Grinding equipment

Abstract

To supply grinding water only to an area where an abrasive wheel contacts with a workpiece to save water in creep feed grinding.SOLUTION: A grinding device includes a grind water supply mechanism 7 having: multiple jet nozzles 75 which jet grinding water to an outer surface of an abrasive wheel 341; a communication passage 76 which allows each jet nozzle 75 and a water supply source 77 to communicate with each other; and valves 74 disposed in the communication passage 76 for the respective jet nozzles 75. Opening or closing of the valves 74 is controlled by a position of a chuck table relative to the abrasive wheel 341 so that the grinding water is jetted only to an area, which contacts with the workpiece 10, of the abrasive wheel 341.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a grinding device for grinding a workpiece. [Background technology]

[0002] The process of holding a workpiece on the holding surface of a chuck table, positioning the lower surface (grinding surface) of the grinding wheel below the upper surface of the workpiece, and moving the chuck table and the rotating grinding wheel relatively horizontally, thereby grinding the upper surface of the workpiece from one end to the other end with the outer surface of the grinding wheel, is called creep feed grinding (see, for example, Patent Document 1).

[0003] Grinding equipment used in creep feed grinding is equipped with a grinding water nozzle that supplies grinding water to the outer surface of the grinding wheel, and the grinding water is used to remove grinding chips and remove heat from the grinding process (see, for example, Patent Document 2). The grinding water nozzle has multiple outlets along the outer surface of the grinding wheel, and sprays grinding water onto the largest area of ​​the grinding wheel that comes into contact with the workpiece, removing grinding chips and removing heat from the grinding process. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2017-056522 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-149222 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in creep feed grinding, a constant amount of grinding water is constantly sprayed, even though the area of ​​the grinding wheel that comes into contact with the workpiece changes as the grinding process progresses. Therefore, when the area of ​​the grinding wheel that comes into contact with the workpiece is small, grinding water is also supplied to parts that do not come into contact with the workpiece, resulting in unnecessary spraying of grinding water. Therefore, in creep feed grinding, there is a problem of saving water by supplying grinding water only to the area where the grinding wheel comes into contact with the workpiece. [Means for solving the problem]

[0006] a grinding device comprising a chuck table for holding a workpiece on a holding surface, a grinding mechanism for grinding the workpiece using an annular grinding wheel attached to the tip of a spindle, and a movement mechanism for relatively moving the chuck table and the grinding wheel in a direction parallel to the holding surface, wherein the lower surface of the grinding wheel is positioned outside the outer periphery of the workpiece held on the holding surface and below the upper surface of the workpiece, and the movement mechanism moves the chuck table and the grinding mechanism relatively to each other, thereby grinding the workpiece with the outer surface of the grinding wheel; and a grinding water supply mechanism for supplying grinding water to an area where the grinding wheel contacts the workpiece, and a control unit, wherein the grinding water supply mechanism sprays grinding water onto the outer surface of the grinding wheel. The grinding wheel is arranged in an arc shape along the outer surface thereof. a plurality of spray nozzles; a communication passage that communicates each of the spray nozzles with a water supply source; and a valve that is disposed in the communication passage for each of the spray nozzles; a dragging air breaking unit for breaking dragging air formed in the same direction as the rotation direction of the grinding wheel on the outer surface side of the grinding wheel, the dragging air breaking unit being a reverse direction injection nozzle for injecting fluid in the direction opposite to the rotation direction of the grinding wheel along the outer surface of the grinding wheel, and being disposed on the extension of the arc of the injection nozzle and upstream of the rotation direction of the grinding wheel; The control unit controls the opening and closing of the valve depending on the position of the chuck table relative to the grinding wheel so that grinding water is sprayed only onto the area of ​​the grinding wheel that comes into contact with the workpiece. [Effects of the Invention]

[0007] In the present invention, by controlling the opening and closing of the valve, grinding water is supplied only to the area of ​​the grinding wheel that is grinding the workpiece, so that grinding water can be saved. Furthermore, by providing a dragging air destruction unit and destroying the dragging air, the supply of grinding water to the grinding wheel is not hindered, so the amount of grinding water sprayed from the spray nozzle can be reduced, further increasing the water-saving effect, and even if the amount of grinding water sprayed is reduced, it is possible to cool the grinding wheel and discharge grinding chips. [Brief explanation of the drawings]

[0008] [Figure 1]FIG. 1 is a perspective view showing an example of a grinding device. [Figure 2] FIG. 2 is a perspective view showing an example of a grinding water supply mechanism. [Figure 3] This is a plan view showing the stages of grinding a circular workpiece by supplying grinding water to a grinding wheel, where (a) shows the state in which grinding water is sprayed from some of the spray nozzles at the start of grinding, (b) shows the state in which grinding water is sprayed from all of the spray nozzles during grinding, and (c) shows the state in which the supply of grinding water from some of the spray nozzles has been stopped. [Figure 4] This is a plan view showing the stages of supplying grinding water to a grinding wheel to grind a rectangular workpiece, where (a) shows the state in which grinding water is sprayed from some of the spray nozzles at the start of grinding, (b) shows the state in which grinding water is sprayed from all of the spray nozzles during grinding, and (c) shows the state in which the supply of grinding water from some of the spray nozzles has been stopped. [Figure 5] FIG. 2 is a plan view showing an example of a dragging air breaking unit. DETAILED DESCRIPTION OF THE INVENTION

[0009] The grinding device 1 shown in Figure 1 is an apparatus that grinds a workpiece 10 held on a chuck table 2 using a grinding mechanism 3. The chuck table 2 is driven by a moving mechanism 4 and can be moved in the Y-axis direction, and the grinding mechanism 3 is driven by a grinding feed mechanism 5 and can be moved in the Z-axis direction.

[0010] The chuck table 2 includes a suction portion 20 formed of a porous member and a frame body 21 that supports the suction portion 20, and the surface of the suction portion 20 forms a holding surface 200 that holds the workpiece 10. The holding surface 200 and the upper surface of the frame body 21 are flush with each other.

[0011] A table base 23 is provided below the chuck table 2, and the table base 23 is supported at least at three points by three chuck support parts 24 (only two are shown in FIG. 1). Each chuck support part 24 is provided with a load measuring device 25 that measures the vertical load when the grinding mechanism 3 presses the workpiece held by the holding surface 200. In addition, at least two chuck support parts 24 have the function of adjusting the height of the chuck table 2 and thereby adjusting the inclination of the holding surface 200.

[0012] The grinding mechanism 3 includes a spindle 30 having a rotation axis 300 in the Z-axis direction, a spindle rotation mechanism 31 that rotates the spindle 30, a spindle housing 32 that rotatably supports the spindle 30, a mount 33 connected to the lower end of the spindle 30, and a grinding wheel 34 attached to the mount 33. When the spindle rotation mechanism 31 rotates the spindle 30, the grinding wheel 34 also rotates. The grinding wheel 34 is composed of a base 340 fixed to the mount 33 and multiple grinding stones 341 fixed in an annular shape to the lower surface of the base 340. The outer periphery of the rotational path of the grinding stones 341 has approximately the same diameter as the workpiece 10. The upper end of the spindle 30 is provided with an inlet 301 through which grinding water flows in.

[0013] The movement mechanism 4 includes a ball screw 40 having a rotation axis 400 in the Y-axis direction, a motor 41 that rotates the ball screw 40, a pair of guide rails 42 arranged parallel to the ball screw 40, and a slide plate 43 whose bottom is in sliding contact with the guide rails 42 and has a nut (not shown) inside that threads onto the ball screw 40. The chuck support 24 and the load measuring device 25 are arranged above the slide plate 43. When the ball screw 40 rotates, the slide plate 43 moves in the Y-axis direction while being guided by the guide rails 42. The chuck table 2 also moves in the Y-axis direction in response to the movement of the slide plate 43 in the Y-axis direction. The frame 21 is rotatably supported by a base 27. A bellows 26 is connected to the side of the base 27 in the Y-axis direction. The chuck table 2 moves in the Y-axis direction as the bellows 26 expands and contracts. The position of the chuck table 2 in the Y-axis direction is detected by an encoder 411 provided on the motor 41.

[0014] The grinding feed mechanism 5 includes a ball screw 50 having a rotation axis 500 in the Z-axis direction, a motor 51 that rotates the ball screw 50, a pair of guide rails 52 arranged parallel to the ball screw 50, a lift plate 53 whose sides are in sliding contact with the guide rails 52 and which has a nut (not shown) inside that screws onto the ball screw 50, and a holder 54 that is connected to the lift plate 53 and supports the spindle housing 32. When the ball screw 50 rotates, the lift plate 53 is guided by the guide rails 52 and moves in a direction perpendicular to the holding surface 200, and the grinding mechanism 3 also moves in the same direction, so that the grinding wheel 341 moves closer to or further away from the holding surface 200. The position of the grinding mechanism 3 in the Z-axis direction is recognized by an encoder 511 provided on the motor 51.

[0015] The grinding device 1 includes a control unit 6 that controls the chuck table 2, the grinding mechanism 3, the moving mechanism 4, and the grinding feed mechanism 5. The control unit 6 includes a CPU and a memory element.

[0016] A grinding water supply mechanism 7 is disposed around the grinding wheel 34, covering approximately half of the grinding stones 341 from the outer periphery and supplying grinding water to the outer surfaces of the grinding stones 341. As shown in FIG. 2, the grinding water supply mechanism 7 includes a main body 71 formed in a substantially semicircular arc shape, a first bracket 72 connected to the upper part of the main body 71 and fixed to the holder 54 of the grinding feed mechanism 5, and a second bracket 73 fixed to the holder 54 separately from the first bracket 72. The second bracket 73 may be separate from the grinding water supply mechanism 7.

[0017] The radius of curvature of the inner periphery of the main body 71 is larger than the radius of curvature of the outer periphery of the trajectory of the grinding wheel 341. A plurality of valves 74 are disposed on the upper part of the main body 71. As shown in FIG. 3, a jet nozzle 75 facing the center of the arc is disposed on the inner periphery of the main body 71. A communication passage 76 through which grinding water flows is formed inside the main body 71, and all of the jet nozzles 75 are connected to a water supply source 77 via the communication passage 76. A valve 74 is disposed in the communication passage 76 for each jet nozzle 75, and the jetting of water from each jet nozzle 75 is controlled by opening and closing the valve 74.

[0018] The lower end of the second bracket 73 is provided with a dragging air destruction unit 78 equipped with a reverse direction jet nozzle 781. The reverse direction jet nozzle 781 is connected to an air source 79 and jets out destroying air 782. As the grinding wheel 341 rotates, dragging air 342 is generated along its outer periphery, but the air jetted from the reverse direction jet nozzle 781 is jetted in the opposite direction to the dragging air 342, destroying it.

[0019] When grinding the upper surface 100 of the workpiece 10 using the grinding mechanism 3, the lower surface 101 of the workpiece 10 is suction-held on the holding surface 200 of the chuck table 2, leaving the upper surface 100 of the workpiece 10 exposed. Then, the movement mechanism 4 moves the chuck table 2 in a direction parallel to the holding surface 200 until all of the grinding wheels 341 are positioned on the outer periphery of the workpiece 10. At this time, the chuck table 2 does not rotate. The spindle rotation mechanism 31 rotates the grinding wheel 34, and the grinding feed mechanism 5 lowers the grinding mechanism 3 until the lower surfaces of the grinding wheels 341 are positioned below the upper surface 100 of the workpiece 10. The height position of the lower surfaces of the grinding wheels 341 is determined depending on the amount to be removed from the upper surface 100 of the workpiece 10.

[0020] Next, the moving mechanism 4 moves the chuck table 2 in the +Y direction, bringing the workpiece 10 closer to the grinding wheels 341. Then, just before the grinding wheels 341 closest to the workpiece 10 come into contact with the workpiece 10, as shown in FIG. 3(a), under the control of the control unit 6, the valve 74 corresponding to the grinding wheel 341 to be ground is opened, and grinding water is sprayed from the spray nozzle 75 facing the grinding wheel 341. Note that the valves 74 and the spray nozzles 75 do not necessarily correspond one-to-one; it is sufficient that the spray nozzle 75 sprays grinding water toward the area where the grinding wheel 341 to be ground is located. In FIG. 3, the open valves 74 are shown in white, and the closed valves 74 are shown in black. In other words, two pairs of valves 74 arranged symmetrically about the axis of the movement direction (+Y direction) of the chuck table 2 may be treated as a single valve. For example, the pair of valves 74 shown in black in FIG. 3(c) may be combined into one valve, and the spray of grinding water from the pair of two spray nozzles 75 connected to that valve may be stopped.

[0021] When the moving mechanism 4 further moves the chuck table 2 in the +Y direction at a predetermined speed, grinding of the workpiece 10 begins with the outer surfaces of the grinding wheels 341, to which grinding water is being supplied. As the chuck table 2 further moves in the +Y direction, the number of grinding wheels 341 that come into contact with the workpiece 10 increases, and accordingly, the number of opened valves 74 also increases. The control unit 6 recognizes the position of the chuck table 2 in the Y axis direction based on the value of the encoder 411 of the moving mechanism 4. The control unit 6 stores in advance the relationship between the position of the chuck table 2 in the Y axis direction and the grinding wheels 341 that come into contact with the workpiece 10. Therefore, by controlling the opening and closing of the valves 74 in accordance with the value of the encoder 411, the control unit 6 can spray grinding water from the spray nozzle 75 only toward the area where the grinding wheels 341 that come into contact with the workpiece 10 are located, depending on the position of the chuck table 2 in the Y axis direction relative to the grinding wheels 341, thereby conserving grinding water.

[0022] As the number of grinding wheels 341 in contact with the upper surface 100 of the workpiece 10 increases in this manner, the number of valves 74 that are opened also gradually increases, and when approximately half of the grinding wheels 341 are being used to grind the workpiece 10, as shown in Figure 3(b), all of the valves 74 corresponding to the spray nozzles 75 facing those approximately half of the grinding wheels 341 are opened, and grinding water is sprayed from all of the spray nozzles 75 to supply the grinding water to the grinding wheels 341 in contact with the workpiece 10.

[0023] When the grinding wheel 341 rotates, entrained air 342 is formed on the outer surface of the grinding wheel 341 in the rotation direction of the grinding wheel 341 and the +Y direction. This entrained air 342 flows between the grinding wheel 341 and the injection nozzle 75, and prevents the grinding water injected from the injection nozzle 75 from reaching the grinding wheel 341. Therefore, during grinding, breaking air 782 is ejected from the reverse direction injection nozzle 781 of the entrained air breaking unit 78 in the direction opposite to the flow direction of the entrained air 342.

[0024] When the chuck table 2 moves further in the +Y direction, the entire top surface 100 of the workpiece 10 is ground, as shown in Figure 3(c). At this time, only two of the valves 74, at both ends, are closed. Then, when the chuck table 2 moves further in the +Y direction, all of the grinding wheels 341 are no longer in contact with the workpiece 80, and all of the valves 74 are closed.

[0025] In this way, by opening and closing the valve 74, grinding water is supplied from the jet nozzle 75 only to the area of ​​the grinding wheels 341 where the grinding wheels are actually in contact with the upper surface 100 of the workpiece 10 and performing grinding, thereby minimizing the amount of grinding water used. Also, since the entrained air 342 can be destroyed by the breaking air 782 jetted from the reverse jet nozzle 781, grinding water can be effectively supplied from the jet nozzle 75 to the grinding wheel 341. As a result, the grinding wheel 341 can be cooled with a small amount of grinding water (weak water flow), and grinding chips adhering to the grinding wheel 341 can also be discharged.

[0026] Although the spray nozzle 75 sprays the grinding water in a direction parallel to the holding surface 200, the grinding water may be sprayed downward, i.e., toward the upper surface 100 of the workpiece 10. Even in this case, the grinding water flowing over the upper surface 100 can reach the outer surface of the grinding wheel 341.

[0027] As shown in Fig. 4, a rectangular workpiece 80 can also be ground. In this case, a chuck table with a rectangular suction portion is used instead of the chuck table 2 shown in Fig. 1. When grinding this workpiece 80, the chuck table 2 is not rotated, but is moved in the +Y direction parallel to the holding surface 200 by the movement mechanism 4, so that the grinding wheel 341 approaches the workpiece 10. In addition, the spindle rotation mechanism 31 rotates the grinding wheel 34, and the grinding feed mechanism 5 lowers the grinding mechanism 3, so that the bottom surface of the grinding wheel 341 is positioned below the top surface 100 of the workpiece 10.

[0028] As the moving mechanism 4 moves the chuck table 2 in the +Y direction, some of the grinding wheels 341 come into contact with the workpiece 80, as shown in Fig. 4(a). Then, under the control of the control unit 6, the corresponding valves 74 are opened so that grinding water is sprayed from the spray nozzles 75 facing those of the grinding wheels 341 that come into contact with the workpiece 80. In Fig. 4 as well, among the valves 74, those that are open are shown in white, and those that are closed are shown in black.

[0029] Furthermore, when the moving mechanism 4 moves the chuck table 2 in the +Y direction at a predetermined speed, the workpiece 10 is ground by the outer surfaces of the grinding wheels 341 to which grinding water is being supplied. As the chuck table 2 moves further in the +Y direction, the number of grinding wheels 341 that come into contact with the workpiece 10 increases, and accordingly, the number of valves 74 that are opened gradually increases. As shown in Figure 4(b), when approximately half of the grinding wheels 341 are being used to grind the workpiece 10, all of the valves 74 corresponding to the spray nozzles 75 facing those approximately half of the grinding wheels 341 are opened, and grinding water is sprayed from all of the spray nozzles 75 to supply the grinding water to the grinding wheels 341 that are in contact with the workpiece 10.

[0030] During grinding, breaking air 782 is jetted from the reverse direction jet nozzle 781 of the entrained air destruction unit 78 in a direction opposite to the flow direction of the entrained air 342. This destroys the entrained air 342 that is generated along the outer surface of the grinding wheel 341 in the rotation direction of the grinding wheel 341, and the grinding water jetted from the jet nozzle 75 can be reliably supplied to the grinding wheel 341.

[0031] 4(c), when the chuck table 2 moves further in the +Y direction, the number of grinding wheels 341 that are not in contact with the workpiece 80 increases, and accordingly, the number of closed valves 74 also increases. Then, when all of the grinding wheels 341 are no longer in contact with the workpiece 80, all of the valves 74 are closed. The chuck table 2 may have a plurality of holding surfaces for respectively holding a plurality of workpieces. As described above, the valve 74 is controlled so that grinding water is supplied only to the area where the grinding wheel comes into contact with the workpiece.

[0032] 3 and 4 may inject breaking water instead of breaking air 782. Also, instead of the reverse jet nozzle 781, a entrained air breaking section 783 shown in FIG. 5 may be used. The entrained air breaking section 783 is a columnar member disposed adjacent to the outer surface of the grinding wheel 341. The entrained air breaking section 783 does not have the function of ejecting air, but is disposed in the path of the entrained air 342 to break the entrained air 342 by obstructing its advance. The embodiment shown in FIG. 5 is configured similarly to the grinding water supply mechanism 7 shown in FIGS. 3 and 4, except for the entrained air breaking section 783. [Explanation of symbols]

[0033] 1: Grinding device 2: Chuck table 20: Suction part 200: Holding surface 21: Frame 23: Table base 24: Chuck support 25: Load measuring device 26 Bellows 27: Base 3: Grinding mechanism 30: Spindle 300: Rotating shaft 301: Inlet 31: Spindle rotation mechanism 32: Spindle housing 33: Mount 34: Grinding wheel 340: Base 341: Grinding wheel 342: Drifting air 4: Movement mechanism 40: Ball screw 400: Rotating shaft 41: Motor 411: Encoder 42: Guide rail 43: Slide plate 5: Grinding feed mechanism 50: Ball screw 500: Rotating shaft 51: Motor 511: Encoder 52: Guide rail 53: Lifting plate 54: Holder 6: Control unit 7: Grinding water supply mechanism 71: Main body 72: First bracket 73: Second bracket 74: Valve 75: Injection nozzle 76: Communication passage 77: Water supply source 78: Air Destruction Unit 781: Reverse jet nozzle 782: Breaking air 783: Entrained air breaking section 79:Air source 10: Workpiece 100: Top surface 101: Bottom surface 80: Workpiece

Claims

[Claim 1] The apparatus comprises a chuck table that holds a workpiece on a holding surface, a grinding mechanism that grinds the workpiece using an annular grinding wheel attached to the tip of a spindle, and a movement mechanism that moves the chuck table and the grinding wheel relatively in a direction parallel to the holding surface, a grinding device in which a lower surface of the grinding wheel is positioned outside an outer peripheral edge of a workpiece held on the holding surface and below an upper surface of the workpiece, the chuck table and the grinding mechanism are moved relatively by the moving mechanism, and the workpiece is ground by the outer surface of the grinding wheel, a grinding water supply mechanism that supplies grinding water to an area where the grinding wheel contacts the workpiece; and a control unit. the grinding water supply mechanism comprises a plurality of spray nozzles arranged in an arc along the outer surface of the grinding wheel for spraying grinding water onto the outer surface of the grinding wheel, a communication passage connecting each of the spray nozzles to a water supply source, and a valve arranged in the communication passage for each of the spray nozzles; a dragged air breaking unit provided on the outer surface side of the grinding wheel for breaking dragged air formed in the same direction as the rotation direction of the grinding wheel; the entrained air breaking unit is a reverse direction injection nozzle that injects fluid along the outer surface of the grinding wheel in a direction opposite to the rotation direction of the grinding wheel, and is disposed on an extension of the arc of the injection nozzle and upstream of the rotation direction of the grinding wheel; the control unit controls opening and closing of the valve depending on the position of the chuck table relative to the grinding wheel so that the grinding water is sprayed only onto an area of ​​the grinding wheel that comes into contact with the workpiece. Grinding equipment.

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