JP2008264920A - Grinding tool, magnetic grinding method, and magnetic grinding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic grinding technique grinding in a narrow range regardless of a size and the like of a magnetic force generating member constituting a grinding tool. <P>SOLUTION: In this grinding tool, a permanent magnet 4 is held by a concave-shaped holding part 3b on a bottom end of a tool shaft 3a. A cap 5 made of non-magnetic silicone rubber and the like with an opening 5a of a diameter D0 bored on a bottom end is attached, and a magnetic fluid M is selectively adsorbed to a portion of the permanent magnet 4 exposed from the opening 5a. A contact range of a workpiece W and the magnetic fluid M is thereby limited to a range of a narrow diameter D1(≤D0) regardless of the size and the like of the permanent magnet 4, so as to grind the workpiece W in a narrow range, such as to correct a shape. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polishing technique, for example, to a polishing technique for polishing a workpiece such as a micro-shaped optical element and an optical element molding die with high accuracy.

  For example, in the field of manufacturing and manufacturing precision products represented by optical elements and the like, a micro-region polishing apparatus using a magnetic fluid as disclosed in Patent Document 1 is used as a finishing process.

  That is, in the case of the polishing apparatus of Patent Document 1, a magnetic sphere magnetized by the permanent magnet is held at the tip of the polishing shaft where the permanent magnet is arranged so as to be able to roll. Polishing is performed by magnetically attracting and holding a fluid abrasive and interposing it between the surface to be polished.

  And in this grinding | polishing apparatus of this patent document, since the magnetic sphere was arrange | positioned so that rolling with respect to a grinding | polishing axis | shaft was carried out, the abrasion of the said magnetic sphere during grinding | polishing processing became uniform by rolling, and high processing The accuracy can be maintained.

  However, in the case of the polishing apparatus disclosed in Patent Document 1, the magnetic fluid abrasive is attached to the entire surface of the magnetic sphere having a magnetic force as described above (see FIG. 2 of Patent Document 1). The contact area between the ferrofluid polishing material and the surface to be polished increases according to the size of the surface, and, for example, when the shape of a specific region of the surface to be polished is corrected, a fine polishing process in a narrow range cannot be performed. There are challenges.

  In addition, the magnetic sphere in Patent Document 1 is made of a high hardness material such as bearing steel (SUJ2) and is only covered with a fluid magnetic fluid abrasive during processing, so that it always has a high hardness. There is also a technical problem that the magnetic sphere may directly contact the surface to be polished, and the surface to be polished may be damaged by contact with the magnetic sphere having high hardness.

Such a contact between the surface to be polished and the magnetic sphere during the polishing process may lead to a fatal product defect in a precision product requiring high accuracy.
JP-A-5-162064

An object of the present invention is to provide a magnetic polishing technique capable of performing polishing in a narrow range regardless of the size or the like of a magnetic force generating member constituting the polishing tool.
Another object of the present invention is to provide a magnetic polishing technique that can reliably prevent the workpiece from being damaged by the contact between the polishing tool and the workpiece.

A first aspect of the present invention is a polishing tool for performing a polishing process by holding a magnetic fluid at a tip portion by a magnetic force,
A magnetic force generating member for holding the magnetic fluid;
There is provided a polishing tool including an opening formed in a region covering the magnetic force generating member and a covering member made of a nonmagnetic material.

According to a second aspect of the present invention, in the polishing tool according to the first aspect,
The covering member provides a polishing tool which is a cap made of a non-magnetic material softer than a workpiece and detachably attached to the magnetic force generating member.

According to a third aspect of the present invention, in the polishing tool according to the second aspect,
The cap provides a polishing tool made of resins or rubbers.
A fourth aspect of the present invention is a magnetic polishing method for processing a workpiece via a magnetic fluid held by a polishing tool,
A magnetic polishing method is provided which covers the polishing tool with a covering member made of a non-magnetic material and having an opening.

According to a fifth aspect of the present invention, in the magnetic polishing method according to the fourth aspect,
The covering member is a cap made of a non-magnetic material softer than the workpiece and is a cap that is detachably attached to the polishing tool.

According to a sixth aspect of the present invention, in the magnetic polishing method according to the fifth aspect,
The cap provides a magnetic polishing method made of resins or rubbers.
A seventh aspect of the present invention is a polishing tool for holding a magnetic fluid;
A displacement control means for controlling a relative displacement of the polishing tool with respect to a workpiece;
A covering member made of a non-magnetic material and having an opening formed in a region covering the polishing tool;
A magnetic polishing apparatus is provided.

According to an eighth aspect of the present invention, in the magnetic polishing apparatus according to the seventh aspect,
The covering member is a cap made of a non-magnetic material softer than the workpiece, and is a cap that is detachably attached to the polishing tool.

According to a ninth aspect of the present invention, in the magnetic polishing apparatus according to the eighth aspect,
The cap provides a magnetic polishing apparatus made of resins or rubbers.
That is, in the present invention, as an example, an opening is formed so that the magnetic fluid adheres to a part of the tip of the polishing tool, and a covering member such as a non-magnetic cap that covers a portion where the magnetic fluid is not desired to be attached is mounted. To do.

In this case, the non-magnetic covering member can be manufactured using, for example, a material having high elasticity such as resins and rubbers.
According to the present invention, since the portion other than the opening portion where the magnetic fluid is not desired to be adhered is covered with the non-magnetic covering member, the magnetic force is blocked and the magnetic fluid does not adhere. Therefore, the magnetic fluid adheres to only a part necessary for processing through the opening of the covering member, and it depends on the size and shape of the opening of the covering member regardless of the shape and size of the magnetic force generating member. A processing region of an arbitrary shape within a narrow range can be set.

  Further, when the covering member is made of resin or rubber, since the resin or rubber is elastic, it is possible to prevent the workpiece from being damaged even when the polishing tool comes into contact with the workpiece. .

ADVANTAGE OF THE INVENTION According to this invention, the magnetic polishing technique which can grind | polish in a narrow range irrespective of the size of the magnetic force generation member which comprises a grinding | polishing tool, etc. can be provided.
In addition, it is possible to provide a magnetic polishing technique that can reliably prevent the workpiece from being damaged by the contact between the polishing tool and the workpiece.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(Embodiment 1)
FIG. 1 is a side view showing an example of the configuration of a magnetic polishing apparatus for performing a magnetic polishing method according to an embodiment of the present invention, and FIG. 2 is a portion of a polishing tool in the magnetic polishing apparatus of the present embodiment. It is sectional drawing which expanded and illustrated.

First, the configuration of the magnetic polishing apparatus 20 according to the first embodiment will be described with reference to FIG. 1 and FIG.
A tool spindle 2 (displacement control means) is attached to the tool table 1 and can be rotated by a spindle motor (not shown) provided inside the tool spindle 2. The tool shaft 3a is detachably chucked on the tool spindle 2, and rotates in conjunction with the rotation of the spindle motor.

A concave holding portion 3b is provided at the tip of the tool shaft 3a. A spherical permanent magnet 4 (magnetic force generating member) is held by the holding portion 3b by a magnetic force to constitute the polishing tool 3. .
In the case of the first embodiment, as illustrated in FIG. 2, in the polishing tool 3, for example, a cap 5 (covering member) made of a non-magnetic silicone rubber is provided on the polishing portion to which the permanent magnet 4 is attached. ) Is attached. An opening 5a having a diameter D0 (for example, 1 mm in this case) for adhering the magnetic fluid M is provided at the center of the cap 5. The thickness of the cap 5 is set to a thickness sufficient to shield the magnetic force of the permanent magnet 4.

As a result, the magnetic fluid M selectively adheres to a narrow region of the permanent magnet 4 exposed from the opening 5a of the nonmagnetic cap 5.
Note that the diameter D0 of the opening 5a can be set to a fine value of 1 mm or less by, for example, drilling with a small diameter drill or laser.

  Further, the shape of the opening 5a is not limited to a circle, and can be set to any shape such as a polygon, a star, an ellipse, a slit, etc., and the magnetic fluid M can be attached to any shape accordingly. Can be set.

The tool table 1 is attached to a slide plate 8 (displacement control means), and the slide plate 8 moves along the guide 9 of the stand 7 in the Z-axis direction.
A work table 21 (displacement control means) is located below the tool table 1, and the work table 21 can be moved in the X-axis and Z-axis directions by a stepping motor (not shown). Further, another motor (not shown) can swing in the B-axis direction around the axial direction (in this case, the vertical direction) of the tool shaft 3a.

  A workpiece W (workpiece) can be detachably mounted on the workpiece table 21, and the workpiece W can be fixed by a fixing screw 22. Below the work table 21, a work spindle (not shown) and a motor (not shown) for rotating the work spindle are attached, whereby the work W can be rotated.

Hereinafter, an example of the operation of the first embodiment will be described. A polishing method by the magnetic polishing apparatus 20 of the first embodiment having the above-described configuration will be described with reference to FIGS.
As illustrated in FIG. 1, first, the work W is placed on the work table 21. Next, when the workpiece W is rotated, the workpiece W is fixed while adjusting the placement position so that the machining surface of the workpiece W is not shaken.

  The tool shaft 3a is made of a magnetic material, and is molded into the R-shaped holding portion 3b so that the spherical permanent magnet 4 can be held at the tip as described above. A spherical permanent magnet 4 is attached to the tip of the tool shaft 3a by a magnetic force, and a cap 5 made of silicone rubber having an opening 5a having a diameter D1 (in this case, for example, 1 mm) at the center is covered. Thus, the polishing tool 3 is configured. The polishing tool 3 is attached to the tool spindle 2 via a tool shaft 3a.

  Next, the magnetic fluid M is supplied to the processing portion at the tip of the polishing tool 3. In the case of the present embodiment, the magnetic fluid M adheres only to the opening 5a portion of the cap 5 in the polishing tool 3 by magnetic force. Further, the magnetic fluid M is also supplied to the workpiece W, and is appropriately supplied during processing.

Subsequently, the tool spindle 2 is rotated by the spindle motor, and the polishing tool 3 is rotated. Further, the work spindle is rotated by the work shaft motor to rotate the work W.
In the processing operation of the workpiece W, the workpiece table 21 is moved so that the polishing tool 3 is positioned above the processing start position of the end surface of the workpiece W. Then, the work table 21 is lowered to a position where the distance h between the work W and the tip of the polishing tool 3 is 1 mm, for example, and the magnetic fluid M is held by the magnetic force between the polishing tool 3 and the work surface of the work W. And start processing.

  At this time, as illustrated in FIG. 2, the size of the contact area of the magnetic fluid M contacting the surface of the workpiece W is, for example, parameters such as the diameter D0 of the opening 5a of the cap 5 and the surface tension of the magnetic fluid M. The diameter D1 (≦ D0).

  During the processing, the distance h between the tip of the polishing tool 3 and the workpiece W is controlled so as to be always constant. Further, the polishing is performed while maintaining the posture so that the tool shaft 3a always acts in the vertical direction with respect to the tangent of the processing point on the surface of the workpiece W.

  For example, when performing polishing to remove the grind existing on the surface of the workpiece W, polishing is started from the end surface of the workpiece W, and the polishing tool 3 passes through the center of the workpiece W to the end surface of the other workpiece W. By scanning, the entire surface of the workpiece W is polished. This operation is set as one cycle, and is repeated until a desired mirror surface shape is obtained on the surface of the workpiece W.

  On the other hand, when correcting the shape of the workpiece W, the polishing tool 3 is retained only in the convex portion that is desired to be removed by polishing in order to obtain a smooth surface from the cross-sectional shape of the workpiece W. This is repeated until a desired shape is obtained on the workpiece W.

  According to the first embodiment, the opening portion of the polishing tool 3 is covered with the silicone rubber cap 5 made of a non-magnetic material, so that the opening portion can be opened regardless of the size of the permanent magnet 4. Since the magnetic fluid M can be attached only to the part necessary for polishing corresponding to the opening area 5a, polishing can be performed in a minute range of the workpiece W (in this case, the area of the diameter D1).

In other words, fine polishing in which the adhesion range of the magnetic fluid M to the workpiece W is limited to a minute region without difficulty such as miniaturization of the size of the permanent magnet 4 becomes possible.
In particular, when the shape correction is performed, it is necessary to partially polish the workpiece W, so that the effect of polishing a minute range such as the diameter D1 (≦ D0) of the workpiece W is great.

Further, since the cap 5 is made of silicone rubber which is an elastic body having a hardness much lower than that of the workpiece W, even if the polishing tool 3 accidentally contacts the workpiece W during processing, the soft cap 5 is interposed between the two. Therefore, the work W can be prevented from being damaged.
(Embodiment 2)
A second embodiment of the present invention will be described with reference to FIG. FIG. 3 is an enlarged cross-sectional view illustrating a schematic configuration of a polishing tool according to Embodiment 2 of the present invention.

Since the configuration of the magnetic polishing apparatus 20 of the second embodiment is the same as that of the first embodiment except for the portion of the polishing tool 3-1, detailed description thereof is omitted.
The polishing tool 3-1 used in the magnetic polishing apparatus 20 of the second embodiment will be described with reference to FIG. The tool shaft 3a is made of stainless steel having magnetism, and the tip thereof is rounded into a concave shape so that the spherical permanent magnet 4 can be held, thereby forming a holding portion 3b. The spherical permanent magnet 4 is held by the magnetic force in the holding portion 3b at the tip.

  In the second embodiment, a cap 6 (covering member) made of a non-magnetic material such as rubber much softer than the workpiece W is attached to the polishing portion to which the permanent magnet 4 at the tip of the tool shaft 3a is attached. Thus, the polishing tool 3-1 is configured.

  In the case of this Embodiment 2, the grinding | polishing object area | region of the workpiece | work W is exhibiting concave shape. And the cap 6 is processed into the R shape at the tip so that it does not interfere with the surface of the workpiece W to be processed during processing, so that the spherical portion 6b is formed.

Further, an opening 6a having a diameter D0 (in this case, for example, 2 mm) for attaching the magnetic fluid M is provided at the center of the lower surface of the cap 6.
A polishing method by the magnetic polishing apparatus 20 of the second embodiment provided with the polishing tool 3-1 having the above-described configuration will be described with reference to FIGS. 1 and 3.

  As illustrated in FIG. 1, first, the work W is mounted on the work table 21. Next, when the workpiece W is rotated, the workpiece W is fixed while being adjusted by the fixing screw 22 so that the machining surface of the workpiece W is not shaken. The polishing tool 3-1 attaches a spherical permanent magnet 4 to the holding portion 3 b at the tip of the tool shaft 3 a by a magnetic force, and the permanent magnet 4 disposed at the tip of the tool shaft 3 a as described above includes Then, a cap 6 made of rubber or the like having an opening 6a having a diameter D0 (for example, 2 mm) is attached to the center portion to constitute the polishing tool 3-1. In this way, the tool shaft 3a on which the polishing tool 3-1 is mounted is attached to the tool spindle 2.

  Next, the magnetic fluid M is supplied to the processing portion at the tip of the polishing tool 3-1. The magnetic fluid M adheres by magnetic force only to the open portion of the central opening 6a of the cap 6 of the polishing tool 3-1. Further, the magnetic fluid M is also supplied to the workpiece W and is appropriately supplied during processing. Thereby, the diameter D1 of the magnetic fluid M which contacts the workpiece | work W is controlled so that it may become smaller than the diameter D0 of the opening part 6a, for example.

  Subsequently, the tool spindle 2 is rotated by the spindle motor, and the polishing tool 3-1 supported by the tool shaft 3a is rotated. Further, the work spindle is rotated by the work shaft motor to rotate the work W.

  In the processing operation of the workpiece W, the work table 21 is moved so that the polishing tool 3-1 is positioned above the processing start position of the end surface of the workpiece W. Then, the work table 21 is lowered to a position where the distance h between the work W and the tip of the polishing tool 3-1 is, for example, 0.5 mm, and the magnetic fluid M is interposed between the polishing tool 3-1 and the work surface of the work W. Is started by the magnetic force, for example, in a state of being held in the contact area of the diameter D1. During processing, the distance between the tip of the polishing tool 3-1 and the workpiece W is controlled to be always constant. Further, the polishing is performed while maintaining the posture so that the tool shaft 3a always acts in the vertical direction with respect to the tangent of the processing point on the surface of the workpiece W.

  For example, when performing polishing to remove “grind” existing on the surface of the workpiece W, polishing is started from the end surface of the workpiece W, passes through the center of the workpiece W, and reaches the end surface of the other workpiece W. The entire surface is polished by scanning 3-1. This operation is set as one cycle and is repeated until a desired mirror surface shape is obtained.

  On the other hand, when correcting the shape, control is performed so that the polishing tool 3-1 stays only on the convex portion unnecessary for making the surface smooth from the cross-sectional shape of the workpiece W. This is repeated until a desired shape is obtained on the workpiece W.

  According to the second embodiment, the same effect as in the first embodiment can be obtained, and the tip of the rubber cap 6 attached to the tip of the polishing tool 3-1 can be used as a sphere such as the spherical portion 6 b. By making the shape, even when a concave region of the workpiece W is polished, the polishing tool 3-1 and the workpiece W can be processed without interference.

  As described above, according to the magnetic polishing technique of each embodiment of the present invention, a portion unnecessary for processing of the tip of the polishing tool is covered with a nonmagnetic cap (covering member), so that a part of the polishing tool is formed. Since only the magnetic fluid can be adhered, the polishing process can be performed in a narrow range of the work regardless of the size of the polishing tool.

  Further, by using a soft material such as resin or rubber as a non-magnetic cap that covers the tip of the polishing tool, damage when the polishing tool mistakenly contacts the workpiece can be reliably prevented.

Needless to say, the present invention is not limited to the configuration exemplified in the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the number of openings 5a in the cap 5 and the number of openings 6a in the cap 6 is not limited to one, and a plurality of openings may be opened.

  Further, in each of the above-described embodiments, the opening 5a in the cap 5 and the opening 6a in the cap 6 are shown as being formed through, but the meat of the opening 5a and the opening 6a is not shown. The thickness may be selectively reduced (non-penetrating) so that the magnetic force in the opening 5a and the opening 6a is larger than the surrounding area.

  Moreover, you may use magnetic force generation members, such as the permanent magnet 4 with which the perimeter was covered with the coating | coated member which consists of a nonmagnetic material in which the opening part was formed. However, in this case, since it is difficult to install a magnetic force generating member by the magnetic force on the tool shaft side, methods such as vacuum suction, adhesion, and screwing are used.

  Further, as the magnetic force generating member, an electromagnet magnetic core may be used instead of the permanent magnet 4.

It is a side view which shows an example of a structure of the magnetic polishing apparatus which enforces the magnetic polishing method which is one embodiment of this invention. It is sectional drawing which expanded and illustrated the part of the polishing tool in the magnetic polishing apparatus which is one embodiment of this invention. It is sectional drawing which expanded and illustrated the structure of the grinding | polishing tool in the magnetic polishing apparatus concerning other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tool table 2 Tool spindle 3 Polishing tool 3-1 Polishing tool 3a Tool shaft 3b Holding part 4 Permanent magnet 5 Cap 5a Opening part 6 Cap 6a Opening part 6b Spherical part 7 Stand 8 Slide plate 9 Guide 20 Magnetic polishing apparatus 21 Work table 22 Fixing screw D0 Diameter D1 Diameter M Magnetic fluid W Work h Distance

Claims (9)

A polishing tool for holding a magnetic fluid at the tip by a magnetic force to perform polishing,
A magnetic force generating member for holding the magnetic fluid;
A polishing tool comprising: a covering member having an opening formed in a region covering the magnetic force generating member and made of a non-magnetic material. The polishing tool according to claim 1, wherein
The polishing tool according to claim 1, wherein the covering member is a cap made of a non-magnetic material softer than a workpiece and detachably attached to the magnetic force generating member. The polishing tool according to claim 2, wherein
The said cap consists of resin or rubbers, The polishing tool characterized by the above-mentioned. A magnetic polishing method for processing a workpiece via a magnetic fluid held by a polishing tool,
A magnetic polishing method comprising covering the polishing tool with a covering member made of a non-magnetic material and having an opening. The magnetic polishing method according to claim 4, wherein
The magnetic polishing method according to claim 1, wherein the covering member is a cap made of a non-magnetic material softer than the workpiece and detachably attached to the polishing tool. The magnetic polishing method according to claim 5, wherein
The magnetic polishing method, wherein the cap is made of a resin or a rubber. A polishing tool for holding magnetic fluid;
A displacement control means for controlling a relative displacement of the polishing tool with respect to a workpiece;
A covering member made of a non-magnetic material and having an opening formed in a region covering the polishing tool;
A magnetic polishing apparatus comprising: The magnetic polishing apparatus according to claim 7, wherein
The magnetic polishing apparatus, wherein the covering member is a cap made of a non-magnetic material softer than the workpiece and detachably attached to the polishing tool. The magnetic polishing apparatus according to claim 8, wherein
The cap is made of resins or rubbers.

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