JPS6080563A - Grinding wheel - Google Patents

Abstract

PURPOSE:To prevent a grinding burn and a grinding crack from being caused even if dry grinding is performed, by holding abrasive grains with lubricating materials by a polyurethane rubber bond, in the case of a grinding wheel suitable for grinding a grind-difficult material. CONSTITUTION:A cup-shaped metallic bed 1 provides on its upper surface 1a a circular annular groove 1b in which an abrasive grain layer 5 in a predetermined thickness is formed. This abrasive grain layer 5, after dispersing diamond abrasive grains 2 with lubricating materials 3 in the groove 1b and injecting a liquid state polyurethane rubber bond 4 to be hardened, is protrusively formed by scraping off the upper surface 1a of the bed 1 to the predetermined height from the bottom surface of the groove 1b. In such way, the grinding wheel, never causing a grinding burn and a grinding crack due to grinding heat even if a grind-difficult material such as titanium nitride system cermet is dry ground, reduces the resistance applied to the abrasive grain layer, enabling the continuous grinding even without performing dressing work further improving grinding ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a grinding wheel suitable for grinding difficult-to-grind materials such as titanium nitride cermets.

As is well known, a grinding wheel is made of abrasive grains bonded with a binder, and the abrasive grains are made of silicon carbide, white arundum,
By selecting and combining cubic boron nitride, etc., and binders such as resin, metal, or glass, we can create products with various properties depending on the workpiece material. is being produced.

By the way, when this grinding wheel is used to dry-grind a difficult-to-grind material such as titanium nitride-based cermet, problems such as grinding burns occur due to grinding heat. In other words, when the grinding wheel comes into contact with the workpiece material and grinding begins, the abrasive grains gradually cut into the workpiece material, until the force acting on the abrasive grains and the workpiece material exceeds a certain value. In this case, the workpiece material is not cut but only elastically deformed. At this time, the abrasive grains do not slide on the workpiece material, and grinding heat is generated.

For example, if the workpiece material is cemented carbide, its thermal conductivity is approximately α
19 (2f/#eC"C" is relatively high, so this grinding heat is removed through the workpiece material itself or by chips. However, when the workpiece material is titanium nitride cermet, Thermal conductivity is α06CIIL/cIr
Because the temperature was as low as L8ec℃, this grinding heat could not be completely dissipated, resulting in oxidation of the surface, resulting in grinding burns, increased stress on the abrasive grains, and accelerated flank wear of the abrasive grains, as well as grinding cracks.
There was a problem that occurred. Therefore, conventionally, wet grinding has been used to grind difficult-to-grind materials such as those described above. However, wet grinding also has the disadvantage that grinding heat cannot be sufficiently dissipated, and continuous grinding is not possible without constant dressing work. In addition, wet grinding requires cleaning the workpiece material, removing dirt from the machine, replenishing the grinding fluid, etc. after the grinding process, and has extremely poor workability.

The present invention solves the above-mentioned conventional problems by holding abrasive grains together with a lubricant by a polyurethane rubber bond.The lubricant and polyurethane rubber bond suppress the generation of grinding heat, resulting in grinding burns. To provide a grinding wheel which can prevent grinding and grinding cracks, and can continuously perform dry grinding of difficult-to-grind materials even when dressing work is performed.

Hereinafter, the present invention will be explained based on the drawings.

1 and 2 show an embodiment of the grinding wheel of the present invention. In the figures, 1 is a cup-shaped alloy made of metal such as steel or brass, and the upper surface 1 of this base metal 1 is
A is provided with an annular groove 1b with its center aligned with the center of the base metal 1. And diamond abrasive grain 2
is held together with a lubricant 3 by a polyurethane rubber bond 4 and adhesively fixed in the groove 1b, forming an abrasive grain layer 5 of a predetermined thickness.

Here, the polyurethane rubber bond 4 is a room temperature curable polyurethane rubber produced by polymerizing a prepolymer produced from diisocyanates and crosslinking it with a crosslinking agent such as glycols or diamines. The lubricant 3 is preferably polyethylene glycol, which is a waxy solid at room temperature.

When manufacturing the above-mentioned grinding wheel, first, a cup-shaped base metal 1 is manufactured, and an annular groove 1b having a predetermined depth is formed in the upper surface 1a of the cup-shaped base metal 1. As shown in FIG. 3(a), diamond abrasive grains 2 are dispersed together with lubricant 3, and liquid polyurethane rubber bond 4 is poured into this groove lb.
This is hardened to form the abrasive grain layer 5. After that, the third
As shown in Figure (b), the upper surface 1a of the base metal 1 is ground down to a predetermined height from the bottom of the groove 1b, and the abrasive grain layer 5 protrudes from the upper surface 1a of the base metal 1 by a predetermined thickness. Just do it like this.

Next, the operation of the grinding wheel of the present invention will be explained.

When grinding a difficult-to-grind material such as the titanium nitride-based cermet described above using the grinding wheel of the present invention, a normal dry grinding method similar to that used when grinding a cemented carbide material can be used, for example. This is because when conventional grinding wheels are used to dry grind difficult-to-grind materials, problems such as high grinding heat and grinding burns occur, but with the grinding wheel of the present invention, diamond abrasive grains 2. Since the lubricant 3 and the lubricant 3 are held by the polyurethane rubber bond 4 and provided on the base metal 1, the generation of grinding heat is suppressed to a low level, and the grinding heat is suppressed to a low level due to the lubrication effect. In addition, the polyurethane rubber 4 binds the diamond abrasive grains 2 with a weak holding force and high elasticity, so when the diamond abrasive grains 2 contact the workpiece material and the workpiece material is elastically deformed, the diamond The force applied to the abrasive grains 2 is appropriately dispersed, and as a result, the grinding heat can be further suppressed.

Furthermore, in the grinding wheel of the present invention, the elasticity of the polyurethane rubber bond 4 reduces the resistance between the abrasive grain layer 5 and the workpiece material, resulting in improved sharpness and a finished surface. The grinding ratio is improved, the grinding ratio is increased, and the required power is reduced.

The following table compares the performance of the grinding wheel of the present invention and a conventional diamond grinding wheel using a resinoid binder.
These are the test results of dry grinding of a titanium nitride cermet with a cutting speed of 2 m/min and a % cut t of 0.001.

As is clear from this table, the conventional grinding wheel generates high grinding heat, but the grinding wheel of the present invention generates almost no grinding heat and does not cause grinding burn. The grinding ratio is higher than before, and the required power is significantly reduced.

Incidentally, in the above embodiment, the base metal 1 is cup-shaped, but it may be flat as shown in FIG. Furthermore, various types of abrasive grains other than diamond, such as cubic boron nitride, can be used as the abrasive grains 2. Further, although the base metal 1 is used in the above example, the grinding wheel may be constructed by simply holding the abrasive grains 2 and the lubricant 3 with the polyurethane rubber bond 4 without using the base metal 1 as the case may be. Furthermore, the elasticity of the polyurethane rubber bond 4 can be appropriately adjusted by incorporating an appropriate amount of an inorganic filler into the polyurethane rubber bond 4.

As described above, according to the present invention, since the abrasive grains are held together with the lubricant by the polyurethane rubber bond, even when dry-grinding difficult-to-grind materials such as titanium nitride cermet, grinding heat causes grinding burn and grinding. In addition to not causing cracks, the resistance on the abrasive grain layer is reduced, and therefore,
It is possible to provide a highly practical grinding wheel that can perform continuous grinding even when dressing work is performed, and has an improved grinding ratio.

[Brief explanation of drawings]

FIGS. 1 and 2 show an embodiment of the grinding wheel of the present invention, with FIG. 1 being a sectional view and FIG. 2 being an enlarged view of the abrasive grain layer. Moreover, 3rd [11U (a) and (b) are sectional views for explaining the manufacturing method of a grinding wheel, and FIG. 4 is a sectional view of a grinding wheel of another shape. 1...Base metal, 2...Diamond abrasive grain, 3
...Lubricant, 4...Polyurethane rubber bond, 5...Abrasive grain layer. Figure 3 (a) 4th @

Claims (1)

[Claims] A grinding wheel characterized in that abrasive grains are held together with a lubricant by a polyurethane rubber bond.