JP2024037577A - polishing pad - Google Patents

Abstract

To provide a polishing pad which can polish a workpiece preferably.SOLUTION: A polishing pad is used to polish a workpiece which is formed of a metal, by using loose grains. The polishing pad has a pad body formed by an elastic sheet. The pad body includes: an annular base; and protruding parts each of which is connected to the base and extends so as to incline relative to a radial direction of the base in a plan view. The protruding part has a tapered shape so as to follow the workpiece.SELECTED DRAWING: Figure 3

Description

FIELD OF THE INVENTION The present invention relates to polishing pads.

Patent Document 1 discloses a polishing pad for polishing a workpiece. This polishing pad has an annular base and a plurality of protrusions that protrude in the radial direction of the base. The tip surface of the protrusion is rectangular. This polishing pad polishes the surface of the workpiece by bringing its tip end surface into contact with the workpiece while rotating.

Japanese Patent Application Publication No. 55-058984

In the polishing pad, the thickness of the protruding part is generally constant from the root to the tip, and the shape of the protruding part is not easily deformed when polishing a workpiece having a curved surface, so that the protruding part contacts the corner R surface in a substantially flat state. . For this reason, the followability to the workpiece is low, and it is difficult to finish the flat portion and the rounded corner surface into a continuous surface, and the workpiece cannot be suitably polished.

An object of the present invention is to provide a polishing pad that can suitably polish workpieces having curved and flat surfaces.

A polishing pad according to a first aspect of the present invention is a polishing pad for polishing a work made of metal using free abrasive grains, and has a pad body made of an elastic sheet, The main body includes an annular base and a protrusion that is connected to the base and extends obliquely with respect to the radial direction of the base in plan view, and the protrusion is tapered to follow the workpiece. It is the shape.

A polishing pad according to a second aspect of the present invention is the polishing pad according to the first aspect, wherein the protruding portion includes a workpiece contacting portion including a tip portion, and a workpiece non-contacting portion connecting the workpiece contacting portion and the base portion. including.

A polishing pad according to a third aspect of the present invention is a polishing pad according to the second aspect, in which the workpiece contact portion includes a first portion including the tip portion, and the first portion and the workpiece non-contact portion. The polishing force of the first part is weaker than the polishing force of the second part.

The polishing pad according to a fourth aspect of the present invention is the polishing pad according to the second aspect or the third aspect, wherein the outer edge of the protruding part is an arc, and the radius of curvature of the outer edge of the workpiece contacting part is It is larger than the radius of curvature of the outer edge of the non-contact part of the workpiece.

A polishing pad according to a fifth aspect of the present invention is a polishing pad according to the fourth aspect, wherein in a virtual circle along an outer edge of the workpiece contacting part, the length of the outer edge of the workpiece contacting part is the length of the outer edge of the workpiece contacting part. It is included in the range of 30% or more and 70% or less of the circumference.

A polishing pad according to a sixth aspect of the present invention is a polishing pad according to any one of the first to fifth aspects, wherein the material constituting the elastic sheet has an A hardness of 50° or more and 95°. It is included in the following range, and the density is included in the range of 0.20 g/cm ³ or more and 0.80 g/cm ³ or less.

A polishing pad according to a seventh aspect of the present invention is the polishing pad according to any one of the first to sixth aspects, wherein the pad bodies are stacked one on top of the other, and are arranged at the center of the base. , has a shaft portion that holds a plurality of the pad bodies, and the shaft portion has a projection or a recess that engages with a recess or a projection formed in the base.

A polishing pad according to an eighth aspect of the present invention is a polishing pad according to the seventh aspect, and includes a disk-shaped jig attached to the pad body, and the jig is a polishing pad according to the seventh aspect, and the jig includes a disc-shaped jig attached to the pad body. A state in which the jig is attached to the pad body, including an upper plate that is stacked on the topmost pad body, and a lower plate that is stacked on the bottom of the stacked pad bodies. In this case, the protrusion is exposed from the upper plate and the lower plate.

A polishing pad according to a ninth aspect of the present invention is a polishing pad according to the eighth aspect, in which the upper plate has an upper opposing surface facing the uppermost pad body, and the lower plate includes: It has a lower opposing surface facing the lowermost pad body, the upper opposing surface has a recess in the thickness direction and a protrusion in the thickness direction along the circumferential direction, and the lower opposing surface has a lower opposing surface facing the upper pad body. It has a convex portion corresponding to the concave portion on the opposing surface, and a concave portion corresponding to the convex portion on the upper opposing surface.

A polishing pad according to a tenth aspect of the present invention is a polishing pad according to the ninth aspect, which includes one set of the recess and the convex part on the upper opposing surface, and the convex part and the recess on the lower opposing surface. There are 2 to 8 protrusions between each pair of the protrusions.

According to the polishing pad according to the present invention, workpieces having curved surfaces and flat surfaces can be suitably polished.

FIG. 1 is a perspective view of a polishing pad according to an embodiment. FIG. 2 is a front view of a workpiece to be polished by the polishing pad of FIG. 1; FIG. 2 is a plan view of a pad body included in the polishing pad of FIG. 1; FIG. 2 is a plan view of a shaft portion included in the polishing pad of FIG. 1; FIG. 2 is a bottom view of an upper plate included in the polishing pad of FIG. 1; FIG. 2 is a sectional view taken along line D6-D6 in FIG. 1; FIG. 2 is a plan view of a spacer included in the polishing pad of FIG. 1; 2 is a diagram for explaining the action of the polishing pad in FIG. 1. FIG. FIG. 7 is a plan view of a pad body included in a polishing pad according to a first modification of the embodiment. FIG. 7 is a plan view of a pad body included in a polishing pad according to a second modification of the embodiment. FIG. 7 is a plan view of a pad body included in a polishing pad according to a third modification of the embodiment. FIG. 7 is a plan view of a pad main body included in a polishing pad according to a fourth modification of the embodiment.

EMBODIMENT OF THE INVENTION Hereinafter, one embodiment of the polishing pad based on this invention is described with reference to drawings.

<1. Overall configuration of polishing pad>
FIG. 1 is a perspective view of a polishing pad 10 according to an embodiment. FIG. 2 is a front view of a workpiece 300 that is polished by the polishing pad 10. As shown in FIG. The polishing pad 10 polishes the side surface of the workpiece 300 using free abrasive grains. The work 300 is a frame of a smartphone, a tablet terminal, or the like. Work 300 is made of metal. The metal constituting the workpiece 300 is, for example, aluminum, titanium, stainless steel, or the like. The workpiece 300 has, for example, a rounded corner 310 and a straight portion 320. The polishing pad 10 of this embodiment is configured to suitably polish the corner portion 310 of the workpiece 300 and the side surface of the straight portion 320. The polishing pad 10 includes a pad portion 20, a shaft portion 60, a jig 70, and a pair of spacers 110 (see FIG. 6).

<2. Pad section>
FIG. 3 is a plan view of the pad body 30 that constitutes the pad section 20. The pad section 20 has a plurality of pad bodies 30. The plurality of pad bodies 30 are stacked one on top of the other so that their outer edges coincide with the virtual circle. The material constituting the pad body 30 can be arbitrarily selected as long as it can be impregnated with free abrasive grains. As the material constituting the pad body 30, for example, an elastic sheet (abrasive cloth) described in Japanese Patent No. 5091613 can be suitably used. The material constituting the pad body 30 preferably has high rigidity so that the amount of polishing per unit time (hereinafter referred to as "polishing rate") is high. In this embodiment, the A hardness of the material constituting the pad body 30 is in the range of 50° or more and 95° or less, preferably 55° or more and 90° or less, and more preferably 60° or more and 85° or less. The density of the material constituting the pad body 30 is 0.20 g/cm ³ or more and 0.80 g/cm ³ or less, preferably 0.30 g/cm ³ or more and 0.60 g/cm ³ or less, and more preferably 0.35 g/cm 3 or less. It is included in the range of 0.55 g/cm ³ or more and 0.55 g/cm ³ or less.

The pad main body 30 constituting the pad section 20 may be composed of a single layer, or may be composed of a plurality of layers laminated, and can be arbitrarily selected. From the viewpoint of increasing the polishing rate, it is preferable that the pad section 20 is composed of a plurality of pad bodies 30. In this embodiment, the pad section 20 is constructed by laminating five pad bodies 30 without using an adhesive. The pad section 20 may be composed of one to four pad bodies 30, or six or more pad bodies 30. When the pad section 20 is composed of a plurality of pad bodies 30, the materials constituting the plurality of pad bodies 30 may be the same or different.

The pad body 30 has an annular base 40 and a protrusion 50 that protrudes from the base 40 . A plurality of recesses 41 are formed in the base 40 and are recessed toward the protrusion 50 . The bottom surface 41A of the recess 41 is curved. The plurality of recesses 41 are formed at regular intervals along the circumferential direction of the base 40. The tips of the plurality of recesses 41 are located on the virtual circle CA. The virtual circle CA is a circle centered on the center OA of the base 40. In other words, the virtual circle CA and the base 40 are concentric circles.

The protrusion 50 extends in a direction inclined to the radial direction of the base 40 in plan view. The number of protrusions 50 that one pad main body 30 has can be arbitrarily selected. From the viewpoint of increasing the polishing rate, it is preferable that one pad main body 30 has a plurality of protrusions 50. In this embodiment, one pad main body 30 has eight protrusions 50. The shapes of the eight protrusions 50 are substantially the same. One pad body 30 may have 1 to 7 or 9 protrusions 50. The eight protrusions 50 are formed at regular intervals in the circumferential direction of the base 40.

The protrusion 50 has a tapered shape that improves followability to the workpiece 300 when viewed from above. In other words, the protrusion 50 has a saw shape extending in a direction inclined to the radial direction of the base 40 . The thickness of the protrusion 50 is approximately constant from the root to the tip 50A. The protruding portion 50 has a workpiece contacting portion 51 including a tip portion 50A, and a workpiece non-contacting portion 52 connecting the workpiece contacting portion 51 and the base portion 40.

The workpiece contact portion 51 polishes the side surface of the workpiece 300 by contacting the workpiece 300 while rotating. The workpiece contact portion 51 has an outer edge 51X. The outer edge 51X is a circular arc. The outer edge 51X is along the virtual circle CB. The virtual circle CB is a circle centered on the center OA of the base 40. In other words, the virtual circle CB and the base 40 are concentric circles.

The work contact portion 51 includes a first portion 51A including a tip portion 50A, and a second portion 51B connecting the first portion 51A and the work non-contact portion 52. The maximum width LA of the first portion 51A in plan view is smaller than the maximum width LB of the second portion 51B. Therefore, when the workpiece contact portion 51 contacts the workpiece 300, the polishing stress, in other words, the polishing force, is smaller in the first portion 51A than in the second portion 51B. In this embodiment, since the workpiece contact portion 51 has the first portion 51A and the second portion 51B having different polishing forces, the workpiece 300 can be polished while varying the strength of the polishing force. Therefore, while the polishing pad 10 is rotating, the depressed workpiece 300 can be held down by the pad body 30, so that the polishing force accompanying the rotation of the polishing pad 10 can be suitably transmitted to the workpiece 300.

The non-workpiece contact portion 52 does not come into contact with the workpiece 300 while the polishing pad 10 is rotating. The workpiece non-contact portion 52 has an outer edge 52X. The shape of the outer edge 52X can be arbitrarily selected. In this embodiment, the shape of the outer edge 52X is an arc. The outer edge 52X may be a straight line.

In this embodiment, the radius of curvature of the outer edge 51X of the workpiece contact portion 51 is larger than the radius of curvature of the outer edge 52X of the non-workpiece contact portion 52. The ratio RA of the length of the outer edge 51X to the circumference of the virtual circle CB can be arbitrarily selected. From the viewpoint of increasing the polishing rate and the followability of the workpiece contact portion 51 to the workpiece 300, the ratio RA is preferably in the range of 30% or more and 70% or less, and is in the range of 40% or more and 60% or less. More preferably, it is included in The ratio RA of the length of the outer edge 51X is determined by determining the central angle θA of the sector formed from the radius of the virtual circle CB (the length of the center OA and the tip 50A) and the arc of the outer edge 51X, and By integrating the number and the central angle θA, the total central angle corresponding to the outer edge 51X can be obtained. The ratio RA can be calculated by dividing the total central angle by 360°. In this embodiment, the ratio RA is 50%.

<3. Shaft＞
FIG. 4 is a plan view of the shaft portion 60. The shaft portion 60 holds the plurality of pad bodies 30. The material constituting the shaft portion 60 can be arbitrarily selected. From the viewpoint of suitably holding the plurality of pad bodies 30, the material forming the shaft portion 60 is preferably a material with higher rigidity than the material forming the pad main bodies 30, such as metal such as stainless steel, glass fiber plastic, Alternatively, fiber-reinforced plastic or the like is preferable. In this embodiment, the material forming the shaft portion 60 is metal. The metal is, for example, stainless steel.

The shaft portion 60 has an annular base portion 61 and a plurality of convex portions 62 protruding from the base portion 61 . Four through holes 61A are formed in the base 61 at positions corresponding to the protrusions 62. A screw 210 (see FIG. 1) for connecting the shaft portion 60 and the upper plate 80 of the jig 70 is inserted into the through hole 61A from the surface side of the base portion 61. A screw (not shown) for connecting the shaft portion 60 and the lower plate 90 of the jig 70 is inserted into the through hole 61A from the back side of the base portion 61. Two non-through holes 61B are formed on the surface of the base 61. A screw 220 (see FIG. 1) for positioning when attaching the upper plate 80 is inserted into the non-through hole 61B. A screw (not shown) is inserted into the back surface of the base 61 for positioning the lower plate 90.

The plurality of convex portions 62 engage with the plurality of concave portions 41 (see FIG. 3) of the pad main body 30. The outer shape of the plurality of convex portions 62 matches the inner shape of the recessed portion 41 . The pad portion 20 and the shaft portion 60 are arranged such that the plurality of convex portions 62 engage with the plurality of concave portions 41. Since the pad section 20 is held by the shaft section 60, the pad main bodies 30 do not come off the shaft section 60 due to rotation during polishing, and the state in which the plurality of pad main bodies 30 are stacked is maintained.

<4. Jig>
The jig 70 includes an upper plate 80 and a lower plate 90 that sandwich the pad portion 20 therebetween. The material constituting the jig 70 can be selected arbitrarily. From the viewpoint of suitably holding the plurality of pad bodies 30, the material constituting the jig 70 is preferably a material having higher rigidity than the material constituting the pad body 30. Specifically, the jig 70 is made of metals such as aluminum, iron, copper, stainless steel, lead, and chromium, paper-based phenolic resin, cloth-based phenolic resin, epoxy resin, urea resin, melamine resin, propylene resin, and styrene. It can be manufactured using a plate made of a highly rigid material such as resin, vinyl chloride resin, fluororesin, polyimide resin, polyamide resin, polycarbonate resin, or FRP. In this embodiment, the material constituting the jig 70 is a cloth-based phenolic resin plate.

FIG. 5 is a bottom view of the top plate 80. The upper plate 80 is stacked on the uppermost pad body 30 of the plurality of pad bodies 30 with the spacer 110 interposed therebetween. The upper plate 80 has an annular base 81 and a disc-shaped plate portion 82 extending from the base 81 .

The base 81 has four through holes 81A. Screws 210 (see FIG. 1) for connecting the shaft portion 60 and the upper plate 80 of the jig 70 are inserted into the four through holes 81A. The base 81 has two recesses 81X recessed in the radial direction. Screws 220 (see FIG. 1) for positioning when attaching the upper plate 80 to the shaft portion 60 are arranged in the two recesses 81X. The bottom surfaces 81Y of the two recesses 81X are curved.

The plate portion 82 faces the uppermost pad body 30 of the plurality of pad bodies 30 via the spacer 110. The outer edge of the plate portion 82 substantially overlaps the virtual circle CA (see FIG. 3) in plan view. Therefore, when the polishing pad 10 is viewed from above, the protruding portion 50 of the pad body 30 is exposed from the upper plate 80. Since the upper plate 80 and the protrusion 50 are unlikely to interfere with each other, the degree of freedom in deforming the protrusion 50 when polishing the workpiece 300 is ensured. The configuration of the lower plate 90 is substantially the same as that of the upper plate 80 except for the configuration of a lower opposing surface 92A of the plate portion 92, which will be described later, so a detailed explanation will be omitted. Note that when the polishing pad 10 is viewed from the bottom, the protruding portion 50 of the pad body 30 is exposed from the lower plate 90. Since the lower plate 90 and the protrusion 50 are unlikely to interfere with each other, the degree of freedom in deforming the protrusion 50 when polishing the workpiece 300 is ensured.

FIG. 6 is a cross-sectional view taken along line D6-D6 in FIG. The plate portion 82 of the upper plate 80 has an upper opposing surface 82A that faces the uppermost pad body 30 of the plurality of pad bodies 30 with the spacer 110 in between. The upper opposing surface 82A has a set of a recess 82X in the thickness direction and a protrusion 82Y in the thickness direction. In this embodiment, the upper plate 80 has four sets of concave portions 82X and convex portions 82Y along the circumferential direction of the plate portion 82.

The plate portion 92 of the lower plate 90 has a lower opposing surface 92A that faces the lowermost pad body 30 of the plurality of pad bodies 30 with the spacer 110 in between. The lower facing surface 92A has a set of a recess 92X in the thickness direction and a convex part 92Y in the thickness direction. The concave portion 92X has a shape corresponding to the convex portion 82Y of the upper plate 80. The convex portion 92Y has a shape corresponding to the concave portion 82X of the upper plate 80. In this embodiment, the lower plate 90 has four sets of concave portions 92X and convex portions 92Y along the circumferential direction of the plate portion 92.

In this embodiment, the concave portion 82X of the upper opposing surface 82A and the convex portion 92Y of the lower opposing surface 92A overlap in plan view, and the convex portion 82Y of the upper opposing surface 82A and the concave portion 92X of the lower opposing surface 92A are Upper plate 80 and lower plate 90 are arranged so as to overlap in plan view. As shown in FIG. 6, the upper opposing surface 82A of the upper plate 80 and the lower opposing surface 92A of the lower plate 90 are non-planar. Since the pad main body 30 sandwiched between the upper plate 80 and the lower plate 90 deforms to follow the shapes of the upper plate 80 and the lower plate 90, the overlapping surfaces of the plurality of pad main bodies 30 are non-linear. For this reason, it is suppressed that only a specific portion of the pad body 30 is unevenly worn due to the specific portion of the pad body 30 coming into contact with the workpiece 300 to be polished.

The number NA of the protrusions 50 located between the pair of recesses 82X and protrusions 82Y on the upper opposing surface 82A and the pair of recesses 92X and protrusions 92Y on the lower opposing surface 92A can be arbitrarily selected. be. The number NA is, for example, 2 to 8. In this embodiment, the number NA is two. The number NA may be one or nine or more.

<5. Spacer>
FIG. 7 is a plan view of the spacer 110. One of the pair of spacers 110 is arranged between the upper plate 80 and the uppermost pad body 30 of the plurality of pad bodies 30. The other of the pair of spacers 110 is arranged between the lower plate 90 and the lowest pad body 30 of the plurality of pad bodies 30. One spacer 110 is bonded to the upper opposing surface 82A of the upper plate 80, for example, with an adhesive. The other spacer 110 is bonded to the lower opposing surface 92A of the lower plate 90 with an adhesive.

The material constituting the spacer 110 can be selected arbitrarily. From the viewpoint of protecting the pad main body 30, from the viewpoint of filling the gap between the highly rigid upper plate 80 and lower plate 90 and the pad main body 30, and improving the force of sandwiching the pad main body 30 between the upper plate 80 and the lower plate 90, and From the viewpoint of making the overlapping surfaces of the pad bodies 30 nonlinear, the material constituting the spacer 110 is preferably a soft material. Specifically, the material constituting the spacer 110 is, for example, a monomer made of vinyl chloride resin, polyethylene, polyethylene terephthalate, ethylene-vinyl acetate copolymer, polyester, polybutadiene, polypropylene, polyamide, ethylene-methacrylate copolymer, etc. A layered sheet or a laminated sheet in which the above-mentioned single layer sheets are laminated can be mentioned. Specific layer configurations of the laminated sheet include, for example, nylon/polyethylene, nylon/polypropylene, polyethylene terephthalate/polyethylene, polyethylene terephthalate/polypropylene, polypropylene/polyethylene, nylon/polypropylene/polyethylene, and the like. In this embodiment, the material forming the spacer 110 is polypropylene.

The spacer 110 has an annular outer shape that is slightly larger than the upper plate 80 and the lower plate 90. A plurality of recesses 111 are formed on the inner edge of the spacer 110. The plurality of recesses 111 have a shape that meshes with the convex portion 62 (see FIG. 4) of the shaft portion 60. The convex portion 62 of the shaft portion 60 is inserted into the concave portion 111.

<6. Effect of polishing pad＞
FIG. 8 is a diagram for explaining the action of the polishing pad 10. Note that, in FIG. 8, only the pad portion 20 among the elements constituting the polishing pad 10 is illustrated.

The polishing pad 10 is arranged so that the workpiece contact portion 51 of the pad body 30 contacts the side surface of the workpiece 300. The polishing pad 10 is driven by an actuator to rotate in the direction of the arrow in FIG. Therefore, the work contact portions 51 of the plurality of protrusions 50 continuously polish the side surface of the work 300.

Workpiece 300 is movable relative to polishing pad 10 . By moving the workpiece 300 relative to the polishing pad 10 while the polishing pad 10 is rotating, the corner portion 310 and the straight portion 320 of the workpiece 300 are polished.

<7. Characteristics of polishing pad＞
According to the polishing pad 10 of this embodiment, the following effects can be obtained.

<7-1>
The polishing pad 10 extends such that the protrusion 50 is inclined with respect to the radial direction of the base 40 . Since the protruding portion 50 has a tapered shape, it can be easily deformed to conform to the shape of the workpiece 300. Polishing that follows not only the straight portion 320 of the workpiece 300 but also the rounded corner portion 310 is possible. Furthermore, even when the side surface of the workpiece 300 has a curvature, the plurality of pad bodies 30 can be elastically deformed one by one in the radial direction according to the curved surface of the side surface of the workpiece 300. Since the polishing pad 10 has high followability to the workpiece 300, the workpiece 300 can be suitably polished.

<7-2>
Since the protruding portion 50 has a tapered shape, it has followability to fit a macroscopic curved surface shape such as the side surface of the workpiece 300 that is subjected to R processing. On the other hand, since the pad body 30 is made of a material with high rigidity, only the microscopic protrusions on the surface of the workpiece 300 can be removed. Therefore, workpieces 300 of various shapes can be suitably polished.

<7-3>
For example, in the case of a polishing pad having a recess for polishing a work, such as the polishing pad disclosed in International Publication No. WO 2015/020082, there is a risk that the recess will be clogged with polishing debris and the like, resulting in clogging. According to the polishing pad 10 of this embodiment, since the surface of the workpiece 300 is polished by the protrusion 50, the possibility of clogging is reduced.

<7-4>
In known brush-shaped polishing tools, only the base of the brush is fixed and almost the entire brush moves freely, so polishing force is not sufficiently transmitted to the workpiece. According to the polishing pad 10 of this embodiment, since the protrusion 50 has a tapered shape, it has high followability to the workpiece 300. Therefore, sufficient polishing force can be transmitted to the workpiece 300.

<7-5>
According to the polishing pad 10, since the workpiece 300 is polished by the protrusion 50 protruding from the base 40, slurry supply and discharge properties are better ensured than in the polishing pad disclosed in International Publication WO2015/020082. be done. Therefore, the slurry is less likely to become clogged.

<7-6>
According to the polishing pad 10, the slurry can be held in the gap between the pad body 30 and the tip 50A of any protrusion 50 and the base of another protrusion 50, thereby preventing deterioration of the pad body 30 due to heat. It can be suppressed.

<7-7>
According to the polishing pad 10, in addition to polishing the workpiece 300 in the horizontal direction, by changing the angle of the workpiece 300 with respect to the polishing pad 10, it is possible to polish the workpiece 300 in an oblique direction.

<7-8>
According to the polishing pad 10, since the pad body 30 is made of a material with high rigidity, the protrusion 50 has the ability to follow the workpiece 300 like a brush and is in closer contact with the workpiece 300 than a brush. Therefore, even if the workpiece 300 is made of a highly rigid material such as metal, it can be suitably polished.

<8. Modified example>
The embodiments described above are examples of the forms that the polishing pad according to the present invention can take, and are not intended to limit the forms. A polishing pad according to the present invention may take a different form from that illustrated in the embodiments. An example thereof is a form in which a part of the configuration of the embodiment is replaced, changed, or omitted, or a form in which a new configuration is added to the embodiment. Some examples of modifications of the embodiment are shown below. Note that the following modifications can be combined with each other within a technically consistent range.

<8-1>
The shape of the pad main body 30 can be arbitrarily changed as long as it has a tapered shape such that the protrusion 50 follows the workpiece 300. FIG. 9 is a plan view of the pad main body 130 included in the polishing pad 10 of the first modified example of the embodiment. The pad body 130 includes a protrusion 150. The protruding portion 150 has a workpiece contacting portion 151 and a workpiece non-contacting portion 152. The shape of the outer edge 151X of the work contact portion 151 and the shape of the outer edge 152X of the work non-contact portion 152 are circular arcs. The radius of curvature of the outer edge 151X and the radius of curvature of the outer edge 152X are equal.

FIG. 10 is a plan view of a pad main body 230 included in the polishing pad 10 of the second modified example of the embodiment. The pad body 230 includes a protrusion 250. The protrusion 250 has a workpiece contacting part 251 and a workpiece non-contacting part 252. The shape of the outer edge 251X of the work contact portion 251 and the shape of the outer edge 252X of the work non-contact portion 252 are circular arcs. The radius of curvature of the outer edge 251X and the radius of curvature of the outer edge 252X are equal.

FIG. 11 is a plan view of a pad main body 330X included in the polishing pad 10 of the third modification of the embodiment. The pad main body 330X includes a protrusion 350X. The protrusion 350X is shorter than the protrusion 50 of the pad main body 30 of the embodiment. The protrusion 350X has a workpiece contacting part 351X and a workpiece non-contacting part 352X. The shape of the outer edge 351XA of the work contact portion 351 and the shape of the outer edge 352XA of the work non-contact portion 352 are circular arcs. The outer edge 351XA of the work contact portion 351X is longer than the outer edge 151X of the work contact portion 151 of the pad body 130 of the first modification shown in FIG. Therefore, the pad main body 330X of the third modification is configured to have a larger ratio RA than the pad main body 130 of the first modification.

FIG. 12 is a plan view of a pad main body 430 included in the polishing pad 10 of the fourth modification of the embodiment. Pad body 430 includes four protrusions 250. The protruding part 450 has a workpiece contacting part 451 and a workpiece non-contacting part 452. The shape of the outer edge 451X of the work contact portion 451 and the shape of the outer edge 452X of the work non-contact portion 452 are circular arcs. The radius of curvature of the outer edge 451X and the radius of curvature of the outer edge 452X are equal. In the fourth modification, the recess 41 is omitted from the base 40 of the pad main body 430. The base portion 40 is formed with a through hole 41X into which a screw for coupling with other elements constituting the pad body 30 is inserted.

<8-2>
In the above embodiment, the concave portion 41 was formed in the base 40 of the pad body 30, and the convex portion 62 was formed in the base 61 of the shaft portion 60, but the relationship between these concave and convex portions may be reversed. That is, a convex portion may be formed on the base portion 40 of the pad body 30, and a concave portion that engages with the convex portion of the base portion 40 may be formed on the base portion 61 of the shaft portion 60.

10: Polishing pad 30, 230, 330X, 430: Pad body 40: Base 41: Recessed portion 50: Projecting portion 50A: Tip portion 51: Workpiece contact portion 51A: First portion 51B: Second portion 51X: Outer edge 52: Non-workpiece Contact portion 52X: Outer edge 60: Shaft 62: Convex portion 70: Jig 80: Upper plate 82A: Upper opposing surface 82X: Concave portion 82Y: Convex portion 90: Lower plate 92A: Lower opposing surface 92X: Concave portion 92Y: Convex portion 300 :work

Claims (10)

A polishing pad for polishing a workpiece made of metal using free abrasive grains,
It has a pad body made of an elastic sheet,
The pad body is
an annular base;
a protrusion connected to the base and extending obliquely with respect to the radial direction of the base in plan view;
The protrusion has a tapered shape that follows the workpiece. The polishing pad. The protruding portion is
A workpiece contact part including the tip part,
The polishing pad according to claim 1 , further comprising a work non-contacting part that connects the workpiece contacting part and the base. The workpiece contacting part includes a first part including the tip part, and a second part connecting the first part and the workpiece non-contacting part,
The polishing pad according to claim 2, wherein the polishing force of the first portion is weaker than the polishing force of the second portion. The outer edge of the protrusion is an arc,
The polishing pad according to claim 2 or 3, wherein the radius of curvature of the outer edge of the workpiece contact portion is larger than the radius of curvature of the outer edge of the non-workpiece contact portion. The polishing pad according to claim 4, wherein in a virtual circle along the outer edge of the workpiece contacting part, the length of the outer edge of the workpiece contacting part is within a range of 30% or more and 70% or less of the circumference of the virtual circle. The material constituting the elastic sheet is
A hardness is included in the range of 50° or more and 95° or less,
The polishing pad according to any one of claims 1 to 3, wherein the polishing pad has a density in the range of 0.20 g/cm ³ or more and 0.80 g/cm ³ or less. A plurality of the pad bodies are stacked,
having a shaft portion disposed at the center of the base portion and holding a plurality of the pad bodies;
The polishing pad according to any one of claims 1 to 3, wherein the shaft portion has a convex portion or a concave portion that engages with a concave portion or a convex portion formed in the base portion. It has a disk-shaped jig attached to the pad body,
The jig is
an upper plate stacked on the uppermost pad body of the stacked pad bodies;
a lower plate stacked on the lowest pad body of the stacked pad bodies;
The polishing pad according to claim 7, wherein the protrusion is exposed from the upper plate and the lower plate when the jig is attached to the pad body. The upper plate has an upper opposing surface facing the uppermost pad body,
The lower plate has a lower opposing surface facing the lowermost pad body,
The upper facing surface has a recess in the thickness direction and a convex part in the thickness direction along the circumferential direction,
The polishing pad according to claim 8, wherein the lower opposing surface has a convex portion corresponding to the concave portion of the upper opposing surface, and a concave portion corresponding to the convex portion of the upper opposing surface. According to claim 9, there are two to eight protrusions between one set of the concave portion and the convex portion of the upper opposing surface and one set of the convex portion and the concave portion of the lower opposing surface. Polishing pad as described.