JP6048657B2 - Water jet processing method and water jet processing apparatus - Google Patents

Description

  The present invention relates to a water jet processing method and a water jet processing apparatus. More specifically, high pressure water mixed with an abrasive is sprayed from a nozzle injection hole toward a work to cut the work. The present invention relates to a water jet machining method and a water jet machining apparatus.

2. Description of the Related Art Conventionally, a water jet machining apparatus in which high-pressure water mixed with an abrasive is sprayed from a nozzle spray hole toward a workpiece to cut the workpiece is already well known.
Although the nozzle injection hole is formed in a perfect circle, the roundness of the nozzle injection hole is gradually impaired while high-pressure water in which abrasive is mixed is circulated in the nozzle injection hole. Therefore, the machining accuracy is lowered (refer to the prior art in Patent Document 1).

JP-A 63-99200

Conventionally, in order to prevent the occurrence of defective products due to a decrease in processing accuracy, the nozzle is replaced when the required processing time has elapsed, and the processing time has been set short to estimate safety. It was an economy.
Further, in Patent Document 1 described above, the nozzle is rotated by providing a rotation mechanism so that the nozzle can be continuously used even when the roundness of the nozzle injection hole is deteriorated. There are disadvantages such as complicated equipment and maintenance of the rotating mechanism.
In view of the above-described circumstances, the present invention makes it possible to measure the roundness of the nozzle injection hole very easily, thereby contributing to economic efficiency by allowing each nozzle to be used to the limit of the allowable range. The present invention provides a water jet machining method and a water jet machining apparatus which are made possible.

That is, the invention of claim 1 is a water jet machining method in which high pressure water mixed with an abrasive is sprayed from a nozzle injection hole toward a workpiece to cut the workpiece.
A step of cutting a preset reference graphic, a step of recognizing the machining shape of the cut workpiece, a difference between the recognized machining shape and the reference graphic, and the magnitude of the calculated difference And a step of determining that the roundness of the nozzle injection hole is abnormal when a predetermined threshold value is exceeded.
According to a fourth aspect of the present invention, there is provided a machining head for injecting high-pressure water mixed with an abrasive toward a workpiece from a nozzle injection hole, a moving means for relatively moving the machining head and the workpiece, A shape recognition unit for recognizing a machining shape of a workpiece machined by the machining head; a storage unit storing a machining path; and a control unit for controlling the shape recognition unit and the moving unit. In a water jet machining apparatus for machining a workpiece by relatively moving the head and the workpiece along the machining path,
The control means stores a machining path for creating a preset reference graphic, moves the machining head and the workpiece relative to each other along the machining path, and processes the workpiece processed by the shape recognition means. It is designed to recognize the processed shape of the workpiece,
In addition, the control unit includes a determination unit that determines whether or not the roundness of the nozzle injection hole is abnormal, and the determination unit includes the machining shape recognized by the shape recognition unit and the reference A difference between figures is calculated, and when the calculated difference exceeds a predetermined threshold value, it is determined that the roundness of the nozzle injection hole is abnormal.

According to the present invention, the preset reference graphic is cut, the machining shape of the cut workpiece is recognized, and the difference between the recognized machining shape and the reference graphic has a predetermined threshold value. If it exceeds, it is determined that the roundness of the nozzle injection hole is abnormal, and therefore the abnormality determination can be performed automatically and very easily.
As a result, the necessity of nozzle replacement can be determined unambiguously, so that the nozzle can be used to the end of its service life while preventing processing defects. Therefore, it is more economical than replacing the nozzle earlier. Can be improved.

The front view which shows one Example of this invention. Sectional drawing of the process nozzle 2. FIG. The top view which shows the process table 51. FIG. The block diagram which shows the structure of the control means 12. FIG. Step diagram of the method of the present invention. The top view for demonstrating a cutting process state. The top view for demonstrating 2nd Example of this invention. The top view for demonstrating 3rd Example of this invention. The top view for demonstrating 4th Example of this invention.

Referring to FIG. 1, a water jet machining apparatus 1 includes a high-pressure water supply means 4 for supplying high-pressure water to a machining head 2 via a high-pressure pipe 3, and an abrasive hose 6 for the machining head 2. Abrasive material supply means 7 for supplying an abrasive material via the nozzle, and after the abrasive material is mixed into the high-pressure water by the processing head 2, the high-pressure water is supported by the processing table 51 via the nozzle 8. The workpiece 9 is sprayed.
The machining head 2 can be moved relative to the XY direction orthogonal to the workpiece 9 in the horizontal plane by the moving means 11 and the upper and lower Z directions. In the illustrated embodiment, the moving means 11 is moved. The X-direction moving means 11A for moving the machining head 2 in the X direction which is the left-right direction in FIG. 1, the Y-direction moving means 11B for moving the workpiece 9 in the Y direction which is perpendicular to the paper surface, Z direction moving means 11C for moving in the Z direction which is the vertical direction.
The operation of the high-pressure water supply unit 4, the abrasive supply unit 7, and the moving unit 11 is controlled by the control unit 12.

As shown in FIG. 2, the processing head 2 includes a cylindrical housing 15 extending in the vertical direction. A high pressure water supply pipe 16 is attached above the shaft portion of the housing 15, and the high pressure water supply pipe 16 is connected to the processing head 2. The high pressure water supply means 4 communicates with the high pressure pipe 3 described above.
Further, an abrasive supply port 17 extending in the lateral direction is formed at an intermediate height position of the housing 15, and this supply port 17 communicates with the abrasive supply means 7 via the abrasive hose 6 described above. is there.
Further, a cylindrical nozzle body 18 is provided below the shaft portion of the housing 15, a wear insert 19 is provided in the nozzle body 18, and the nozzle 8 is attached below the wear insert 19.

The wear insert 19 includes branch passages 19a and 19b therein, and one of the branch passages 19a is sandwiched between a passage 18a formed in the shaft portion of the nozzle body 18 and the high-pressure water supply pipe 16 and the nozzle body 18. The high pressure water supply means 4 is communicated through the orifice 20 and the high pressure water supply pipe 16 and the high pressure pipe 3.
The other branch passage 19 b communicates with the abrasive supply means 7 through the passage 18 b formed in the side portion of the nozzle body 18 and the supply port 17 and the abrasive hose 6.
Then, the high-pressure water from the high-pressure water supply means 4 supplied to one branch passage 19a was mixed with the abrasive from the abrasive supply means 7 supplied to the other branch passage 19b, and the abrasive was mixed. The high-pressure water flows from the wear insert 19 into the nozzle injection hole 8a of the nozzle 8 and is jetted toward the work 9 from here.

In FIG. 1, the processing head 2 is provided with a laser distance meter 21, and the measurement result by the laser distance meter 21 is input to the control device 12, and the lower end surface of the nozzle 8 and the surface of the work 9 are The distance between them can be measured accurately.
The processing head 2 is provided with a photographing unit 22 as a shape recognizing unit for recognizing a processing shape processed by the water jet processing device 1. The processing shape photographed by the photographing unit 22 is the control device 12. To be input.

Further, as shown in FIG. 3, the inspection work 9 is fixed to a predetermined position on the processing table 51 by a clamp 52.
The processing table 51 includes four side frames 53 and a plurality of cross members 54 arranged in parallel to the longitudinal direction of the processing table 51, and the workpiece 9 is placed on the cross members 54. It is like that.
The inspection work 9 has a size that allows a hole 31 for measuring roundness, which will be described later, to be formed. In the illustrated embodiment, the inspection work 9 is positioned at a required position on the lower left side of the processing table 51 and described above. It is fixed by a clamp 52.
In order to clearly photograph the hole 31 by the photographing means 22 after the hole 31 is formed, that is, to prevent the crosspiece member 54 from being reflected in the hole 31 through the hole 31. A background plate 55 can be inserted between the workpiece 9 and the crosspiece member 54.
The background plate 55 is controlled to advance and retreat by a driving means 56 such as an air cylinder. The background plate 55 is inserted between the workpiece 9 and the crosspiece member 54 at the advanced position of the background plate 55, and the workpiece 9 at the retracted position. And the crosspiece member 54 are discharged to the outside so as not to hinder the cutting of the hole 31 by the water jet machining apparatus 1.

In the above configuration, when the roundness of the nozzle injection hole 8 a is inspected, first, the inspection work 9 is positioned at a required position on the lower left of the processing table 51 and fixed by the clamp 52. At this time, the background plate 55 is positioned at the retracted position and is discharged to the outside from between the workpiece 9 and the crosspiece member 54.
Once the inspection work 9 is fixed at a required position on the processing table 51, the operator then gives a command to that effect to the control device 12 via the input means 24 shown in FIG. The roundness inspection may be automatically performed before each operation or after a predetermined time of operation.
When a circularity inspection command is given to the control device 12, the control device 12 controls the moving device 11 by the moving means control unit 25, and a machining path for creating a reference graphic preset in the storage unit 26. 27, the nozzle 8 is positioned at a predetermined start position with respect to the work 9 for inspection, and is moved in the Z direction so that the distance between the work 9 and the nozzle 8 is precisely the required distance by the signal from the laser distance meter 21. The apparatus 11C is controlled.
In this embodiment, as shown in FIGS. 5 and 6, in this embodiment, a reference figure, for example, a perfect hole 31 having a diameter of 6 mm is cut in the work 9 for inspection. At this time, a piercing hole is first formed in the center portion of the hole 31 (not shown) according to the processing path 27, and the hole 31 is subsequently cut and processed. In addition, the disk of the center part produced | generated when forming the said hole 31 comes to fall from the clearance gap between the table | surfaces in which the workpiece | work 9 is mounted.

In FIG. 6, a small-diameter perfect circle 32 described by a solid line indicates a cross-sectional shape of a water jet flow ejected from the nozzle ejection hole 8a in a state where the roundness of the nozzle ejection hole 8a is good. When the roundness of the nozzle injection hole 8a is good, the cross-sectional shape of the water jet flow is also a perfect circle 32. When the nozzle 8 is new, the diameter of the perfect circle 32 is, for example, 1 mm.
In a state in which the hole 31 is cut based on the reference figure that is a perfect circle by the water jet flow having the perfect circle 32, the hole 31 is also a perfect circle as indicated by a solid line, and therefore the diameter R thereof is all At the same angular position.
On the other hand, a small-diameter ellipse 33 indicated by an imaginary line indicates the cross-sectional shape of the water jet flow injected from the nozzle injection hole 8a when the roundness of the nozzle injection hole 8a is deteriorated. In general, when the roundness of the nozzle injection hole 8a deteriorates, the shape thereof becomes an ellipse, and accordingly, the cross-sectional shape of the water jet flow also becomes an ellipse 33. Further, the diameter of the ellipse 33 on the short axis is slightly larger than the diameter of the perfect circle 32 at the time of the new article.
When the hole 31 is cut by a water jet flow having a cross-sectional shape of an ellipse 33, the hole 31 becomes an elliptical hole 31 'as indicated by an imaginary line, and therefore its diameter R is a measurement angular position. Will be inconsistent.

When the hole 31 is cut, the background plate 55 is then moved from the retracted position to the advanced position by the driving means 56, whereby the background plate 55 is inserted between the workpiece 9 and the crosspiece member 54, It is possible to prevent the crosspiece member 54 and the like from being reflected in 31. In this state, the photographing unit 22 photographs the hole 31 that is the processed shape of the workpiece, and the image is input to the control unit 12.
As shown in FIG. 4, the control unit 12 includes a determination unit 35 that determines whether or not the roundness of the nozzle injection hole 8 a is abnormal. The determination unit 35 includes the imaging unit 22. As shown in FIG. 5 and FIG. 6, four diameters R at 45 degrees are calculated from the image of the hole 31 photographed by the above.
In other words, in this embodiment, the reference figure is a perfect circle 31 and has four measurement reference points set at 45 degrees each having the same dimension, and each of the reference points in the recognized machining shape. The actual dimensions of the corresponding parts are measured.
Then, the determination unit 35 determines the maximum value Rmax, the minimum value Rmin, and the average value Rmean from the obtained diameters as the four actual dimensions, and then stores the difference between the maximum value Rmax and the minimum value Rmin. When the predetermined threshold value α stored in the unit 26 is exceeded, it is determined that the roundness of the nozzle injection hole 8a is abnormal, and the alarm means 36 (FIG. 4) is activated. It has become.

On the other hand, when the difference between the maximum value Rmax and the minimum value Rmin is equal to or less than the threshold value α, the determination unit 35 corrects the machining path based on the average value Rmean. For example, even when the diameter of the nozzle injection hole 8a is increased due to long-term use, the ellipse is not so elliptical that there is an abnormality in roundness. More specifically, this is a case in which, for example, a perfect hole 31 of 6.02 mm is obtained, although the perfect hole 31 having a diameter of 6 mm is cut.
In this case, the processing path correction unit 37 of the control unit 12 performs correction to shift the processing path in the case of a perfect circle in a direction away from the planned cutting line by 0.01 mm for the radius of 0.02 mm that has been expanded. Done. By performing such correction, a round hole 31 having a diameter of 6 mm can be obtained in the next operation.

In the first embodiment, the reference figure is a perfect circle, but the invention is not limited to this.
For example, FIG. 7 shows a second embodiment in which the reference figure is a regular octagon and four measurement reference points are set at 45 degrees each having the same dimension. In this case, the work 9 is a regular octagon. The hole 41 may be formed, and the inner diameter of the hole 41 may be measured at each measurement reference point.
FIG. 8 shows a third embodiment in which the reference figure is a regular square and two measurement reference points are set at the same size by 90 degrees. In this case, the work 9 has a regular square shape. The hole 42 may be formed, and the inner diameter of the hole 42 may be measured at each measurement reference location.

Furthermore, in the first to third embodiments described above, the reference graphic has a plurality of reference points set to the same size, but the present invention is not limited to this, and the reference graphic is each You may have the some reference | standard location set to the different reference | standard dimension.
For example, FIG. 9 shows a fourth embodiment in which the reference figure is rectangular, and the fourth embodiment has two measurement reference points set to different reference dimensions. In this case, a rectangular hole 43 may be formed in the work 9 and the inner diameter of the hole 43 may be measured at two measurement reference points, the long side and the short side.
In this case, the determination unit 35 calculates the machining error at each reference location from the actual dimensions of the location corresponding to each reference location in the rectangular machining shape, and the maximum and minimum values of each machining error are calculated. What is necessary is just to calculate a difference.
Thus, various shapes can be selected as the reference graphic. In short, as long as the difference between the maximum value and the minimum value can be obtained from the error between the reference figure and the actual machining shape, the reference figure may be any shape.

Furthermore, in any of the above-described embodiments, the holes 31, 41 to 43 are formed and the inner diameter thereof is measured. However, for example, the outer diameter of the cut disc may be measured. In the above embodiment, the disk to be cut out is subjected to piercing processing. However, when measuring the outer diameter of the cut out disk, the piercing is performed outside the disk, and the disk is a table. It is desirable to devise measures such as narrowing the arrangement pitch of the crosspieces so as not to fall downward.
In the above embodiment, the photographing unit 22 is used as the shape recognizing unit. However, the present invention is not limited to this. For example, a touch probe type measuring unit may be used.

DESCRIPTION OF SYMBOLS 1 Water jet processing apparatus 2 Processing head 4 High pressure water supply means 7 Abrasive supply means 8 Nozzle 8a Nozzle injection hole 11 Moving means 12 Control means 21 Laser distance meter 22 Imaging means (shape recognition means)
26 Memory 27 Processing path 31 Hole (perfect circle) 31 'Hole (ellipse)
41-43 holes

Claims (6)

In the water jet processing method of cutting the workpiece by spraying high pressure water mixed with abrasives from the nozzle injection hole toward the workpiece,
A step of cutting a preset reference graphic, a step of recognizing the machining shape of the cut workpiece, a difference between the recognized machining shape and the reference graphic, and the magnitude of the calculated difference And a step of determining that the roundness of the nozzle injection hole is abnormal when exceeding a predetermined threshold value.   The reference figure has a plurality of measurement reference points set to the same dimensions, and measures the actual dimensions of the recognized machining shapes at the locations corresponding to the reference positions. The water jet processing method according to claim 1, wherein a difference between the maximum value and the minimum value of the water jet is calculated. The reference figure has a plurality of measurement reference points set to different reference dimensions,
In the recognized machining shape, the actual dimensions of the respective locations corresponding to the respective reference locations are measured, and the machining errors at the respective reference locations are calculated based on the respective measurement results, and the maximum and minimum values of each machining error are calculated. The water jet machining method according to claim 1, wherein a difference between values is calculated. A processing head for spraying high-pressure water mixed with abrasives from a nozzle injection hole toward a workpiece, a moving means for moving the processing head and the workpiece relative to each other, and a workpiece processed by the processing head A shape recognizing unit for recognizing a machining shape of an object, a storage unit storing a machining path, and a control unit for controlling the shape recognizing unit and the moving unit. In a water jet processing apparatus that processes a workpiece by relatively moving along a processing path,
The control means stores a machining path for creating a preset reference graphic, moves the machining head and the workpiece relative to each other along the machining path, and processes the workpiece processed by the shape recognition means. It is designed to recognize the processed shape of the workpiece,
In addition, the control unit includes a determination unit that determines whether or not the roundness of the nozzle injection hole is abnormal, and the determination unit includes the machining shape recognized by the shape recognition unit and the reference A water jet machining apparatus that calculates a difference between figures and determines that the roundness of a nozzle injection hole is abnormal when the magnitude of the calculated difference exceeds a predetermined threshold value. The reference figure has a plurality of measurement reference points set to the same dimensions,
The determination unit measures an actual dimension of a location corresponding to each of the reference locations in the recognized machining shape, and calculates a difference between a maximum value and a minimum value of each actual size. Item 5. A water jet machining apparatus according to Item 4. The reference figure has a plurality of measurement reference points set with different reference dimensions,
The determination unit measures the actual dimensions of the locations corresponding to the respective reference locations in the recognized machining shape, calculates the machining error at each reference location based on each measurement result, The water jet machining apparatus according to claim 4, wherein a difference between the maximum value and the minimum value is calculated.

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