JP5886596B2 - Polishing tool and surface treatment apparatus using the same - Google Patents

Description

  The present invention relates to a polishing tool used in a surface treatment apparatus for treating the surface of a processing object such as a metal material or a resin material using a magnetic polishing liquid (paste material) that flows in conjunction with the action of a magnetic field, More specifically, the present invention relates to a technique suitable for a surface of a complex shape body having a complicated uneven shape such as a precision machine part, a mold, or a resin product.

  One of the techniques for polishing the surface of various materials or mirror finishing is a so-called magnetic polishing method. In this magnetic polishing method, a magnetic fluid (MF) or a magnetorheological fluid (MRF) is mixed with abrasive particles, and the mixture is moved by a magnetic field to perform polishing.

  The polishing tool is equipped with a permanent magnet to serve as a magnetic field source. When a magnetic polishing liquid (paste material) is attached around the polishing tool, ferromagnetic particles (for example, iron particles) in MF or MRF are generated by magnetic attraction. , Many magnetite particles aggregate to form a magnetic cluster. Since this magnetic cluster follows the magnetic flux, it takes a form in which a large number of needles are arranged in opposition to the object to be polished. Therefore, the magnetic polishing liquid adheres to the polishing bite to form a magnetic brush.

  When the magnetic brush or the object to be polished rotates, the magnetic brush moves in contact with the surface of the object to be polished by relative movement between the two. As a result, the unevenness of the surface to be polished is polished by the magnetic brush with the abrasive particles, a smoother surface can be obtained, and non-contact fluid polishing can be performed.

  A polishing tool used in a magnetic polishing apparatus for carrying out this type of magnetic polishing method is disclosed in, for example, Patent Document 1 and the like. FIG. 1 shows an example of such a polishing tool. As shown in the figure, a permanent magnet 1 is provided at the tip of a polishing tool to serve as a magnetic field generation source. The permanent magnet 1 is formed in a spherical shape or a curved body shape having an appropriate curved surface, and is embedded in the end face of the cylindrical support body 2 so that substantially half is exposed. The shaft portion 3 extending integrally from the support 2 is linked to the driving means to perform a motion operation such as rotation.

  When a magnetic polishing liquid (magnetic paste 6) is attached around the polishing tool, a large number of ferromagnetic particles (for example, iron particles) and magnetite particles in MF and MRF are aggregated to form a magnetic cluster by magnetic attraction. Since this magnetic cluster is along the magnetic flux, it takes a form in which a large number of needles stand in opposition to the object 5. As a result, the magnetic paste 6 adheres to the polishing tool (permanent magnet 1) to form a magnetic brush. Then, when the magnetic brush or the object 5 rotates, the magnetic brush moves in contact with the surface of the object 5 due to the relative movement between them. As a result, the unevenness of the surface of the object 5 is polished by a magnetic brush with abrasive particles, a smoother surface can be obtained, and non-contact fluid polishing can be performed.

JP 2007-313634 A

  In this type of magnetic polishing apparatus, a certain spatial gap is provided between the polishing tool (permanent magnet 1) and the surface of the polishing object 5, and a magnetic polishing liquid interposed in the spatial gap is used. Surface treatment. If this spatial gap is too wide, the magnetic flux density is lowered and magnetic polishing cannot be performed.

  On the other hand, when the object to be polished is a complicated shape body having a complicated uneven shape such as a precision machine part, a mold or a resin product, there are small depressions and protrusions at various points on the surface. Therefore, if the size and shape of the tip surface of the polishing tool 2 facing the object to be polished are large, the tip surface cannot enter the recess or approach the rising portion of the protrusion. Therefore, the space gap becomes wide and sufficient magnetic polishing cannot be performed.

  In order to suppress the space gap within a certain distance, it is conceivable to reduce the size and shape of the polishing tool (permanent magnet) so that the tip of the polishing tool can enter the recess. However, as the outer diameter of the magnet becomes smaller (thinner), the polishing area becomes narrower even if the magnetic flux density is the same magnet material, and the magnetic field lines along the magnetic pole direction (the magnetic force directed toward the object to be polished) ) Tends to diverge and the polishing power is significantly reduced.

  Further, when the surface to be polished is a three-dimensional shape, the conventional polishing apparatus is to attach the polishing bit to a multi-axis cutting device or an articulated robot in order to move the polishing bit according to the three-dimensional shape. Become. Therefore, there is a problem that the apparatus becomes large.

  An object of the present invention is to further increase the magnetic flux density around the tip of the polishing tool. In addition, a highly versatile polishing tool and technique that enables polishing by hand using a hand grinder (hand leuter) without using a large multi-axis cutting device or a multi-joint robot as a polishing device to attach a polishing tool. It is about.

In order to solve the above-described problems, the polishing tool of the present invention is (1) a polishing tool for performing surface treatment by magnetic action, and includes a front end magnet and a rear magnet disposed behind the front end magnet. And at least a part of the rear magnet is located outside the outer periphery of the tip magnet, and a magnetic pole of the tip magnet and an end surface of the rear magnet on the side close to the tip magnet. A magnetic pole is the same, a cover member made of a non-magnetic material is disposed between the tip magnet and the rear magnet, and the outer dimension of the cover member is larger than the outer dimension of the rear magnet. I made it bigger . One or more rear magnets may be installed. There are various types of surface treatments such as normal polishing, mirror finishing, and cutting.

  A rear magnet is arranged behind the tip magnet, and at least a part of the rear magnet is positioned outside the outer periphery of the tip magnet, and the magnetic lines of force from the rear magnet are the outer periphery of the front magnet. Pass outside. Moreover, since the magnetic pole of the tip magnet is set to be the same as the magnetic pole of the end face on the side close to the tip magnet of the rear magnet, the vertical component in the magnetization vector 3 direction is increased and the magnetic flux from the tip magnet is increased. The magnetic field lines are prevented from spreading outwardly and come into contact with the object to be polished vertically. Therefore, the magnetic flux density in front of the tip magnet is improved, and the polishing power and the like are improved. Stable polishing and other surface treatments are possible.

  (2) It is preferable that the rear magnet is a ring type or a cylindrical magnet, and the outer diameter of the rear magnet is larger than the outer dimension of the tip magnet. If it does in this way, the outer periphery of a rear part magnet can take the structure which covers the outer periphery of a front-end | tip part magnet entirely, and it can suppress that the magnetic force line from a front-end | tip part magnet spreads outside in a perimeter direction.

  (3) The rear magnet is a ring-type magnet, and is movable in the axial direction with respect to a support on which the rear magnet is mounted, and the relative position of the rear magnet and the tip magnet can be adjusted. Good. By changing the distance between the rear magnet and the tip magnet, the magnetic flux density in front of the tip magnet can be changed, and the polishing force and the like can be adjusted.

  (4) The rear magnet may be an electromagnet or a permanent magnet. By using an electromagnet, the magnetic flux density ahead of the tip magnet can be easily adjusted. In addition, if the permanent magnet is used, the configuration becomes simple. (5) The tip magnet may be any one of a cylindrical shape, a spherical shape, and a curved surface shape.

Between the front Symbol tip magnet and the rear portion magnet, since the arranged cover member made of a nonmagnetic material, suppressed by the cover member adsorption (movement of the polishing paste) to the rear portion magnet side of Migaku Ken paste In addition, since the polishing paste is stably present on the tip magnet, stable polishing can be realized without contact with the tip magnet.

Dimensions of the cover member, because there was large comb than the outside dimensions of the rear portion magnet can be prevented movement of the polishing paste Ri to reliably rear portion magnet good.

(6) The surface treatment apparatus of the present invention is configured by mounting the polishing bit according to any one of (1) to (5) above on the tip of a hand grinder. If it does in this way, it can polish by a human hand using a hand grinder (hand leuter), and it can be set as a highly versatile grinding tool.

  Since the present invention can improve the magnetic flux density in front of the tip magnet, even if the tip magnet is small in size, it can be polished sufficiently.

It is a figure which shows an example of the conventional magnetic polishing apparatus. It is a figure which shows 1st Embodiment of the grinding | polishing bite which concerns on this invention. It is a figure explaining an effect | action. It is a figure which shows a modification. It is a figure which shows a modification. It is a figure which shows a modification. It is a figure which shows a modification. It is a figure explaining analysis conditions. It is a figure which shows the analysis result (spatial magnetic flux density) of the analysis patterns 1-3. It is a figure which shows the analysis result of the magnetization vector (direct direction component (mT)) of the anti-plane analysis point of the analysis patterns 1-3. It is a figure which shows the analysis result of the magnetization vector (vertical direction component (mT) with respect to a 45-degree inclined surface) of the anti-inclined surface analysis point of the analysis patterns 1-3. (A) is an analysis pattern 4, (b) is a figure which shows the analysis result (spatial magnetic flux density) of the analysis pattern 5. FIG. (A) is an analysis pattern 6, (b) is a figure which shows the analysis result (spatial magnetic flux density) of the analysis pattern 7. FIG. It is a figure which shows the analysis result of the magnetization vector (direct direction component (mT)) of the plane-to-plane analysis point of the analysis patterns 4-7. It is a figure which shows the analysis result of the magnetization vector (vertical direction component (mT) with respect to a 45-degree inclined surface) of the anti-inclined surface analysis point of the analysis patterns 4-7. It is a figure explaining analysis conditions. It is a figure which shows the analysis result (spatial magnetic flux density) of the analysis patterns 11-13. It is a figure which shows the analysis result of the magnetization vector (direct direction component (mT)) of the anti-plane analysis point of the analysis patterns 11-13. It is a figure which shows the analysis result of the magnetization vector (vertical direction component (mT) with respect to a 45 degree | times inclined surface) of the anti-inclined surface analysis point of the analysis patterns 11-13. It is a figure which shows the analysis result (spatial magnetic flux density) of the analysis patterns 14-16. It is a figure which shows the analysis result of the magnetization vector (direct direction component (mT)) of the plane-to-plane analysis point of the analysis patterns 14-16. It is a figure which shows the analysis result of the magnetization vector (vertical direction component (mT) with respect to a 45-degree inclined surface) of the anti-inclined surface analysis point of the analysis patterns 14-16. It is a figure explaining analysis conditions. It is a figure which shows the analysis result (spatial magnetic flux density) of the analysis patterns 21-23. It is a figure which shows the analysis result of the magnetization vector (direct direction component (mT)) of the plane-to-plane analysis point of the analysis patterns 21-23. It is a figure which shows the analysis result (spatial magnetic flux density) of the analysis patterns 24-26.

It is a figure which shows the analysis result of the magnetization vector (direct direction component (mT)) of the plane-to-plane analysis point of the analysis patterns 24-26. It is a figure explaining 2nd Embodiment. It is a figure explaining the experimental conditions of 2nd Embodiment. It is a figure which shows an experimental result. It is a figure which shows an experimental result. It is a figure which shows an experimental result. It is a figure which shows an experimental result. It is a figure explaining embodiment applied to the handy type polisher. It is a figure which shows an experimental result. It is a figure which shows an experimental result. It is a figure which shows an experimental result.

  FIG. 2 shows a first embodiment of a polishing tool according to the present invention. In the present embodiment, a tip magnet 12 is attached to the tip of a columnar support 11 made of a nonmagnetic material. The tip magnet 12 is a permanent magnet formed in a spherical shape or a curved body shape having an appropriate curved surface. As the kind of permanent magnet, for example, a neodymium magnet is used. The tip magnet 12 is mounted in the tip embedding portion of the support 11 so that substantially half of the tip magnet 12 is exposed. The base end side of the support 11 is linked to a driving means (not shown) to perform a movement operation such as rotation. This basic configuration is the same as the conventional one, and various types of shapes such as the support 11 and the tip magnet 12 can be used.

  In the present embodiment, the rear magnet 14 is attached to a predetermined position of the support 11 (behind the front magnet 12). The rear magnet 14 is formed of the same neodymium magnet as the permanent magnet constituting the tip magnet 12, but different types of permanent magnets may be used. Furthermore, an electromagnet may be used instead of the permanent magnet.

  The rear magnet 14 has a ring shape, and the inner diameter thereof matches the outer diameter of the support 11. In the present embodiment, the diameter of the tip magnet 12 is made substantially equal to the outer diameter of the support 11, and the center of the spherical tip magnet 12 is arranged on the central axis of the support 11. When projected from the axial direction of the body 11, the inner space of the rear magnet 14 and the tip magnet 12 overlap.

  As shown in FIG. 2B, the magnetic poles of the tip magnet 12 and the magnetic poles on the end surface close to the tip of the rear magnet 14 are set to face in the same direction. In addition, the rear magnet 14 is a ring-type magnet that is mounted on the support 11, and has an outer diameter that is larger than the outer diameter of the tip magnet 12 and protrudes to the outer periphery. In this way, by making the magnetic poles of both the magnets 12 and 14 in the same direction, the lines of magnetic force from the rear magnet 14 having a large outer diameter surround the outer periphery of the tip magnet 12, and FIG. As shown to (a), the direction which suppresses that the magnetic force line of the front-end | tip part magnet 12 diverges and a magnetic flux density falls by the magnetic force of the back part magnet 14, ie, the direction perpendicular | vertical with respect to the grinding | polishing target object 16 is directed. The magnetic flux density around the tip of the polishing tool can be further increased. Therefore, the spreading of the polishing liquid 18 can also be suppressed and converged toward the front. On the other hand, as shown in FIG. 3 (b), in the conventional configuration in which the rear magnet 14 is not provided, the magnetic lines of force by the tip magnet 12 spread, and the magnetic lines of force increase as the distance from the center of the tip magnet 12 increases. It comes to be suitable for. Therefore, the magnetic flux density around the tip of the polishing tool is reduced, the polishing liquid 18 is also diffused, and the polishing power is weakened.

  FIG. 4 is a modification of the first embodiment. In the first embodiment, since the shape of the rear magnet 14 is a ring shape, it is inserted and fixed to the outer periphery of the columnar support 11, but the shape of the rear magnet is not limited to a column shape. For example, a cylindrical shape can be used. In this case, as shown in FIG. 4, the support 11 includes a first support 11a and a second support 11b on which the head magnet 12 is mounted, and is provided between the first support 11a and the second support 11b. A cylindrical rear magnet 14 'is disposed so as to be sandwiched between the two. Furthermore, the outer diameter of the rear magnet is set to be larger than the outer diameter (diameter) of the head magnet 12, and the outer peripheral portion of the rear magnet 14 ′ projects outside the head magnet 12. Also in this modified example, as shown in FIG. 4B, the magnetic pole of the tip magnet 12 and the magnetic pole of the end surface on the side close to the tip of the rear magnet 14 'are set to face in the same direction. ing.

  FIG. 5 shows still another modification. In the first embodiment, the shape of the front magnet 12 is spherical, but the present invention is not limited to this, and the shape of the front magnet 12 'is changed to the shape of the tip of the cylinder as shown in FIG. A curved body formed in a hemispherical shape or the shape of the front magnet 12 ″ can be formed in a columnar shape as shown in FIG. 5 (b). In addition, the description which is the same as the modified example is omitted.

  Further, as shown in FIG. 6, even in the type in which the rear magnet 14 'shown in FIG. 4 is constituted by a cylindrical magnet, the shape of the front magnet 12' is a curved body in which the tip of the cylinder is formed in a hemisphere. (FIG. 6 (a)), or the shape of the side magnet 12 ″ may be a columnar shape (FIG. 6 (b)). The description which is the same as that of the modification is omitted.

  FIG. 7 shows still another modification. In this modified example, a plurality of magnets (for example, columnar magnets) are used as the rear magnet 14 ″. In the example shown in the figure, four magnets are used, but the number of installations is arbitrary. As shown in (b), it is of course possible to use a curved body or a cylindrical one instead of the tip magnet 12. The other configurations, functions and effects are the same as those of the above-described embodiments and modifications. That description is omitted.

[inspection result]
The following analysis was performed to verify the effect of the present invention. As shown in FIG. 8, the diameter of the tip magnet 12 made of a spherical magnet is B, the outer diameter of the rear magnet 14 made of a ring magnet is RD, the inner diameter is Rd, and the length is RH. In this analysis, B = 10 mm, RD = 20 mm, Rd = 10.1 mm, and RH = 20 mm. Both permanent magnets used were neodymium magnets (NEDK 42SH manufactured by TDK). The characteristics of this magnet are
Residual magnetic flux density (Br) 1300mT
Coercive force (HCB) 979 kA / m
Coercive force (HCJ)> 1671 kA / m
Maximum energy product (BH) max 326kJ / m ^ 3
It was.

  The installation position of the rear magnet 14 was defined by a distance RL from the tip of the tip magnet to the end surface on the tip of the rear magnet, and was fixed at 5 mm. The magnetic field region to be analyzed is a distance A1 (7.0 mm) in the width direction from the center of the tip magnet (polishing tool), a distance A2 (7.0 mm) in the tip direction from the center of the tip magnet, A distance A3 (5.0 mm) from the center to the tip of the tip magnet. As the spatial point of the analysis point, a line 0.5 mm away from the tip of the tip magnet was set at 1 mm intervals on the opposite plane. In addition, the spatial point of the analysis point on the inclined surface was set at an interval of 0.5 mm in the 45 ° direction with respect to the angle formed by the diameter from the center of the tip magnet toward the tip.

  Further, the magnetization direction is a direction along the axis of the support, ring-shaped rear permanent magnet 14, downward in FIG. 8 (the polishing object side is N pole: magnetization 1), and upward in FIG. 8 (the polishing object side is Two types of S pole: magnetization 2) are assumed. The magnetization direction of the tip magnet was fixed downward (magnetization 1), and the magnetization direction of the rear magnet 14 was swung as a parameter. Specifically, the analysis pattern 1 is only the tip magnet (without the rear magnet), the analysis pattern 2 is in the same direction as the tip magnet (downward: magnetization 1), and the analysis pattern 3 is opposite to the tip magnet. (Upward direction: magnetization 2). That is, the analysis pattern 2 is an example corresponding to the present invention, and the analysis pattern 1 is a comparative example corresponding to a conventional product corresponding to the example (a comparative example for demonstrating the superiority of the present product over the conventional product). The analysis pattern 3 is a comparative example for demonstrating the relationship between the magnetization directions of the tip magnet and the rear magnet.

  FIGS. 9A, 9B, and 9C are color representations of the spatial magnetic flux densities of the analysis patterns 1, 2, and 3, respectively. On the right side of FIG. 9A, a color sample with respect to the magnitude of the spatial magnetic flux is shown as an indicator. In the figure, 0.4 to 0.8T are expressed. In other words, the spatial magnetic flux density starts from blue of 0.4, and as the spatial density increases, the hue gradually changes from green to yellow and becomes red at the highest spatial density of 0.8T. One memory of this indicator is 0.1T. Although not shown on the left side in each analysis diagram, the analysis is axisymmetric about the central axis of the polishing tool.

  From the above analysis results, it is apparent that the analysis pattern 2 corresponding to the present invention shown in FIG. 9B has a high magnetic flux density at the tip of the polishing tool. On the other hand, the analysis pattern 3 in which the magnetic pole direction of the auxiliary rear magnet is opposite to the tip magnet has an adverse effect.

  The specific spatial magnetic flux density at each analysis point in the analysis region is as shown in the graph below. FIG. 10 shows the magnetic flux of the vertical direction component (same as magnetization 1) at the analysis point set at an interval of 1 mm from the center toward the outside at the position of 0.5 mm from the tip magnet, that is, the direction component facing the polishing object. The density is shown. As can be seen from FIG. 10, there is a difference of about 90 to 120 mT depending on the presence or absence of the rear magnet (ring magnet). That is, the polishing bit in which the rear magnet of the analysis pattern 2 corresponding to the present invention is arranged in the same magnetization direction as the tip magnet is compared with the polishing bit not provided with the rear magnet of the analysis pattern 1 corresponding to the conventional example. Although different depending on the point location, the magnetic flux density takes a large value at any analysis point location. This difference is a value that greatly influences polishing when performing anti-planar polishing. On the other hand, even if the rear magnet is arranged, the analysis pattern 3 in which the magnetization direction is reversed between the tip magnet and the rear magnet is 90 to 120 mT than the polishing bit of the analysis pattern 1 in which the rear magnet is not provided. It turns out that it is close to the opposite.

  FIG. 11 shows the magnetic flux density of the magnetization vector (vertical component with respect to the 45 ° inclined surface) at the anti-inclined surface analysis points set at 0.5 mm intervals on the 45 ° inclined surface from the center of the tip magnet. This magnetic flux density is obtained from the vertical component and the horizontal component of the magnetization vector at the analysis point of the inclined plane. As is clear from FIG. 11, there is a difference of about 60 to 100 mT with or without the rear magnet. That is, the polishing bit in which the rear magnet of the analysis pattern 2 corresponding to the present invention is arranged in the same magnetization direction as the tip magnet is compared with the polishing bit not provided with the rear magnet of the analysis pattern 1 corresponding to the conventional example. Although different depending on the point location, the magnetic flux density takes a large value at any analysis point location. This difference is a value that greatly influences polishing when performing anti-planar polishing. On the other hand, even if the rear magnet is arranged, the analysis pattern 3 in which the magnetization direction is reversed between the tip magnet and the rear magnet is 60 to 100 mT than the polishing bit of the analysis pattern 1 in which the rear magnet is not provided. It turns out that it is close to the opposite.

  Next, the influence of the position of the rear magnet was verified. A1, A2, and A3 for specifying the space area to be verified are set to 7, 7, and 5, respectively, to be the same as analysis patterns 1 to 3. The diameter B of the tip magnet was 4 mm. The rear magnets were verified for two types, a ring magnet and a columnar magnet. The ring magnet had an outer diameter RD = 15 mm, an inner diameter Rd = 5.1 mm, and a length RH = 10 mm. The cylindrical magnet had an outer diameter RD = 15 mm, an inner diameter Rd = 0 mm, and a length RH = 10 mm. In any analysis pattern, the magnetization direction of the tip magnet was downward (magnetization 1), and the magnetization direction of the rear magnet was also downward (magnetization 1). Under this condition, an analysis pattern 4 in which no rear magnet corresponding to the conventional example is provided, analysis patterns 5 and 6 using a ring magnet as a rear magnet, and an analysis pattern 7 using a cylindrical magnet as a rear magnet. The following four analysis patterns were prepared. The distance RL from the tip of the tip magnet that specifies the position of the rear magnet to the tip face of the tip of the rear magnet was 5 mm for the analysis pattern 5 and 10 mm for the analysis patterns 6 and 7.

  12 and 13 are color representations of the spatial magnetic flux density of each analysis pattern. Specifically, FIG. 12A shows the analysis pattern 4, FIG. 12B shows the analysis pattern 5, FIG. 13A shows the analysis pattern 6, and FIG. 13B shows the analysis pattern 7. Further, on the right side of FIGS. 12A and 13B, a color sample with respect to the magnitude of the spatial magnetic flux is shown as an indicator.

  As is clear from comparison between the figures, compared to FIG. 12A, which is the analysis result of the analysis pattern 4, all the other figures have a higher magnetic flux density in the front region of the tip magnet. Thereby, first, the superiority of providing the rear magnet can be confirmed regardless of the installation position and shape of the rear magnet. Then, as is apparent from a comparison between the analysis pattern 5 (FIG. 12B) using the ring magnet as the rear magnet and the analysis pattern 6 (FIG. 13A), an analysis with a short distance RL = 5 mm is performed. The pattern 5 has a higher magnetic flux density in the front region of the tip magnet. A high magnetic flux density is obtained in the front region of the tip magnet by using a cylindrical magnet instead of the ring-type magnet that is separated from RL = 10 mm.

  Therefore, it can be said that it is preferable to use a cylindrical magnet as the rear magnet in terms of increasing the magnetic flux density. Further, the magnetic flux density in the front space of the tip magnet changes according to the distance between the front magnet and the rear magnet. Accordingly, when the rear magnet is a ring magnet and the ring magnet is mounted so as to be movable in the axial direction with respect to the support, the position of the ring magnet (rear magnet) is changed in the axial direction of the support. This is preferable because there is a merit that the magnetic flux density (polishing force) in the region on the front side of the tip magnet can be finely adjusted. Adjustment of the magnetic flux density at the tip is important for magnetic polishing.

  The specific spatial magnetic flux density at each analysis point in the analysis region is as shown in the graph below. FIG. 14 shows the magnetic flux density of the vertical direction component at the analysis points set at intervals of 1 mm from the center toward the outside at the position of 0.5 mm from the tip magnet, that is, the direction component facing the object to be polished. As apparent from FIG. 13, the analysis pattern 4 has the lowest spatial magnetic flux density, and the spatial magnetic flux density increases in the order of analysis pattern 6 → analysis pattern 5 → analysis pattern 7 in the following order. As a specific value, the analysis pattern 5 is higher than the analysis pattern 4 by about 150 mT. The analysis pattern 6 is about 66 mT higher than the analysis pattern 4. Further, the analysis pattern 7 is higher than the analysis pattern 4 by about 190 mT.

  FIG. 15 shows the magnetic flux density of the magnetization vector (vertical component with respect to the 45 ° inclined surface) at the anti-inclined surface analysis points set at 0.5 mm intervals on the 45 ° inclined surface from the center of the tip magnet. This magnetic flux density is obtained from the vertical component and the horizontal component of the magnetization vector at the analysis point of the inclined plane. As is apparent from FIG. 8, the analysis pattern 4 also has the lowest spatial magnetic flux density at this anti-slope analysis point as in the anti-plane analysis point shown in FIG. The spatial magnetic flux density increases in the order of 7. As a specific value, the analysis pattern 5 is higher than the analysis pattern 4 by about 130 mT. The analysis pattern 6 is higher than the analysis pattern 4 by about 60 mT. Further, the analysis pattern 7 is higher than the analysis pattern 4 by about 190 mT. In the case of the analysis pattern 4 which does not provide the rear magnet corresponding to the conventional example, the last magnetic flux density was only obtained in use, but the present invention in which the rear magnet is arranged has a sufficient magnetic flux density. Thus, the polishing effect can be improved.

Next, as shown in FIG. 16, an analysis of a polishing tool composed of a combination of a front magnet 12 ′ having a curved body having a cylindrical main body and a hemispherical tip and a rear magnet 14 made of a ring magnet. The results will be explained. The analysis condition is that the tip magnet 12 'has a main body diameter B, an axial length BL, and a hemisphere diameter BR at the tip. An outer diameter of the rear magnet 14 made of a ring magnet is RD, an inner diameter is Rd, and a length is RH. In this analysis, B = 10 mm, BL = 20 mm, BR = 5 mm, RD = 20 mm, Rd = 10.1 mm, and RH = 20 mm. Both permanent magnets used were neodymium magnets (NEDK 42SH manufactured by TDK). The characteristics of this magnet are
Residual magnetic flux density (Br) 1300 mT
Coercive force (HCB) 979 kA / m
Coercive force (HCJ)> 1671 kA / m
Maximum energy product (BH) max 326kJ / m ^ 3
It was.

  The installation position of the rear magnet 14 was defined by the distance RL from the tip of the tip magnet 12 'to the end surface on the tip side of the rear magnet 14 and fixed at 5 mm. The magnetic field region to be analyzed is a distance A1 (7.0 mm) in the width direction from the center of the hemispherical tip portion of the tip magnet 12 ′, a distance A2 (7.0 mm) in the tip direction from the center of the tip portion, A distance A3 (5.0 mm) from the center of the tip magnet to the tip of the tip magnet. As the spatial point of the analysis point, a line 0.5 mm away from the tip of the tip magnet was set at 1 mm intervals on the opposite plane. In addition, the spatial point of the analysis point on the inclined surface was set at an interval of 0.5 mm in the 45 ° direction with respect to the angle formed by the diameter from the center of the tip magnet toward the tip.

  Further, the magnetization direction is the direction along the axis of the support, ring-shaped rear permanent magnet 14, downward in FIG. 16 (the polishing object side is N pole: magnetization 1), and upward in FIG. 16 (the polishing object side is Two types of S pole: magnetization 2) are assumed. The magnetization direction of the tip magnet 12 'was fixed downward (magnetization 1), and the magnetization direction of the rear magnet 14 was swung as a parameter. Specifically, the analysis pattern 11 is only the tip magnet (without the rear magnet), the analysis pattern 12 is in the same direction as the tip magnet (downward: magnetization 1), and the analysis pattern 13 is opposite to the tip magnet. (Upward direction: magnetization 2). That is, the analysis pattern 12 is an embodiment corresponding to the present invention, and the analysis pattern 11 is a comparative example corresponding to a conventional product corresponding to the embodiment (a comparative example for demonstrating the superiority of the present product over the conventional product). The analysis pattern 13 is a comparative example for demonstrating the relationship between the magnetization directions of the tip magnet and the rear magnet.

  FIGS. 17A, 17B, and 17C are color representations of the spatial magnetic flux densities of the analysis patterns 11, 12, and 13, respectively. A color sample with respect to the magnitude of the spatial magnetic flux is shown as an indicator on the right side of FIG. In the figure, 0.4 to 0.8T are expressed. Although not shown on the left side in each analysis diagram, the analysis is axisymmetric about the central axis of the polishing tool.

  From the above analysis results, it is apparent that the analysis pattern 12 corresponding to the present invention shown in FIG. 17 (b) has a high magnetic flux density at the tip of the polishing tool, and the high range spreads forward. On the other hand, the analysis pattern 13 in which the magnetic pole direction of the auxiliary rear magnet is opposite to that of the tip magnet has an adverse effect.

  The specific spatial magnetic flux density at each analysis point in the analysis region is as shown in the graph below. FIG. 18 shows a magnetic flux of a vertical direction component (same as magnetization 1) at an analysis point set at an interval of 1 mm from the center toward the outside at a position of 0.5 mm from the tip magnet, that is, a directional component toward the object to be polished. The density is shown. As is apparent from FIG. 18, there is a difference of about 90 to 120 mT depending on the presence or absence of the rear magnet (ring magnet). That is, the polishing bit in which the rear magnet of the analysis pattern 12 corresponding to the present invention is arranged in the same magnetization direction as the tip magnet is compared with the polishing bit not provided with the rear magnet of the analysis pattern 11 corresponding to the conventional example. Although different depending on the point location, the magnetic flux density takes a large value at any analysis point location. This difference is a value that greatly influences polishing when performing anti-planar polishing. On the other hand, even if the rear magnet is arranged, the analysis pattern 13 in which the magnetization direction is reversed between the tip magnet and the rear magnet is 90 to 120 mT than the polishing bit of the analysis pattern 11 without the rear magnet. It turns out that it is close to the opposite.

  FIG. 19 shows the magnetic flux density of the magnetization vector (vertical component with respect to the 45 ° inclined surface) at the anti-inclined surface analysis points set at 0.5 mm intervals on the 45 ° inclined surface from the center of the tip portion of the tip magnet. . This magnetic flux density is obtained from the vertical component and the horizontal component of the magnetization vector at the analysis point of the inclined plane. As is clear from FIG. 19, there is a difference of about 60 to 100 mT with or without the rear magnet. That is, the polishing bit in which the rear magnet of the analysis pattern 12 corresponding to the present invention is arranged in the same magnetization direction as the tip magnet is compared with the polishing bit not provided with the rear magnet of the analysis pattern 11 corresponding to the conventional example. Although different depending on the point location, the magnetic flux density takes a large value at any analysis point location. This difference is a value that greatly influences polishing when performing anti-planar polishing. On the other hand, even if the rear magnet is arranged, the analysis pattern 13 in which the magnetization direction is reversed between the tip magnet and the rear magnet is 60 to 100 mT than the polishing bit of the analysis pattern 11 without the rear magnet. It turns out that it is close to the opposite.

  Next, the influence of the position of the rear magnet was verified. A1, A2, and A3 that specify the space area to be verified are set to 7, 7, and 5, respectively, to be the same as the analysis patterns 11 to 13. The diameter B of the main body portion of the tip magnet was 4 mm. The rear magnet was a ring magnet, and had an outer diameter RD = 15 mm, an inner diameter Rd = 5.1 mm, and a length RH = 10 mm. In any analysis pattern, the magnetization direction of the tip magnet was downward (magnetization 1), and the magnetization direction of the rear magnet was also downward (magnetization 1). Under these conditions, three analysis patterns were prepared: an analysis pattern 14 that does not include a rear magnet corresponding to the conventional example, and analysis patterns 15 and 16 that use a ring magnet as the rear magnet. The distance RL from the tip of the tip magnet that specifies the position of the back magnet to the tip surface of the tip of the back magnet was 5 mm for the analysis pattern 15 and 10 mm for the analysis pattern 16.

  FIG. 20 is a color display of the spatial magnetic flux density of each analysis pattern. Specifically, FIG. 20A shows the analysis pattern 14, FIG. 20B shows the analysis pattern 15, and FIG. 20C shows the analysis pattern 16. Furthermore, the color sample with respect to the magnitude | size of space magnetic flux is shown as an indicator on the right side of Fig.20 (a).

  As is clear from comparison between the figures, as compared with FIG. 20A, which is the analysis result of the analysis pattern 14, all the other figures have a higher magnetic flux density in the front region of the tip magnet. Thereby, first, the superiority of providing the rear magnet can be confirmed regardless of the installation position and shape of the rear magnet. The analysis result of the analysis pattern 15 shown in FIG. 20B has a higher magnetic flux in the front region of the tip magnet than the analysis pattern 16 in which the distance between the tip magnet and the rear magnet shown in FIG. Density is obtained.

  The specific spatial magnetic flux density at each analysis point in the analysis region is as shown in the graph below. FIG. 21 shows the magnetic flux density of the vertical direction component at the analysis points set at intervals of 1 mm from the center toward the outside at the position of 0.5 mm from the tip magnet, that is, the direction component facing the object to be polished. As is clear from FIG. 21, the analysis pattern 14 has the lowest spatial magnetic flux density, and the spatial magnetic flux density increases in the order of the analysis pattern 16 → the analysis pattern 15 in the following order. As a specific value, the analysis pattern 15 is higher than the analysis pattern 14 by about 145 mT. The analysis pattern 16 is about 67 mT higher than the analysis pattern 14.

  FIG. 22 shows the magnetic flux density of the magnetization vector (vertical component with respect to the 45 ° inclined surface) at the anti-inclined surface analysis points set at 0.5 mm intervals on the 45 ° inclined surface from the center of the tip portion of the tip magnet. . This magnetic flux density is obtained from the vertical component and the horizontal component of the magnetization vector at the analysis point of the inclined plane. As is clear from FIG. 22, the analysis pattern 14 has the lowest spatial magnetic flux density at the anti-slope analysis point as well as the anti-plane analysis point shown in FIG. Spatial magnetic flux density increases. As a specific value, the analysis pattern 15 is about 130 mT higher than the analysis pattern 14.

Next, as shown in Fig. 23, the analysis result of a polishing tool composed of a combination of a columnar tip magnet 12 "and a rear magnet 14 made of a ring magnet will be described. For 12 ″, the diameter is B, and the axial length is BL. An outer diameter of the rear magnet 14 made of a ring magnet is RD, an inner diameter is Rd, and a length is RH. In this analysis, B = 10 mm, BL = 20 mm, RD = 20 mm, Rd = 10.1 mm, and RH = 20 mm. Both permanent magnets used were neodymium magnets (NEDK 42SH manufactured by TDK). The characteristics of this magnet are
Residual magnetic flux density (Br) 1300 mT
Coercive force (HCB) 979 kA / m
Coercive force (HCJ)> 1671 kA / m
Maximum energy product (BH) max 326kJ / m ^ 3
It was.

  The installation position of the rear magnet 14 is defined by the distance RL from the tip of the tip magnet 12 ″ to the tip end surface of the rear magnet 14 and fixed at 5 mm. The magnetic field region to be analyzed is the tip magnet 12 ″. The distance A1 (7.0 mm) in the width direction from the central axis, the distance A2 (7.0 mm) in the tip direction from the axial center position, and the distance A3 (5.5 from the axial center position to the tip of the tip magnet). 0 mm). As the spatial point of the analysis point, a line 0.5 mm away from the tip of the tip magnet was set at 1 mm intervals on the opposite plane.

  Further, the magnetization direction is a direction along the axis of the support, ring-shaped rear permanent magnet 14, downward in FIG. 23 (the polishing object side is N pole: magnetization 1), and upward in FIG. 23 (the polishing object side is Two types of S pole: magnetization 2) are assumed. The magnetization direction of the tip magnet 12 'was fixed downward (magnetization 1), and the magnetization direction of the rear magnet 14 was swung as a parameter. Specifically, the analysis pattern 21 has only the tip magnet (without the rear magnet), the analysis pattern 22 has the same direction as the tip magnet (downward: magnetization 1), and the analysis pattern 23 is opposite to the tip magnet. (Upward direction: magnetization 2). That is, the analysis pattern 22 is an embodiment corresponding to the present invention, and the analysis pattern 21 is a comparative example corresponding to a conventional product corresponding to the embodiment (a comparative example for demonstrating the superiority of the present product over the conventional product). The analysis pattern 23 is a comparative example for demonstrating the relationship between the magnetization directions of the tip magnet and the rear magnet.

  FIGS. 24A, 24B, and 24C are color representations of the spatial magnetic flux densities of the analysis patterns 21, 22, and 23, respectively. A color sample with respect to the magnitude of the spatial magnetic flux is shown as an indicator on the right side of FIG. In the figure, 0.4 to 0.8T are expressed. Although not shown on the left side in each analysis diagram, the analysis is axisymmetric about the central axis of the polishing tool.

  From the above analysis results, it is apparent that the analysis pattern 22 corresponding to the present invention shown in FIG. 24 (b) has a high magnetic flux density at the tip of the polishing tool, and the high range spreads forward. On the other hand, the analysis pattern 23 in which the magnetic pole direction of the auxiliary rear magnet is opposite to that of the tip magnet has an adverse effect.

  The specific spatial magnetic flux density at each analysis point in the analysis region is as shown in the graph below. FIG. 25 shows a magnetic flux of a vertical direction component (same as magnetization 1) at an analysis point set at an interval of 1 mm from the center toward the outside at a position of 0.5 mm from the tip magnet, that is, a directional component toward the object to be polished. The density is shown. As is apparent from FIG. 25, there is a difference of about 90 mT depending on the presence or absence of the rear magnet (ring magnet). This difference greatly affects the polishing in the flat surface polishing. On the other hand, even if the rear magnet is arranged, the analysis pattern 23 in which the magnetization direction is reversed between the tip magnet and the rear magnet is nearly 90 mT lower than the polishing bit of the analysis pattern 21 without the rear magnet. And it turns out that it becomes the opposite effect.

  Next, the influence of the position of the rear magnet was verified. A1, A2, and A3 for specifying the space area to be verified are set to 7, 7, and 5, respectively, to be the same as the analysis patterns 21 to 23. The diameter B of the tip magnet was 4 mm. The rear magnet was a ring magnet, and had an outer diameter RD = 15 mm, an inner diameter Rd = 5.1 mm, and a length RH = 10 mm. In any analysis pattern, the magnetization direction of the tip magnet was downward (magnetization 1), and the magnetization direction of the rear magnet was also downward (magnetization 1). Under these conditions, three analysis patterns were prepared: an analysis pattern 24 that does not include a rear magnet corresponding to the conventional example, and analysis patterns 25 and 26 that use a ring magnet as the rear magnet. The distance RL from the tip of the tip magnet that specifies the position of the back magnet to the tip surface of the tip of the back magnet was 5 mm for the analysis pattern 15 and 10 mm for the analysis pattern 16.

  FIG. 26 is a color display of the spatial magnetic flux density of each analysis pattern. Specifically, FIG. 26A shows the analysis pattern 24, FIG. 26B shows the analysis pattern 25, and FIG. 26C shows the analysis pattern 26. Further, on the right side of FIG. 26A, a color sample with respect to the magnitude of the spatial magnetic flux is shown as an indicator.

  As is clear from comparison between the figures, compared to FIG. 26A, which is the analysis result of the analysis pattern 24, all other figures have a higher magnetic flux density in the front region of the tip magnet. Thereby, first, the superiority of providing the rear magnet can be confirmed regardless of the installation position and shape of the rear magnet. The analysis result of the analysis pattern 25 shown in FIG. 26B has a higher magnetic flux in the front region of the tip magnet than the analysis pattern 26 in which the distance between the tip magnet and the rear magnet shown in FIG. Density is obtained.

  The specific spatial magnetic flux density at each analysis point in the analysis region is as shown in the graph below. FIG. 27 shows the magnetic flux density of the vertical direction component at the analysis points set at intervals of 1 mm from the center toward the outside at the position of 0.5 mm from the tip magnet, that is, the direction component facing the object to be polished. As apparent from FIG. 27, the analysis pattern 24 has the lowest spatial magnetic flux density, and the spatial magnetic flux density increases in the order of the analysis pattern 26 → the analysis pattern 25 in the following order. As a specific value, the analysis pattern 25 is about 145 mT higher than the analysis pattern 24. The analysis pattern 26 is about 67 mT higher than the analysis pattern 24.

  As mentioned above, regardless of the shape of the tip magnet or the back magnet, a small-diameter polishing tool that can obtain a magnetic flux density effective for polishing even if the outer diameter of the tip magnet is a small diameter of φ4 or less. It can be confirmed.

  FIG. 28 is a diagram for explaining a second embodiment of the present invention. FIG. 28A shows an example in which the first magnet 12 ′ made of a curved body and the rear magnet 14 made of a ring magnet are used as an example of the first embodiment described above. A polishing paste 18 is present at the tip of the tip magnet 12 '. In order to polish using such a magnetic polishing tool, the polishing tool is rotated. Then, as shown in FIG. 28 (b), a part of the polishing paste 18 may be scattered during the polishing and may be attracted (moved) to the surface of the rear magnet 14. When such a situation occurs, the polishing paste 18 existing between the tip magnet 12 'and the object to be polished located at the tip thereof decreases, and the polishing characteristics become unstable.

  Therefore, in the second embodiment, the cover member is arranged so as to cover the front end side end surface of the rear magnet 14. Specifically, for example, various other forms such as a truncated cone-shaped cover member 20 as shown in FIG. 28C and a flat cover member 20 ′ as shown in FIG. 28D are used. Can do. In either case, the material is a non-magnetic material. Here, it is made of resin. As the material of the cover member, silicon rubber, nonmagnetic metal (aluminum, SUS304, etc.), POM material, rubber-based resin, or the like may be used.

  Furthermore, by making the outer dimensions of the cover members 20 and 20 ′ larger than the outer diameter of the rear magnet 14, the rear magnet 14 is enclosed and the adsorption of the polishing paste 18 to the rear magnet 14 is more reliably avoided. . Furthermore, as shown in FIG. 28 (c), it is preferable to cover the side surface of the rear magnet 14 because adhesion of the polishing paste 18 can be further suppressed. The cover members 20 and 20 'and the rear magnet 14 may be in contact with each other or may not be in contact with each other. Moreover, the shape of each magnet is also arbitrary, and various forms can be used.

  In order to verify the effect of the second embodiment, the following experiment was performed. As shown in FIG. 29 (a), the tip magnet 12 ″ is a cylindrical magnet, and the rear magnet 14 is a ring magnet. The polishing object 16 is a SUS420J2 (52HRC) flat plate. After using the cutting process shown below as a reference surface (initial surface), magnetic polishing was performed under the same conditions for the case where the ring magnet was disposed in the rear magnet and the case where the ring magnet was not disposed.

  First, cutting conditions were such that a flat end mill (φ10 FLAT) was used as a cutting tool, the spindle rotation speed was 10000 rpm, the tool feed speed was 1000 mm / min, and the scanning line machining pitch was 0.10 mm.

The magnetic polishing conditions were the following four conditions, and polishing was performed by changing the polishing time under each condition. First, as a common specification, as shown in FIG. There is a configuration in which the rear magnet 14 and the cover member 20 'are not provided depending on conditions.

Condition 1
Tip magnet: outer diameter B = 4mm, length BL = 20mm
Back magnet: None Polishing gap: 0.3 mm
Spindle speed: 1500rpm
Polishing time / feed pitch: (a) 101/10
(B) 20/50
(C) 10/100
Scanning pitch: 0.1mm
The polishing time unit is min / cm ^ 2, and the feed pitch unit is mm / min.

Condition 2
Tip magnet: outer diameter B = 4mm, length BL = 20mm
Rear magnet: outer diameter RD = 11 mm, inner diameter Rd = 4 mm, length RH = 10 mm
Rear magnet position: RL = 12mm
Polishing gap: 0.3mm
Spindle speed: 1500rpm
Polishing time / feed pitch: (a) 101/10
(B) 20/50
(C) 10/100
Scanning pitch: 0.1mm
The polishing time unit is min / cm ^ 2.
Unit of feed pitch is mm / min

Condition 3
Tip magnet: outer diameter B = 6mm, length BL = 20mm
Back magnet: None Polishing gap: 0.3 mm
Spindle speed: 1300rpm
Polishing time / feed pitch: (a) 101/10
(B) 20/50
(C) 10/100
Scanning pitch: 0.1mm
The polishing time unit is min / cm ^ 2, and the feed pitch unit is mm / min.

Condition 4
Tip magnet: outer diameter B = 6mm, length BL = 20mm
Rear magnet: outer diameter RD = 9 mm, inner diameter Rd = 6 mm, length RH = 10 mm
Rear magnet position: RL = 7mm
Polishing gap: 0.3mm
Spindle speed: 1300rpm
Polishing time / feed pitch: (a) 101/10
(B) 20/50
(C) 10/100
Scanning pitch: 0.1mm
The polishing time unit is min / cm ^ 2.
Unit of feed pitch is mm / min

  As the magnetic polishing paste, FDK magnetic polishing paste (MPL-S2SOD) was used, and 0.1 g for conditions 1 and 2 and 0.2 g for conditions 3 and 4 were used. In the polishing, as shown in FIG. 29B, a polishing tool (tip magnet) was scanned with respect to a square polishing area having a side of 10 mm in parallel with one side and a scanning line pitch of 0.1 mm.

Polishing was performed according to each polishing condition, and the roughness before polishing (initial) and the roughness after polishing were measured to evaluate whether polishing was performed. The surface roughness was measured using a “three-dimensional laser measuring device” (KS-1100 manufactured by Keyence Corporation) as a measuring device, and the polishing depth was determined. As shown in FIG. 30, the polishing depth was an average value of the polishing depths of three measurement lines straddling the polishing area. The polishing depth of each measurement line is
Polishing depth = overall Ry− (reference surface Ry / 2) − (polishing surface Ry / 2)
Ask for. Here, Ry is the maximum height.

  As a result, the depth after polishing was as shown in FIGS. From the results of the polishing depth test, in comparison of the polishing depth between Condition 1 and Condition 2 using a φ4 cylindrical polishing tool having a relatively small diameter as an example, Condition 2 in which a magnet is arranged at the rear is 20 to 30% polishing depth. It can be confirmed that the depth is deep and the polishing power is high (see FIGS. 31 and 32). Similarly, in conditions 3 and 4 using a cylindrical polishing tool of φ6 as an example, it was confirmed that the condition 4 in which the magnet was arranged at the back was 30 to 50% deep and the polishing power was high (see FIG. 31, see FIG. 33). Thus, according to the verification test, it was confirmed that the polishing power was improved by 20 to 50% in the condition 2 and the condition 4 in which the rear magnet was arranged. This result supports the previous analysis result.

  FIG. 34 shows an embodiment applied to a handy type polishing apparatus. In each figure, the polishing apparatus 30 to which the polishing tool 10 is attached includes a hand grinder 31 and a speed reducer 32. A reduction gear 32 having a reduction ratio of 1: 3.8 is used. Thereby, the rotation speed of the polishing tool can be adjusted to 500 to 3000 rpm. The hand grinder 31 is not necessarily required as long as the rotation speed of 500 to 3000 rpm can be obtained.

  FIG. 34 (a) shows a polishing tool 10 having a curved body (outer diameter B is 6 mm and tip portion radius BR is 3 mm) with a tip of a cylindrical body as a tip magnet 12 ′ (bullet type). A ring-shaped magnet (inner diameter Rd is 6 mm, outer diameter RD is 9 mm, length RH is 10 mm) is attached to the support 11 as a rear magnet 14, and is a disc-shaped cover made of silicon rubber. The member 20 'is mounted. Further, FIG. 34B is based on the configuration shown in FIG. 34A, and the cover member 20 is changed to a truncated cone shape. In FIG. 34 (c), a conventional type polishing tool 9 that is not equipped with a rear magnet or the like is attached to the polishing apparatus 30.

  Magnetic polishing was actually performed under the following conditions using the above-described components. First, in any configuration, the rotation speed was set to 1000 rpm. As the polishing paste, 0.6 g of MPL-PC3LBOD (mainly for nonmagnetic SUS, aluminum and polycarbonate) manufactured by FDK was used. The object to be polished was a SUS316L flat plate, and the polishing time was 1 minute. In the polishing, hand polishing was performed so as to draw a “no” shape while lightly pressing against the polishing surface of the object to be polished.

  In the conventional type shown in FIG. 34 (c), the magnetic polishing paste attached to the tip of the polishing tool is pushed from around 30 seconds, the magnet is exposed, and the tip of the magnet contacts the object to be polished. There were many. As a result, the portion where the tip magnet was in contact was finished with a non-uniform surface that was severely scratched and extremely shaved. On the other hand, the method of the present invention was able to uniformly polish a wide area compared to the conventional method without any contact.

  This shows that the results of the present invention shown in FIG. 35 and the roughness evaluation results, which are experimental results of the conventional method shown in FIG. 36, are more beautiful than the conventional method. . Here, the roughness evaluation conditions were a “color 3D laser microscope” (VK-8700, manufactured by Keyence Corporation) as a measuring instrument, and the surface before and after polishing was measured. The measurement item was roughness (JIS1994 standard). Accordingly, Ra (arithmetic average roughness), Ry (maximum height), and Rz (ten-point average roughness) were used.

  37 shows the surface before polishing (FIG. 37 (a) and after polishing (FIGS. 37 (b) and (c)) observed with a laser microscope.The method of the present invention shown in FIG. The polishing result shown in the conventional method shown in Fig. 37 (c) was found to have more scratches on the polished surface than the polishing result obtained by the method described above, which is the effect of providing a rear magnet such as a ring magnet as described in the analysis result. As a result, the component in the vertical direction in the magnetization vector 3 direction is increased, and the magnetic field lines are perpendicularly applied to the object to be polished, thereby enabling stable polishing.

  Furthermore, by attaching a silicon rubber as a cover member between the rear magnet and the tip magnet, there is no adsorption of the polishing paste to the rear magnet (the movement of the polishing paste), and the polishing paste is applied to the tip magnet. Stable polishing can be realized without contact with the tip magnet due to the stable presence.

[Industrial applicability]
The present invention relates to a dedicated magnetic polishing tool when magnetic polishing is used for polishing and polishing complex shaped objects. Specifically, it is effective as a polishing application for final surface finishing at the time of mold production and as a polishing field for improving the appearance of design products. In particular, it is possible to insert a polishing tool (polishing tool) capable of efficiently polishing a bottom surface having a concave step of several millimeters on a flat surface, which is effective as a polishing means having a complicated shape. Furthermore, it is a highly versatile polishing tool and polishing method that enables polishing by a human hand using a hand grinder (hand leuter) without using a large-scale multi-axis cutting device or a multi-joint robot.

DESCRIPTION OF SYMBOLS 10 Polishing bit 11 Support body 12,12 ', 12 "Tip magnet 14,14', 14" Rear magnet 20,20 'Cover member

Claims (6)

A polishing tool for surface treatment by magnetic action,
A tip magnet and a rear magnet disposed behind the tip magnet;
At least a part of the rear magnet is located outside the outer periphery of the tip magnet,
The magnetic pole of the tip magnet and the magnetic pole of the end surface on the side close to the tip magnet of the rear magnet are configured the same ,
A cover member made of a nonmagnetic material is disposed between the tip magnet and the rear magnet ,
A polishing tool characterized in that an outer dimension of the cover member is larger than an outer dimension of the rear magnet. The rear magnet is a ring type or a cylindrical magnet,
The polishing tool according to claim 1, wherein an outer diameter of the rear magnet is larger than an outer dimension of the tip magnet. The rear magnet is a ring magnet,
3. The polishing according to claim 1, wherein the rear magnet can be moved in an axial direction with respect to a support on which the rear magnet is mounted, and the relative position of the rear magnet and the tip magnet can be adjusted. Part-Time Job.   The polishing tool according to any one of claims 1 to 3, wherein the rear magnet is an electromagnet or a permanent magnet.   The polishing tool according to any one of claims 1 to 4, wherein the tip magnet is one of a cylindrical shape, a spherical shape, and a curved surface shape.   A surface treatment apparatus comprising the polishing tool according to claim 1 attached to a tip of a hand grinder.