Grinding device

Abstract

The present application provides a grinding device which is constituted at a low cost. While air is sprayed from an air nozzle (7) provided in a grinding device (1) which performs grinding processing on a workpiece (14) to rotate a grinding wheel (36) at a low speed (for example, 10 rpm), a front end detection unit (5) is used to detect a segment grinding tool (360), and a counter (60) is used to count the number of segment grinding tools (360) and the like. Then, the count value counted by the counter (60) is compared with the number of segment grinding tools (360) which is stored in advance in a judging section (61), so that it is judged whether the segment grinding tool (360) is dropped or not. The grinding device (1) does not need to have a motor or the like for rotating the grinding wheel (36) at a low speed, so that the grinding device (1) can be constituted at a low cost.

Description

Technical Field

[0001] This invention relates to grinding apparatus. Background Technology

[0002] As disclosed in Patent Document 1, the grinding wheel installed in the grinding apparatus for grinding the workpiece has: a base; and a plurality of grinding wheel segments arranged in a ring on the base with gaps between them.

[0003] During the grinding of the workpiece, the grinding wheel is rotated, and the chuck table holding the workpiece is rotated, so that the section of the grinding wheel enters from the outer periphery of the workpiece toward the center.

[0004] When the section abrasive enters from the outer periphery of the workpiece, it may sometimes fall off the base due to impacts or other reasons.

[0005] When a section of the grinding wheel has broken off, it can create an arc pattern on the ground surface, resulting in a thickness difference in the unground portion.

[0006] Therefore, as disclosed in Patent Document 2, there is an invention for detecting the detachment of section molds.

[0007] Patent Document 1: Japanese Patent Application Publication No. 2003-089065

[0008] Patent Document 2: Japanese Patent Application Publication No. 2017-127936

[0009] However, in order to detect the detachment of the grinding wheel section, it is necessary to rotate the grinding wheel at a low speed of about 10 rpm. To make the grinding wheel rotate at a low speed, it is necessary to install an encoder that detects the rotation angle of the rotating shaft, a servo motor that rotates the grinding wheel while feeding back the rotation angle detected by the encoder, and a control unit that rotates the servo motor at a specified rotation angle, which results in high cost.

[0010] Therefore, the following issue exists in grinding equipment: it is not necessary to install an expensive electric motor unit to rotate the grinding wheel at a low speed to detect the detachment of the grinding wheel section. Summary of the Invention

[0011] The present invention was made in view of the above-mentioned problems, and its object is to provide a grinding apparatus that is configured at a low cost.

[0012] This invention relates to a grinding apparatus comprising: a holding unit for holding a workpiece on a holding surface; a grinding unit having a rotatable grinding wheel, the grinding wheel having a plurality of segmented grinding tools arranged in a ring on a base with gaps, the grinding unit using the segmented grinding tools to grind the workpiece held by the holding unit; a grinding feed unit for moving the grinding unit in a direction perpendicular to the holding surface; and a front end detection unit for detecting the front end of the segmented grinding tools. The grinding apparatus further comprises: an air nozzle for injecting air into the grinding wheel positioned at a location where the front end detection unit can detect the front end of the segmented grinding tools, causing the grinding wheel to rotate at a speed detectable by the front end detection unit; a counter for counting the number of segmented grinding tools or the number of gaps during the rotation of the grinding wheel; and a judgment unit for judging whether the segmented grinding tools have fallen off based on the value of the counter.

[0013] Preferably, the front-end detection unit of the grinding apparatus described above includes: a light-projecting section that projects measuring light; a light-receiving section that is disposed opposite to the light-projecting section in such a way that the section of grinding wheel can enter between the light-receiving section and the light-projecting section and receives the measuring light projected from the light-projecting section; and a detection section that detects the section of grinding wheel or the gap based on the change in the amount of light received by the light-receiving section caused by the section of grinding wheel entering between the light-projecting section and the light-receiving section.

[0014] Preferably, the air nozzle of the grinding apparatus described above has: a light-emitting part air jetting part that jets air into the light-emitting part; and a light-receiving part air jetting part that jets air into the light-receiving part.

[0015] According to the present invention, it is not necessary to have a special electric motor or the like to rotate the grinding wheel at a low speed; the low-speed rotation of the grinding wheel can be achieved by blowing air. Therefore, an inexpensive grinding device capable of detecting the detachment of sections of the grinding wheel can be constructed, which is economical. Attached Figure Description

[0016] Figure 1 It is a three-dimensional view showing the entire grinding apparatus.

[0017] Figure 2 This is a bottom view of the first grinding wheel.

[0018] Figure 3 This is a front view showing the state of light projected from the projection section passing through the gap.

[0019] Figure 4 It is a graph showing the voltage change when the grinding wheel intermittently blocks the measuring light from the projection section.

[0020] Label Explanation

[0021] 1: Grinding device; 10: Base; 11: Column; 14: Workpiece; 140: Upper surface; 2: Holding unit; 20: Suction part; 200: Holding surface; 21: Frame; 210: Upper surface of the frame; 27: Fold; 28: Cover; 3: Grinding unit; 30: Spindle; 31: Housing; 32: Motor; 33: Mounting base; 35: Rotary shaft; 36: Grinding wheel; 360: Section grinding wheel; 361: Base; 362: Lower surface; 363: Clearance; 364: Section length; 365: Inner side; 366: Outer side; 4: Grinding feed Unit; 40: Ball screw; 41: Guide rail; 42: Z-axis motor; 43: Lifting plate; 44: Holding seat; 45: Rotating shaft; 5: Front-end detection unit; 50: Light projection section; 51: Light receiving section; 52: Light projection and receiving section; 53: Base; 54: Light projection and receiving element; 540: Recess; 55: Detection section; 60: Counter; 61: Judgment section; 7: Air nozzle; 70: Air jet section of light projection section; 71: Air jet section of light receiving section; 72: Air source; 80: Section threshold; 81: Gap threshold; 82: First light receiving voltage; 83: Second light receiving voltage. Detailed Implementation

[0022] 1. Structure of the grinding device

[0023] Figure 1 The grinding apparatus 1 shown is a grinding apparatus that uses grinding unit 3 to perform grinding processing on workpiece 14. The structure of grinding apparatus 1 will be described below.

[0024] like Figure 1 As shown, the grinding apparatus 1 includes: a base 10 extending in the Y-axis direction; and a column 11 erected on the +Y direction side of the base 10.

[0025] A grinding feed unit 4 supporting the grinding unit 3 is disposed on the side of the column 11 in the -Y direction. The grinding unit 3 includes: a spindle 30 having a rotation axis 35 in the Z-axis direction; a housing 31 supporting the spindle 30 so that it can rotate; a motor 32 driving the spindle 30 to rotate about the rotation axis 35; a mounting base 33 connected to the lower end of the spindle 30; and a grinding wheel 36 mounted on the lower surface of the mounting base 33. The grinding wheel 36 can be attached to and detached from the mounting base 33, and other types of grinding wheels can be mounted on the mounting base 33 to replace the grinding wheel 36.

[0026] The grinding wheel 36 has a base 361 and multiple segments of grinding wheel 360 with a generally rectangular parallelepiped shape arranged in a ring on the lower surface of the base 361.

[0027] like Figure 2As shown, two adjacent abrasive sections 360 are arranged with a gap 363 between them, and all the abrasive sections 360 are arranged in a ring as a whole. Each abrasive section 360 has a section length 364 in the circumferential direction. The lower surface 362 of the abrasive section 360 becomes the grinding surface for grinding the workpiece 14.

[0028] use Figure 1 The motor 32 shown causes the spindle 30 to rotate about the rotation axis 35. As a result, the mounting base 33 connected to the spindle 30 and the grinding wheel 36 mounted on the mounting base 33 rotate about the rotation axis 35 in the Z-axis direction passing through the center of the base 361.

[0029] The grinding feed unit 4 includes: a ball screw 40 having a rotation axis 45 in the Z-axis direction; a pair of guide rails 41 arranged parallel to the ball screw 40; a Z-axis motor 42 connected to the upper end of the ball screw 40, causing the ball screw 40 to rotate about the rotation axis 45; a lifting plate 43, the nut inside of which is screwed into the ball screw 40, and the side of the lifting plate 43 slidingly contacting the guide rails 41; and a retaining seat 44 connected to the lifting plate 43 to retain the spindle 30.

[0030] By using the Z-axis motor 42 to drive the ball screw 40, when the ball screw 40 rotates about the rotation axis 45, the lifting plate 43 is guided by the guide rail 41 and moves up and down in the Z-axis direction. At the same time, the grinding unit 3 held in the holding seat 44 moves in the direction perpendicular to the holding surface 200 (Z-axis direction).

[0031] A holding unit 2 is provided on the base 10. The holding unit 2 has a circular plate-shaped suction part 20 and an annular frame 21 supporting the suction part 20. The suction part 20 is a porous component with multiple fine holes, and the upper surface of the suction part 20 becomes a holding surface 200 for attracting and holding the workpiece 14. The upper surface 210 of the frame 21 and the holding surface 200 are formed in the same plane.

[0032] An attraction source (not shown) is connected to the holding surface 200 of the holding unit 2. For example, when the workpiece 14 is placed on the holding surface 200, the workpiece 14 can be attracted and held on the holding surface 200 by activating the attraction source.

[0033] In addition, a rotating mechanism (not shown) is provided in the holding unit 2. By using this rotating mechanism, the holding unit 2 can be rotated.

[0034] A cover 28 is provided around the retaining unit 2, and the cover 28 is connected to the pleats 27 in a telescopic manner.

[0035] When the retaining unit 2 moves in the Y-axis direction, the cover 28 moves integrally with the retaining unit 2 in the Y-axis direction, and the pleats 27 extend and retract.

[0036] A front-end detection unit 5 is provided on the +Y direction side of the holding unit 2. The front-end detection unit 5 is fixed to the cover 28, for example, and can move together with the holding unit 2 in the ±Y direction. The front-end detection unit 5 has a base 53 and a light-emitting and receiving element 54 disposed on the base 53. The light-emitting and receiving element 54 has a light-emitting part 50 for projecting measurement light and a light-receiving part 51 for receiving measurement light projected from the light-emitting part 50. The light-receiving part 51 is arranged opposite to the light-emitting part 50. A recess 540 extending in the X-axis direction is formed between the light-emitting part 50 and the light-receiving part 51. The section abrasive 360 ​​can enter the recess 540.

[0037] In addition, the front-end detection unit 5 has a detection unit 55 for detecting the section mold 360 or the gap 363. The detection unit 55 has the following functions: converting the amount of light received by the light-receiving part 51, which changes due to the section mold 360 entering between the light-emitting part 50 and the light-receiving part 51, into a voltage value and measuring it, and detecting the section mold 360 or the gap 363 based on the change in voltage.

[0038] like Figure 2 and Figure 3 As shown, the grinding apparatus 1 has an air nozzle 7 that sprays air onto the grinding wheel 36, which is positioned so that the front end of the section grinding tool 360 can be detected by the front end detection unit 5. The air nozzle 7 has a light-emitting air jet section 70 that blows air to the light-emitting section 50 and a light-receiving air jet section 71 that sprays air to the light-receiving section 51. The light-emitting air jet section 70 and the light-receiving air jet section 71 are connected to an air source 72.

[0039] like Figure 2 As shown, the air jet section 70 for the projection section and the air jet section 71 for the light receiving section are arranged such that the direction of the air ejected from each section is neither parallel nor perpendicular to the tangent direction of the rotation trajectory of the section grinding tool 360 at the point where the air contacts the section grinding tool 360. Furthermore, at the point where the air contacts the section grinding tool 360, the angle between the direction of the air ejected from the air jet section 70 and the tangent direction of the rotation trajectory of the section grinding tool 360 is approximately equal to the angle between the direction of the air ejected from the air jet section 71 and the tangent direction of the rotation trajectory of the section grinding tool 360. Additionally, as... Figure 3 As shown, the air jet section 70 for the projection section and the air jet section 71 for the light receiving section are configured such that the direction of the air jetted from each section is neither parallel nor perpendicular to the lower surface 362 of the section abrasive 360.

[0040] In addition, in the example shown, the air nozzle 7 and the front detection unit 5 are integrated, but they can also be configured as separate units.

[0041] With the grinding wheel 36 positioned such that the front end of the section grinding wheel 360 can be detected by the front end detection unit 5, air is injected from the light-emitting air jet section 70 and the light-receiving air jet section 71 of the air nozzle 7 toward the inner surface 365, outer surface 366, and lower surface 362 of the grinding wheel 36, thereby causing the grinding wheel 36 to rotate. Furthermore, the rotational speed of the grinding wheel 36 can be adjusted by regulating the air flow rate supplied from the air source 72 in the air nozzle 7.

[0042] Furthermore, the air nozzle 7 has the following function: it ejects air from the light-projecting air jet section 70 and the light-receiving air jet section 71 to remove water droplets and the like adhering between the light-projecting section 50 and the light-receiving section 51. That is, in the illustrated example, the light-projecting air jet section 70 and the light-receiving air jet section 71 both serve the functions of rotating the grinding wheel 36 and removing water droplets. Alternatively, other nozzles besides the light-projecting air jet section 70 and the light-receiving air jet section 71 can be provided, and the functions of rotating the grinding wheel 36 and removing water droplets can be achieved by using different nozzles.

[0043] A counter 60 is connected to the front-end detection unit 5 to count the number of sections of grinding wheel 360 or the number of gaps 363 during the rotation of the grinding wheel 36. In addition, a judgment unit 61 is connected to the counter 60 to determine whether the section of grinding wheel 360 has fallen off based on the value of the counter 60.

[0044] The counter 60 has the function of incrementing the count of the number of grinding sections 360 each time the detection unit 55 detects a section of grinding wheel 360. Additionally, the counter 60 has the function of counting the number of gaps 363 each time the detection unit 55 detects a gap. For example, when the grinding wheel 36 rotates at a speed of 10 rpm, which allows the front-end detection unit 5 to detect both the grinding sections 360 and the gaps 363, the counter 60 increments when the detection unit 55 detects a grinding section 360. The counter 60, for example, can count the number of grinding sections 360 detected by the detection unit 55 during one revolution of the grinding wheel 36.

[0045] In addition, the number of segment grinding tools 360 can be pre-stored in the judgment unit 61. By comparing the number of segment grinding tools 360 per revolution of the grinding wheel 36 obtained by counting by the counter 60 with the number of segment grinding tools 360 stored in the judgment unit 61, it is possible to determine whether a segment grinding tool 360 has fallen off.

[0046] 2. Operation of the grinding device

[0047] (Grinding process)

[0048] The operation of the grinding apparatus 1 when grinding the workpiece 14 is performed using the above-described grinding apparatus 1 will be explained.

[0049] When using the grinding device 1 to perform grinding on the workpiece 14, firstly, Figure 1 The workpiece 14 shown is placed on the holding surface 200 of the holding unit 2. Then, an attraction source (not shown) connected to the holding unit 2 is activated, transmitting the generated attraction force to the holding surface 200. As a result, the workpiece 14 is attracted and held on the holding surface 200.

[0050] With the workpiece 14 held on the holding surface 200 by attraction, the holding unit 2 is moved in the +Y direction and positioned below the grinding unit 3 by using a Y-axis moving unit (not shown).

[0051] Next, the holding unit 2 is rotated using a rotating mechanism (not shown), causing the workpiece 14 held on the holding surface 200 to rotate, and the section grinding tool 360 is rotated about the rotation axis 35 using a motor 32.

[0052] With the workpiece 14 rotating about the rotation axis 25 and the section grinding wheel 360 rotating about the rotation axis 35, the grinding unit 3 is lowered in the -Z direction using the grinding feed unit 4. By lowering the section grinding wheel 360 in the -Z direction, the lower surface 362 of the section grinding wheel 360 comes into contact with the upper surface 140 of the workpiece 14.

[0053] With the lower surface 362 in contact with the upper surface 140 of the workpiece 14, the section grinding tool 360 is further lowered in the -Z direction, thereby grinding the workpiece 14.

[0054] After the grinding of the workpiece 14 is completed, the grinding unit 3 is moved in the +Z direction by the grinding feed unit 4 so that the section grinding wheel 360 leaves the upper surface 140 of the workpiece 14, and then the workpiece 14 is removed from the holding surface 200 of the holding unit 2.

[0055] (Judging the detachment of section grinding molds)

[0056] In the grinding apparatus 1, it is determined at an opportune time, before the grinding of the workpiece 14, whether the section of the grinding tool 360 has fallen off. The operation of the grinding apparatus 1 when determining whether the section of the grinding tool 360 has fallen off will be explained below.

[0057] When determining whether the section mold 360 has fallen off, make Figure 1 The front-end detection unit 5 shown operates to project measurement light from the projection section 50 toward the light-receiving section 51, and moves the front-end detection unit 5 so that the rotation trajectory of the section mold 360 is above the recess 540.

[0058] Then, the grinding wheel 36 is lowered an appropriate distance in the -Z direction using the grinding feed unit 4. As a result, the section grinding wheel 360 enters the recess 540 of the light-emitting element 54, positioning the lower surface 362 of the section grinding wheel 360 at a point relative to the light-emitting and receiving beam 52 obtained by connecting the light-emitting part 50 and the light-receiving part 51 with a straight line (see reference). Figure 2 The height position is at the lower part.

[0059] Next, for example, make Figure 2 The air source 72 shown operates to supply air to the air jet section 70 for the projection section and the air jet section 71 for the light-receiving section. As a result, a predetermined flow rate of air is jetted from the air jet section 70 and the air jet section 71 toward the two sides 365, 366 and the lower surface 362 of the grinding wheel 36, causing the grinding wheel 36 to rotate under the thrust of the air. The rotational speed of the grinding wheel 36 is, for example, set to 10 rpm.

[0060] In other words, the air jet 71 is positioned below the section grinding wheel 360 and jets air diagonally upward, thus enabling the grinding wheel 36 to rotate along the direction of air jetting.

[0061] Here, when the grinding wheel 36 rotates on the lower surface 362 of the section grinding wheel 360 at a position lower than the height of the light-emitting and light-receiving beam 52 obtained by connecting the light-emitting part 50 and the light-receiving part 51 by a straight line, the light-emitting and light-receiving beam 52 alternately repeats the state in which the section grinding wheel 360 overlaps on the light-emitting and light-receiving beam 360 and is blocked, and the light-emitting and light-receiving beam 52 does not overlap on the light-emitting and light-receiving beam 360 and is not blocked.

[0062] exist Figure 4 The diagram shows a graph of the voltage change detected by the detection unit 55 when the measuring light projected from the projection unit 50 is repeatedly blocked by the rotating section of the abrasive mold 360 and when the light is not blocked.

[0063] The detection unit 55 has a preset segment threshold 80 and a gap threshold 81. For example, when the measured light-receiving voltage is greater than the gap threshold 81, the measurement light projected from the projection unit 50 is considered to be unobstructed and is detected as gap 363. Conversely, when the measured light-receiving voltage is less than the segment threshold 80, the measurement light projected from the projection unit 50 is considered to be obstructed by the segment mold 360 and is detected as segment mold 360.

[0064] When the measuring light projected from the projection section 50 is repeatedly blocked and unblocked by the rotating section mold 360, such as Figure 4 As shown, for example, the two values ​​of the first photosensitive voltage 82 and the second photosensitive voltage 83 are measured alternately.

[0065] When the measured light-receiving voltage is the first light-receiving voltage 82, since the first light-receiving voltage 82 is smaller than the segment threshold 80, the detection unit 55 detects it as segment mold 360. Furthermore, when the measured light-receiving voltage is the second light-receiving voltage 83, since the second light-receiving voltage 83 is larger than the gap threshold 81, the detection unit 55 detects it as gap 363.

[0066] Therefore, the section mold 360 and the gap 363 are alternately detected by the detection unit 55.

[0067] As the grinding wheel 36 begins to rotate, the counter 60 begins to count the number of grinding sections 360. Thus, each time the detection unit 55 detects a grinding section 360, the count value of the counter 60 increases. After the counter 60 has counted the number of grinding sections 360 detected by the detection unit 55 during one revolution of the grinding wheel 36, the operation of the counter 60 is stopped, and air injection from the air nozzle 7 is stopped, thus halting the rotation of the grinding wheel 36.

[0068] Then, the judgment unit 61 compares the count value obtained by the counter 60 during one revolution of the grinding wheel 36 with the number of the section grinding wheel 360 stored in the judgment unit 61 in advance.

[0069] At this time, if the count value obtained by the counter 60 during one revolution of the grinding wheel 36 is the same as the number of section grinding tools 360 pre-stored in the judgment unit 61, it is determined that the section grinding tool 360 has not fallen off. On the other hand, if the count value obtained by the counter 60 during one revolution of the grinding wheel 36 is less than the number of section grinding tools 360 pre-stored in the judgment unit 61, it is determined that the section grinding tool 360 has fallen off.

[0070] In addition, instead of comparing the number of section molds 360 to determine the detachment of section molds 360 as described above, the method of comparing the number of gaps 363 can be used to determine the detachment of section molds 360.

[0071] Specifically, the determination unit 61 stores the number of gaps 363 present in the grinding wheel 36 in advance, and positions the section grinding tool 360 at an appropriate height so that it enters the recess 540. Then, while projecting measuring light from the projection unit 50, air is injected from the projection air jet unit 70 of the air nozzle 7 to rotate the grinding wheel 36. Whenever the detection unit 55 detects a gap 363, the counter 60 counts the number of gaps 363. By counting the number of gaps 363 detected by the detection unit 55 during one revolution of the grinding wheel 36, and comparing the number of gaps 363 stored in the determination unit 61 with the counted number of gaps 363, it is possible to determine whether the section grinding tool 360 has fallen off.

[0072] In the grinding apparatus 1, when determining the detachment of the section grinding wheel 360, air is blown by the air nozzle 7 to make the grinding wheel 36 rotate at a low speed of about 10 rpm. Therefore, there is no need for a motor to make the grinding wheel 36 rotate at a low speed or a control unit to control the rotation, which is economical.

Claims

1. A grinding apparatus, comprising: A holding unit that holds the workpiece on a holding surface; A grinding unit has a rotatable grinding wheel, which has multiple sections of grinding tools arranged in a ring on a base with gaps. The grinding unit uses these sections of grinding tools to grind the workpiece held by the holding unit. A grinding feed unit that moves the grinding unit in a direction perpendicular to the holding surface; as well as The front-end detection unit detects the front end of the mold section. in, This grinding device has the following features: An air nozzle sprays air onto the grinding wheel, which is positioned so that the front end of the section of the grinding wheel can be detected by the front end detection unit, so that the grinding wheel rotates at a speed that the front end detection unit can detect. A counter that counts the number of grinding wheels in that section or the number of gaps during the rotation of the grinding wheel; and The judgment unit determines the detachment of the mold section based on the value of the counter.

2. The grinding apparatus according to claim 1, wherein, The front-end detection unit has the following features: The projection section projects the measuring light; The light-receiving part is configured opposite to the light-projecting part in such a way that the section of the abrasive can enter between the light-receiving part and the light-projecting part, and receives the measuring light projected from the light-projecting part; as well as The detection unit detects the section of the abrasive or the gap based on the change in the amount of light received by the light-receiving part caused by the section of the abrasive entering between the projection part and the light-receiving part.

3. The grinding apparatus according to claim 2, wherein, The air nozzle has: An air jet section for the projection section, which jets air into the projection section; and The light-receiving air jet section jets air toward the light-receiving part.

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