JP2000024934A - Super abrasive grain grinding wheel for mirror finished surface - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a super abrasive grain grinding wheel for mirror finishing optimum for a rotary table type plane grinder to which a cup type super abrasive grain grinding wheel is to be fitted. SOLUTION: A single layer of super abrasive grain 2 of an average grain size of 10 to 200 μm is sticked on a base metal 3 surface by nickel plating or a wax material. The end part of the super abrasive grain 2 is formed flat with steps between each other being within 1 μm by means of tooling and the flat portion is formed with a minute groove or a recessed part of less than 5 μm deep by means of dressing. These act as cutting edges and makes highly efficient ad accurate mirror finishing of hard and brittle material possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superabrasive grindstone used for mirror-finishing hard and brittle materials such as silicon, glass, ceramics, ferrite, quartz, and cemented carbide, and a truing and dressing method therefor. .

[0002]

2. Description of the Related Art Recently, high-precision mirror finishing has been demanded due to rapid integration of semiconductors and rapid technological innovation in processing of ceramics, glass, ferrite and the like. This mirror finishing is a grinding method generally called lapping, in which loose abrasive grains mixed with lapping liquid are supplied between the lapping plate and the workpiece, and rubbed while applying pressure to the lapping plate and the workpiece. This is a processing method for shaving a workpiece by a rolling action of loose abrasive grains and a scratching action to obtain a highly accurate mirror surface. However, the lapping process consumes a lot of free abrasive grains, so a large amount of a mixture of used free abrasive grains, cutting chips, and lapping liquid, that is, sludge, is generated. Had become.

[0003] The grinding method using the loose abrasive grains has been revised, and research and development of a mirror finishing method using fixed fine superabrasive grains have been actively conducted. As a mirror-polishing method using fixed fine-grain super-abrasive grains, a processing method using a resin-bonded super-abrasive grindstone that elastically holds super-abrasive grains having an average particle size of several μm, An ELID grinding method in which dressing and grinding are performed while melting a bond material is well known.

[0004]

However, in the case of a resin-bonded superabrasive grindstone, fine superabrasive grains are used, so that the sharpness of the grindstone is poor, and the abrasion of the grindstone is large. Easy and frequent truing
There was a problem that had to be dressed. In metal bond superabrasive grindstones, it is necessary to make superabrasive grains finer than resin bond because the bond material is highly rigid when trying to obtain a mirror surface comparable to resin bond,
There was a problem that the sharpness worsened.

[0005]

SUMMARY OF THE INVENTION The present invention provides not only free abrasive processing but also fixed abrasive processing, as well as truing and dressing of a coarse-grain superabrasive wheel with RD.
It is an object of the present invention to provide a super-abrasive grindstone for mirror-finishing having extremely good sharpness and a long life. Coarse-grain superabrasives enable large-capacity chip pockets to smoothly discharge chips and enable high-efficiency machining, and flat grooves or recesses increase the number of working abrasives, similar to fine-grained superabrasives A high-quality surface roughness is obtained, and the coarse superabrasive grains are firmly held by nickel plating or brazing material, so that the abrasive grains hardly fall off and a long life is obtained. That is, it is an object of the present invention to provide a super-abrasive grindstone for mirror finishing having both features of coarse particles and fine particles.

[0006] A feature thereof is a cup-type superabrasive grinding wheel mounted on an in-feed notch surface grinding machine having a rotatable water table having an axis parallel to the grinding wheel axis, Super-abrasive grains having an average particle diameter of 10 to 200 μm are further fixed by nickel plating or brazing material, and the tip of the super-abrasive grains has a flat portion with a mutual step difference of 1 μm or less by truing, and is further dressed. A micro-groove or concave part having a depth of 5 μm or less is formed in a flat part, and this is a super-abrasive grindstone for mirror-finished hard and brittle material that acts as a cutting edge.

[0007] Here, an in-feed cutting type surface grinder is a machine in which either a superabrasive grindstone or a work table is provided with a cut only in the direction of the rotation axis. , A vertical axis rotary table type surface grinder, a horizontal axis rotary table type surface grinder, and the like. As the brazing material, an Ag-Cu-based brazing material is preferable, but an Ag-Cu-Ti-based brazing material containing a small amount of Ti or the like is more preferable because it particularly wets the surface of diamond well.
Diamond, CBN, brazing or nickel plating
By containing 2 to 40% by volume of hard particles such as SiC and Al ₂ O _{3, the} wear resistance of the bond material can be improved, and the abrasive particles can be more firmly held. The average particle diameter of the superabrasive grains is preferably 50 μm or more, since the larger the grains, the better the results are obtained in consideration of the life of the grindstone and the holding power of the abrasive grains.

[0008] The superabrasive is a highly crushable, irregularly shaped synthetic superabrasive for resin bonding, and a groove for discharging cutting chips is formed on the grinding surface with respect to the entire grinding surface. And an area ratio of 5 to 40%.

Synthetic superabrasives for resin bond are more friable than synthetic superabrasives for metal bond and synthetic blades for saw blades. It is particularly suitable for forming a sharp cutting edge. Fig. 3 shows the RD,
2 shows an enlarged three-dimensional image of dressed synthetic diamond abrasive grains for a resin bond. It can be seen that a number of small grooves of about 0.5 μm are formed on the flat surface after truing. At the time of mirror finishing, it is considered that these minute grooves act as cutting edges. FIG. 4 shows truing and dressing of synthetic diamond abrasive grains for saw blades under the same conditions. It can be seen that fine grooves are less likely to be formed than for resin.

As synthetic superabrasives for resin bonding, GE
Super AVG, RVG, RVG-D, RV
GW or Tomei Diamond Co., Ltd., IRV,
IRV-NP or De Bierce, CDA, CD
AM can be applied. Grooves for the purpose of discharging cutting chips are provided in an area ratio of 5 to 40% with respect to the entire grinding operation surface in a form such as a radial shape or a mesh shape on the grinding operation surface. In the case of a cup-type superabrasive grindstone having an outer diameter of Φ150 mm to Φ400 mm, a groove having a width of 1 mm to 10 mm is formed on the outer periphery of the grindstone by
It is common to provide them radially so as to divide them into 64 equal parts.

The mutual step of the flat portion after truing is
The thickness must be within 1 μm, and preferably within 0.5 μm if a higher quality mirror surface is to be obtained. Further, the area (S) of the flat portion per super abrasive grain formed after truing needs to be within the above range of 8 × 10 ⁻⁵ mm ² ≦ S ≦ 3 × 10 ⁻² mm ² . The upper and lower limits are defined by the maximum flat area when the average particle diameter is 200 μm and the minimum flat area when the average particle diameter is 10 μm.

RD for truing and dressing
Is most preferable in consideration of efficiency and molding accuracy, but instead of RD, the diamond particle size is # 30 (particle size 6).
It is also possible to use a metal-bonded grindstone or an electrodeposited grindstone in which the variation in the height of the tip of the diamond abrasive particles is reduced to about 50 μm).

Regarding the truing and dressing conditions, when the superabrasive grindstone and the RD are rotated in the same direction at the contact point (down dressing), the radial wear of the RD is small, and good results can be obtained. First, details of the truing conditions will be described. Peripheral speed ratio (peripheral speed of superabrasive grinding wheel /
If the value (q) of the RD peripheral speed), the RD contact width (b), the traversal amount of the RD (F), the cutting depth per pass of the RD (a), the truing condition is 0.01 ≦ q ≦ 0.1 F = (0.05-0.3) × b / rev. 1 μm ≦ a ≦ 10 μm. The following setting range is more preferable, and the truing efficiency is particularly improved as the peripheral speed ratio (q) approaches 0.01. 0.01 ≦ q ≦ 0.05 F = (0.2-0.3) × b / rev. 1 μm ≦ a ≦ 3 μm

Next, the details of the dressing conditions will be described. Peripheral speed ratio (peripheral speed of superabrasive grinding wheel / peripheral speed of RD) (qd), RD contact width (b), traverse amount of RD (Fd), depth of cut per pass of RD (a
d), the dressing conditions are as follows: 0.1 ≦ qd ≦ 0.9 F = (0.01 to 0.2) × b / rev. 1 μm ≦ ad ≦ 5 μm. More preferably, the following setting range is set, and as the peripheral speed ratio (q) approaches 0.9, the RD crushing action increases, and many fine grooves or concave portions are formed on the surface of the superabrasive grindstone. The sharpness of the superabrasive grindstone is significantly improved. 0.6 ≦ qd ≦ 0.9 F = (0.01 to 0.1) × b / rev. 1 μm ≦ ad ≦ 3 μm

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described in the following Examples.

[0016]

(Example 1) RD was prepared by uniformly dispersing diamond abrasive grains and further fixing with a nickel plating.
With truing dressing. Then, mirror processing of single crystal silicon was performed, and the effect of the present invention was confirmed. The details of the experimental conditions are shown below. 1. Specifications of superabrasive grindstone Size Φ125-3w (6A2 type) Superabrasive grain size Diamond (average particle size 150μm) Binder Nickel plating 2. 2. Specifications of RD Size Φ150-5t (1A1 type) Particle size Average particle size 600μm Binder Nickel plating 3. Truing conditions Super-abrasive wheel peripheral speed 47 m / min (120 rpm) RD peripheral speed 1130 m / min (2500 rpm) Peripheral speed ratio 0.04 Cutting depth 1 μm / pass Traverse speed 150 mm / min (1. 25 mm / rev.) Dressing conditions Super-abrasive grindstone peripheral speed 785 m / min (2000 rpm) RD peripheral speed 1130 m / min (2500 rpm) Peripheral speed ratio 0.67 Cutting depth 1 μm / pass Traverse speed 150 mm / min (0. 08 mm / rev.) 5. 5. Grinding test conditions Super-abrasive grindstone peripheral speed 25m / sec Cutting speed 5μm / min Workpiece material Single crystal silicon Grinding fluid JIS W2 2% aqueous solution 6. Result Surface roughness 0.05 μmRa Good sharpness and no clogging.

(Example 2) Diamond abrasive grains finer than those in Example 1 were uniformly dispersed, and a superabrasive grain stone further fixed by nickel plating was subjected to truing and dressing by RD. Then, mirror processing of single crystal silicon was performed, and the effect of the present invention was confirmed. The details of the experimental conditions are shown below. 1. Specification of superabrasive grindstone Size Φ125-3w (6A2 type) Superabrasive grain size Diamond (average particle size 50μm) Binder Nickel plating Groove A 2mm wide groove is radially provided on the grinding surface in 24 equal parts 2 . 2. Specifications of RD Size Φ150-5t (1A1 type) Size Φ150-5t (1A1 type) Particle size Average particle size 600 μm Binder Nickel plating Truing conditions Super-abrasive grindstone peripheral speed 47 m / min (120 rpm) RD peripheral speed 1130 m / min (2500 rpm) Peripheral speed ratio 0.04 Cutting depth 2 μm / pass Traverse speed 150 mm / min (1. 25 mm / rev.) 4. Dressing conditions Super-abrasive grindstone peripheral speed 785 m / min (2000 rpm) RD peripheral speed 1130 m / min (2500 rpm) Peripheral speed ratio 0.67 Cutting depth 1 μm / pass Traverse speed 150 mm / min (0. 08 mm / rev.) 5. 5. Grinding test conditions Super-abrasive grindstone peripheral speed 25m / sec Cutting speed 5μm / min Workpiece material Single crystal silicon Grinding fluid JIS W2 2% aqueous solution 6. Result Surface roughness 0.04 μmRa Good sharpness and no clogging.

Example 3 Diamond abrasive grains coarser than those of Examples 1 and 2 were uniformly dispersed, and a superabrasive grain stone further fixed with a brazing material was truing and dressed by RD.
Then, mirror processing of single crystal silicon was performed, and the effect of the present invention was confirmed. The details of the experimental conditions are shown below. 1. Specification of superabrasive grindstone Size Φ250-3w (6A2 type) Superabrasive grain size Diamond (average particle size 200μm) Binder Brazing material (Ag-Cu-Ti system) Groove 4mm wide groove is formed radially on the grinding surface In 24 equal parts. 2. 2. Specifications of RD Size Φ150-5t (1A1 type) Particle size Average particle size 600μm Binder Nickel plating 3. Truing conditions Super-abrasive wheel peripheral speed 47 m / min (120 rpm) RD peripheral speed 1130 m / min (2500 rpm) Peripheral speed ratio 0.04 Cutting depth 1 μm / pass Traverse speed 150 mm / min (1. 25 mm / rev.) Dressing conditions Super-abrasive wheel peripheral speed 785 m / min (2000 rpm) RD peripheral speed 1130 m / min (2500 rpm) Peripheral speed ratio 0.67 Cutting depth 1 μm / pass Traverse speed 150 mm / min (0. 08 mm / rev.) Grinding test conditions Super-abrasive grindstone peripheral speed 30 m / sec Cutting speed 6 μm / min Workpiece material Single crystal silicon Grinding fluid JIS W2 2% aqueous solution 7. Result Surface roughness 0.05 μmRa Very sharp, no clogging.

[0018]

According to the present invention, hard brittle materials such as silicon, glass, ceramics and ferrite can be mirror-finished with high quality and high efficiency by truing and dressing a coarse-grain superabrasive grindstone.

[Brief description of the drawings]

FIG. 1 is a diagram showing a superabrasive grinding wheel of one embodiment and a layout at the time of grinding.

FIG. 2 is a diagram showing a layout of a truing and dressing of a superabrasive grindstone.

FIG. 3 (a) Enlarged three-dimensional image of diamond abrasive tip for resin bond after truing and dressing (b) Surface roughness as above

FIG. 4 (a) Enlarged three-dimensional image of diamond abrasive tip for saw blade after truing and dressing (b) Surface roughness as above

[Explanation of symbols]

 Reference Signs List 1 superabrasive grindstone 2 superabrasive grain 3 base metal 4 RD (diamond rotary dresser) 5 work table 6 workpiece b contact width of RD

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B24D 3/06 B24D 3/06 BF Term (Reference) 3C047 AA04 AA05 AA13 AA15 AA31 3C063 AA02 AB05 BA24 BB02 BB07 BC02 BC03 BG10 CC09 CC13 EE10 EE15 EE16 EE17 FF20 FF23 FF30

Claims (5)

[Claims] 1. A cup-type superabrasive grinding wheel having an axis parallel to a grinding wheel axis and mounted on an in-feed notch type surface grinding machine having a rotatable work table, wherein the average particle diameter is 10 to 10. A super-abrasive grain of 200 μm is further fixed to the base metal surface by nickel plating or brazing material, and the tip of the super-abrasive grain has a flat portion with a step difference of 1 μm or less by truing, and the flat portion is further dressed. A micro-groove or recess with a depth of 5 μm or less is formed in
A super-abrasive grinding wheel characterized in that this acts as a cutting edge and is used for mirror finishing of hard and brittle materials. 2. The super-abrasive grain is a synthetic super-abrasive grain for resin bond having a high friability and an irregular shape, and a groove for the purpose of discharging chips is formed on the grinding action surface. 2. The superabrasive grinding wheel according to claim 1, wherein 5 to 40% of the total area is provided. 3. A truing wherein the area (S) of a flat portion per superabrasive grain formed after the truing satisfies 8 × 10 ⁻⁵ mm ² ≦ S ≦ 3 × 10 ⁻² mm ^2. The superabrasive grinding wheel according to claim 1, wherein the grinding wheel is made. 4. The truing is performed by using a diamond rotary dresser (RD), wherein the superabrasive grindstone and the RD rotate in the same direction at a contact point, and have a peripheral speed ratio (superabrasive grindstone). If the value (q) of (peripheral speed of RD / peripheral speed of RD) is 0.01 ≦ q ≦ 0.1 and the contact width of RD is (b), the traverse amount of RD per rotation of the superabrasive grindstone (F) ), F = (0.05-0.3) × b / rev. 3. The cutting depth (a) per pass of the RD is set within a range of 1 μm ≦ a ≦ 10 μm or more.
Or a superabrasive grinding wheel according to 3. 5. The dressing is performed using a diamond rotary dresser (RD), wherein the superabrasive grindstone and the RD rotate in the same direction at a contact point, and have a peripheral speed ratio (superabrasive grindstone). Traverse amount (Fd) of the RD per one rotation of the superabrasive grindstone, assuming that the value (qd) of the peripheral speed of the RD / (the peripheral speed of the RD) is 0.1b. ), Fd = (0.01-0.2) × b / rev. The cutting depth (ad) per pass of the RD is set in a range of 1 μm ≦ ad ≦ 5 μm or more.
The superabrasive grindstone according to 2, 3, or 4.