JP2016137553A - Polishing apparatus and polishing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new polishing apparatus capable of easily and inexpensively polishing a polishing object composed of a non-magnetic material without much restrictions.SOLUTION: The polishing apparatus comprises s polishing tool 10 and a polishing agent 20 applied onto the polishing tool 10. The polishing agent 20 includes: a plurality of spheres 21 composed of a magnetic material; a liquid binder 22 adhering like a film to the surface of each of the plurality of spheres 21; and a plurality of abrasive grains 23 comprising non-magnetic materials retained by the liquid binder 22 while dispersed on the surface of each of the spheres 21. In the vicinity of the surface of the polishing tool 10, a magnetic field is created by formation of a pair of magnetic poles in the polishing tool in such a way that the magnetic poles go out from a part of the surface of the polishing tool 10 and returns to the other part of the surface of the polishing tool 10, and a magnetic cluster is formed in the polishing agent 20 by magnetic attraction of the plurality of spheres 21 to the polishing tool 10. Even when in polishing work, such a state that the magnetic cluster is formed by the magnetic field only is maintained.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a polishing apparatus and a polishing method for polishing a polishing object made of a nonmagnetic material.

  Conventionally, various polishing methods are used for surface finishing of various products as polishing objects. Among these, it is preferable when the polishing object has a relatively complicated surface shape (for example, when the polishing object includes a curved surface with a substantially constant curvature or some uneven surface). As a polishing method that can be used, a magnetic polishing method is known.

  In the magnetic polishing method, a magnet is disposed around the processing portion of a polishing apparatus, magnetic abrasive grains are used as abrasive grains contained in the polishing agent, and polishing is performed by pressing the magnetic abrasive grains against an object to be polished using a magnetic force. To do. In the magnetic polishing method, the magnetic abrasive grains are arranged along the magnetic field lines to form an aggregate of brush-like magnetic abrasive grains (generally referred to as a particle brush) at the tip of the polishing tool. The surface of a relatively complicated shape can be polished by pressing the magnetic abrasive grains substantially uniformly against the object by a magnetic force.

  Here, when a polishing object made of a magnetic material is polished using the magnetic polishing method, a corresponding pair of magnetic poles are formed between the polishing object and a magnet installed in the polishing apparatus. Thus, a magnetic field is generated, and the above-described particle brush is formed by the magnetic field so that polishing is performed.

  On the other hand, when a polishing object made of a non-magnetic material is polished using the magnetic polishing method, a magnetic field needs to be generated so as to pass through the polishing object, and the polishing apparatus is sandwiched between the polishing objects. A pair of magnets are installed, and a corresponding pair of magnetic poles are formed between the pair of magnets so that a magnetic field is generated, and the above-described particle brush is formed by the magnetic field so that polishing is performed. To do.

  References that specifically disclose this magnetic polishing method include, for example, Japanese Patent Application Laid-Open No. 2002-265933 (Patent Document 1), Japanese Patent Application Laid-Open No. 5-1111821 (Patent Document 2), and Japanese Patent Application Laid-Open No. 2010-52123. There exists a gazette (patent document 3) etc.

  Among these, Patent Documents 2 and 3 disclose a magnetic polishing method in which a plurality of spheres made of a magnetic material are added to an abrasive containing magnetic abrasive grains, and polishing is performed using the abrasive containing the sphere. ing. In the magnetic polishing methods disclosed in Patent Documents 2 and 3, it is possible to prevent the magnetic force acting on the magnetic abrasive grains from being weakened by a nonmagnetic material such as lubricating oil contained in the abrasive. A decrease in the pressing force against the object to be polished can be suppressed.

  Further, although different from the above-described magnetic polishing method in that magnetic abrasive grains are not used, a polishing method using magnetic force is disclosed in Japanese Patent Laid-Open No. 5-42476 (Patent Document 4). In the polishing method disclosed in Patent Document 4, abrasive particles made of a non-magnetic material are previously applied to a polishing object made of a magnetic material using an oily wax or the like, and between the polishing tool and the polishing object, The polishing tool is composed of a magnet so that a corresponding pair of magnetic poles is formed, and polishing is performed while a plurality of spheres made of a magnetic material are interposed between the polishing tool and the object to be polished. .

  The polishing method disclosed in Patent Document 4 is to act to press a plurality of spheres made of a magnetic material by magnetic force against abrasive grains previously applied to an object to be polished. This is the same as the above-described magnetic polishing method in that a corresponding pair of magnetic poles are formed between the object to be polished.

JP 2002-265933 A Japanese Patent Laid-Open No. 5-111821 JP 2010-52123 A JP-A-5-42476

  Here, the magnetic abrasive grains are formed by bonding a plurality of abrasive grains made of a non-magnetic material to the surface of magnetic grains made of a magnetic material. Generally, abrasive grains are formed on the surface of magnetic grains. It is manufactured by bonding by sintering or chemical methods. Therefore, the abrasive | polishing agent containing the said magnetic abrasive grain is very expensive compared with a general abrasive | polishing agent, and there existed a problem that the cost required for grinding | polishing will increase as a result.

  Further, when a polishing object made of a non-magnetic material is polished using the magnetic polishing method as disclosed in Patent Documents 1 to 3, a pair of polishing apparatuses are sandwiched between the polishing objects as described above. It is necessary to install a magnet.

  In that case, if the thickness of the polishing object made of a non-magnetic material is sufficiently thin, a magnetic field can be generated so as to pass through the polishing object by generating a very strong magnetic field. Although equipment is required, the polishing can be performed.

  However, when the thickness of the polishing object made of a non-magnetic material is somewhat thick, it is practically impossible to generate a strong magnetic field to such an extent that the magnetic abrasive grains can be pressed against the polishing object with a sufficient pressing force. Therefore, the polishing itself becomes difficult.

  Further, even when the magnetic polishing method as disclosed in Patent Documents 1 to 3 is used, a polishing object made of a nonmagnetic material has a very complicated shape (for example, polishing) In the case where the object includes a free curved surface whose curvature radius changes for each part), it becomes difficult to press the magnetic abrasive grains against the object to be polished with a uniform pressing force. Therefore, polishing with desired accuracy cannot be performed.

  As described above, even when the magnetic polishing method is used, when polishing a polishing object made of a nonmagnetic material, the cost required for polishing is greatly increased, or polishing with a desired accuracy is performed. However, there was a problem that polishing could not be performed or the polishing itself could not be performed in the first place.

  Further, even when the polishing method as disclosed in Patent Document 4 is used, although the cost required for polishing can be partially reduced in that no magnetic abrasive grains are used, the object to be polished is also made of a nonmagnetic material. In the case of polishing an object, there have been problems that the cost required for polishing is greatly increased, polishing with a desired accuracy cannot be performed, or polishing itself cannot be performed in the first place.

  Accordingly, an object of the present invention is to provide a novel polishing apparatus and polishing method capable of polishing an object to be polished made of a nonmagnetic material easily and inexpensively without many restrictions, and in particular, a nonmagnetic material. To provide a polishing apparatus and a polishing method capable of polishing with a desired accuracy even when the polishing object is made of a thick material or when the polishing object has a very complicated surface shape. is there.

A polishing apparatus according to the present invention is for polishing a polishing object made of a non-magnetic material, and is a polishing tool that can move relative to the polishing object, and an abrasive applied to the polishing tool. It has. The abrasive is dispersed on the surface of each of the plurality of spheres by the plurality of spheres made of a magnetic material, a liquid binder adhered to the surface of each of the plurality of spheres, and the liquid binder. And a plurality of abrasive grains made of a nonmagnetic material held in a wet state. A magnetic field is generated in the vicinity of the surface of the polishing tool by forming a pair of magnetic poles on the polishing tool so as to exit from a part of the surface of the polishing tool and return to another part of the surface of the polishing tool. The plurality of spheres are magnetically attached to the polishing tool by the magnetic field, so that magnetic clusters are formed in the abrasive. In the polishing apparatus according to the present invention, when polishing the polishing object by moving the polishing tool relative to the polishing object while pressing the abrasive against the polishing object with the polishing tool, only the magnetic field is used. Thus, the state in which the magnetic cluster is formed is maintained.
In the polishing apparatus according to the present invention, the polishing tool is preferably capable of rotating about an axis, and in this case, the polishing tool is preferably rotated when polishing an object to be polished. .

  In the polishing apparatus according to the present invention, it is preferable that the abrasive is applied to a tip portion located in the axial direction of the polishing tool.

  In the polishing apparatus according to the present invention, it is preferable that one of the pair of magnetic poles is formed at the tip of the polishing tool.

  In the polishing apparatus according to the present invention, it is preferable that the tip portion of the polishing tool has a shape bulging outward along the axial direction of the polishing tool.

  In the polishing apparatus according to the present invention, the means for generating the magnetic field may be a permanent magnet, and in that case, the tip of the polishing tool is constituted by the permanent magnet. Is preferred.

  In the polishing apparatus according to the present invention, the cross-sectional shape orthogonal to the axial direction at the root portion of the tip of the polishing tool may be circular, and the outer shapes of the plurality of abrasive grains are Either may be spherical or indefinite. In this case, if the diameter at the root portion of the tip of the polishing tool is R, the average diameter of the plurality of spheres is D, and the maximum outer dimension of the plurality of abrasive grains is d, R / 1000 ≦ It is preferable that the condition of D ≦ R / 10 and the condition of D / 1000 ≦ d ≦ D / 10 are satisfied.

  In the polishing apparatus according to the present invention, it is preferable that the plurality of spheres are steel balls, the plurality of abrasive grains are alumina-based abrasive grains, and the liquid binder is oil.

  The polishing method according to the present invention is a method for polishing an object to be polished made of a non-magnetic material, and is attached to the surfaces of a plurality of spheres made of a magnetic material and the plurality of spheres. A polishing agent comprising a liquid binder and a plurality of abrasive grains made of a non-magnetic material held in a dispersed state on each surface of the plurality of spheres by the liquid binder, relative to the object to be polished By applying to a movable polishing tool, a pair of magnetic poles are formed on the polishing tool so as to exit from a part of the surface of the polishing tool and return to another part of the surface of the polishing tool. A step of causing the plurality of spheres to be magnetically attached to the polishing tool by a magnetic field formed in the vicinity of the surface of the polishing tool so that magnetic clusters are formed in the polishing agent; and Polishing the polishing object while maintaining the state in which the magnetic cluster is formed only by the magnetic field by moving the polishing tool relative to the polishing object while pressing the polishing object with the polishing tool. And a process of performing.

  According to the present invention, it becomes possible to easily and inexpensively polish an object to be polished made of a nonmagnetic material without many restrictions, and particularly when the object to be polished made of a nonmagnetic material is thick. Even when the object has a very complicated surface shape, polishing can be performed with a desired accuracy.

It is a block diagram of the polish device in an embodiment of the invention. It is a schematic diagram which shows the structure of the process part of the grinding | polishing apparatus shown in FIG. FIG. 2 is an enlarged schematic view of the vicinity of a tip portion of a polishing tool of the polishing apparatus shown in FIG. 1. It is an expansion schematic cross section inside the abrasive | polishing agent in the state apply | coated to the grinding | polishing tool. It is a schematic diagram which shows the 1st example of the grinding | polishing method using the grinding | polishing apparatus shown in FIG. It is a schematic diagram which shows the 2nd example of the grinding | polishing method using the grinding | polishing apparatus shown in FIG. It is an expansion schematic diagram of the front-end | tip part vicinity of the grinding | polishing tool of the grinding | polishing apparatus which concerns on a 1st modification. It is an expansion schematic diagram of the front-end | tip part vicinity of the polishing tool which concerns on a 2nd and 3rd modification. It is an enlarged schematic diagram of the front-end | tip part vicinity of the grinding | polishing tool of the grinding | polishing apparatus which concerns on a 4th modification. It is a figure which shows the 1st thru | or 3rd conditions in a verification test. It is a photograph which shows the state of the abrasive | polishing agent before the grinding | polishing process in a verification test. It is a photograph which shows the state of the abrasive | polishing agent in the grinding | polishing process in a verification test. It is a photograph which shows the state of the abrasive | polishing agent after the grinding process in a verification test. It is a table | surface which shows the result of a verification test.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments, the same or common parts are denoted by the same reference numerals in the drawings, and description thereof will not be repeated.

  FIG. 1 is a block diagram of a polishing apparatus according to an embodiment of the present invention. FIG. 2 is a schematic diagram illustrating a configuration of a processing unit of the polishing apparatus illustrated in FIG. 1, and FIG. 3 is an enlarged schematic diagram of the vicinity of the tip of the polishing tool of the polishing apparatus illustrated in FIG. FIG. 4 is an enlarged schematic cross-sectional view of the inside of the abrasive when applied to the polishing tool. Hereinafter, with reference to these FIG. 1 thru | or FIG. 4, the grinding | polishing apparatus 1 in this Embodiment is demonstrated.

  As shown in FIGS. 1 to 3, the polishing apparatus 1 includes a polishing tool 10, a polishing agent 20 applied to the tip of the polishing tool 10, a table 30 that holds a workpiece 100 as an object to be polished, The drive mechanisms 40 to 45 and various control units 50 and 60 for controlling the operations of the various drive mechanisms 40 to 45 are mainly provided.

  The main shaft of the polishing apparatus 1 extends along the Z-axis direction shown in FIG. A main shaft rotation drive mechanism 40 made of, for example, a spindle is attached to the main shaft, and the above-described polishing tool 10 is attached to the main shaft via the main shaft rotation drive mechanism 40. As a result, the polishing tool 10 is driven to rotate about the Z axis shown in FIG. Further, an X-axis direction feed drive mechanism 41, a Y-axis direction feed drive mechanism 42, and a Z-axis direction feed drive mechanism 43 using, for example, a motor as a drive source are attached to the main shaft. As a result, the polishing tool 10 is driven to be movable in three axial directions orthogonal to the X-axis direction, the Y-axis direction, and the Z-axis direction shown in FIG.

  The operation of the spindle rotation driving mechanism 40 described above is controlled by the rotation control unit 50. More specifically, the rotation control unit 50 controls the rotational movement of the main shaft by driving the main shaft rotation drive mechanism 40, thereby controlling the rotation of the polishing tool 10. On the other hand, the operations of the X-axis direction feed drive mechanism 41, the Y-axis direction feed drive mechanism 42, and the Z-axis direction feed drive mechanism 43 described above are controlled by the feed control unit 60. More specifically, the feed control unit 60 controls the translational movement of the main shaft by driving the X-axis direction feed drive mechanism 41, the Y-axis direction feed drive mechanism 42, and the Z-axis direction feed drive mechanism 43, thereby polishing. The movement of the tool 10 is controlled.

  A chuck (not shown) is rotatably provided on the upper surface of the table 30, and the table 30 holds the workpiece 100 by fixing the workpiece 100 to the chuck. For example, a B-axis feed mechanism 44 using a motor or the like as a drive source is attached to the table 30, and a C-axis feed drive mechanism 45 using a motor or the like as a drive source is attached to the chuck. . Thereby, the workpiece 100 is driven to be rotatable in two directions around the B axis and the C axis shown in FIG. Here, the B axis is an axis that matches the X axis described above when the table 30 is in the initial position, and the C axis is an axis that matches the Z axis described above when the table 30 is in the initial position. It is.

  The operations of the B-axis feed driving mechanism 44 and the C-axis feed driving mechanism 45 described above are controlled by the feed control unit 60. More specifically, the feed control unit 60 controls the rotational movement of the table 30 and the chuck provided thereon by driving the B-axis feed drive mechanism 44 and the C-axis feed drive mechanism 45, thereby 100 rotations are controlled. The feed control unit 60 controls the translational motion of the main shaft and the rotational motion of the chuck in synchronization.

  Here, it is preferable to use a table 30 made of a nonmagnetic material. However, in a case where the distance between the polishing tool 10 and the table 30 is far enough that a magnetic field generated by a permanent magnet 12 described later provided in the polishing tool 10 is not affected during polishing, etc. The table 30 may be entirely or partially made of a magnetic material.

  As shown in FIG. 1, the polishing apparatus 1 includes a spindle position detection unit 46 and a chuck position detection unit 47 in addition to the functional blocks described above. The main shaft position detector 46 detects the position of the main shaft in the three orthogonal directions, and outputs this to the feed controller 60. Further, the chuck position detection unit 47 detects the position of the chuck in the two rotation directions, and outputs this to the feed control unit 60. The feed control unit 60 servo-controls the various feed drive mechanisms 41 to 45 as necessary based on the position information input from the spindle position detection unit 46 and the chuck position detection unit 47, thereby controlling the spindle and chuck. And the relative position between the polishing tool 10 and the workpiece 100 is adjusted.

  As described above, the polishing tool 10 is configured to be capable of relative movement with respect to the workpiece 100, and the workpiece 100 is maintained while pressing the abrasive 20 against the workpiece 100 during polishing described later. Can move relative to

  As shown in FIG. 3, the polishing tool 10 includes a columnar rotating body 11 extending along the axis AX direction of the polishing tool 10 and a permanent magnet fixed to one end of the rotating body 11 in the axis AX direction. 12. The rotating body 11 is fixed to the above-described spindle at the other end (not shown) in the direction of the axis AX so that the axis AX of the polishing tool 10 matches the above-described main axis. As a result, the tip end portion of the polishing tool 10 is constituted by the permanent magnet 12, and the polishing tool 10 composed of the rotating body 11 and the permanent magnet 12 is arranged around the axis AX as indicated by an arrow DR1 in the drawing. It is configured to be able to rotate.

  Here, when the rotator 11 is made of a magnetic material, the permanent magnet 12 may be magnetically attached to the rotator 11, or they may be coupled by another method. May be. Moreover, when the rotary body 11 is comprised with the nonmagnetic material, these will be couple | bonded by methods other than magnetic attachment.

  The permanent magnet 12 constituting the tip of the polishing tool 10 has a hemispherical tip surface. Thereby, the front-end | tip part of the grinding | polishing tool 10 has a shape which bulges outside along the axis line AX direction.

  Further, the permanent magnet 12 is fixed to the rotating body 11 so that the pair of magnetic poles (N pole and S pole) are aligned in the axis AX direction. Here, in the present embodiment, the permanent magnet 12 is arranged so that the S pole of the pair of magnetic poles is formed at the tip of the polishing tool 10. Thereby, a magnetic field (in the drawing, the magnetic field is schematically represented by a line of magnetic force L on the surface in the vicinity of the front end portion of the polishing tool 10 so as to exit from the front end surface of the polishing tool 10 and return to the peripheral surface of the polishing tool 10. Will be generated).

  On the other hand, as shown in FIGS. 3 and 4, the abrasive 20 includes a plurality of spheres 21 made of a magnetic material, a liquid binder 22, and a plurality of abrasive grains 23 made of a nonmagnetic material. A predetermined amount of the abrasive 20 is applied to the above-described tip of the polishing tool 10 and the vicinity thereof, and the tip of the polishing tool 10 and the vicinity thereof are covered with the abrasive 20.

  The plurality of spheres 21 are magnetized by the magnetic field generated by the permanent magnet 12 described above. Therefore, the plurality of spheres 21 are magnetically attached to the vicinity of the tip of the polishing tool 10 by the magnetic field, and a magnetic cluster is formed in the abrasive 20 by the plurality of spheres 21 magnetically attached. Become.

  The liquid binder 22 fills the gaps between the plurality of spheres 21 forming the magnetic clusters and covers the outer surfaces of the plurality of spheres 21 constituting the outermost shell portion of the magnetic clusters. More specifically, the liquid binder 22 is attached in the form of a film on the surface of each of the plurality of spheres 21 due to its surface tension. Here, the liquid binder 22 may completely fill the gaps between the plurality of spheres 21, but in the present embodiment, as shown in FIG. 4, many fine voids 24 are included therein. It is trying to become. In FIG. 2 and FIGS. 4 and 5 to be described later, the gap 24 is not shown for the sake of drawing.

  The plurality of abrasive grains 23 are held in a dispersed state on the surfaces of the plurality of spheres 21 by the liquid binder 22. Thereby, like the liquid binder 22, the some abrasive grain 23 is located in the clearance gap between the some spheres 21 which form a magnetic cluster, and the some sphere of the part which comprises the outermost shell part of a magnetic cluster Also located on the outer surface of 21.

  Here, the weight ratio of the liquid binder 22 contained in the abrasive 20 may be sufficiently smaller than the weight ratio of the plurality of spheres 21 contained in the abrasive 20. That is, the liquid binder 22 naturally functions as a lubricant, but its main function is to hold a plurality of abrasive grains 23 on the surfaces of the plurality of spheres 21. If retention is realized, there is no need to increase the amount more than necessary. In other words, when the amount of the liquid binder 22 contained in the abrasive 20 is too large, the magnetic force acting on the plurality of spheres 21 is weakened by this, and as a result, the necessary amount of the spheres 21 are magnetically attached. May become difficult, or the excess liquid binder 22 containing the abrasive grains 23 may fall off from the polishing tool 10.

  Therefore, it is preferable that the amount of the liquid binder 22 added to the abrasive 20 be the minimum necessary in consideration of these. Therefore, in the present embodiment, as described above, in the state where the abrasive 20 is applied to the tip of the polishing tool 10, the liquid binder 22 adheres to the surface of the plurality of spheres 21 in the form of a film. The weight ratio of the plurality of spheres 21, the liquid binder 22, and the abrasive grains 23 is adjusted so that many voids are included in 20.

  A steel ball can be preferably used as the sphere 21 described above, but any sphere made of a magnetic material can be used. Also, as the above-described liquid binder, oil can be preferably used. However, any liquid binder can be used as long as it can hold a plurality of abrasive grains 23 on the surface of the plurality of spheres 21 and functions as a lubricant. Anything can be used. As the abrasive grains 23, alumina-based abrasive grains can be preferably used, but other types of abrasive grains can naturally be used depending on the workpiece 100 that is the object to be polished. The outer shape of the abrasive grains 23 may be spherical or non-spherical indefinite.

  Here, the diameter of the polishing tool 10 in the cross section orthogonal to the axis AX at the base portion of the tip of the polishing tool 10 is R, the average diameter of the plurality of spheres 21 is D, and the maximum outer dimensions of the plurality of abrasive grains 23. Is d, it is preferable that R, D and d satisfy the condition of R / 1000 ≦ D ≦ R / 10 and the condition of D / 1000 ≦ d ≦ D / 10. By satisfying the condition, a magnetic cluster having a size suitable for polishing can be formed during polishing, which will be described later, and the abrasive grains 23 can be appropriately pressed against the workpiece 100.

  FIG. 5 is a schematic view showing a first example of a polishing method using the polishing apparatus shown in FIG. Hereinafter, a first example of the polishing method in the present embodiment using the polishing apparatus 1 described above will be described with reference to FIG. 5 and FIG. 2 described above.

  As shown in FIG. 2, when performing polishing using the above-described polishing apparatus 1, first, the polishing tool 10 and the table 30 are set to an initial position.

  Next, as shown in FIGS. 2 and 5A, a predetermined amount of abrasive 20 is applied to the tip of the polishing tool 10, and the surface to be polished of the workpiece 100 made of a non-magnetic material that is a polishing target. The workpiece 100 is set on the table 30 so that 101 is exposed. At this time, as described above, in the abrasive 20 applied to the tip portion of the polishing tool 10, the plurality of spheres 21 are made to the polishing tool 10 by the magnetic field generated by the permanent magnet 12 provided in the polishing tool 10. Magnetic clusters are formed by being magnetically attached to each other.

  Next, as shown in FIG. 5A, the polishing tool 10 is rotated about the axis AX in the direction of the arrow DR1 in the figure. At this time, the centrifugal force acts on the polishing agent 20 by appropriately adjusting the magnetizing force of the permanent magnet 12 to the plurality of spheres 21 in advance and appropriately managing the peripheral speed of rotation of the polishing tool 10. Thus, it is possible to reliably prevent the abrasive 20 from dropping from the tip of the polishing tool 10.

  Next, in the first example shown in FIG. 5, the polishing agent 10 applied to the tip of the polishing tool 10 is lowered by lowering the polishing tool 10 along the Z-axis direction in the direction of the arrow DR2 in the figure. The workpiece 100 is pressed toward the surface 101 to be polished. At this time, after the polishing tool 10 is lowered, the tip of the polishing tool 10 and the surface to be polished 101 of the workpiece 100 do not come into contact with each other, and a gap in the axis AX direction between them is ensured by a predetermined distance. Like that.

  At that time, when the lower surface of the abrasive 20 comes into contact with the surface 101 to be polished of the workpiece 100, the magnetic cluster in the abrasive 20 changes its shape. Here, since the magnetic cluster is magnetized only by the permanent magnet 12 as described above, the shape is freely changed by applying an external force exceeding the magnetizing force. It changes into a shape that follows the shape of the surface to be polished 101 at the part that 20 contacts.

  Therefore, the pressing force by the polishing tool 10 is applied to the abrasive grains 23 located in contact with the polishing target surface 101 of the workpiece 100 through the magnetic cluster, and the abrasive grains 23 apply the abrasive 20 to the abrasive 20. Polishing of the surface 101 to be polished in contact with the portion proceeds.

  Next, as shown in FIG. 5B, the Z-axis direction of the polishing tool 10 so that the distance between the tip of the polishing tool 10 and the surface 101 to be polished of the workpiece 100 is always kept constant. The polishing tool 10 is moved relative to the workpiece 100 by feeding the polishing tool 10 at a predetermined speed along the X-axis direction in the direction of the arrow DR3 shown in the drawing while adjusting the position at Thus, the polishing of the surface 101 to be polished of the workpiece 100 is further advanced.

  Even when the polishing tool 10 is fed along the X-axis direction, the abrasive 20 remains attached to the tip of the polishing tool 10, and the portion of the surface 101 to be polished that contacts the abrasive 20 is in contact with the polishing tool 10. The surface of the object to be polished 101 is polished in the range in which the polishing tool 10 is scanned by changing the shape of the magnetic cluster every moment according to the change in shape.

  Thereafter, the relative movement of the polishing tool 10 with respect to the workpiece 100 is continued while variously changing the feeding direction of the polishing tool 10 until the polishing of the entire surface 101 of the workpiece 100 is completed, and the entire surface of the polishing target surface 101 is thereby changed. When the polishing is completed, the polishing tool 10 is raised along the Z-axis direction, and then the rotation of the polishing tool 10 is stopped.

  Thus, the polishing of the workpiece 100 is completed. In the above description, the polishing tool 10 is rotated before the abrasive 20 is brought into contact with the workpiece 100. However, the polishing tool 10 is rotated after the abrasive 20 is brought into contact with the workpiece 100. It is good as well.

  As described above, a polishing tool that can freely change the shape of its tip according to the shape of the surface to be polished by performing polishing according to the polishing method as in the first example described above while using the polishing apparatus 1 described above. Can be realized. Therefore, not only when the object to be polished includes a curved surface with a substantially constant curvature or some uneven surface, but the object to be polished includes a free curved surface or the like whose curvature radius changes for each part. Even in such cases, it becomes possible to press the abrasive grains toward the surface to be polished with a substantially uniform pressing force, and polishing with a desired accuracy can be performed.

  Further, as apparent from the above description, non-magnetic material other than the magnet provided in the polishing tool is obtained by performing polishing according to the polishing method as in the first example described above while using the polishing apparatus 1 described above. It is not necessary to arrange another magnet so as to sandwich the object to be polished. This is because the polishing method based on the present embodiment is different from the magnetic polishing method disclosed in Patent Documents 1 to 3 and the polishing method disclosed in Patent Document 4 described above. Rather than pressing the abrasive grains against the object to be polished, a polishing tool that can freely change its tip shape using magnetic force and pressing the abrasive grains against the object to be polished by the pressing force of the polishing tool Because it is.

  Therefore, polishing can be performed regardless of the shape of the polishing object made of a nonmagnetic material (that is, whether the polishing object made of the nonmagnetic material is thin or thick). In addition to the effects that can be achieved, it is possible to obtain an effect that polishing of a polishing object made of a nonmagnetic material can be performed inexpensively and easily without requiring large and expensive equipment.

  Furthermore, it is not necessary to use a polishing agent containing expensive abrasive grains such as magnetic abrasive grains by performing polishing according to the polishing method as in the first example described above while using the polishing apparatus 1 described above. In this sense as well, it is possible to easily polish an object to be polished made of a nonmagnetic material at low cost.

  Therefore, according to the polishing method based on the present embodiment, it becomes possible to polish a polishing object made of a nonmagnetic material easily and inexpensively without many restrictions.

  FIG. 6 is a schematic diagram showing a second example of a polishing method using the polishing apparatus shown in FIG. Hereinafter, a second example of the polishing method in the present embodiment using the above-described polishing apparatus 1 will be described with reference to FIG.

  As shown in FIG. 6A, in the second example shown in FIG. 6, after setting the polishing target surface 101 of the workpiece 100 made of a nonmagnetic material, which is a polishing target, on the table 30, the table 30 is The surface to be polished 101 of the workpiece 100 is arranged around the tip of the polishing tool 10 coated with the abrasive 20 by rotating around the B axis.

  Next, after rotating the polishing tool 10 around the axis AX in the direction of the arrow DR1 in the figure, the polishing tool 10 is moved along the Y axis direction in the direction of the arrow DR4 in the figure so as to approach the workpiece 100. As a result, the abrasive 20 applied to the tip of the polishing tool 10 is pressed toward the surface 101 to be polished of the workpiece 100. At this time, after the movement of the polishing tool 10, the circumferential surface of the portion adjacent to the tip of the polishing tool 10 and the polishing target surface 101 of the workpiece 100 do not come into contact with each other, and the direction perpendicular to the axis AX direction therebetween. The gap at is secured by a predetermined distance.

  At that time, when the side surface of the abrasive 20 contacts the surface to be polished 101 of the workpiece 100, the magnetic cluster in the abrasive 20 changes its shape. Here, since the magnetic cluster is magnetized only by the permanent magnet 12 as described above, the shape is freely changed by applying an external force exceeding the magnetizing force. It changes into a shape that follows the shape of the surface to be polished 101 at the part that 20 contacts.

  Therefore, the pressing force by the polishing tool 10 is applied to the abrasive grains 23 located in contact with the polishing target surface 101 of the workpiece 100 through the magnetic cluster, and the abrasive grains 23 apply the abrasive 20 to the abrasive 20. Polishing of the surface 101 to be polished in contact with the portion proceeds.

  Next, as shown in FIG. 6B, the distance between the peripheral surface of the portion adjacent to the tip of the polishing tool 10 and the polishing target surface 101 of the workpiece 100 is always kept constant. While adjusting the position of the polishing tool 10 in the Y-axis direction, the polishing tool 10 is sent to the workpiece 100 with respect to the workpiece 100 by feeding the polishing tool 10 along the X-axis direction in the direction of the arrow DR5 shown in the drawing. By relatively moving, the polishing of the surface 101 to be polished of the workpiece 100 is further advanced.

  Even when the polishing tool 10 is fed along the X-axis direction, the abrasive 20 remains attached to the tip of the polishing tool 10, and the portion of the surface 101 to be polished that contacts the abrasive 20 is in contact with the polishing tool 10. The surface of the object to be polished 101 is polished in the range in which the polishing tool 10 is scanned by changing the shape of the magnetic cluster every moment according to the change in shape.

  Thereafter, the relative movement of the polishing tool 10 with respect to the workpiece 100 is continued while variously changing the feeding direction of the polishing tool 10 until the polishing of the entire surface 101 of the workpiece 100 is completed, and the entire surface of the polishing target surface 101 is thereby changed. When the polishing is completed, the polishing tool 10 is moved away from the workpiece 100 along the Y-axis direction, and then the rotation of the polishing tool 10 is stopped.

  Thus, the polishing of the workpiece 100 is completed. In the above description, the polishing tool 10 is rotated before the abrasive 20 is brought into contact with the workpiece 100. However, the polishing tool 10 is rotated after the abrasive 20 is brought into contact with the workpiece 100. It is good as well.

  As described above, a polishing tool that can freely change the shape of its tip according to the shape of the surface to be polished by performing polishing according to the polishing method as in the second example described above while using the polishing apparatus 1 described above. Can be realized. Therefore, also in this case, the same effect as that described in the first example can be obtained.

  Here, in the first example described above, a case where polishing is performed in a state where the axis AX of the polishing tool 10 and the polishing target surface 101 of the workpiece 100 are substantially orthogonal to each other is illustrated, and in the second example described above, A case where the polishing is performed in a state where the axis AX of the polishing tool 10 and the surface to be polished 101 of the workpiece 100 are substantially parallel is illustrated. However, since the polishing method according to the present embodiment realizes a polishing tool whose tip shape can be freely changed using magnetic force as described above, the polishing tool 10 is applied to the workpiece 100. Polishing can be performed by bringing them close to each other at an arbitrary angle within a range where interference does not occur. Therefore, during polishing, it is possible to change the angle of the table 30 while feeding the polishing tool 10 in a predetermined direction, and the degree of freedom in processing becomes very high.

  Further, in the first example and the second example described above, the case where the polishing tool 10 is sent by being translated with respect to the workpiece 100 is exemplified, but the feed direction of the polishing tool 10 is limited to this. First, this may be sent so that the polishing tool 10 revolves with respect to the workpiece 100, or any other feeding method may be adopted. Further, the polishing tool 10 does not necessarily have to rotate, and the workpiece 100 side may be rotated, or none of them may be rotated. In other words, it is sufficient that the polishing tool 10 and the workpiece 100 relatively move in some form during polishing, and the mode is not limited at all.

  Further, the abrasive 20 need not necessarily be applied to the tip of the polishing tool 10, and may be applied only to the peripheral surface of a roller-like polishing tool, for example. That is, as long as the polishing agent 20 comes into contact with the workpiece 100 during polishing, the mode is not limited at all.

  FIG. 7 is an enlarged schematic view of the vicinity of the tip of the polishing tool of the polishing apparatus according to the first modification. FIG. 8 is an enlarged schematic view of the vicinity of the tip of the polishing tool according to the second and third modifications. FIG. 9 is an enlarged schematic view of the vicinity of the tip of the polishing tool of the polishing apparatus according to the fourth modification. Hereinafter, with reference to these FIG. 7 thru | or FIG. 9, the grinding | polishing tool which concerns on a 1st thru | or 4th modification is demonstrated.

  As shown in FIG. 7, the polishing tool 10 according to the first modified example is different from the above-described embodiment only at the positions of the pair of magnetic poles formed on the permanent magnet 12 attached to the rotating body 11. ing. That is, in the polishing tool 10 according to the first modification, the N pole and the S pole, which are a pair of magnetic poles, are formed side by side in a direction orthogonal to the axis AX of the polishing tool 10.

  Even in such a configuration, it is possible to realize a polishing tool whose tip shape can be freely changed according to the shape of the surface to be polished. Therefore, also in this case, the same effect as the effect described in the above embodiment can be obtained.

  As shown in FIG. 8A, the polishing tool 10 according to the second modified example is different from the above-described embodiment only in the shape of the tip in the axis AX direction. Specifically, in the polishing tool 10 according to the second modification, a flat portion is formed at the center position of the tip portion, and the flat portion and the peripheral surface of the polishing tool 10 are arranged at the peripheral position of the tip portion. A curved surface is formed so as to connect gently. Also in this case, the tip of the polishing tool 10 has a shape that bulges outward along the axis AX direction.

  As shown in FIG. 8B, the polishing tool 10 according to the third modification is also different from the above-described embodiment only in the shape of the tip in the axis AX direction. Specifically, in the polishing tool 10 according to the third modification, the tip portion is formed only by the flat portion. In this case, the tip of the polishing tool 10 does not have a shape that bulges outward along the axis AX direction.

  In any case configured as described above, it is possible to realize a polishing tool whose tip shape can be freely changed according to the shape of the surface to be polished. Therefore, in any of these cases, the same effects as those described in the above-described embodiment can be obtained. However, when the surface to be polished of the object to be polished made of a non-magnetic material is curved to a considerable extent, the abrasive containing magnetic clusters can be more stably pressed toward the surface to be polished. It is preferable that the tip end bulges outward to some extent.

  As shown in FIG. 9, the fourth modification is configured by only the rotating body 11 without the permanent magnet being provided in the polishing tool 10. Instead, the electromagnet 70 is added to the polishing apparatus including the polishing tool 10. Shows a configuration provided with. In this case, the electromagnet 70 is fixedly arranged in an annular shape so as to face the circumferential surface of the polishing tool 10 with a predetermined distance, for example.

  In that case, when the electromagnet 70 is energized, a pair of magnetic poles is formed on the polishing tool 10 as in the above-described embodiment, and the surface near the tip of the polishing tool 10 is formed on the surface. Then, a magnetic field is generated so as to exit from the front end surface of the polishing tool 10 and return to the peripheral surface of the polishing tool 10.

  Even in such a configuration, it is possible to realize a polishing tool whose tip shape can be freely changed according to the shape of the surface to be polished. Therefore, also in this case, the same effect as that described in the above-described embodiment can be obtained.

  FIG. 10 is a diagram illustrating first to third conditions in the verification test. 11 to 13 are photographs showing the state of the abrasive before, during, and after the polishing process in the verification test. FIG. 14 is a table showing the results of the verification test. Hereinafter, test conditions and test results of a verification test for confirming the effect of the present invention will be described.

  As shown in FIG. 10, in this verification test, the polishing apparatus in the above-described embodiment is actually constructed, and using this, the polishing tool 10 is made of a nonmagnetic material at different angles according to the polishing method in the above-described embodiment. Polishing is performed close to the workpiece 100 as an object to be polished.

  As the polishing tool 10, a cylindrical permanent magnet with a spherical permanent magnet having a diameter of 10 [mm] fixed to the tip of a rotating body having a diameter of 10 [mm] was used. As the abrasive 20, a lubricant mixed with a steel ball having a diameter of 0.35 [mm] and alumina having an average particle diameter of 1.0 [μm] was used. Here, the weight ratio of the steel balls, alumina, and lubricating oil is 9: 1: 3. The said abrasive | polishing agent 20 was a paste-form slurry, and the application quantity to the grinding | polishing tool 10 was 6.5 [g].

  As the workpiece 100 made of a nonmagnetic material, disc-shaped brass was used. As for the surface roughness of the workpiece 100 before polishing, Ra (arithmetic mean roughness) is 1.00 [μm] and Rz (maximum height roughness) is 4.77 [μm]. Met.

  In the polishing process, the test conditions as shown in FIGS. 10A to 10C were adopted as the first to third conditions, respectively.

  That is, as shown in FIG. 10A, the first condition is that the angle (θ) formed between the axis AX of the polishing tool 10 and the surface to be polished 101 of the workpiece 100 is 90 [deg]. Then, the abrasive 20 is in contact with the surface to be polished 101 and is sent in the X-axis direction shown in the figure.

  As shown in FIG. 10B, the second condition is that the angle (θ) formed between the axis AX of the polishing tool 10 and the surface to be polished 101 of the workpiece 100 is 45 [deg], This is a state in which the polishing agent 20 is in contact with the surface to be polished 101 and is sent in the X-axis direction shown in the figure.

  As shown in FIG. 10C, the third condition is that the angle (θ) formed between the axis AX of the polishing tool 10 and the surface to be polished 101 of the workpiece 100 is 0 [deg], This is a state in which the polishing agent 20 is in contact with the surface to be polished 101 and is sent in the X-axis direction shown in the figure.

In any of the first to third conditions, the rotational speed of the polishing tool 10 is 750 [min ⁻¹ ], the feed rate is 10 [mm / min], the tip of the polishing tool 10 and the workpiece 100 are The gap with the surface 101 to be polished was always maintained at 1.0 [mm], and the processing time was 20 [min].

  Here, as shown in FIG. 11, in the state before the polishing process, the abrasive 20 adhered in a substantially spherical shape so as to cover the tip of the polishing tool 10 in any of the first to third conditions. Confirmed to be in a state. In addition, in the range which can be observed from the outside, it has confirmed that the steel balls contained in the abrasive | polishing agent 20 were mutually magnetized.

  As shown in FIG. 12A, in the first condition, the polishing agent 20 is attached to the tip of the polishing tool 10 in a substantially truncated cone shape during the polishing process, and the lower surface is the object to be polished of the workpiece 100. It was confirmed that the surface 101 was in contact.

  As shown in FIG. 12B, in the second condition, the abrasive 20 is attached to the tip of the polishing tool 10 in a substantially conical shape during the polishing process, and the peripheral surface thereof is the workpiece 100. It was confirmed that the surface to be polished 101 was in contact.

  Further, as shown in FIG. 12C, in the third condition, the polishing agent 20 is attached to the tip of the polishing tool 10 in a substantially bottomed cylindrical shape during the polishing process, and its peripheral surface is the workpiece. It was confirmed that 100 surfaces to be polished 101 were in contact.

  That is, in any of the first to third conditions, it was confirmed that the abrasive 20 changed into a shape following the surface to be polished 101 during the polishing process, and the magnetic clusters were freely deformed.

  As shown in FIG. 13 (A), in the first condition, the abrasive 20 is attached to the tip of the polishing tool 10 in a substantially truncated cone shape after the polishing, as in the polishing. It was confirmed that the tip of the polishing tool 10 was covered with the abrasive 20 without being exposed. That is, it is presumed that the lower surface of the abrasive 20 was in contact with the entire surface 101 to be polished during the polishing process.

  As shown in FIG. 13 (B), under the second condition, the abrasive 20 was attached to the tip of the polishing tool 10 in a substantially conical shape even after the polishing, as in the polishing.

  As shown in FIG. 13 (C), under the third condition, the abrasive 20 was attached to the tip of the polishing tool 10 in a substantially bottomed cylindrical shape even after the polishing, as in the polishing. It was.

  As shown in FIG. 14, in the first condition, the surface roughness after polishing of the surface to be polished 101 of the workpiece 100 is such that Ra in the X-axis direction is 0.52 [μm], and in the X-axis direction. It was confirmed that Rz was reduced to 3.02 [μm], Ra in the Y-axis direction was reduced to 0.72 [μm], and Rz in the Y-axis direction was reduced to 3.57 [μm]. .

  Further, under the second condition, the surface roughness after polishing of the surface to be polished 101 of the workpiece 100 is such that Ra in the X-axis direction is 0.68 [μm] and Rz in the X-axis direction is 2.85. In [μm], it was confirmed that Ra in the Y-axis direction was reduced to 0.82 [μm] and Rz in the Y-axis direction was reduced to 3.66 [μm].

  In the third condition, the surface roughness of the workpiece 100 after the polishing of the surface 101 to be polished is such that Ra in the X-axis direction is 0.80 [μm] and Rz in the X-axis direction is 3.56. In [μm], it was confirmed that Ra in the Y-axis direction was reduced to 0.66 [μm] and Rz in the Y-axis direction was reduced to 2.89 [μm].

  Based on the above results, it can be said that it was confirmed that the polishing could be performed under any of the first to third conditions, and the workpiece as a polishing object made of a nonmagnetic material at different angles. It can be said that even when the polishing was performed close to 100, it was confirmed that the polishing could be performed almost evenly.

  Therefore, by polishing the nonmagnetic material using the polishing apparatus and polishing method based on the present invention, a polishing tool whose tip shape can be freely changed according to the shape of the surface to be polished is realized. As a result, not only when the object to be polished includes a curved surface with a substantially constant curvature or some uneven surface, but also a free-form surface whose curvature radius changes for each part of the object to be polished Can be polished with a desired accuracy, and even from expensive non-magnetic materials without using expensive magnetic abrasive grains or large and expensive equipment. It can be said that it was confirmed experimentally that it becomes possible to polish the polishing object.

  The polishing apparatus and the polishing method based on the present invention can be polished by any material as long as it is made of a non-magnetic material without distinction between metal and non-metal. It can be suitably applied to surface finishing of mold surfaces and surface finishing of optical components.

  The above-described embodiment and modifications thereof disclosed herein are illustrative in all respects and are not restrictive. The technical scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Polishing apparatus, 10 Polishing tool, 11 Rotating body, 12 Permanent magnet, 20 Abrasive, 21 Sphere, 22 Liquid binder, 23 Abrasive grain, 24 Gap, 30 Table, 40 Spindle rotation drive mechanism, 41 X axis direction feed drive mechanism 42 Y-axis direction feed drive mechanism, 43 Y-axis direction feed drive mechanism, 44 B-axis feed mechanism, 45 C-axis feed drive mechanism, 46 spindle position detector, 47 chuck position detector, 50 rotation controller, 60 Feed control unit, 70 electromagnet, 100 workpiece, 101 surface to be polished.

Claims (9)

A polishing apparatus for polishing a polishing object made of a nonmagnetic material,
A polishing tool capable of relative movement with respect to an object to be polished;
An abrasive applied to the polishing tool,
The abrasive is dispersed on the surface of each of the plurality of spheres by the plurality of spheres made of a magnetic material, a liquid binder attached to the surface of each of the plurality of spheres, and the liquid binder. A plurality of abrasive grains made of a non-magnetic material held in a state of
Near the surface of the polishing tool, a magnetic field is generated by forming a pair of magnetic poles on the polishing tool so as to exit from a part of the surface of the polishing tool and return to another part of the surface of the polishing tool. The magnetic particles are magnetically attached to the polishing tool by the magnetic field to form magnetic clusters in the abrasive,
When polishing the polishing object by moving the polishing tool relative to the polishing object while pressing the polishing agent against the polishing object with the polishing tool, the magnetic cluster is formed only by the magnetic field. Is maintained, polishing equipment. The polishing tool is capable of rotating about an axis;
The polishing apparatus according to claim 1, wherein the polishing tool rotates when the object to be polished is polished.   The polishing apparatus according to claim 2, wherein the polishing agent is applied to a tip portion located in an axial direction of the polishing tool.   The polishing apparatus according to claim 3, wherein one of the pair of magnetic poles is formed at the tip portion of the polishing tool.   The polishing apparatus according to claim 3 or 4, wherein the tip portion of the polishing tool has a shape that bulges outward along the axial direction of the polishing tool. The means for generating the magnetic field is a permanent magnet;
The polishing apparatus according to claim 3, wherein the tip portion of the polishing tool is constituted by the permanent magnet. The cross-sectional shape orthogonal to the axial direction at the root portion of the tip of the polishing tool is circular,
The outer shapes of the plurality of abrasive grains are all spherical or indefinite shapes,
R / 1000 ≦ D ≦ when the diameter at the root portion of the tip of the polishing tool is R, the average diameter of the plurality of spheres is D, and the maximum external dimension of the plurality of abrasive grains is d. The polishing apparatus according to claim 3, wherein the polishing apparatus satisfies the condition of R / 10 and satisfies the condition of D / 1000 ≦ d ≦ D / 10. The plurality of spheres are steel balls,
The plurality of abrasive grains are alumina-based abrasive grains,
The polishing apparatus according to claim 1, wherein the liquid binder is oil. A polishing method for polishing a polishing object made of a nonmagnetic material,
A plurality of spheres made of a magnetic material, a liquid binder adhered to the surface of each of the plurality of spheres, and a state of being dispersed on each surface of the plurality of spheres by the liquid binder. A polishing agent containing a plurality of abrasive grains made of a non-magnetic material is applied to a polishing tool that can move relative to the object to be polished, so that the surface of the polishing tool is removed from a part of the surface of the polishing tool. By forming a pair of magnetic poles on the polishing tool so as to return to another part of the surface, the plurality of spheres are magnetically attached to the polishing tool by a magnetic field formed in the vicinity of the surface of the polishing tool. Allowing magnetic clusters to form in the abrasive;
While moving the polishing tool relative to the polishing object while pressing the abrasive against the polishing object by the polishing tool, the state where the magnetic cluster is formed only by the magnetic field is maintained. A polishing method comprising: polishing a polishing object.