JPH09295255A - Grinding wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a groove shape appropriate for a very fine grain diamond wheel by providing a spiral groove from the center to the outside in the direction opposite to the rotating direction of a wheel. SOLUTION: In a very fine grain diamond wheel, a grinding grain layer 5 of the very fine grain diamond is formed on a metal base 3. A surface of the grinding grain layer 5 is formed with a spiral groove 7. Depth of the groove is set at 1.5mm, width thereof is set at 2mm and a center-to-center distance of the adjacent grooves is set at 5mm. Since the spiral groove is formed from the center to the outside in the direction opposite to the rotating direction of the wheel, the grinding liquid is smoothly flowed from the center of the wheel to the outside along the spiral wheel by the centrifugal force, and grinding chips generated in a grinding part is discharged outside with the grinding liquid, and at the same time, the grinding liquid is evenly supplied to working points. Since the spiral groove forms an escape way of the grinding liquid, film thickness is reduced, and floating of a work can be restricted small. Grinding ability can be thereby improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION This invention relates to a grinding wheel,
It is suitable for an ultrafine grain diamond wheel that processes a flat surface of hard and brittle materials such as silicon and ceramics and various metal materials into a mirror surface with extremely small surface roughness.

[0002]

2. Description of the Related Art Lapping and polishing using free abrasive grains have been used more frequently than before when flat surfaces such as optical materials, electronic parts, and ceramics are processed into mirror surfaces. However, while these processing methods easily obtain a mirror surface having a small processed surface roughness, they are not good in shape accuracy, processing accuracy, workability, and the like. In addition, there is a problem that dust is generated during work, which deteriorates the work environment.

Therefore, it is considered to replace these operations with a fixed abrasive grain, that is, a grinding process using an ultrafine grain diamond wheel and a high-precision plane honing machine. However, in the ultrafine-grained diamond wheel, the amount of diamond abrasive grains forming the cutting edge is as small as several μm, and therefore the amount of protrusion of the abrasive grains from the surface of the bond layer is extremely small. For this reason, it is difficult to smoothly supply the grinding liquid to the processing point, and it is easy for abrasion of diamond abrasive grains due to grinding heat and adhesion of clogging (clogging). As a result, the ultrafine-grained diamond wheel is less sharp and has a shorter life than the coarse-grained diamond wheel.

Further, when the wheel is rotated at a high speed, the workpiece may be lifted up by the dynamic pressure levitation force of the grinding fluid film, which may hinder the grinding.

In order to suppress these phenomena, conventionally, radial grooves (FIG. 1) and concentric circular grooves (FIG. 2) are provided on the surface of the abrasive grain layer of the diamond wheel. As a result, the supply of the grinding liquid to the grinding point is promoted to some extent and the floating of the work piece is suppressed to some extent, but a sufficient effect cannot be obtained as the diamond abrasive grain size becomes smaller. Furthermore, for wheels with concentric circular grooves,
If grinding is performed while the workpiece is fixed (without rotating), unevenness (waviness) corresponding to the wheel groove pitch is generated on the grinding surface, and there is a problem that the grinding surface accuracy deteriorates.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a groove shape suitable for an ultrafine diamond wheel.

[0007]

In the present invention, a groove provided on the surface of an abrasive grain layer of an ultrafine grain diamond wheel is spirally formed (FIG. 3). The number of spiral grooves may be one or plural. The spiral groove is provided so as to be opposite to the rotation direction of the wheel when tracing from the center to the outside. In order to improve the flow of the grinding liquid, radial grooves may be provided in addition to the spiral grooves.

The grooved diamond wheel can be manufactured by any of metal bonding, resin bonding and electrodeposition. In the case of metal bond, a metal base is placed in a carbon-made sintering mold and filled with a mixture of diamond abrasive grains and metal powder (Fe, Co, etc.),
This is heated to 700 to 900 ° C. and an abrasive grain layer is formed at a pressure of 300 to 500 Kg / cm 2. Then, during the molding, the pressing die is pressed to transfer the spiral groove to the abrasive grain layer.

In the case of resin bond, resin powder (phenol, polyimide, etc.) is used instead of metal powder,
Heat to ~ 220 ℃, mold at a pressure of 600 ~ 800 Kg / cm2, and transfer the groove using a pressing mold on the way. In the case of electrodeposition, a spiral groove is preliminarily formed on the base and diamond abrasive grains are fixed to the spiral groove by electro nickel plating or electroless nickel plating.

[0010]

By providing the spiral groove in this way, the grinding fluid flows outward from the center of the wheel along the spiral groove due to the centrifugal force generated by the rotation of the wheel, thereby spreading the grinding fluid to the machining point. At the same time, the grinding dust is discharged to the outside.

Further, since the distance from the wheel center is not constant at each point on the spiral groove and the position of the groove on the surface of the abrasive grain layer constantly changes with respect to the work piece, the work surface does not rotate even if the work piece does not rotate. The groove shape is not transferred to the surface, and problems such as waviness do not occur.

As described above, since the groove shape is not transferred to the workpiece in the spiral groove, it is possible to make the pitch small and densely engrave the entire surface of the abrasive grain layer. When rotated by, the workpiece can be prevented from rising due to the dynamic pressure levitation force of the grinding liquid film generated.

[0013]

EXAMPLE FIG. 3 shows an ultrafine diamond wheel, in which an abrasive layer 5 of ultrafine diamond is formed on a metal base 3. 1 on the surface of the abrasive layer
A spiral groove 7 is formed. Groove depth is 1.5m
m, width 2 mm, center distance between adjacent grooves 5 mm.

The spiral grooved wheel 1 is attached to a flat honing machine for use as shown in FIG. In the figure,
Reference numeral 9 is a workpiece, reference numeral 11 is a motor for rotating the workpiece, and reference numeral 13 is a spring for pressing the workpiece against the grinding wheel. Reference numeral 15 is a grinding liquid supply nozzle.

In order to verify the effect of the spiral groove, comparative experiments were performed on a grooveless wheel, a radial grooved wheel, and a spiral grooved hole. Table 1 shows the wheel specifications and processing conditions used.

[Table 1] FIG. 5 is a comparison of changes in processing amount when zirconia ceramics are ground for 5 minutes. It can be seen that the spiral grooved wheel can process 2.4 times as much as the ungrooved wheel and 1.3 times as much as the radial grooved wheel. FIG.
Indicates the change in the machined surface roughness at that time, and the two machined wheels are inferior in machined surface roughness compared to the spiral grooved wheel. This is because the ungrooved and radiation grooved wheels have inferior grinding ability and cannot sufficiently remove the machined surface roughness generated in the pre-machining of the workpiece.

FIG. 7 shows the roughness of the ground surface when the zirconia ceramics were processed with the spiral grooved wheels of grain sizes # 1500 and # 5000. Rmax 48n in case of # 1500 with processing time of about 5 minutes
In the case of m and # 5000, a very small machined surface roughness of Rmax 30 nm can be obtained.

[0017]

As described above, according to the present invention, the spiral groove is formed in the grinding hole, and when the spiral groove is traced from the center, the rotation direction is opposite to the rotation direction of the wheel. The grinding fluid smoothly flows outward from the center of the wheel along the spiral groove to the outside due to the centrifugal force, whereby the grinding debris generated in the grinding section is efficiently discharged together with the grinding fluid, and at the same time, the grinding fluid Since evenly distributed over the processing points, the grinding ability is improved.

When the wheel is rotated at high speed,
In the grinding fluid film that causes the dynamic pressure levitation force to float up the work piece, the spiral groove provides an escape path for the grinding fluid, so the film thickness becomes smaller, and the work piece lift can be suppressed to a small level. .

Further, since the distance from the wheel center is not constant at each point on the spiral groove and the position of the groove on the surface of the abrasive grain layer constantly changes relative to the work piece, the work surface does not rotate even if the work piece does not rotate. The groove shape is not transferred to the surface, and problems such as waviness do not occur. Thereby, the quality of the processed surface of the workpiece can be improved.

[Brief description of drawings]

FIG. 1 is an illustration of a grinding wheel with radial grooves.

FIG. 2 is an explanatory diagram of a concentric grooved wheel.

FIG. 3 is an explanatory view of a spiral grooved wheel according to the present invention.

FIG. 4 is a schematic diagram of a high precision plane honing machine.

FIG. 5 is a chart showing a change in cumulative processing amount.

FIG. 6 is a chart showing a change in processed surface roughness.

[Explanation of symbols]

 1 Wheel 5 Abrasive Layer 7 Spiral Groove 9 Workpiece

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[Procedure amendment]

[Submission date] June 28, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of drawings]

FIG. 1 is an illustration of a grinding wheel with radial grooves.

FIG. 2 is an explanatory diagram of a concentric grooved wheel.

FIG. 3 is an explanatory view of a spiral grooved wheel according to the present invention.

FIG. 4 is a schematic diagram of a high precision plane honing machine.

FIG. 5 is a chart showing a change in cumulative processing amount.

FIG. 6 is a chart showing a change in processed surface roughness.

[Fig. 7] Table showing the finished surface roughness of zirconia ceramics
It is a chart.

[Explanation of Codes] 1 Wheel 5 Abrasive Grain Layer 7 Spiral Groove 9 Workpiece

Claims (1)

[Claims] 1. A surface of an abrasive grain layer perpendicular to a rotation axis,
A grinding wheel in which a spiral groove is provided so as to move away from the rotation center as it orbits the rotation center, and the rotation direction of the spiral groove traced from the center is opposite to the rotation direction of the wheel.