High-gloss polishing process and process for manufacturing a high-gloss polishing tool

Abstract

High-gloss polishing process for forming a high-gloss surface on a workpiece (W) by means of a high-gloss polishing tool (10), comprising the steps of: Inclining a shaft (12) of the high-gloss polishing tool (10) relative to a machined surface (Wa) of the workpiece (W), wherein a conically shaped cutting tool (14) is brazed to a distal end of the shaft (12), the cutting tool (14) being made of polycrystalline diamond or cubic boron nitride; and Performing high-gloss polishing by applying a conical surface of the cutting tool (14) to the machined surface (Wa), characterized by the fact that a counterforce acting on the cutting tool (14) from the workpiece (W) when the cutting tool (14) is pressed against the machined surface (Wa) is transferred to a brazing section (16) located between the cutting tool (14) and the shank (12), which is divided into an axial direction and a radial direction of the high-gloss polishing tool.

Description

BACKGROUND OF THE INVENTION Area of ​​the invention

[0001] The present invention relates to a high-gloss polishing method for forming a high-gloss surface on a workpiece by means of a high-gloss polishing tool and a method for manufacturing a high-gloss polishing tool. Description of the related technique

[0002] Japanese utility model disclosure no. JP H06-53 004 U discloses a tool for high-gloss polishing in which a monocrystalline diamond tip is attached to the distal end of a shaft by means of an insert.

[0003] Furthermore, JP 2015-33 726 A discloses a conically shaped grinding tool which is attached to a distal end of the shank and is inclined during grinding such that a conical surface of the grinding tool engages with the workpiece. Further grinding tools and corresponding machining methods are known from DE 60 2005 001 590 T2 and DE 36 32 482 A1.

[0004] The manufacture of a conically shaped grinding tool made of polycrystalline diamonds is described in WO 2017 / 027 730 A1. In this process, a diamond layer is formed on a substrate of the shank using a high-pressure, high-temperature (HPHT) process to produce a cutting element consisting of the shank and the diamond layer. For use in a grinding tool, it is proposed to braze the cutting element into a receptacle of the grinding tool.

[0005] A method for producing a high-gloss polishing tool from polycrystalline diamond using a wire electrode in a wire-cutting electrical discharge machining (EDM) machine is known from US 2013 / 0138241A1. BRIEF SUMMARY OF THE INVENTION

[0006] If the workpiece material is aluminum or a similar material with relatively low hardness, the monocrystalline diamond tip disclosed in Japanese Utility Model Publication No. JP H06-53 004 U can be used for high-gloss polishing. However, if the workpiece is made of a high-hardness material such as stainless steel or titanium, a monocrystalline diamond tip cannot be used for high-gloss polishing. Instead of monocrystalline diamond, materials with higher hardness, such as polycrystalline sintered diamond or cubic boron nitride, are used as the tip. Due to the high hardness, however, there are numerous restrictions on the machining shape, so the width of the cutting tool cannot be increased, resulting in low productivity.

[0007] The present invention was conceived to solve the above problems, and it is therefore an object of the present invention to provide a high-gloss polishing method capable of improving productivity in high-gloss polishing of a workpiece, and a manufacturing method for a high-gloss polishing tool.

[0008] One aspect of the present invention is a high-gloss polishing method for producing a high-gloss surface on a workpiece using a high-gloss polishing tool, comprising the steps of: tilting a shank of the high-gloss polishing tool relative to a surface of the workpiece to be machined, wherein a conically shaped cutting tool is brazed to a distal end of the shank, the cutting tool being made of polycrystalline diamond or cubic boron nitride; and performing high-gloss polishing by applying a conical surface of the cutting tool to the surface to be machined. A counterforce acting on the cutting tool from the workpiece when the cutting tool is pressed against the surface to be machined is transmitted to a brazed section located between the cutting tool and the shank, decomposed into an axial direction and a radial direction of the high-gloss polishing tool.

[0009] According to the present invention, it is possible to improve productivity when performing high-gloss polishing on a workpiece.

[0010] The above and other problems, features and advantages of the present invention will become clearer from the following description when viewed in conjunction with the accompanying drawings, in which a preferred embodiment of the present invention is shown as an illustrative example. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] They show: Fig. 1 a schematic diagram showing a configuration of a high-gloss polishing tool; Fig. 2 a schematic diagram showing a method for manufacturing a high-gloss polishing tool; Fig. 3. A diagram to explain a high-gloss polishing process of a workpiece using a high-gloss polishing tool; Fig. 4 a schematic diagram showing a configuration of a high-gloss polishing tool of a comparative example from the prior art; and Fig. 5 a diagram to explain a high-gloss polishing process of a workpiece by a high-gloss polishing tool of a comparative example from the known prior art. DESCRIPTION OF PREFERRED EXECUTION FORMS

[0012] The present invention will now be described with reference to embodiments of the invention. The following embodiments do not limit the invention as defined in the claims. Not all combinations of features described in the embodiments are essential for the solvents of the invention. First embodiment configuration of the high-gloss polishing tool

[0013] Fig. Figure 1 is a schematic diagram showing a configuration of a high-gloss polishing tool 10 of the present embodiment. The high-gloss polishing tool 10 is mounted on a spindle of a machine tool (not shown) and is used for high-gloss (or mirror) polishing of the surface of a workpiece W ( Fig. 3), which is made of stainless steel or titanium.

[0014] In the high-gloss polishing tool 10, a cutting tool 14 is attached to the distal end of a shaft 12, which is clamped by a chuck (not shown) of the spindle by means of a brazed section 16. The cutting tool 14 is conical in shape and is made of polycrystalline diamond (hereinafter referred to as PCD) or cubic boron nitride (hereinafter referred to as cBN). Manufacturing process of a high-gloss polishing tool

[0015] Fig. Figure 2 is a schematic diagram illustrating a method for manufacturing the high-gloss polishing tool 10. After the cutting tool 14 has been attached to the distal end of the shank 12 by means of the brazing section 16, the cutting tool 14 of the high-gloss polishing tool 10 is machined into a conical shape by a wire EDM machine 20. Specifically, the wire EDM machine 20 machined the cutting tool 14 of the high-gloss polishing tool 10 into a conical shape by electrical discharge machining while axially rotating the high-gloss polishing tool 10 with a wire electrode 26, which is clamped between upper and lower wire guides 22, 24 and inclined relative to a straight line perpendicular to the horizontal plane.In this process, the discharge condition between the wire electrode 26 and the cutting tool 14 is suitable for multiple changes during a single revolution of the high-gloss polishing tool 10 around its axis. The discharge condition can be changed periodically or non-periodically (at irregular intervals). This process of machining the cutting tool 14 while changing the discharge condition during electrical discharge machining (EDM) allows the cutting tool 14 to be formed with an irregular, non-isotropic surface. It should be noted that the cutting tool 14 can be subjected to EDM machining in a state where the axis of the high-gloss polishing tool 10 is inclined relative to the horizontal plane, while the wire electrode 26 is tensioned to be perpendicular to the horizontal plane. Processing method using the high-gloss polishing tool

[0016] Fig. Figure 3 is a view to explain a high-gloss polishing process of the workpiece W using the high-gloss polishing tool 10. As in Fig. As shown in Figure 3, during high-gloss polishing of the workpiece W by the high-gloss polishing tool 10, the high-gloss polishing tool 10 is moved relative to the workpiece W in the processing direction, the axis of the high-gloss polishing tool 10 (shank 12) being inclined relative to the direction perpendicular to the machined surface of the workpiece W, denoted Wa, so that the conical surface of the cutting tool 14 can be brought into contact with the workpiece surface Wa. This allows the counterforce (machining load) acting on the cutting tool 14 from the workpiece W, when the cutting tool 14 is pressed against the machined surface Wa, to be transmitted to the brazing section 16 as two components: a shear force component (in the axial direction of the high-gloss polishing tool 10) and a radial force component (in the radial direction of the high-gloss polishing tool 10). Operation and effect

[0017] Traditionally, high-gloss polishing of workpieces made of aluminum and similar materials is performed using a high-gloss polishing tool with a monocrystalline diamond (hereinafter referred to as SCD) as the cutting tool. However, it is difficult to achieve a high-gloss finish on a workpiece made of stainless steel, titanium, or similar materials, which have a higher hardness than aluminum and similar materials, using the SCD cutting tool. Therefore, high-gloss polishing tools with cutting tools made of PCD and cBN, which have a higher hardness than SCD, have recently appeared. Current high-gloss polishing tools using PCD and cBN as their cutting tool offer a narrow cutting width because the cutting tool is spherical. To increase the cutting width, the cutting tool must be made wider. However, with PCD and cBN, it is difficult to increase the width of the cutting tool compared to SCD for the following reasons.

[0018] The first reason is that, although PCD and cBN are artificially synthesized like SCD, they are difficult to enlarge compared to SCD. The second reason is that, because PCD and cBN are harder than SCD and, unlike SCD, are not dependent on hardness or orientation, machining the cutting tool is difficult, and the shape of the cutting tool that can be machined is limited.

[0019] Given the above limitations, it is conceivable to form the cutting tool into a cylindrical shape to make the PCD or cBN cutting tool wider. Fig. Figure 4 is a schematic diagram showing a configuration of a high-gloss polishing tool 30 of a comparative example from the prior art. The high-gloss polishing tool 30 of the comparative example differs from the high-gloss polishing tool 10 of the present embodiment in that its cutting tool, designated 32, has a cylindrical shape. Fig. Figure 5 is a diagram to explain a high-gloss polishing process of the workpiece W using the high-gloss polishing tool 30 of the comparison example.

[0020] In the high-gloss polishing tool 30, the high-gloss polishing tool 10 is moved relative to the workpiece W in the machining direction, with the side of the cylindrical cutting tool 32 bearing against the machined surface Wa. The counterforce (machining load) on the cutting tool 32 from the workpiece W, when the cutting tool 32 is pressed against the machined surface Wa, acts in the radial direction of the cutting tool 32, so that the force component in the radial direction is also exerted on the brazed section 16. The brazed section 16 is less resistant to the force in the radial direction than to the axial (thrust) force. Therefore, the high-gloss polishing tool 30 of the comparison example carries the risk that the cutting tool 32 will fall off during machining of the workpiece W.Although it is possible to prevent the cutting tool 32 from falling off by keeping the lower surface section of the cylindrical cutting tool 32 in contact with the machined surface Wa of the workpiece W, it is not possible to machine the machined surface Wa with the lower surface section of the cutting tool 32 if the machined surface Wa has an arc-shaped inner circumferential surface.

[0021] To accomplish this, in the present embodiment the cutting tool 14 is formed in a conical shape and is used to machine the workpiece W by moving the high-gloss polishing tool 10 (shank 12) in the processing direction relative to the workpiece W, its axis being inclined relative to the direction perpendicular to the machined surface Wa of the workpiece W, and the conical surface of the cutting tool 14 bearing against the workpiece surface Wa. This transfers the counterforce (machining load) acting on the cutting tool 14 from the workpiece W when the cutting tool 14 is in contact with the machined surface Wa to the brazed section 16 as a shear force component (in the axial direction of the high-gloss polishing tool 10) and as a radial force component (in its radial direction).Accordingly, the force acting on the brazed section 16 is distributed to a force component in the axial direction (thrust direction), in which the brazed section 16 has a higher strength than in the radial direction, in order to prevent the cutting tool 14 from falling off. Furthermore, the cutting tool 14 is formed in a conical shape and can therefore be made wider to ensure a large cutting width for the high-gloss polishing tool 10, which leads to improved productivity.

[0022] Furthermore, according to the invention, the cutting tool 14 is formed into a conical shape by electrical discharge machining. If the high-gloss polishing tool 10 is further according to the invention rotated one revolution around its axis, the discharge condition between the wire electrode 26 and the cutting tool 14 is changed multiple times. This makes it possible to provide the cutting tool 14, which is configured to contact the machined surface Wa of the workpiece W with an irregular surface without isotropy. This allows the machined surface Wa of the workpiece W to be formed into a surface without polishing lines after high-gloss polishing by the high-gloss polishing tool 10. Technical ideas derived from the embodiments

[0023] The technical ideas that can be deduced from the above embodiment are described below.

[0024] In a high-gloss polishing process for forming a high-gloss surface on the workpiece (W) by means of the high-gloss polishing tool (10), wherein the high-gloss polishing tool (10) comprises the shank (12) and the conically shaped cutting tool (14) attached to a distal end of the shank (12), wherein the cutting tool (14) is made of polycrystalline diamond or cubic boron nitride, the process comprises a step of: performing high-gloss polishing by applying the conical surface of the cutting tool (14) to a machined surface (Wa) of the workpiece (W), wherein the shank (12) is inclined in relation to the machined surface (Wa) of the workpiece (W).This decomposes the counterforce (machining load) acting on the cutting tool (14) from the workpiece (W) when the cutting tool (14) is pressed against the workpiece (W) into the axial force component (in the thrust direction of the high-gloss polishing tool (10)) and the radial force component (in the radial direction of the high-gloss polishing tool (10)), thus preventing the cutting tool (14) from falling off.

[0025] In a method for manufacturing the high-gloss polishing tool (10), which comprises the shank (12) and the conically shaped cutting tool (14) attached to a distal end of the shank (12), wherein the cutting tool (14) is made of polycrystalline diamond or cubic boron nitride, the method comprises a step of: machining the cutting tool (14) into a conical shape while the cutting tool (14) is rotated relative to the wire electrode (26) by the wire EDM machine (20). This allows the surface of the cutting tool (14) that bears against the workpiece (W) to be made into an irregular, non-isotropic surface, so that the machined surface (Wa) of the workpiece (W) can be formed into a surface without polishing lines after high-gloss polishing by the high-gloss polishing tool (10).

[0026] In the process for manufacturing the high-gloss polishing tool (10), when the cutting tool (14) is machined to a conical shape while being rotated relative to the wire electrode (26) by the wire EDM machine (20), the discharge condition between the wire electrode (26) and the cutting tool (14) can be changed during one revolution of the cutting tool (14). This allows the surface of the cutting tool (14) that contacts the workpiece (W) to be made irregular and non-isotropic, so that the machined surface (Wa) of the workpiece (W) after high-gloss polishing by the high-gloss polishing tool (10) can be formed as a surface without polishing lines.

Claims

[1] High-gloss polishing process for forming a high-gloss surface on a workpiece (W) by means of a high-gloss polishing tool (10), comprising the steps of: Inclining a shaft (12) of the high-gloss polishing tool (10) relative to a machined surface (Wa) of the workpiece (W), wherein a conically shaped cutting tool (14) is brazed to a distal end of the shaft (12), the cutting tool (14) being made of polycrystalline diamond or cubic boron nitride; and Performing high-gloss polishing by applying a conical surface of the cutting tool (14) to the machined surface (Wa), characterized by , that a counterforce acting on the cutting tool (14) from the workpiece (W) when the cutting tool (14) is pressed against the machined surface (Wa) is transferred to a brazing section (16) located between the cutting tool (14) and the shank (12), which is divided into an axial direction and a radial direction of the high-gloss polishing tool. [2] Method for manufacturing a high-gloss polishing tool (10), comprising the steps of: Inclining a cutting tool (14) attached to a distal end of a shaft (12) of the high-gloss polishing tool (10) in relation to a direction in which a wire electrode (26) of a wire-cutting electrical discharge machining (EDM) machine (20) extends, wherein the cutting tool (14) is made of polycrystalline diamond or cubic boron nitride; and Machining the cutting tool (14) into a conical shape by the wire EDM machine (20) while the cutting tool (14) is rotated axially, characterized by , that in the step of machining the cutting tool (14) a discharge condition between the wire electrode (26) and the cutting tool (14) is changed during one revolution of the cutting tool (14).

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