JPH07136936A - Diamond grinding wheel - Google Patents

Abstract

PURPOSE:To provide excellent abrasion resistance and fracture resistance strength so as to improve surface roughness of a machined surface by fixing plural pillar monocrystal diamonds on a grinding working face of a wheel at the equal height in the predetermined arrangement pattern while respectively arranging their crystal orientations in the equal direction. CONSTITUTION:As the crystal orientations of plural pillar monocrystal diamond chips 4 buried in the circumferential face of a cylindrical wheel 1 are arranged in the equal direction, any crystalline grain on a grinding working face 1A is abraded uniformly, so that truing work is required at only the first time. When an interval and a projection amount of the diamond chips 4 are increased, a clearance between the chips 4, in other words, a chip pocket can be increased, so that dressing work can be greatly reduced. On the other hand, the projection amount of the chip pocket 4 is minimized, and the chips 4 are arranged in the crystal orientations having strong strength against the grinding direction, so that the crystalline grains are hardly fractured fragilely during the action, and abrasive grains hardly fall off as the abrasive grains are uniformly held, and consequently, deterioration in the surface roughness can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a diamond grindstone suitable for grinding a brittle material such as silicon, glass or ceramics with a minute depth of cut below the brittle ductile transition point, and particularly to a base metal or a wheel as a base material. The present invention relates to a diamond grindstone in which single crystal diamond grains are fixed on the peripheral surface or the end surface.

[0002]

2. Description of the Related Art Conventionally, as a diamond grindstone, natural diamond crushed fine diamond is mixed with a bonding agent and fired into a wheel shape, or crushed fine diamond is fired into a pellet shape together with a bonding agent. It is known that the bases are arranged and fixed in a predetermined pattern on a grinding work surface of a wheel or a base metal. In this case, since the cutting edge of the diamond abrasive grains is preferably opposed to the surface to be processed vertically, the diamond abrasive grains are embedded in the wheel or base metal so as to be perpendicular to the grinding work surface of the grindstone, It is fixed. For example, Japanese Patent Publication 57-2535
In Japanese Patent Laid-Open No. 1, a cover provided with a through hole that is spaced apart from the surface of a base metal to which diamond abrasive grains are fixed and through which diamond abrasive grains having a large aspect ratio can pass in the vertical direction is arranged, and vibration is applied to the whole. It is disclosed that diamond abrasive grains are scattered on a cover and the diamond abrasive grains that have passed through the through holes of the cover in an upright state are attached to the surface of a base metal below. The diamond tool for rock drilling disclosed in Japanese Patent Laid-Open No. 2-262963 uses a magnetic field to erect diamond grains up and down, and in this state, the diamond grains are allowed to fall freely into the lower carbon mold and sintered and fixed together with a binder. As a result, the cutting edge of each diamond grain stands upright against the work piece.

[0003]

Generally, diamond grindstones have different fracture strengths and wear characteristics depending on the crystal orientation of the abrasive grains, but conventional diamond grindstones have irregular crystal orientations of the diamond grains, so that when actually used Wear becomes uneven. In the above two prior art diamond grindstones, the crystal grains are arranged in an upright state so as to face the workpiece, but this is because the shapes of the crystal grains are aligned in one direction, and the crystal orientation is Since they are disjointed, there is a difference in the wear rate of each diamond grain for one grindstone, sufficient surface accuracy cannot be obtained, and parts with high strength and weak parts in the grinding direction coexist. It causes brittle fracture during work. Further, in the conventional method, when the diamond is fired during the manufacturing process of the grindstone, cracks are generated in the diamond crystal and the diamond crystal is fixed to the base material with the crystal orientations being uneven, so that the crystal is easily broken during grinding.

Further, conventional diamond grindstones which are prepared by mixing finely ground diamonds with a bonding agent and firing are weak in the bond between the bonding agent and the diamond crystal grains, and there is a risk that the diamond grains may fall off during the grinding operation. . If the abrasive grains fall off, the surface roughness of the machined surface is deteriorated even in the case of minute cuts of 0.1 μm or less, for example. In order to solve this problem, diamond has been made finer to a size of several μm or less and the diamond abrasive grains have been firmly fixed with a metal such as bronze, but this has not been a complete solution to the above problems. Since the diamond abrasive grains fall off, the number of times truing and dressing increases, which hinders the improvement of the grinding work efficiency.

The present invention solves the above-mentioned conventional problems and is particularly excellent in wear resistance and fracture resistance, and the number and arrangement of single crystal diamonds can be easily selected according to the processing conditions and the required accuracy of the processed surface. Another object of the present invention is to provide a diamond whetstone that can reduce the number of truing and dressing operations.

[0006]

DISCLOSURE OF THE INVENTION A diamond grindstone according to the present invention has a plurality of pillar-shaped single crystal diamonds whose crystal orientations are aligned in the same direction on a grinding work surface of a wheel.
They are fixed at the same height and in a predetermined arrangement pattern. According to one aspect of the invention, the cutting edge of the columnar single crystal diamond is fixed vertically to the grinding work surface of the wheel.

[0007]

[Function] Since the crystal orientations of a plurality of columnar single-crystal diamond tips embedded in the peripheral surface of the cylindrical wheel or the tip surface of the cup-shaped wheel are aligned, any crystal grains on the grinding work surface are evenly worn. Therefore, the truing work is done only at the beginning. By increasing the distance between the diamond tips and the protrusion amount, the gap between the tips, that is, the tip pocket can be increased, and the dressing work can be greatly reduced. In addition, by reducing the amount of protrusion of the tip to the necessary minimum and aligning the crystal orientation with strong strength in the grinding direction, brittle fracture of crystal grains during operation does not occur easily, and the retention of abrasive grains is uniform Therefore, the abrasive grains are less likely to fall off during operation, and deterioration of the surface roughness of the processed surface can be prevented. By arranging relatively large crystal pieces at the same height, the number of effective working abrasive grains increases, and it becomes possible to improve the surface roughness by making a very small cut below the brittle ductile transition point.

[0008]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a partial sectional view of a diamond grindstone according to an embodiment of the present invention, which is cut along a plane perpendicular to a grinding work surface of the grindstone, and FIGS. 2A and 2B are respectively shown in FIG.
3 shows various examples of the implanting direction of the single crystal diamond tip, that is, the crystal orientation of each tip when viewed from the F direction. A plurality of holes 2 having a predetermined depth are bored in a grinding work surface 1A of a wheel 1 which is a base material for holding a diamond grindstone, and a columnar single crystal diamond chip 4 is provided in each of these holes 2 via a bonding agent 3. Is embedded. The single crystal diamond tip 4 in this case may be either natural diamond or artificial synthetic diamond, but synthetic diamond is preferable in order to keep the shape and size constant. The tip 4 of the example is a prismatic synthetic diamond tip having a length of about 2 to 5 mm and a lateral width of about a few.
An appropriate size is selected depending on the grinding conditions or the like within the range of 0 μm to several mm, and each chip 4 has the same shape for one wheel. The protrusion heights of the respective chips 4 from the grinding work surface 1A are all the same.

In this embodiment, the cutting edge of the single crystal diamond tip 4 is fixed vertically to the grinding work surface 1A of each tip 4. As the actual grinding conditions,
It is best to fix the cutting edge vertically to the grinding work surface 1A, but it may be tilted to some extent from the vertical state.

As shown in the enlarged view of FIG. 3, the prismatic single crystal diamond tip 4 has crystal planes (110) and (11).
1), (211), ..., And they are cut so that their crystal orientations (indicated by arrows in the drawing) are the same for each chip. Such diamond tips 4 are all implanted in the holes 2 of the wheel 1 with their crystal orientations aligned in the same direction as shown in FIG. 2 (A) or (B),
It is fixed by a strong bonding agent 3 such as an adhesive, resin or plating. The arrangement pattern is arranged in one row in the grinding direction or in a plurality of rows as illustrated in FIG. 4 at equal intervals, and the pitch P (chip spacing) or the total number is the surface roughness of the work surface, the material of the work material or It is arbitrarily determined according to grinding conditions such as processing cycle time. Also each chip 4
The protrusion amount h from the grinding work surface 1A is also determined by the grinding conditions in consideration of the size of the tip 4.

FIGS. 5A and 5B show an embodiment in which the single crystal diamond tip 4 is embedded in the cup-shaped wheel 5 by applying the present invention, and FIGS. 6A and 6B are shown. It is an example in which the present invention is applied to a cylindrical wheel 6. The prism-shaped single crystal diamond tips 4 with the crystal orientations aligned are arranged in a row on the tip surface 5A (FIG. 5) of the cup-shaped wheel 5 or in a row on the outer peripheral surface 6A (FIG. 6) of the cylindrical wheel 6. It is embedded and fixed with a bond agent. The protrusion amount h of the tip 4 from the wheel surface and the mounting pitch P are the same for one wheel 5 or 6, but as described above, these dimensions are determined by the tip size and grinding conditions. The truing of the grinding wheel configured in this way is
For example, a method using pellets of sintered diamond, a method using a lapping plate and diamond paste, or the like is adopted.

Here, regarding how to distinguish the crystal orientation of the single crystal diamond tip 4, the crystal orientation is confirmed with an optical microscope. Further, in one method of fixing the single crystal diamond chip 4 to the hole 2 of the wheel 1, the single crystal diamond chip 4 is fixed with an epoxy resin adhesive or the like.

The single crystal diamond grindstone according to the present invention is
For example, brittle materials such as silicon single crystal, ceramics, and glass are suitable for improving the processing accuracy, particularly the surface roughness, by performing ductile mode grinding, that is, finish grinding with a minute cut below the brittle ductile transition point. Finish grinding of brittle materials is conventionally performed by utilizing a self-developing blade with ultra-fine abrasive grains, but a relatively large abrasive grain firmly fixed as in the present invention, that is, a single crystal diamond tip is used as a wheel. It is possible to improve the surface roughness due to the above-mentioned minute cuts by adhering the chips to the grinding work surface in a uniform height, increasing the number of effective working abrasive grains, and aligning the crystal orientation of each chip.

[0014]

As described above, according to the present invention, by aligning the crystal orientations of columnar single crystal diamond chips in the same direction, the chips are uniformly worn and the truing of the grindstone is maintained well. , The efficiency of grinding work is improved. The wear resistance of the entire grindstone can be improved by aligning the crystal orientation of the diamond tip with a direction that is resistant to wear. The amount of protrusion of each tip, the number of attachments, and the mounting interval can be selected according to the grinding conditions.By increasing the amount of protrusion of the tip, the tip pocket can be made larger, the number of dressings can be reduced, and conversely, the amount of protrusion can be set small. In addition, by aligning each chip in a crystal orientation with high strength, it is possible to prevent brittle fracture of the chip during processing and to improve the surface roughness of the processed surface.

[Brief description of drawings]

FIG. 1 is a partial vertical sectional view of a single crystal diamond grinding wheel according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a direction in which a diamond tip is embedded in a wheel as seen from a direction F of FIG.

FIG. 3 is a partial perspective view showing an example of a prismatic diamond tip applied to the present invention.

FIG. 4 is a diagram showing an example of an array pattern of a single crystal diamond tip according to the present invention.

FIG. 5 is a diagram showing a diamond grindstone using a cup-shaped wheel according to an embodiment of the present invention.

FIG. 6 is a view showing a diamond grindstone using a cylindrical wheel according to another embodiment of the present invention.

[Explanation of symbols]

 1 Wheel 2 Holes 3 Bonding Agent 4 Single Crystal Diamond Tip 5 Cup Type Wheel 6 Cylindrical Wheel

Claims (2)

[Claims] 1. A plurality of columnar single crystal diamonds are aligned in the same direction in the same direction on the grinding work surface of the wheel.
A diamond grindstone characterized by being fixed at the same height and in a predetermined arrangement pattern. 2. The diamond grindstone according to claim 1, wherein the cutting edge of the columnar single crystal diamond is vertically fixed to a grinding work surface of the wheel.