JP4918298B2 - Polishing method and polishing apparatus - Google Patents

Description

  The present invention relates to a polishing method and a polishing apparatus, and more particularly to a polishing method and a polishing apparatus suitable for polishing a surface that does not have a rotation axis, or a micro, micro aspherical surface.

For example, a minute aspherical glass lens and an aspherical surface of a molding die thereof are conventionally performed by a point-stained polisher made of a synthetic resin without being polished by a total shape.
JP 2001-300843 A

  However, miniaturization of lenses and molds has reached the limit, and it is becoming difficult to produce a polisher itself that is small and has sufficient polishing ability. Polishing with a polisher may cause waviness components due to the overlapping portions of the trajectory, and the roughness is improved, but there is also a problem that the overall surface accuracy is lowered.

  An object of the present invention is to obtain a polishing method capable of polishing an object to be polished such as a microlens or a metal mold without using a spot polisher based on the above problem awareness.

  The present invention uses a transfer mold having a transfer surface in which the shape of the surface to be polished is opposite to that of the surface to be polished, and in the presence of an abrasive, the object to be polished and the transfer mold are relatively free of relative rotation. By applying such fine vibration, the processed shape before polishing is not disturbed and polishing is performed uniformly on the surface, not on the point.

In one aspect of the polishing method of the present invention, a step of producing a transfer mold made of a metal material or glass material having a transfer surface having irregularities opposite to the shape of the surface to be polished of the object to be polished, resin particles, and the resin particles In a slurry in which abrasive fine particles having a smaller diameter and higher polishing ability are dispersed, a step of making the transfer surface of the transfer mold face the surface to be polished of the object to be polished, And polishing the surface of the object to be polished by applying a relative fine vibration to the surface of the object to be polished without applying relative rotation.
According to another aspect of the polishing method of the present invention, a step of preparing a slurry in which resin particles and abrasive fine particles having a smaller diameter and a higher polishing ability than the resin particles are dispersed, the surface shape and unevenness of the object to be polished Manufacturing a transfer mold having a reverse transfer surface on which a large number of resin particle holding recesses having a depth equal to or less than the radius of the resin particles are formed on the transfer surface, transferring the transfer mold in the slurry The surface and the surface to be polished of the object to be polished, and the resin particles held in the resin particle holding recess simultaneously contact both the transfer surface of the transfer mold and the surface to be polished of the object, and In a state where the transfer surface of the transfer mold and the surface to be polished of the object to be polished are not in direct contact with each other, the transfer surface of the transfer mold and the surface to be polished of the object to be polished opposed to each other are relatively rotated without giving a relative rotation. The surface to be polished of the object to be polished is polished by applying a slight vibration. Is characterized by having steps, a.

  One important point of the method of the present invention is that no relative rotation is given to the object to be polished and the transfer mold. The relative rotation is not given in the polishing method of the present invention because there is a portion (on the rotation center axis) where the relative rotation speed is zero. This is because polishing is not performed in the vicinity, and the polishing amount increases toward the outer periphery, so that uniform polishing is not achieved. Specifically, the direction of vibration is a direction in which the distance between the polishing surface and the transfer surface changes in size, a direction in which the surface to be polished and the transfer surface slide, or a combination direction of both.

  Further, the magnitude (amplitude) of the fine vibration can be set from sub μm to several hundred μm depending on the size and accuracy of the surface to be polished.

Examples of the material of the object to be polished are metal, new ceramics or glass .

  Resin particles having an average particle diameter of 1 μm to 100 μm can be used, and abrasive particles having a particle diameter of 0.01 μm to 10 μm can be used.

  As the resin particles, a material suitable for polishing, that is, a material that can hold the abrasive and has elasticity to some extent is suitable. Specifically, one or more of polyurethane (rubber), vinyl chloride, and silicone rubber can be used. As the abrasive fine particles, one or more of colloidal silica, alumina, diamond, cerium oxide, silicon carbide, and cubic boron nitride can be used.

  The method of the present invention can be applied to a spherical surface having a rotation axis, but is particularly useful for polishing an aspherical surface or free-form surface having no rotation axis.

A polishing apparatus for carrying out the method of the present invention applies a relative rotation between a work support member that supports an object to be polished, a transfer mold support member that supports a transfer mold, and the work support member and the transfer mold support member. And an actuator that gives a relative minute vibration without any problems. A large number of resin particle holding recesses having a depth not larger than the radius of the resin particles can be formed on the transfer surface of the transfer mold of the polishing apparatus.

This actuator can be composed of an actuator that gives a slight vibration in the three orthogonal directions alone or in combination .

The workpiece support member is provided with a slurry holding cylinder for holding a slurry containing resin particles and abrasive fine particles, and an object to be polished supported by the workpiece support member is positioned in the slurry holding cylinder (to be polished in the slurry). Can be immersed) .

  According to the present invention, polishing can be performed regardless of the shape of the surface to be polished without using a spot polisher.

  1 and 2 are conceptual views of an embodiment of a polishing method according to the present invention. A surface to be polished W1 of a workpiece (a metal mold or glass) W is, for example, a free-form surface or an axisymmetric aspheric surface. The transfer mold T for polishing the surface to be polished W1 is formed with a transfer surface T1 having irregularities opposite to the surface to be polished W1. The polished surface W1 and the transfer surface T1 are each machined with sufficient surface accuracy. Further, the surface to be polished W1 and the transfer surface T1 are non-rotation symmetric shapes having no rotation axis, and the concavities and convexities are reversed at a specific rotation phase around the Z axis. The transfer mold T can be made of metal, glass, resin material, or pitch.

  In the present embodiment, the workpiece W and the transfer mold T are both placed with the slurry 10 containing (dispersed) the resin particles 11 and the abrasive fine particles 12 interposed between the surface to be polished W1 and the transfer surface T1. Polishing is performed by applying a relative fine vibration in the direction Z (and / or) the direction X and / or the direction of sliding. No relative rotational movement about the axis Z is given between the surface to be polished W1 (work W) and the transfer surface T1 (transfer mold T).

  The slurry 10 is configured, for example, by mixing 1 to 5% by weight of resin particles 11, 1 to 5% by weight of abrasive fine particles 12, and the remaining (90 to 98% by weight) of a lubricating liquid. As the resin particles 11, one or more of polyurethane, vinyl chloride, and silicone rubber having an average particle diameter of 1 μm to 100 μm can be used, and the abrasive particles 12 have an average particle diameter of 0.01 μm to 10 μm (resin used) One or more kinds of colloidal silica, alumina, diamond, and cerium oxide having an average particle size of 1/10000 to 1/2 of the average particle diameter of the particles 11 can be used. The resin particles 11 also have a polishing ability, but the polishing ability of the abrasive fine particles 12 is higher than that of the resin particles 11.

  Specific examples of the resin particles 11 and the abrasive fine particles 12 are disclosed in, for example, Japanese Patent Application Laid-Open No. 2001-300843. The resin particles 11 may be, for example, a benzoquamine resin (trade name “Eposter L15” or “Eposter MS”) manufactured by Nippon Shokubai Co., Ltd. “Snowtex 30” can be used.

  The relative fine vibration amplitude given to the surface to be polished W1 (work W) and the transfer surface T1 (transfer mold T) depends on the shape of the surface to be polished W1 (transfer surface T1), the material of the resin particles 11 and the abrasive particles 12, and In consideration of the average particle diameter, it is determined in the range of sub-μm (less than 1 μm) to several hundred μm. When such a slight vibration is applied to the workpiece W and the transfer mold T in a state where the slurry 10 is interposed between the surface to be polished W1 and the transfer surface T1, the distance between the surface to be polished W1 and the transfer surface T1 is particularly large. By the movement in the shrinking direction, the resin particles 11 and the abrasive fine particles 12 are strongly pressed against the surface to be polished W1 to perform polishing, and conversely, depending on the movement in the direction in which the interval between the surface to be polished W1 and the transfer surface T1 is widened, the resin particles 11 Then, the force applied to the abrasive fine particles 12 is released, and a new slurry 10 can be supplied (absorbed) between the polishing surface W1 and the transfer surface T1.

  FIG. 3 is a conceptual diagram showing an example of an apparatus for carrying out the polishing method according to the present invention. The polishing apparatus includes an XY table (work support member) 20 that supports the workpiece W below and an XYZ actuator (transfer type support member) 30 that supports the transfer die T below. The XY table 20 includes an X stage 21X that is movable in the X direction within a horizontal plane, and a Y stage 21Y that is supported on the X stage 21X so as to be movable in the Y direction perpendicular to the X direction. A rotary table 22 that can change the rotation phase about the vertical axis Z is supported above. The work W is fixed to a work chuck (work support member) 23 on the rotary table 22.

  The X stage 21X can be moved in the same direction by an X direction actuator 24X, the Y stage 21Y can be moved in the same direction by a Y direction actuator 24Y, and the rotational phase of the rotary table 22 is detected and controlled by an encoder. .

  The XYZ actuator 30 has a tool chuck (transfer type support member) 31 that supports the transfer mold T, and can give a fine vibration by the triaxial actuator (actuator) 32 singly or in combination with the XYZ triaxial directions. it can. Specifically, the XYZ actuator 30 can be composed of a piezo element, for example.

  A slurry holding cylinder 25 shown as a half section is provided on the work chuck 23, and a stirrer 26 is located in the slurry holding cylinder 25. In the slurry holding cylinder 25, the slurry 10 of the resin particles 11 and the abrasive fine particles 12 is put at least to a level where the liquid surface 25X is above the surface W1 to be polished of the workpiece W. The agitator 26 agitates the slurry 10 in the slurry holding cylinder 25 so as to sufficiently disperse the resin particles 11 and the abrasive fine particles 12 as necessary.

  According to this polishing apparatus, the workpiece W supported by the workpiece chuck 23 is positioned on the axis of the transfer mold T supported by the tool chuck 31 by the XY table 20, and the rotational phase of the workpiece W is rotated by the rotary table 22. And the rotational phase of the transfer mold T can be matched. In a state where the level of the liquid surface 25X in the slurry holding cylinder 25 is sufficiently higher than the surface to be polished W1, the surface to be polished W1 of the workpiece W and the transfer surface T1 of the transfer mold T are moved by the XYZ actuator 30 and the triaxial actuator 32. The method of the present invention can be executed by adjusting the interval and finely vibrating the transfer mold T in the Z direction or the X direction (or Y direction) by the XYZ actuator 30 and the triaxial actuator 32 at the adjusted interval. it can.

  4 and 5 show an embodiment in which a large number of resin particle holding recesses T1 'are formed on the transfer surface of the transfer mold T. FIG. The depth of the holding recess T <b> 1 ′ is preferably set to a depth equal to or less than the radius of the resin particle 11 so that the transfer mold T and the work W are not in direct mechanical contact. In the drawing, the size of the holding recess T1 'and the resin particles 11 is exaggerated. A number of holding recesses T1 ′ are formed on the transfer mold T without forming the macroscopic shape of the transfer surface T1 after forming an accurate transfer surface T1 as shown in FIGS. When the unevenness is smoothed, the average transfer surface T1 ″ parallel to the transfer surface T1 is formed. The difference between FIG. 4 and FIG. 5 is the difference in the shape of the resin particle holding recess T1 ′. The recess T1 ′ is preferably formed in a linear shape when viewed in plan, and the linear shape can be selected from a spiral shape, a concentric shape, a random shape, and the like.

  The method of the present invention is particularly useful for polishing a free-form surface or an aspherical surface having no rotation axis, but can also be used for polishing a spherical surface having a rotation axis. It is effective because it is difficult to manufacture. Further, since polishing is performed on the surface, uniform polishing can be performed while maintaining the pre-processed shape without any shape undulation due to polish polishing (per point).

1 is a schematic cross-sectional view of an object to be polished and a transfer mold, showing an example of a polishing method according to the present invention. FIG. 3 is a schematic cross-sectional view showing a state of polishing when a fine vibration in an approaching / separating direction is applied to an object to be polished and a transfer mold. It is a perspective view which shows the specific example of the grinding | polishing apparatus for implementing this invention method. It is a schematic cross section which shows embodiment which formed many resin particle holding recessed parts in the transfer surface of a transfer type. It is a schematic cross section which shows other embodiment which formed many resin particle holding | maintenance recessed parts in the transfer surface of a transfer type.

Explanation of symbols

W Work W1 Polished surface T Transfer mold T1 Transfer surface T1 ′ Resin ball holding recess 10 Slurry 11 Resin particle 12 Polishing fine particle 20 XY table (work support member)
22 Rotary table 23 Work chuck (work support member)
25 Slurry holding cylinder 26 Stirrer 30 XYZ actuator (transfer type holding member)
31 Tool chuck (transfer type holding member)
32 3-axis actuator (actuator)

Claims (14)

Producing a transfer mold made of a metal material or a glass material having a transfer surface in which the surface to be polished and the unevenness of the object to be polished are reversed;
In a slurry in which resin particles and abrasive fine particles having a diameter smaller than that of the resin particles and having a high polishing ability are dispersed, the transfer surface of the transfer mold and the surface to be polished are made to face each other. on the polished surface of the transfer-type transfer surface and the polishing of, without providing relative rotation, giving a relative fine vibration, polishing the surface of the object to be polished step,
A polishing method characterized by comprising: Preparing a slurry in which resin particles and fine abrasive particles having a smaller diameter than the resin particles and high polishing ability are dispersed;
The step of the surface to be polished shapes and irregularities of the polishing target have a reverse of the transfer surface, to produce a transfer type multiple resin particle retention recess of radius less depth is formed of the resin particles to the transfer surface,
In the slurry, the step of facing the transfer surface of the transfer mold and the surface to be polished of the object to be polished; and
The resin particles held in the resin particle holding recess simultaneously contact both the transfer surface of the transfer mold and the surface to be polished of the object to be polished, and the transfer surface of the transfer mold and the surface to be polished of the object to be polished are directly with no contact, to a polished surface of the transfer-type transfer surface and the polishing of which are opposed, without providing relative rotation, giving a relative slight vibration, the polished surface of the object to be polished Polishing step,
A polishing method characterized by comprising: 3. The polishing method according to claim 1 or 2 , wherein the direction of the minute vibration is a direction in which the distance between the surface to be polished and the transfer surface is changed to be large or small. 3. The polishing method according to claim 1, wherein the direction of the minute vibration is a direction in which the surface to be polished and the transfer surface slide together. 3. The polishing method according to claim 1, wherein the direction of the fine vibration is a direction in which a direction in which the distance between the polished surface and the transfer surface is changed to a large size and a direction in which the polished surface and the transfer surface slide are combined. A polishing method. 6. The polishing method according to claim 1, wherein the amplitude of the minute vibration is from sub [mu] m to several hundred [mu] m. In the polishing method of any one of claims 1 to 6, the object to be polished, the polishing method comprising a metal, new ceramic or glass.   8. The polishing method according to claim 1, wherein the average particle diameter of the resin particles is 1 μm to 100 μm, and the average particle diameter of the abrasive fine particles is 0.01 μm to 10 μm.   9. The polishing method according to claim 1, wherein the resin particles are one or more of polyurethane, vinyl chloride, and silicone rubber, and the abrasive particles are colloidal silica, diamond, alumina, cerium oxide, silicon carbide. A polishing method comprising at least one of cubic boron nitride.   10. The polishing method according to claim 1, wherein the surface to be polished is an aspherical surface or a free curved surface.   A polishing apparatus for performing the polishing method according to any one of claims 1 to 10, wherein the work support member supports the workpiece, the transfer mold support member supports the transfer mold, and A polishing apparatus comprising: an actuator that applies a relative fine vibration without applying a relative rotation between a work support member and a transfer mold support member. 12. The polishing apparatus according to claim 11, wherein a large number of resin particle holding recesses having a depth less than or equal to the radius of the resin particles are formed on the transfer surface of the transfer mold. 13. The polishing apparatus according to claim 11 or 12, wherein the actuator is an actuator that applies a slight vibration in the three orthogonal directions alone or in combination.   The polishing apparatus according to any one of claims 11 to 13, wherein the work support member includes a slurry holding cylinder that holds a slurry containing the resin particles and abrasive fine particles, and the slurry holding cylinder includes: A polishing apparatus in which an object to be polished supported by the workpiece support member is located.

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