Workpiece loading device

Abstract

[Problem] To provide a workpiece loading device enabling high-precision positioning of a workpiece with respect to a cylindrical grinder. [Solution] A workpiece loading device 100 for loading a cylindrical workpiece 101 into a cylindrical grinder 200 is provided with: a pair of arms 128, 130 sandwiching a side surface 101a of a workpiece from above and below with the workpiece in a side-lying orientation; a pivot shaft 136 for rotating the arms in a vertical plane from a loading / unloading side of the workpiece toward the cylindrical grinder; a movement mechanism 104 for causing the pivot shaft to advance / withdraw in the horizontal direction with respect to the cylindrical grinder; a pair of strain gauges 168, 170 respectively attached to the bases of the arms; a center calculation device 172 for calculating vertical and horizontal offset of the center position of the workpiece with respect to the cylindrical grinder on the basis of the strains detected by the strain gauges; and a correction device 174 for adjusting the torsion angle of the pivot shaft to correct the vertical offset and driving the movement mechanism to correct the horizontal offset.

Description

Work Loading Device

[0001] The present invention relates to a work loading device for carrying a silicon ingot, which is a cylindrical work, into a cylindrical grinding machine.

[0002] A cylindrical grinding machine for silicon ingots is a processing device that grinds the outer peripheral surface of a silicon ingot (hereinafter referred to as a work) conveyed by a work loading device.

[0003] The work loading device is controlled by numerical control (NC), and controls the positioning of the work relative to the cylindrical grinding machine by, for example, a high-resolution encoder of a servo motor. A disk-shaped semiconductor wafer is formed by cutting the work after outer peripheral grinding into a predetermined thickness with a band saw or the like.

[0004] Patent Document 1 discloses a cylindrical grinding device and a work conveying device. The work conveying device described in Patent Document 1 clamps a cylindrical work (silicon ingot) from above with a pair of claws 251a and 251b, moves the work, and carries the work into and out of the cylindrical grinding device.

[0005] Japanese Unexamined Patent Application Publication No. 2025-009422

[0006] When the work is configured to be gripped from above as in Patent Document 1, the work conveying device is disposed so as to cover the cylindrical grinding device, which results in an increase in size of the device. To solve this problem, it is conceivable to carry the work in and out by inserting the work from the side of the cylindrical grinding device.

[0007] However, a silicon ingot is a heavy object weighing several tens of kilograms to more than 100 kilograms. Therefore, when the body of a cylindrical work is clamped by an arm and an attempt is made to carry the work into the cylindrical grinding device from the side, non-negligible deflection occurs in the arm. Furthermore, when the length and diameter of the silicon ingot change and the weight of the work changes, the deflection of the arm that grips the work also changes minutely. For this reason, it is difficult to position the work with high accuracy by the above-described NC control.

[0008] Furthermore, cylindrical grinding machines may process notch grooves or OF (orientation flat) surfaces indicating the crystal orientation of the wafer on a workpiece after outer circumference grinding. In this case, centering and positioning the workpiece relative to the cylindrical grinding machine is generally done manually. However, manual centering and positioning can lead to variations in processing accuracy depending on the operator's skill.

[0009] The present invention aims to provide a workpiece loading device that can accurately position a workpiece relative to a cylindrical grinding machine.

[0010] To solve the above problems, a typical configuration of the work loading device according to the present invention is a work loading device for loading a cylindrical workpiece, such as a silicon ingot, into a cylindrical grinding machine, comprising: a pair of arms that clamp the sides of the workpiece from above and below in a horizontal position; a pivot axis that rotates the pair of arms in a vertical plane toward the cylindrical grinding machine from the loading / unloading side of the workpiece; a moving mechanism that moves the pivot axis horizontally toward and away from the cylindrical grinding machine; a pair of strain gauges attached to the base of each of the pair of arms; a center calculation device that calculates the vertical and horizontal deviations of the center position of the workpiece relative to the cylindrical grinding machine based on the strain detected by the pair of strain gauges; and a correction device that corrects the deviations calculated by the center calculation device, wherein the correction device corrects the vertical deviation by adjusting the twist angle of the pivot axis and corrects the horizontal deviation by driving the moving mechanism.

[0011] The above-mentioned correction device preferably corrects for vertical and horizontal misalignment to align the center position of the workpiece with the center position of the workpiece spindle.

[0012] According to the present invention, a workpiece loading device can be provided that can accurately position a workpiece relative to a cylindrical grinding machine.

[0013] This figure shows the configuration of a work loading device in an embodiment of the present invention. This figure shows the analysis results of the strain generated in the pair of arms in Figure 1. This figure illustrates the operation and surrounding structure of the work loading device in Figure 1. This figure, following Figure 3, illustrates the operation and surrounding structure of the work loading device. This figure shows the displacement of the center position of the workpiece held between the pair of arms in Figure 4(b). This figure illustrates the operation to correct the displacement of the center position of the workpiece in Figure 5.

[0014] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. The dimensions, materials, and other specific numerical values ​​shown in these embodiments are merely examples to facilitate understanding of the invention and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals to avoid redundant explanations, and elements not directly related to the present invention are omitted from the illustrations.

[0015] Figure 1 shows the configuration of a work loading device 100 in an embodiment of the present invention. The work loading device 100 is a device for loading cylindrical silicon ingots (hereinafter referred to as work 101) into a cylindrical grinding machine 200 (see Figure 3). A support stand 300 is positioned on the loading / unloading side of the work loading device 100 shown in Figure 3. The work 101 is placed on the upper part 302 of the support stand 300.

[0016] The work loading device 100 comprises a base 102 and a moving mechanism 104, as shown in Figure 1. The moving mechanism 104 has two rails 106, a table 110, and a motor 112 for moving forward and backward. The rails 106 are fixed to the upper surface of the base 102 and extend in the Z-axis direction (horizontal direction) as shown in the figure, and are arranged parallel to each other.

[0017] Multiple brackets 114 are fixed to the underside of the table 110. As shown in Figure 1, the brackets 114 are movably mounted to rails 106 fixed to the upper surface of the base 102. As a result, the table 110 is guided to move horizontally relative to the base 102.

[0018] The forward / backward motor 112 is fixed to the upper surface of the base 102. The forward / backward motor 112 is positioned between the two rails 106 and rotates the shaft 122. When the shaft 122 rotates, a movable member (not shown) fixed to the lower surface of the table 110 moves horizontally. Therefore, the moving mechanism 104 can move the table 110 horizontally relative to the base 102 by driving the forward / backward motor 112.

[0019] Two support members 124 are erected on the upper surface of the table 110. Between the support members 124, a holding member 132 is positioned to hold a pair of arms 128 and 130. A pivot shaft 136 passes through the support members 124 and the holding member 132. The pivot shaft 136 is connected to a rotation motor 138. When the rotation motor 138 is driven, the pivot shaft 136 rotates in the R direction shown in the figure.

[0020] The support member 124 rotatably supports the pivot shaft 136. The holding member 132 is fixed to the pivot shaft 136. Therefore, the holding member 132 can rotate in the R direction together with the pivot shaft 136 by driving the rotation motor 138.

[0021] Rails 140 are fixed to the end faces of the two holding members 132. The rails 140 extend in the Y-axis direction (vertical direction) as shown in the figure and are arranged parallel to each other. Four brackets 144 are also assembled to the rails 140 so as to be movable in the vertical direction.

[0022] Arm 128 has a base 156 that can move up and down by a bracket 144, and a claw portion 158 attached to the base 156. Arm 130 has a base 160 that can move up and down by a bracket 144, and a base 162 attached to the base 160.

[0023] Furthermore, a ball screw 164 passes through the base 156 of arm 128 and the base 160 of arm 130. The ball screw 164 is also connected to an opening / closing motor 166. As a result, when the opening / closing motor 166 is driven, the claw portion 158 of arm 128 and the base 162 of arm 130 rotate as the ball screw 164 rotates, clamping the side surface 101a of the workpiece 101 from above and below in a horizontal position as shown in Figure 1. This generates a clamping force on arms 128 and 130.

[0024] Figure 2 shows the analysis results of the strain generated in the pair of arms 128 and 130 in Figure 1. The workpiece 101, which is a silicon ingot, is a heavy object weighing several tens of kilograms to over 100 kilograms. Therefore, when attempting to load the workpiece 101 into the cylindrical grinding machine 200 (see Figure 3) by gripping its side surface 101a with the pair of arms 128 and 130, a significant deflection occurs in the arms 128 and 130.

[0025] The figure shows the strain analysis results when the workpiece 101 weighs 10 kg. According to the strain analysis results, the strain at the base 156 of arm 128, which is the darker colored area (indicated by the arrow in this case), is "maximum". When deflection occurs in arms 128 and 130, the center position C of workpiece 101 (see Figure 5) is displaced (misaligned) relative to the cylindrical grinding machine 200.

[0026] Therefore, the work loading device 100 is equipped with strain gauges 168 and 170 as shown in Figure 1, a center calculation device 172, and a correction device 174, and employs a configuration that can correct the positional misalignment of the workpiece 101 relative to the cylindrical grinding device 200. Specifically, the strain gauges 168 and 170 are attached to the bases 156 and 160, which are the roots of the arms 128 and 130, respectively. The strain gauges 168 and 170 detect the strain of the arms 128 and 130 caused by the clamping force generated on the arms 128 and 130 and the weight of the workpiece 101.

[0027] The center calculation device 172 calculates the vertical and horizontal deviations of the center position C of the workpiece 101 relative to the cylindrical grinding machine 200 based on the strain detected by the strain gauges 168 and 170. The correction device 174 corrects the deviations calculated by the center calculation device 172 (described later). The center calculation device 172 and the correction device 174 can be implemented, for example, by a program executed on a computer.

[0028] Figure 3 is a diagram illustrating the operation and surrounding structure of the work loading device 100 shown in Figure 1. First, the cylindrical grinding device 200 comprises a base 202 shown in Figure 3(a), a tailstock 204 and a headstock 206 installed on the base 202, and a grinder 207 which is a polishing tool (grinding tool).

[0029] The base 202 is installed on the floor of a factory or similar facility. Rails 208 and 210 are fixed to the sides of the base 202. The rails 208 and 210 extend in the X-axis direction (left-right direction) as shown in Figure 3(a), are arranged parallel to each other, and are further spaced apart in the vertical direction (see Figure 3(b)).

[0030] As shown in Figure 1, the lower surface of the base 102 of the work loading device 100 is fixed to the support legs 176 and the bracket 180. In addition, the bracket 184 is fixed to the side of the support leg 176 that faces the cylindrical grinding device 200.

[0031] As shown in Figure 3(a), bracket 180 is movably mounted to rail 208 fixed to the side of base 202 of cylindrical grinding machine 200. Bracket 184 is also movably mounted to rail 210 fixed to the side of base 202. As a result, the work loader 100 is guided to move in the left-right direction relative to base 202.

[0032] The tailstock 204 and headstock 206 also contact both end faces of the workpiece 101, clamping the workpiece 101 (see Figure 4(b)). The grinder 207 grinds the side surface 101a (outer surface) of the workpiece 101 clamped between the tailstock 204 and the headstock 206, and further processes notch grooves and OF surfaces on the workpiece 101 after outer surface grinding.

[0033] The operation of the work loading device 100 will now be described. First, as shown in Figure 3(a), the workpiece 101 is placed on the upper part 302 of the stand 300 in a horizontal position. The work loading device 100 is positioned so that the arm 128 faces the lower side surface 101a of the workpiece 101, and the arm 130 faces the upper side surface 101a of the workpiece 101.

[0034] Next, as shown in Figure 3(b), the work loading device 100 drives the motor 112 for the advancement and retraction of the moving mechanism 104. This causes the work loading device 100 to move the arms 128 and 130 horizontally (see arrow Za) relative to the cylindrical grinding machine 200, bringing them closer to the workpiece 101. The work loading device 100 then inserts arm 128 into the gap between the lower side 101a of the workpiece 101 and the upper part 302 of the base 300, and positions arm 130 facing the upper side 101a of the workpiece 101.

[0035] Furthermore, the work loading device 100 drives the opening / closing motor 166 to rotate the ball screw 164. As a result, the work loading device 100 holds the workpiece 101 in a horizontal position, gripping its side 101a from above and below with the arms 128 and 130.

[0036] Figure 4 is a diagram illustrating the operation and surrounding structure of the work loading device 100, following Figure 3. As shown in Figure 4(a), the work loading device 100 drives a rotary motor 138 (see Figure 1) to rotate the pivot shaft 136. This causes the work loading device 100 to rotate the arms 128 and 130, which grip the side surface 101a of the workpiece 101, in a vertical plane along arrow Ra, from the loading / unloading platform 300 located on the loading / unloading side of the workpiece 101 toward the cylindrical grinding machine 200.

[0037] The work loading device 100 also drives the motor 112 for moving the moving mechanism 104 forward and backward. This causes the work loading device 100 to move the arms 128 and 130 horizontally (see arrow Zb) relative to the cylindrical grinding machine 200, bringing them closer to the cylindrical grinding machine 200.

[0038] Furthermore, as shown in Figure 4(b), the work loading device 100 drives the rotary motor 138 to rotate the pivot shaft 136, causing the arms 128 and 130 to rotate in a vertical plane along arrow Rb. This causes the work loading device 100 to position both ends of the workpiece 101, which is held between the arms 128 and 130, between the tailstock 204 and headstock 206 of the cylindrical grinding machine 200.

[0039] The cylindrical grinding machine 200 clamps the workpiece 101 with the tailstock 204 and headstock 206, and grinds the side surface 101a of the workpiece 101 with the grinder 207.

[0040] Figure 5 shows the displacement of the center position C of the workpiece 101 sandwiched between the pair of arms 128 and 130 in Figure 4(b). When machining notch grooves or OF surfaces on the workpiece 101 after outer circumference grinding using the grinder 207, it is necessary to align the center position C of the workpiece 101 shown in Figure 5(a) with the center positions of the tailstock 204 and headstock 206 (the center position of the workpiece spindle).

[0041] However, due to the clamping force generated on arms 128 and 130 and the weight of the workpiece 101, arms 128 and 130 deflect, causing the center position C of the workpiece 101 to shift to center position C' as shown in Figure 5(b). Therefore, the center calculation device 172 calculates the horizontal displacement α and vertical displacement β of the center position C' of the workpiece 101 relative to the cylindrical grinding machine 200 based on the strain detected by strain gauges 168 and 170.

[0042] Fig. 6 is a diagram for explaining an operation of correcting a shift of a center position C' of a workpiece 101 by the workpiece loading apparatus 100 of Fig. 1. The shift of the center position C' of the workpiece 101 includes a horizontal shift α and a vertical shift β calculated by a center calculation device 172.

[0043] A correction device 174 controls a rotation motor 138 to adjust a twist angle of a turning shaft 136, and turns arms 128 and 130 (see arrow Rc) to correct the vertical shift β. The correction device 174 also drives an advancing / retracting motor 112 of a moving mechanism 104 to move the arms 128 and 130 (see arrow Zc), and corrects the horizontal shift α. Accordingly, the correction device 174 can correct the shift of the center position C of the workpiece 101, and adjust the position of the workpiece 101 to the center position of a workpiece spindle.

[0044] Therefore, according to the workpiece loading apparatus 100, positioning of the workpiece 101 relative to a tailstock 204 and a headstock 206 of a cylindrical grinding machine 200 can be performed with high accuracy. In addition, since the positioning of the workpiece 101 is automatically performed, working efficiency can be improved. Furthermore, in the workpiece loading apparatus 100, when a notch groove or an OF surface is processed on the workpiece 101 after outer periphery grinding by a grinder 207 of the cylindrical grinding machine 200, processing accuracy can be improved.

[0045] Preferred embodiments of the present invention have been described above with reference to the accompanying drawings. Needless to say, the present invention is not limited to such examples. It is obvious that a person skilled in the art can conceive various changes or modifications within the scope of the claims, and it is understood that these naturally belong to the technical scope of the present invention.

[0046] This application claims the priority based on Japanese Patent Application No. 2025-37683 filed in Japan on March 10, 2025 (Reiwa 7), the content of which is incorporated herein by reference into the specification, claims, and drawings of the present application.

[0047] The present invention can be used as a workpiece loading apparatus for carrying a silicon ingot, which is a cylindrical workpiece, into a cylindrical grinding machine.

[0048] 100...Work loading device, 101...Workpiece, 101a...Side view of workpiece, 102...Base, 104...Movement mechanism, 106, 140, 208, 210...Rails, 110...Table, 112...Motor for forward / backward movement, 114, 144, 180, 184...Brackets, 122...Shaft, 124...Support member, 128, 130...Arm, 132...Holding member, 136...Swivel axis, 138...Motor for rotation 156, 160... Arm base, 158... Arm claw, 162... Arm base, 164... Ball screw, 166... ​​Opening / closing motor, 168, 170... Strain gauge, 172... Center calculation device, 174... Correction device, 176... Support leg, 200... Cylindrical grinding machine, 202... Base, 204... Tailstock, 206... Headstock, 207... Grinder, 300... Stand, 302... Top of stand

Claims

1. A work loading device for loading a cylindrical workpiece, a silicon ingot, into a cylindrical grinding machine, comprising: a pair of arms that clamp the side of the workpiece from above and below in a horizontal position; a pivot axis that rotates the pair of arms in a vertical plane toward the cylindrical grinding machine from the loading / unloading side of the workpiece; a moving mechanism that moves the pivot axis horizontally toward and away from the cylindrical grinding machine; a pair of strain gauges attached to the base of each of the pair of arms; a center calculation device that calculates the vertical and horizontal deviations of the center position of the workpiece relative to the cylindrical grinding machine based on the strain detected by the pair of strain gauges; and a correction device that corrects the deviations calculated by the center calculation device, wherein the correction device corrects the vertical deviation by adjusting the twist angle of the pivot axis and corrects the horizontal deviation by driving the moving mechanism.

2. The work loading device according to claim 1, characterized in that the correction device corrects the vertical and horizontal misalignments to align the center position of the workpiece with the center position of the workpiece spindle.

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