Grinding method

Abstract

To provide a polishing method using a rotary barrel polishing apparatus that can improve polishing power. [Solution] A polishing method for barrel polishing a workpiece using a rotary barrel polishing apparatus equipped with a barrel tank configured to rotate with the workpiece and media contained within it, wherein the media comprises a substantially spherical first media and a substantially spherical second media whose volume is 0.49% or less of the volume of the first media, and the second media is contained in the media at a ratio of 0.5 vol% to 30.0 vol% relative to the first media.

Description

Technical Field

[0001] The present disclosure relates to a polishing method using a rotary barrel polishing apparatus.

Background Art

[0002] Patent Document 1 discloses composite particles for polishing that can stably exhibit good polishing power.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inventor has found a polishing method using a rotary barrel polishing apparatus not disclosed in Patent Document 1, which can improve the polishing power.

[0005] The present disclosure aims to provide a polishing method using a rotary barrel polishing apparatus that can improve the polishing power.

Means for Solving the Problems

[0006] A polishing method according to one aspect of the present disclosure is a polishing method for barrel-polishing the workpiece using a rotary barrel polishing apparatus including a barrel tank configured to rotate with the workpiece and media accommodated therein, where the media includes a substantially spherical first media and a substantially spherical second media having a volume of 0.49% or less of the volume of the first media, and the second media is included in the media at a ratio of 0.5 vol% to 30.0 vol% with respect to the first media.

Effects of the Invention

[0007] According to this disclosure, a polishing method using a rotary barrel polishing apparatus that can improve polishing power can be realized. [Brief explanation of the drawing]

[0008] [Figure 1] A schematic diagram showing a rotary barrel polishing apparatus used in a polishing method according to one aspect of the present disclosure. [Figure 2] A schematic diagram of a second media used in a polishing method according to one embodiment of the present disclosure. [Figure 3] A flowchart illustrating a polishing method according to one aspect of the present disclosure. [Figure 4] A schematic diagram showing a portion of the media used in a polishing method according to one aspect of this disclosure. [Figure 5] A schematic diagram showing the rotating barrel polishing apparatus in operation (Figure 1). [Figure 6] A schematic diagram of the chip component used in the example. [Figure 7] The table shows the evaluation results of barrel polishing the chip component shown in Figure 6 using a rotary polishing machine with multiple different media configurations. [Modes for carrying out the invention]

[0009] Various aspects of this disclosure will be described below.

[0010] The polishing method of the first embodiment is A polishing method for barrel polishing a workpiece using a rotary barrel polishing apparatus that includes a barrel tank configured to rotate while containing the workpiece and media, The media comprises a substantially spherical first media and a substantially spherical second media whose volume is 0.49% or less of the volume of the first media. The aforementioned media contains the second media in a ratio of 0.5 vol% to 30.0 vol% relative to the first media.

[0011] The polishing method of the second embodiment is, in the polishing method of the first embodiment, The second medium has a first diameter and a second diameter orthogonal to the first diameter, and the ratio of the first diameter to the second diameter is in the range of 0.85 to 1.15.

[0012] The polishing method of the third aspect is the polishing method of the first aspect or the second aspect, where the medium is made of a material containing ceramics, and the ceramics include at least one of zirconia, alumina, silica, silicon nitride, and silicon carbide.

[0013] The polishing method of the fourth aspect is the polishing method of the first aspect to the third aspect, where the barrel polishing device is configured to rotate the barrel around a rotation axis passing through the center of gravity of the barrel and to revolve the barrel around a revolution axis different from the rotation axis, and the revolution speed of the barrel is greater than or equal to the rotation speed of the barrel.

[0014] The polishing method of the fifth aspect is the polishing method of the fourth aspect, where the revolution speed of the barrel is at least twice the rotation speed of the barrel.

[0015] The polishing method of the sixth aspect is the polishing method of the first aspect to the fifth aspect, where the volume of the second medium is 0.34% or less of the volume of the first medium.

[0016] The polishing method of the seventh aspect is the polishing method of the sixth aspect, where the volume of the second medium is 0.012% or less of the volume of the first medium.

[0017] The polishing method of the eighth aspect is the polishing method of the first aspect to the seventh aspect, where the second medium is contained in the medium at a ratio of 0.5 vol% to 6.7 vol% with respect to the first medium.

[0018] The embodiments of this disclosure will be described below with reference to the drawings. The following description is not limiting to this disclosure and is essentially illustrative, and may be modified as appropriate without departing from the spirit of this disclosure. The drawings are schematic, and the proportions of the dimensions, etc., do not necessarily correspond to those of reality.

[0019] A polishing method according to one aspect of the present disclosure is performed, for example, using a rotary barrel polishing apparatus 1 shown in Figure 1. The rotary barrel polishing apparatus 1 includes a barrel tank 2 configured to rotate with a workpiece 10 and media 20 contained within it. The rotary barrel polishing apparatus 1 is configured to rotate the barrel tank 2 around a rotation axis P1 passing through the center of gravity of the barrel tank 2, and to revolve the barrel tank 2 around an orbital axis P2 different from the rotation axis P1. As an example, the rotation axis P1 is an arbitrary virtual straight line passing through the center of gravity of the barrel tank 2, and the orbital axis P2 is an arbitrary virtual straight line that does not pass through the center of gravity of the barrel tank 2 (in other words, it is radially away from the center of gravity of the barrel tank 2 with respect to the rotation axis P1).

[0020] The workpiece 10 includes, for example, a chip component (see Figure 6). If the workpiece 10 has a roughly rectangular parallelepiped base body 11, polishing and rounding the corners 12 and edges 13 of the base body 11 reduces stress during measurement and suppresses mounting defects.

[0021] The media 20 includes a first media 21 and a second media 22. The first media 21 has a substantially spherical shape. The second media 22 has a substantially spherical shape with a volume of 0.49% or less of the volume of the first media 21. The second media 22 is contained in the media 20 in a ratio of 0.5 vol% to 30.0 vol% relative to the first media 21. The first media 21 and the second media 22 are composed of materials including, for example, ceramics (e.g., at least one of zirconia, alumina, silica, silicon nitride, and silicon carbide).

[0022] In this embodiment, the media 20 includes a plurality of first media 21 and a plurality of second media 22. Each second media 22 has a first diameter D1 and a second diameter D2, as shown in Figure 2. The second diameter D2 is the diameter of any second media 22 that is perpendicular to the first diameter D1. The ratio of the first diameter D1 to the second diameter D2 is in the range of 0.85 to 1.15.

[0023] Referring to Figure 3, an example of a polishing method using the rotary barrel polishing apparatus 1 of this disclosure will be described. The method shown in Figure 3 describes, as an example, the case in which a chip part after firing is used as the workpiece 10 for barrel polishing.

[0024] As shown in Figure 3, the operator fires the chip components (step S1) and places the fired chip components and media 20 into the barrel tank 2 of the rotary barrel polishing apparatus 1 (step S2). The fired chip components are harder than the unfired chip components, which may make barrel polishing difficult.

[0025] After step S2, the operator operates the rotary barrel polishing apparatus 1 to rotate the barrel tank 2 containing the fired chip components and media 20 (step S3). For example, the rotary barrel polishing apparatus 1 rotates the barrel tank 2 so that its orbital speed is greater than or equal to its rotational speed (for example, more than twice). This polishes the chip components.

[0026] The polishing method can produce the following effects:

[0027] The polishing method of this disclosure is a method for barrel polishing a workpiece 10 using a rotary barrel polishing apparatus 1 equipped with a barrel tank 2 configured to rotate with the workpiece 10 and media 20 contained within it. The media 20 includes a substantially spherical first media 21 and a substantially spherical second media 22 whose volume is 0.49% or less of the volume of the first media 21. The second media 22 is contained in the media 20 in a ratio of 0.5 vol% to 30.0 vol% relative to the first media 21.

[0028] In the polishing method of this disclosure, since the volume of the second medium 22 is 0.49% or less of the volume of the first medium 21, the second medium 22 can pass through the gap 23 between adjacent first media 21 (see Figure 4). For example, if the first medium 21 is a sphere with a diameter of 1 mm, the second medium 22 is a sphere with a maximum diameter of 155 μm. While the barrel tank 2 is rotating, the second medium 22 is positioned adjacent to the wall surface of the barrel tank 2, and the bearing effect activates the movement of the first medium 21 near the wall surface of the barrel tank 2. This is thought to increase the speed of the first medium 21 (see Figure 5). Normally, the stress applied to the first medium 21 located near the wall surface of the barrel tank 2 is large, and its speed is small, resulting in a small polishing force. In the polishing method of this disclosure, the speed of the first medium 21 near the wall surface of the barrel tank 2 can be increased, so the polishing force can be improved. Furthermore, even if the maximum diameter of the second media 22 is greater than 155 μm when the diameter of the first media 21 is 1 mm, the above effect will still be achieved if the volume of the second media 22 is 0.49% or less of the volume of the first media 21.

[0029] The second media 22 has a first diameter D1 and a second diameter D2 perpendicular to the first diameter D1. The ratio of the first diameter D1 to the second diameter D2 is in the range of 0.85 to 1.15. With this configuration, the shape of the second media 22 becomes closer to a sphere, and the bearing effect is increased, thereby improving the polishing force. This enables a polishing method using the rotary barrel polishing apparatus 1. As for the method of measuring the first diameter D1 and the second diameter D2, first, an arbitrary cross-section of the second media 22 is taken, and the diameter in a specific direction in that cross-section is defined as the first diameter D1, and the diameter in a direction perpendicular to the first diameter D1 is defined as the second diameter D2.

[0030] The media 20 is composed of a material containing ceramics, and the ceramics include at least one of zirconia, alumina, silica, silicon nitride, and silicon carbide. With this configuration, a polishing method using a rotary barrel polishing apparatus 1 can be realized that can improve polishing power while suppressing wear, cracking, and chipping of the media 20.

[0031] The rotary barrel polishing apparatus 1 is configured to rotate the barrel tank 2 around a rotation axis P1 that passes through the center of gravity of the barrel tank 2, and to revolve the barrel tank 2 around an orbital axis P2 that is different from the rotation axis P1. The orbital speed of the barrel tank 2 is greater than or equal to the rotational speed of the barrel tank 2. This configuration increases the bearing effect and allows for a greater improvement in polishing power.

[0032] The orbital speed of barrel tank 2 is more than twice the rotational speed of barrel tank 2. This configuration increases the bearing effect, allowing for a greater improvement in polishing power.

[0033] The polishing method can be configured as follows:

[0034] The rotary barrel polishing apparatus 1 is not limited to a configuration in which the barrel tank 2 rotates around the rotation axis P1 and revolves around the orbital axis P2. For example, a rotary barrel polishing apparatus may be used in which the barrel tank is configured to rotate only or to revolve only.

[0035] The ratio of the first diameter D1 to the second diameter D2 of the second media 22 is not limited to being in the range of 0.85 to 1.15, but may also be less than 0.85 or greater than or equal to 1.15.

[0036] The material of media 20 may or may not contain ceramics. [Examples]

[0037] The present disclosure will be further described with reference to the following examples, but is not limited to the examples.

[0038] Using the rotary barrel polishing apparatus 1 shown in Figure 1, the workpiece 10 shown in Figure 6 was barrel polished, and the results were evaluated. A 0603 size fired film inductor chip was used as the workpiece 10. As shown in Figure 6, the workpiece 10 has a roughly rectangular parallelepiped shape, with external electrodes 14 formed on some of its sides 13. The barrel polishing time was 30 minutes, and the following three items were evaluated using media with multiple different configurations. The evaluation results are shown in Figure 7. • The radius of the edge 13 of the workpiece 10. This is shown in the column "R radius of the edge of the chip after barrel polishing" in Figure 7. • The amount of abrasive powder (alumina) adhering to the surface of the external electrode 14 (calculated by EDX analysis). This is shown in the "Amount of abrasive powder adhering to the external electrode surface" column of Figure 7. • Exposure rate of metal (Ag) on ​​the surface of the external electrode 14. This is shown in the "Metal Exposure Rate on the External Electrode Surface" column of Figure 7.

[0039] The composition of the media used is shown below. Conventional example 1: First media + abrasive powder • Conventional example 2: First media Examples 1-7: First media + second media (volume of second media relative to first media = 0.49% or less) • Comparison example: First media + second media (volume of second media relative to first media = 0.80)

[0040] Referring to the evaluation results of Conventional Example 1 and Conventional Example 2 in Figure 7, Conventional Example 1, in which the media contains abrasive powder, had a larger radius (R) at the edge portion 13 of the workpiece 10 after barrel polishing, but a lower metal exposure rate on the surface of the external electrode 14, compared to Conventional Example 2, in which the media does not contain abrasive powder.

[0041] Depending on the type of chip component (mainly by the manufacturing method), some chip components undergo barrel polishing before firing, while others undergo barrel polishing after firing. Fired chip components are hard and difficult to machine, making barrel polishing more difficult than for unfired chip components. Therefore, barrel polishing of fired chip components is generally performed by adding fine polishing powder such as alumina or SiC. However, since polishing powder is an insulator, if it adheres to the surface of the external electrode 14, the connectivity with the internal electrode may deteriorate. Furthermore, when barrel polishing chip components that already have external electrodes formed, the adhesion of polishing powder to the surface of the external electrode 14 can make plating difficult.

[0042] Referring to the evaluation results of Examples 1-7 and the comparative example in Figure 7, the examples in which the volume of the second media relative to the first media was 0.49% or less had a larger radius (R) of the edge portion 13 of the workpiece 10 after barrel polishing than the comparative example in which the volume of the second media relative to the first media was greater than 0.49% (0.80%). When the volume of the second media relative to the first media was 0.34% or less (Example 6), the difference with the comparative example became even larger, and when the volume of the second media relative to the first media was 0.0125% or less (Example 2), the difference with the comparative example became even larger. In other words, the polishing power can be further improved by configuring the volume of the second media 22 to be 0.34% or less of the volume of the first media 21. The polishing power can be further improved by configuring the volume of the second media 22 to be 0.0125% or less of the volume of the first media 21.

[0043] Referring to the evaluation results of Examples 1 to 4 in Figure 7, Examples 1 to 3, where the volume ratio of the amount of second media 22 added to the first media was in the range of 0.5 vol% to 6.7 vol%, had a larger radius (R) on the edge portion 13 of the workpiece 10 after barrel polishing than Example 4, where the volume ratio of the amount of second media 22 added to the first media exceeded 6.7 vol% (20.0 vol%). In other words, by configuring the media 20 so that the second media 22 is included in the media 20 at a ratio of 0.5 vol% to 6.7 vol% relative to the first media 21, the polishing power can be further improved.

[0044] Referring to the evaluation results of Examples 2 and 5 in Figure 7, where only the orbital speed and rotational speed of the barrel tank 2 differ, the radius of the radius (R) of the edge portion 13 of the workpiece 10 was larger in Example 2, where the orbital speed of the barrel tank 2 was more than twice (for example, four times) the rotational speed, compared to Example 5, where the orbital speed and rotational speed of the barrel tank 2 were the same. In other words, by making the orbital speed of the barrel tank 2 more than twice the rotational speed of the barrel tank 2, the polishing power can be greatly improved.

[0045] The polishing method described herein can be applied not only to chip components after firing (finished), but also to chip components before firing.

[0046] The embodiments and variations of this disclosure can be combined with each other, or with each other, or with each other. Features included in the embodiments and variations of this disclosure can also be combined with each other.

[0047] As will be apparent to those skilled in the art, many modifications and variations of this disclosure can be realized without departing from the scope and spirit of this disclosure. This disclosure is limited only by the terms of the claims, along with the entire scope of the equivalents to which the claims are entitled. [Explanation of Symbols]

[0048] 1. Rotary barrel polishing machine 2 barrel tanks 10 Work 11 Base Body 12 corners 13 Sides 14 External electrode 20 Media 21 First Media 22 Second Media 23 gaps

Claims

1. A polishing method for barrel polishing a workpiece using a rotary barrel polishing apparatus that includes a barrel tank configured to rotate while containing the workpiece and media, The media comprises a substantially spherical first media and a substantially spherical second media whose volume is 0.49% or less of the volume of the first media. A polishing method in which the second medium is contained in the aforementioned medium in a ratio of 0.5 vol% to 30.0 vol% relative to the first medium.

2. The second medium has a first diameter and a second diameter perpendicular to the first diameter, The polishing method according to claim 1, wherein the ratio of the first diameter to the second diameter is in the range of 0.85 to 1.

15.

3. The aforementioned media is composed of a material containing ceramics, The polishing method according to claim 1 or 2, wherein the ceramics include at least one of zirconia, alumina, silica, silicon nitride, and silicon carbide.

4. The rotary barrel polishing apparatus is configured to rotate the barrel tank around a rotation axis passing through the center of gravity of the barrel tank, and to revolve the barrel tank around an orbital axis different from the rotation axis. The polishing method according to claim 1 or 2, wherein the orbital speed of the barrel tank is greater than or equal to the rotational speed of the barrel tank.

5. The polishing method according to claim 4, wherein the orbital speed of the barrel tank is twice or more the rotational speed of the barrel tank.

6. The polishing method according to claim 1 or 2, wherein the volume of the second medium is 0.34% or less of the volume of the first medium.

7. The polishing method according to claim 6, wherein the volume of the second medium is 0.0125% or less of the volume of the first medium.

8. The polishing method according to claim 1 or 2, wherein the second medium is contained in the media in a ratio of 0.5 vol% to 6.7 vol% relative to the first medium.

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