JP5025275B2 - Polishing tool - Google Patents

Description

The present invention relates to a polishing bytes for performing a fluid polishing in the presence of a magnetic polishing liquid between the polishing object, and more specifically, a surface such as a precision machine parts or mold or resin products The present invention relates to an improvement in magnetic field distribution and motion behavior of a polishing tool for polishing to a mirror surface.

  As a technique for finishing a surface to be polished into a mirror surface, a magnetic polishing technique is known in which polishing is performed by applying a magnetic field as seen in Patent Documents 1 and 2, for example. Patent Document 1 proposes a technique that improves the performance of the polishing liquid by adjusting dispersed particles in the magnetic polishing liquid, and can be applied to precise polishing and finishing. In Patent Document 2, the behavior of polishing is improved by causing the relative movement between the particle brush made of magnetic abrasive grains and the object to be polished appropriately, and by coating the magnetic abrasive grains with a nonmagnetic layer. There are proposals of techniques that can be applied to smooth polishing and finishing. Such magnetic polishing has a merit that it can perform so-called non-contact polishing and can perform polishing without stress even on a polishing object having low strength, and is preferred for use in precision finishing.

In magnetic polishing, magnetic abrasive grains (particle brushes), that is, grinding tools, are activated by a magnetic field. Therefore, polishing has a characteristic that the facing portion where the magnetic pole of the magnetic field generation source faces the object to be polished proceeds well. Therefore, the magnetic field generating source is, for example, a permanent magnet, which is assembled to a polishing tool and rotated by a driving means, and a mirror polishing is performed in which a magnetic polishing liquid is present between the polishing objects facing each other and fluid polishing is performed. There is a technology.
JP 2002-170791 A JP 2002-283216 A

  However, the conventional mirror polishing technique has the following problems. In other words, if the object to be polished is a complex shape with many irregularities (complex shape body), it may not be able to polish properly, and it will not be able to perform a uniform mirror finish along its surface shape and will be polished to an unintended shape May end up. This is greatly affected by the distribution of the magnetic field generated by the polishing tool, for example, when the permanent magnet of the magnetic field source has a prismatic or cylindrical shape, and the distance from the object to be polished is not uniform in such a magnetic field source. Therefore, an unintended shape change may occur due to a difference in polishing rate between the concave portion and the convex portion.

The object of the present invention is to solve the above-described problems. The object of the present invention is to make it possible to polish evenly on the unevenness of the surface even if the object to be polished is a complex shape having a large number of unevenness, and to obtain an appropriate mirror surface. it is to provide a polishing bytes that can be finished.

In order to achieve the above-described object, the polishing tool according to the present invention is a polishing tool that performs fluid polishing by keeping a non-contact state with respect to an object to be polished and interlocking with a magnetic polishing liquid existing in the periphery. Then, the polishing tool is provided with a permanent magnet as a magnetic field generation source, and the shape of the permanent magnet is changed to a spherical shape or a curved surface shape having an appropriate curved surface, and the second inside the support body supporting the permanent magnet. A permanent magnet is disposed in an embedded state, and the second permanent magnet is disposed at a predetermined position in contact with the permanent magnet .

  In addition, the permanent magnet is set so that the magnetization direction is substantially coincident with or substantially parallel to the rotation axis of the polishing tool, or is inclined with respect to the rotation axis of the polishing tool, and the inclination angle is 90 degrees or less with respect to the rotation axis. The scissor angle. The permanent magnet has a multipolar magnetization configuration having a plurality of magnetization directions.

  Further, the support body supporting the permanent magnet is configured to be coupled to the shaft portion of the polishing tool by interposing a flexible coupling means that allows lateral movement. The flexible connecting means has a configuration in which permanent magnets are embedded in the end portion of the support and the end portion of the shaft portion, respectively, and are connected by the magnetic attraction force of both. Alternatively, the flexible connecting means has a rod-like elastic member, and the elastic member is connected to the end portion of the support body and the end portion of the shaft portion in an embedded state. A cylindrical elastic member is provided, and the elastic member is connected by being placed over the end of the support and the end of the shaft. The elastic member can be a rubber or a coiled spring.

Also, as a mirror polishing method using the above polishing tool , the polishing tool is linked with the driving means, and the permanent magnet is disposed so as to face the object to be polished in a non-contact manner, and a magnetic polishing liquid is placed between the object to be polished. Abrasive grains are mixed in the magnetic polishing liquid, and the driving means is activated to cause the polishing tool to perform a predetermined motion, and the magnetic polishing liquid is constantly timed by the magnetic field of the permanent magnet. Alternatively, fluid polishing is performed by applying a variable magnetic field.

  The driving means has a multi-axis control function for at least the x-axis, y-axis, and z-axis, and when the driving means is activated, the polishing tool is caused to perform a three-dimensional movement motion. The three-dimensional movement operation of the polishing tool is an operation of sequentially raising the contour line for the polishing object, or an operation of scanning the projection surface all over the polishing object. Further, the polishing tool is caused to rotate in the forward and reverse directions in the axial direction, or to vibrate in a forward and reverse direction.

  Therefore, in the present invention, the polishing tool has a spherical or curved permanent magnet, which is caused to perform a predetermined motion by the driving means.

  There is a magnetic polishing liquid between the polishing tool and the object to be polished, and the magnetic polishing liquid contains abrasive grains. When a permanent or variable magnetic field is applied to the magnetic polishing liquid by a permanent magnet, a magnetic cluster is formed. Generate. That is, a large number of ferromagnetic particles (eg, iron particles) and magnetite particles in the magnetic polishing liquid are aggregated by the magnetic attractive force to form a magnetic class. Since the magnetic class is along the magnetic flux, a large number of needles are arranged in opposition to the object to be polished, so that the abrasive grains present in the magnetic polishing liquid are suppressed to the surface of the object to be polished. At this time, since the polishing tool and the object to be polished move relative to each other, the abrasive grains move and cut (grind) while contacting the surface of the object to be polished.

  By the way, in the magnetic polishing, even if the distance between the polishing tool and the object to be polished is constant, the magnetic flux distribution in the permanent magnet has a concentrated portion and a non-concentrated portion depending on the shape, resulting in a difference in the amount of grinding action. Occurs. The corner portion of the permanent magnet has a particularly high density of magnetic contour lines and a high magnetic flux density. Therefore, the amount of grinding action tends to change significantly, and unevenness tends to occur.

  However, in the present invention, since the permanent magnet of the polishing tool has a spherical shape or a curved shape, there are few places where the magnetization contour lines become overcrowded, and this is a magnetic flux generated by a cylindrical or prismatic permanent magnet having corners. Remarkably less than the distribution. For this reason, the grinding action by the abrasive grains can be made uniform regardless of the place.

  Further, by moving the polishing tool in a three-dimensional manner, the polishing tool can be moved in accordance with the uneven shape of the object to be polished, so that the entire surface can be properly polished.

  Further, when the second permanent magnet is disposed in the embedded state inside the support that supports the permanent magnet, the second permanent magnet is disposed at a predetermined position in contact with the permanent magnet. Correspondingly, the magnetization direction of the permanent magnet is automatically determined.

  Further, in the configuration in which the support supporting the permanent magnet is connected to the shaft portion with the flexible connecting means interposed, when an external force is applied to the tip portion, the tip side is swayed.

  In the polishing tool according to the present invention, since the permanent magnet of the magnetic field generation source has a spherical shape or a curved surface shape, there are few places where the magnetization contour lines become overcrowded, and therefore the grinding action by the abrasive grains is uniform regardless of the place. It can be made. Further, by moving the polishing tool in a three-dimensional manner, the polishing tool can be moved in accordance with the uneven shape of the object to be polished, so that the entire surface can be properly polished. As a result, even if the object to be polished is a complex shape having a large number of irregularities, the irregularities on the surface can be uniformly polished and finished to an appropriate mirror surface.

  Further, when the second permanent magnet is disposed in the embedded state inside the support that supports the permanent magnet, the second permanent magnet is disposed at a predetermined position in contact with the permanent magnet. Correspondingly, the magnetization direction of the permanent magnet is automatically determined. Therefore, when the permanent magnet is embedded in the end face of the support, adjustment of the alignment is not particularly necessary, and the direction of magnetization of the permanent magnet can be set correctly and positioning can be performed easily.

  In addition, in the configuration in which the support supporting the permanent magnet is connected to the shaft portion with a flexible connecting means interposed, when an external force is applied to the tip portion, the tip side is swayed. Can be prevented.

(Reference example)
FIG. 1 shows a reference example of the present invention. In this reference example , the polishing tool is provided with a permanent magnet 1 at its tip to serve as a magnetic field generation source. The polishing tool maintains a non-contact state with respect to the object to be polished, and fluid polishing is performed by interlocking with a magnetic polishing liquid existing in the periphery. It is the composition which performs.

  The permanent magnet 1 is formed in a spherical shape or a curved surface shape having an appropriate curved surface, embedded in the end surface of the cylindrical support body 2 so that substantially half is exposed, and the support body 2 is attached to the shaft portion 3. It is integrally connected to the tip.

  As shown in FIG. 2A, the permanent magnet 1 may have a magnetization direction that is substantially coincident with the rotation axis s of the polishing tool, and may have a relationship that is substantially parallel at the shift position. Further, as shown in FIG. 2B, the magnetization direction of the permanent magnet 1 is set to be inclined with respect to the rotation axis s of the polishing tool, and the inclination angle is a scissor angle of 90 degrees or less with respect to the rotation axis s. Also good. Furthermore, the permanent magnet 1 may have a multipolar magnetization configuration having a plurality of magnetization directions.

  The polishing tool is linked to driving means, and performs a predetermined motion by driving the driving means. That is, in the mirror polishing that finishes the surface of the polishing object into a mirror surface, the permanent magnet 1 is disposed so as to face the polishing object in a non-contact manner, and the magnetic polishing liquid is present between the polishing object and the magnetic polishing liquid. Is mixed with abrasive grains, and the driving means is started to cause the polishing tool to perform a predetermined motion, and a permanent or variable magnetic field is applied to the magnetic polishing liquid by the magnetic field of the permanent magnet 1 in time. Then, fluid polishing is performed with the magnetic clusters generated in the magnetic polishing liquid.

The magnetic polishing liquid contains nonmagnetic abrasive grains. Specifically, ferromagnetic particles having a particle diameter of 1 to 80 μm are dispersed in a dispersion medium such as water or kerosene having a kinematic viscosity of about 0.01 to 100 mm ² / s. A composite in which spherical magnetite particles having a particle diameter of 10 to 50 nm are mixed with 5 to 90 wt% of a fluid in which water is uniformly dispersed in a dispersion medium such as water or kerosene having electrical insulation properties with respect to 10 to 95 wt% of the dispersed fluid. Non-fluid abrasive grains having a particle diameter of 0.01 to 100 μm are mixed in the fluid, and a fibrous substance such as α-cellulose or a resin such as polyvinyl alcohol is mixed as a thickener in an amount of 5 to 90 wt%. This magnetic polishing liquid is supplied by a supply means between the object to be polished and the polishing tool. The shape of the permanent magnet 1 may be a curved body shape having an appropriate curved surface. For example, as shown in FIG. Further, since the exposed side only needs to have a curved body shape when embedded in the support body 2, as shown in FIG.

  The driving means is assumed to have a multi-axis control function for at least the x-axis, y-axis, and z-axis, and when the driving means is activated, the polishing tool is caused to perform a three-dimensional movement motion. As the driving means, for example, an NC machine tool may be used, and the grinding tool shaft 3 is attached to a rotating shaft (chuck part) of a drilling machine, a lathe, an NC lathe, a milling machine, etc., and is attached or detached.

  The three-dimensional movement operation of the polishing tool is an operation in which the contour lines of the polishing object 4 are sequentially raised as shown in FIGS. 4 (a) and 4 (b), for example. Alternatively, as shown in FIGS. 5A and 5B, the projection surface of the object to be polished 4 is scanned all over. At this time, the magnetic polishing liquid 5 is supplied to the periphery of the polishing tool, and the polishing tool is caused to rotate in the forward and reverse directions in the axial direction, or to be vibrated to move forward and backward.

  NC (Numerical Control) is effective for three-dimensional operation control of the polishing tool. If there is three-dimensional shape data (eg IGES file) to be polished, general-purpose CAD / CAM software can be used. It is converted into an NC code offset by a distance. An NC machine tool is operated from the created NC program, and magnetic polishing is performed using a polishing tool.

  As described above, in the present invention, the polishing tool is provided with the spherical or curved permanent magnet 1, and a predetermined moving operation is performed by the driving means.

  A magnetic polishing liquid 5 exists between the polishing tool and the object 4 to be polished, and the magnetic polishing liquid 5 contains nonmagnetic abrasive grains. The permanent magnet 1 makes the magnetic polishing liquid constant or variable in time. When a magnetic field is applied, a magnetic cluster is generated. That is, a large number of ferromagnetic particles (eg, iron particles) and magnetite particles in the magnetic polishing liquid are aggregated by the magnetic attractive force to form a magnetic class. Since the magnetic class is along the magnetic flux, a large number of needles are arranged in opposition to the object 4 to be polished, so that the abrasive grains present in the magnetic polishing liquid are suppressed on the surface of the object 4 to be polished. At this time, since the polishing tool and the object 4 to be polished move relative to each other, the abrasive grains move and cut (grind) while contacting the surface of the object 4 to be polished.

  By the way, in the magnetic polishing, even if the distance between the polishing tool and the object to be polished 4 is constant, the magnetic flux distribution in the permanent magnet 1 has a concentrated portion and a non-concentrated portion depending on the shape. There will be a difference. The corner portion of the permanent magnet 1 has a particularly high density of magnetic contour lines and a high magnetic flux density. Therefore, the amount of grinding action tends to change significantly, and unevenness tends to occur. This has been confirmed by model analysis. FIG. 6 shows an analysis model for the permanent magnet of the polishing tool, (a) is an explanatory diagram showing details of the spherical shape model, and (b) shows details of the cylindrical shape model. It is explanatory drawing shown. When the analysis is performed under the conditions shown in the figure, in the spherical shape model, the magnetic flux distribution is uniform as shown in FIG. 7, whereas in the cylindrical shape model, the magnetic flux is concentrated at the corners as shown in FIG. It was confirmed that is seen.

  In the present invention, since the permanent magnet 1 of the polishing tool has a spherical shape or a curved surface shape, there are few places where the magnetization contour lines become overcrowded, and this is a magnetic flux generated by a cylindrical or prismatic permanent magnet having corners. Remarkably less than the distribution. For this reason, the grinding action by the abrasive grains can be made uniform regardless of the place. Further, by moving the polishing tool in a three-dimensional manner, the polishing tool can be moved in accordance with the concavo-convex shape of the object 4 to be polished, so that the entire surface can be properly polished. As a result, even if the object to be polished is a complex shape having a large number of irregularities, the irregularities on the surface can be uniformly polished and finished to an appropriate mirror surface. Of course, since the polishing is performed by the magnetic cluster, the polishing can be performed without applying a large stress to the polishing object 4.

( First embodiment)
9 (a) and 9 (b) show a first embodiment of the present invention. In this embodiment, the polishing tool has a configuration in which the permanent magnet 1 is provided at the tip as the magnetic field generation source in the same manner as in the above reference example, but the second permanent magnet is provided inside the support 2 that supports the permanent magnet 1. 6 is arranged in an embedded state, and the second permanent magnet 6 is arranged at a predetermined position in contact with the permanent magnet 1.

  In this case, since the second permanent magnet 6 is disposed at a predetermined position in contact with the permanent magnet 1, the magnetization direction of the permanent magnet 1 is determined corresponding to the position where the second permanent magnet 6 is embedded. That is, when the embedding of the second permanent magnet 6 is concentric with the rotation axis s as shown in FIG. 9A, the magnetization direction of the permanent magnet 1 can be set to a relationship that is substantially coincident with the rotation axis s. Further, as shown in FIG. 9B, when the embedding of the second permanent magnet 6 is inclined with respect to the rotation axis s, the magnetization direction of the permanent magnet 1 becomes a predetermined inclination angle with respect to the rotation axis s. Can be set to relationship.

  By the way, since the permanent magnet 1 has a spherical shape or a curved surface shape, when the permanent magnet 1 is embedded in the end surface of the support 2, it is necessary to correctly adjust the magnetization direction to the design specification. For this, a method of adjusting the attitude (position) of the permanent magnet 1 by measuring a magnetic field using a measuring instrument, or the attitude of the permanent magnet 1 by facing a predetermined permanent magnet prepared as a jig (position). In any case, adjustment of the direction of magnetization takes some effort, such as adopting an adjustment method.

  Therefore, in this embodiment, since the second permanent magnet 6 is disposed at a predetermined position in contact with the permanent magnet 1, the magnetization direction of the permanent magnet 1 can be adjusted. The embedding position of the second permanent magnet 6 is determined in advance for the support 2 according to the design specifications. Therefore, when the permanent magnet 1 is embedded in the end surface of the support 2, the alignment adjustment is performed. There is no particular need, and it is automatically determined according to the embedded position of the second permanent magnet 6. That is, since the second permanent magnet 6 is attached, the magnetization direction of the permanent magnet 1 can be set correctly and positioning can be performed easily.

( Second Embodiment)
10 to 12 show a second embodiment of the present invention. In this embodiment, the polishing tool has a configuration in which the permanent magnet 1 is provided at the tip to serve as a magnetic field generation source. However, the support 2 supporting the permanent magnet 1 is allowed to swing in the lateral direction with respect to the shaft portion 3. The flexible connecting means is used for connection.

  As the flexible connecting means, as shown in FIGS. 10A and 10B, permanent magnets 7 and 7 are embedded in the end portion of the support 2 and the end portion of the shaft portion 3, respectively. It is possible to adopt a configuration in which connection is made by a simple suction force. The permanent magnet 7 is preferably formed from neodymium or the like.

  Further, as shown in FIGS. 11A and 11B, the flexible connecting means includes a rod-like elastic member 8, and the elastic member 8 is attached to the end of the support 2 and the end of the shaft portion 3. It is good also as a structure connected by passing to an embedding state. Alternatively, as shown in FIGS. 12A and 12B, a cylindrical elastic member 9 is provided, and the elastic member 9 is connected to the end portion of the support 2 and the end portion of the shaft portion 3. It can also be configured. The elastic members 8 and 9 are preferably formed of, for example, rubber or a coil spring.

  By the way, since this polishing tool is used for fluid polishing, an external force should not basically act on the tip portion or the like. However, in actuality, the tip part may come into contact with the object to be polished 4 due to some chance during fluid polishing, and damage may occur when an external force acts on the tip part.

  Therefore, in the present embodiment, the support body 2 and the shaft portion 3 are connected by interposing a flexible connecting means. Therefore, when an external force is applied to the tip portion, FIG. 10 (b) and FIG. 11 (b) ), As shown in FIG. 12 (b), the tip end side thereof moves and can be prevented from being damaged.

  As shown in FIGS. 10A and 10B, in the configuration in which the two permanent magnets 7 are flexible connection means, when an external force is applied to the tip portion, the support 2 is separated from the shaft portion 3. However, since neither the support body 2 nor the shaft portion 3 is damaged, the support body 2 may be reconnected to the shaft portion 3 as it is. In the case of the configuration in which the two permanent magnets 7 are flexible connection means, the support 2 can be easily attached to and detached from the shaft portion 3. For example, as the tip bit, a plurality of shapes and magnetization directions of the permanent magnet 1 are different. The support 2 is prepared, and the support 2 (tip bit) can be subjected to magnetic polishing such that it can be easily replaced with one touch according to the demand of the polishing process.

  As shown in FIGS. 11 and 12, in the configuration in which the elastic members 8 and 9 are flexible connection means, the elastic members 8 and 9 are bent and deformed when an external force is applied to the distal end portion, so that each part can be prevented from being damaged. As the external force disappears and the deformation is restored, the polishing tool can be automatically used as it is.

The sample was polished using the polishing tool shown in FIG. That is, in order to verify the effect of the present invention, the sample was polished under the predetermined polishing conditions shown in Table 1, and the surface roughness of the sample was evaluated.

  The polishing tool according to the present invention is attached to a chuck portion of a three-axis polishing apparatus capable of performing simultaneous three-axis automatic control, and a magnetic polishing liquid (or magnetic polishing paste) is acclimated to the polishing tool, and the magnetic polishing liquid is centrifuged. Polishing was performed while maintaining a state in which the polishing tool was offset by a certain distance (about 1 mm) from the sample, with the setting of rotating at a rotational speed (500 rpm) that was not scattered by force. The movement operation of the polishing tool was an operation of scanning the projection surface throughout the sample. As a result, it was confirmed that even a sample having many irregularities could be polished uniformly and an appropriate mirror surface could be obtained.

It is a side view which shows the reference example of the grinding | polishing tool based on this invention. It is a side view explaining the permanent magnet of the grinding tool, and shows two examples in which the direction of magnetization is substantially coincident with the rotation axis (a) and tilt (b). It is a side view which shows the grinding | polishing bite by other examples (a) and (b) of a permanent magnet. It is side view (a) and top view (b) explanatory drawing which show an example of the movement operation | movement of a grinding | polishing tool. It is side view (a) and top view (b) explanatory drawing which show the other example of the movement operation | movement of a grinding | polishing tool. An analysis model is shown about the permanent magnet of a grinding tool, (a) is an explanatory view showing details of a spherical shape model, and (b) is an explanatory view showing details of a cylindrical shape model. It is a graph of magnetic flux distribution showing the analysis result of the sphere shape model. It is a graph of magnetic flux distribution showing an analysis result of a cylindrical shape model. It is a side view which shows 1st Embodiment of the grinding | polishing byte | cutting_tool based on this invention, and has shown two examples with the direction of magnetization being substantially the same (a) and inclination (b) with a rotating shaft. It is a side view which shows 2nd Embodiment of the grinding | polishing bite which concerns on this invention, and is the operation | movement (b) at the time of the 1st example (a) of a flexible connection means, and the effect | action of external force. It is a side view which shows 2nd Embodiment of the grinding | polishing tool | tool according to this invention, and is the operation | movement (b) at the time of the 2nd example (a) of a flexible connection means, and the effect | action of external force. It is a side view which shows 2nd Embodiment of the grinding | polishing cutting tool which concerns on this invention, and is the operation | movement (b) at the time of the action of the 3rd example (a) of a flexible connection means, and an external force.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,7 Permanent magnet 2 Support body 3 Shaft part 4 Polishing object 5 Magnetic polishing liquid 6 2nd permanent magnet 8, 9 Elastic member s Rotating shaft

Claims (8)

A polishing tool that maintains a non-contact state with respect to the object to be polished and performs fluid polishing by interlocking with a magnetic polishing liquid existing in the periphery,
The polishing tool is provided with a permanent magnet as a magnetic field generation source, and the shape of the permanent magnet is a spherical shape or a curved body shape having an appropriate curved surface ,
A polishing tool , wherein a second permanent magnet is disposed in an embedded state within a support that supports the permanent magnet, and the second permanent magnet is disposed at a predetermined position in contact with the permanent magnet .   The polishing tool according to claim 1, wherein the permanent magnet has a magnetization direction substantially coincident or substantially parallel to a rotation axis of the polishing tool.   2. The permanent magnet according to claim 1, wherein the direction of magnetization of the permanent magnet is set to be inclined with respect to the rotation axis of the polishing tool, and the inclination angle is a scissor angle of 90 degrees or less with respect to the rotation axis. Polishing tool.   2. The polishing tool according to claim 1, wherein the permanent magnet has a multipolar magnetization configuration having a plurality of magnetization directions. The support that supports the permanent magnet is connected via a flexible connecting means that allows lateral movement of the shaft of the polishing tool,
The flexible connecting means is configured such that a permanent magnet is embedded in an end portion of the support and an end portion of the shaft portion, and the both are connected by a magnetic attraction force of both. The polishing bit according to any one of 1 to 4. The support that supports the permanent magnet is connected via a flexible connecting means that allows lateral movement of the shaft of the polishing tool,
The flexible connecting means includes a rod-like elastic member, and the elastic member is connected to the end portion of the support body and the end portion of the shaft portion by being embedded in an embedded state. Item 5. A polishing tool according to any one of Items 1 to 4. The support that supports the permanent magnet is connected via a flexible connecting means that allows lateral movement of the shaft of the polishing tool,
The said flexible connection means has a cylindrical elastic member, It is the structure connected by covering the said elastic member to the edge part of the said support body, and the edge part of the said shaft part, It is characterized by the above-mentioned. The polishing bit according to any one of 1 to 4.   8. The polishing tool according to claim 6, wherein the elastic member is rubber or a coiled spring.

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