In this manner, as shown in
The abrasive supply device 8 appropriately controls the rotational speed of the carrier rotor 83 with the control unit (not shown), thereby allowing uniform and smooth supply of an appropriate amount of the abrasive material G1 (coated abrasive G3) to the mixing chamber 13 with proper timing, or allowing supply of the abrasive G by causing the switching unit 88 to operate and automatically select the abrasive material G1 or the coated abrasive G3 with proper timing according to the workpiece W, or allowing alternate supply of the abrasive material G1 and the coated abrasive G3 with proper timing.
<Construction of Catcher Tank>As shown in
The water level adjusting tank 3 is a tank of an inverted container shape with a bottom opening. The water level adjusting tank 3 is provided with: an airtight chamber 3a that is formed in a ceiling portion inside the water level adjusting tank 3; a partition wall 3b that partitions the water level adjusting tank 3 and the catcher tank 2; a lower trough portion 3c that is formed below the partition wall 3b to communicate with a region filled with water inside the catcher tank 2; a pump P1 that leads air into and out of an upper portion inside the airtight chamber 3a; and a water level adjusting pipe 51 that is vertically disposed inside the airtight chamber 3a.
The airtight chamber 3a is an air pocket formed in the ceiling portion inside the water level adjusting tank 3 having an inverted container shape. The amount of air in the airtight chamber is adjusted by the pump P1 to be described later so that the water level of the liquid 6 in the water level adjusting tank 3 is adjusted.
The partition wall 3b is a wall for partitioning the water level adjusting tank 3 and the catcher tank 2 and forming the lower trough portion 3c therebelow so that the water level of the liquid 6 in the water level adjusting tank 3 and the water level of the liquid 6 in the catcher tank 2 are linked together.
The lower trough portion 3c is a portion for forming a flow passage allowing the liquid 6 to flow between the water level adjusting tank 3 and the catcher tank 2 according to the fluctuation in the water level of the liquid 6 in the water level adjusting tank 3.
The pump P1 is a pump to lower the water level of the liquid 6 in the water level adjusting tank 3, with increases in the air pressure in the airtight chamber 3a, by sending air into the airtight chamber 3a and force the liquid 6 into the catcher tank 2 through the lower trough portion 3C to raise the water level of the liquid 6 in the catcher tank 2. Furthermore, when discharging air to the inside of the airtight chamber 3a, the pump P1 is designed to, for example, with the pump P1 in its OFF position, discharge the air in the airtight chamber 3a to the outside and reduce the internal air pressure of the airtight chamber 3a to cause the liquid 6 in the catcher tank 2 to flow into the water level adjusting tank 3 so as to lower the water level of the catcher tank 2.
The water level adjusting pipe 51 is a tubular member that is provided within the water level adjusting tank 3 for water level adjustment, which constitutes a portion of the liquid level adjusting device 5 to be described later. The water level adjusting pipe 51 is designed to adjust the water level so that the water level matches the thickness of the workpiece W to be cut, by adjusting its longitudinal position and changing the position of an opening edge of a lower end thereof. The lower end of the water level adjusting pipe 51 has an opening at the same level as the minimum water level in which the water level in the water level adjusting tank 3 is the lowest, and an upper end of the water level adjusting pipe 51 penetrates the water level adjusting tank 3 and has an external opening in an open state.
<Construction of Liquid Level Adjusting Device>As shown in
The discharge pipe 52 has a lower end 52b turnably (tiltably) mounted on a side wall of the catcher tank 2, and is provided so that the discharge port 52a at an upper end thereof can be displaced with respect to the liquid surface of the liquid 6 by causing the discharge pipe 52 to pivot about the lower end 52b. The discharge pipe 52 is composed of a cylindrical overflow pipe that has: the discharge port 52a formed in the upper opening end; and the lower end 52b formed by bending in an L-shape and journaled to the side wall in the vicinity of an inner bottom of the catcher tank 2.
The discharge port 52a is an opening for discharging the liquid 6 and the coated abrasive G3 floating on the liquid 6 to the outside of the catcher tank 2, and formed by the upper opening of the discharge pipe 52. In the case where the discharge pipe 52 is disposed vertically as shown by the solid line in
For example, at the time of cutting the workpiece W using the coated abrasive G3, when the abrasive water jet AWJ ejected from the abrasive nozzle 15 shown in
The position of the discharge port 52a (i.e. the water level of the liquid 6) can be adjusted as appropriate by adjusting a tilt angle θ of the discharge pipe 52 according to the height of the workpiece W. The excessive liquid 6 in the catcher tank 2 and the coated abrasive G3 floating on the liquid 6 can be discharged to the outside of the catcher tank 2 by tilting the discharge pipe 52 and thereby lowering the heights H1 and H2 of the discharge port 52a.
Furthermore, when air is sent into the airtight chamber 3a by the pump P1, the water level of the liquid 6 in the catcher tank 2 increases, so that the liquid 6 and the coated abrasive G3 floating on the liquid 6 can be discharged from the discharge port 52a to the outside of the catcher tank 2.
The coated abrasive recovery device 7 is a separation device that is disposed below the lower opening end of the discharge pipe 52 to separate and recover the used liquid 6 and coated abrasive G3 discharged from the discharge pipe 52. The coated abrasive recovery device 7 includes: a separator 71 that separates a turbid liquid composed of a mixture of the immersion liquid 6 and the coated abrasive G3 into the immersion liquid 6 and the coated abrasive G3; an used coated abrasive discharge pipe 72 that supplies the used coated abrasive G3, etc. discharged from the discharge pipe 52; an used coated abrasive recovery pipe 73 that receives the used coated abrasive G3 having undergone the separator 71; and an used liquid recovery pipe 74 that receives the used liquid 6 having undergone the separator 71.
The separator 71 is a device that separates the used liquid 6 and coated abrasive G3 overflowing and entering the discharge port 52a of the catcher tank 2, into the liquid 6 and the coated abrasive G3 for recycled use thereof. The separator 71 is, for example, a centrifugal machine that centrifugally separates the turbid liquid into the liquid 6 and the coated abrasive G3 by gravity difference.
The used coated abrasive discharge pipe 72 is a pipe for sending, to the separator 71, the turbid liquid composed of a mixture of the used coated abrasive G3 and liquid 6. The used coated abrasive discharge pipe 72 is connected to the discharge pipe 52 at its upstream side and connected to an upper end of the separator 71 at its downstream side.
The used coated abrasive recovery pipe 73 is a pipe that is connected to an upper end of a side surface of the separator 71 at its upstream side and connected to the coated abrasive supply pipe 80b at its downstream side to return the used coated abrasive G3 to the coated abrasive supply pipe 80b and circulate it, thereby enabling recycled use thereof.
The used liquid recovery pipe 74 is a pipe that is connected to a lower end of the separator 71 at its upstream side and connected to the high-pressure water supply device 101 (see
It should be noted that the coated abrasive recovery device 7 may have any structure that can recover the used coated abrasive G3 in the catcher tank 2, and its structure or the like is not particularly limited. For example, the coated abrasive recovery device 7 may include a coated abrasive recovery filter or filtering device that separates, into the liquid 6 and the coated abrasive G3, the used liquid 6 and coated abrasive G3 overflowing and entering the discharge port 52a.
Furthermore, as shown in
For example, the coated abrasive recovery device 7 may be such that the discharge pipe 52 of the liquid level adjusting device 5 extends directly downward of the catcher tank 2 and penetrates an inner bottom of the catcher tank 2 to be connected in communication to the separator 71, thereby recovering the coated abrasive G3 or the like.
Alternatively, the coated abrasive recovery device 7 may be an external device that is installed outside the catcher tank 2, such as disposing it outside the side wall of the catcher tank 2.
<Construction of Abrasive Material Recovery Device>The abrasive material recovery device 9 is a device that separately recovers the liquid 6, abrasive material G1, and sludge-like chips in the catcher tank 2 so as to enable recycled use of the used liquid 6 and abrasive material G1 in the catcher tank 2. For example, the abrasive material recovery device 9 is a classifying machine that separates liquid 6, the abrasive material G1, and chips according to gravity and grain diameter by centrifugal force. The abrasive material recovery device 9 includes: an abrasive material discharge pipe 91 for recovering the abrasive material G1 settling at the inner bottom of the catcher tank 2; a suction pump P2 that is provided in the abrasive material discharge pipe 91; a classifier 92 that separates the liquid 6, abrasive material G1, and chips sucked by the suction pump P2; a chip recovery pipe 93 that receives the chips having undergone the classifier 92; an abrasive material recovery pipe 94 that receives the abrasive material G1 having undergone the classifier 92; and an liquid recovery pipe 95 for discharging the liquid 6 having undergone the classifier 92.
As shown in
The suction pump P2 is a pump that is disposed on the way of the abrasive material discharge pipe 91 to suck the abrasive material G1 sinking in the liquid 6 together with the immersion liquid 6 and send it to the classifier 92. The suction pump P2 is driven by an electric motor (not shown).
The chip recovery pipe 93 is a pipe for discharging the chips having undergone the classifier 92. The chip recovery pipe 93 is connected to a lower end of the classifier 92 at its upstream side and disposed, for example, on a disposal tank (not shown) at its downstream side.
The abrasive material recovery pipe 94 is a pipe for discharging the abrasive material G1 having undergone the classifier 92. The abrasive material recovery pipe 94 is connected to an upper side surface of the classifier 92 at its upstream side and connected to the abrasive material supply pipe 80a (see
The liquid recovery pipe 95 is a pipe for discharging the liquid 6 having undergone the classifier 92. The liquid recovery pipe 95 is connected to an upper end of the classifier 92 at its upstream side and connected to the high-pressure water supply device 101 (see
It should be noted that the abrasive material recovery device 9 may have any structure that can recover the used abrasive material G1 in the catcher tank 2, and its structure or the like is not particularly limited. For example, the abrasive material recovery device 9 may include an abrasive material recovery filter or filtering device that recovers the used abrasive material G1 settling at the inner bottom of the catcher tank 2 and separates the abrasive material G1 from the chips and the liquid 6.
<Construction of Pedestal>As shown in
Each of the thin plates 4a, with a plane of a thin horizontally long flat member in a vertical position, is extended in a width direction of the catcher tank 2, and a number of the thin plates 4a are arranged in parallel with slit spaces thereamong along the liquid surface of the liquid 6 in the catcher tank 2 so that the workpiece W is placed thereon for underwater cutting.
<Operation>Next, referring mainly to the accompanying drawings, an apparatus and method for abrasive water jet machining according to the embodiment of the present invention will be described in the order of an operation process.
As shown in
Next, the pump P1 is switched to the ON position, and the position of the discharge port 52a is adjusted by setting the discharge pipe 52 to the desired angle θ, thereby allowing machining with the water level of the liquid 6 in the catcher tank 2 at a position lower than the workpiece W or machining with the water level of the liquid 6 at a position (in water) higher than the workpiece W. For example, in the case of machining in liquid, as shown in
Subsequently, the high-pressure water supply device 101 shown in
At the time of the cutting, firstly, piercing of the workpiece W is performed by the low-pressure abrasive water jet AWJ. Then, after the pressure of the abrasive water jet AWJ is increased, the cutting is performed starting from a hole formed by piercing. It should be noted that machining is performed while adjusting a machining condition in accordance with the material of the workpiece W because there is a difference in feed speed, tilt angle, etc. between the case where the workpiece W is glass which is hard to cut and the case where the workpiece W is a relatively easy-to-cut material, such as aluminum or stainless steel.
Furthermore, at the time of machining, either the abrasive material G1 of the first abrasive supply device 8A or the coated abrasive G3 of the second abrasive supply device 8B is selected as appropriate by selecting the switching unit 88 and supplied to the nozzle 1.
In this case, agglomeration of the abrasive G in the nozzle 1, etc. or clogging with the abrasive G can be eliminated especially by selecting the switching unit 88 to the second abrasive supply device 8B and supplying the coated abrasive G3 to the nozzle 1. This is because, as shown in
Furthermore, at the time of cutting the workpiece W, the abrasive material G1 is composed of abrasive grains having an angular shape with acute-angle corners and superior in cutting quality as compared with the abrasive grains of the coated abrasive G3.
Thus, at the time of machining with the abrasive water jet machining apparatus 100, cutting is performed while selecting the abrasive G between the abrasive material G1 and the coated abrasive G3 or alternately supplying the abrasive material G1 and the coated abrasive G3 with proper timing by switching the switching unit 88 of the abrasive supply device 8 as appropriate according to a machining condition, such as the shape, material, thickness, or finishing of the workpiece W. Thus, even if the abrasive material G1 agglomerates, the abrasive material G1 can be dispersed separately and stabilized by the action of the super water-repellency of the coated abrasive G3.
As shown in
Furthermore, the abrasive material G1 ejecting from the nozzle and chips falling into the catcher tank 2 by cutting sinks to the inner bottom of the catcher tank 2 and is sucked into the abrasive material discharge pipe 91 by the suction pump P2 to be separated by the abrasive material recovery device 9 so that it can be recycled, and then is recirculated into the abrasive material supply pipe 80a of the first abrasive supply device 8A, and the chips are discarded through the chip recovery pipe 93.
It should be noted that the abrasive material G1 and chips sinking to the inner bottom of the catcher tank 2 may be recovered from the catcher tank 2 by the abrasive material recovery device 9 or the like and then discarded without being recycled.
After the machining of the workpiece W is finished, the pump P1 is turned OFF to cause the air in the airtight chamber 3a to be discharged to the outside, and the water in the catcher tank 2 with the water level raised by the machining is moved by its own weight to the water level adjusting tank 3 with the water level lowered, thereby lowering the water level in the catcher tank 2. In this state, the machined workpiece W is removed from the pedestal 4 located inside the catcher tank 2, and machining work is completed.
<Modification>It should be noted that the present invention is not limited to the above-described embodiment, and various modifications and changes may be made without departing from the technical idea of the present invention. The present invention, of course, also extends to alternative embodiments which incorporate these modifications and changes, and a modification will be described referring mainly to
In the above-described embodiment, as an example of the abrasive water jet machining apparatus 100, as shown in
In this case, the liquid supply portion 8C is composed of a device that supplies, to the nozzle 1 supplied with the processing fluid Q and the abrasive G, the water-repellent material or flow promoting material G2 composed of any one of liquids of a fluorine-based material, silicon-based material, a coating material composed of a mixture of a fluorine-based material or silicon-based material and an oily raw material, paraffin, and fats. The liquid supply portion 8C includes: a liquid supply pipe 80c that supplies the water-repellent material or flow promoting material G2 stored in a storage tank not shown; a storage portion 81C that is composed of a tank temporarily storing the water-repellent material or flow promoting material G2 and having a discharge port 86C; and a liquid suction pipe 87C that couples the storage portion 81C and the switching unit 88.
For example, in order to supply the water-repellent material or flow promoting material G2 to the processing fluid Q supplied from the high-pressure pipe 102 to the nozzle 1, the switching unit 88 is switched so that the water-repellent material or flow promoting material G2 flows from the storage portion 81C to the nozzle 1, and the supply of the abrasive G from the abrasive material suction pipe 87A is stopped. Thus, the processing fluid Q and the water-repellent material or flow promoting material G2 can be supplied to the nozzle 1 and mixed together.
Furthermore, in order to supply the abrasive G and the water-repellent material or flow promoting material G2 to the nozzle 1, the high-pressure water supply device 101 is stopped to stop the supply of the processing fluid Q, and the switching unit 88 is switched so as to enable the supply from both the abrasive material suction pipe 87A and the liquid suction pipe 87C. Thus, the abrasive G is supplied to the abrasive suction pipe 89 from the abrasive material suction pipe 87A through the switching unit 88, and the water-repellent material or flow promoting material G2 is supplied to the abrasive suction pipe 89 from the liquid suction pipe 87C through the switching unit 88, so that the abrasive G and the water-repellent material or flow promoting material G2 are mixed to be supplied to the nozzle 1.
In this manner, the water-repellent material or flow promoting material G2 in the liquid supply portion 8C is supplied to the nozzle 1 to be mixed into the processing liquid Q or abrasive G, thereby improving the flowability of the processing liquid Q or abrasive G with the water-repellent material or flow promoting material G2 so that it can smoothly flow through the nozzle 1.
<Another Modification>For example, although in the above-described embodiment, the description has been made using, as an example, the abrasive supply device 8 which includes the first abrasive supply device 8A and the second abrasive supply device 8B, the arrangement may be such that the abrasive supply device 8 includes only the second abrasive supply device 8B to supply only the coated abrasive G3 to the nozzle 1.
Furthermore, in the above-described embodiment, the case where the supply port 13a is provided at one place of the mixing chamber 13 has been described. However, the supply port 13a may be provided at a plurality of places, and a plurality of the abrasive supply devices 8 may be provided corresponding to the plurality of supply ports 13a.
EXAMPLESNext, referring mainly to tables 1 and 2, examples will be described.
In the examples, two kinds of related art abrasive materials with different grain sizes and the coated abrasive G3 (water-repellent abrasive) of the present invention are supplied to the nozzles 1 having two different nozzle diameters, and it has been confirmed that the coated abrasive G3 (water-repellent abrasive) has the function of eliminating clogging.
Table 1 shows a result of a first experiment in which, using the abrasive water jet machining apparatus 100 according to the embodiment of the present invention, each of a related art abrasive material with a grain size of #120, a related art abrasive material with a grain size of #220, and the coated abrasive G3 (water-repellent abrasive) of the present invention with a grain size of #220 is supplied to the nozzle 1 having the abrasive nozzle 15 with a pressure of 300 MPa and an inner diameter of φ0.5 mm. The result is represented as “Good” if the abrasive G is not agglomerated, as “Fair” if the abrasive G is slightly agglomerated but does not cause clogging, as “Poor” if the abrasive G is agglomerated and causes clogging.
As shown in Table 1, in the case of the abrasive nozzle 15 with an inner diameter of φ0.5 mm, as for any of the related art abrasive material with a grain size of #120, the related art abrasive material with a grain size of #220, and the coated abrasive G3 (water-repellent abrasive) of the present invention with a grain size of #220, agglomeration of the abrasive G and clogging did not occur. Consequently, all the results were “Good”
Table 2 shows a result of a second experiment in which, using the abrasive water jet machining apparatus 100 according to the embodiment of the present invention, each of a related art abrasive material with a grain size of #120, a related art abrasive material with a grain size of #220, and the coated abrasive G3 (water-repellent abrasive) of the present invention with a grain size of #220 is supplied to the nozzle 1 having the abrasive nozzle 15 with a pressure of 300 MPa and an inner diameter of φ0.3 mm.
As shown in Table 2, in the case of the abrasive nozzle 15 with an inner diameter of φ0.3 mm, as for both the related art abrasive material with a grain size of #120 and the related art abrasive material with a grain size of #220, clogging occurred entirely, except that the related art abrasive material with a grain size of #120 did not cause clogging when the abrasive grain ejection amount is 20 and 40 (g/min).
On the other hand, as for the coated abrasive G3 (water-repellent abrasive) of the present invention with a grain size of #220, it has been confirmed that, in any case, the abrasive G does not agglomerate and the inside of the nozzle 1 is not clogged.
Claims
1. An abrasive water jet machining apparatus that performs machining by directing an abrasive water jet at a workpiece, the abrasive water jet being composed of a mixture of a high-pressure processing fluid with an abrasive, comprising:
- a nozzle that directs the abrasive water jet;
- a processing fluid supply portion that supplies the processing fluid to the nozzle; and
- an abrasive supply portion that supplies the abrasive to the processing fluid,
- wherein the abrasive is composed of a coated abrasive, the coated abrasive being produced by coating a surface of an abrasive material composed of abrasive grains with a water-repellent material or flow promoting material, and
- the abrasive supply portion supplies the coated abrasive to the nozzle.
2. The abrasive water jet machining apparatus according to claim 1, wherein the coated abrasive has a property of floating in the processing fluid.
3. The abrasive water jet machining apparatus according to claim 1,
- wherein the abrasive supply portion includes: an abrasive material supply portion that supplies the abrasive material to the processing fluid; a coated abrasive supply portion that supplies the coated abrasive to the processing fluid; and a switching unit for selectively supplying the abrasive material supplied from the abrasive material supply portion or/and the coated abrasive supplied from the coated abrasive supply portion.
4. An abrasive water jet machining apparatus that performs machining by directing an abrasive water jet at a workpiece, the abrasive water jet being composed of a mixture of a high-pressure processing fluid with an abrasive, comprising:
- a nozzle that directs the abrasive water jet;
- a processing fluid supply portion that supplies the processing fluid to the nozzle;
- an abrasive supply portion that supplies the abrasive to the processing fluid; and
- a liquid supply portion that supplies a water-repellent material or flow promoting material to the processing fluid or the abrasive.
5. The abrasive water jet machining apparatus according to claim 1, wherein the water-repellent material or flow promoting material is composed of any one of a fluorine-based material, silicon-based material, a coating material composed of a mixture of a fluorine-based material or a silicon-based material and an oily raw material, paraffin, and fats.
6. The abrasive water jet machining apparatus according to claim 1, further comprising:
- a catcher tank that stores liquid for machining the workpiece under liquid; and
- a discharge port that discharges the liquid stored in the catcher tank,
- wherein the coated abrasive floating on the liquid is discharged and recovered from the discharge port.
7. The abrasive water jet machining apparatus according to claim 6, further comprising a liquid level adjusting device that adjusts a liquid level of the liquid by adjusting a height of the discharge port.
8. An abrasive water jet machining method in which machining is performed by directing an abrasive water jet at a workpiece, the abrasive water jet being composed of a mixture of a high-pressure processing fluid with an abrasive, the method comprising:
- producing a coated abrasive as the abrasive by coating a surface of an abrasive material composed of abrasive grains with a water-repellent material or flow promoting material.
9. An abrasive water jet machining method in which machining is performed by directing an abrasive water jet at a workpiece, the abrasive water jet being composed of a mixture of a high-pressure processing fluid with an abrasive, the method comprising:
- supplying a water-repellent material or flow promoting material to the processing fluid or the abrasive.
10. The abrasive water jet machining apparatus according to claim 2,
- wherein the abrasive supply portion includes: an abrasive material supply portion that supplies the abrasive material to the processing fluid; a coated abrasive supply portion that supplies the coated abrasive to the processing fluid; and a switching unit for selectively supplying the abrasive material supplied from the abrasive material supply portion or/and the coated abrasive supplied from the coated abrasive supply portion.
Type: Application
Filed: Sep 25, 2013
Publication Date: Mar 27, 2014
Applicant: SUGINO MACHINE LIMITED. (Uozu-shi)
Inventors: Masaru OGAWA (Toyama-shi), Nobuyuki TERA (Kurobe-shi), Masashi TSUNEMOTO (Uozu-shi)
Application Number: 14/036,737
International Classification: B24C 11/00 (20060101);