JPS6080564A - 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 finely crushing an abrasive grain unit, in which abrasive grains are bound by a binding agent, to be held by a polyurethane rubber bond, in the case of a grinding wheel for a grind-difficult material. CONSTITUTION:A cup-shaped metallic bed 1 provides on its upper suface 1a a circular annular groove 1b, and an abrasive grain layer 4, after both dispersing abrasive grain units 2 and injecting a liquid state-polyurethane rubber bond 3 to be hardened, is formed by scraping off the upper surface 1a to the predetermined height. This abrasive grain unit 2, in which diamond abrasive grains are bound by a binding agent of resinoid and metal bond or the like, is formed to be broken into fine pieces in a required size, preferably to a size about ten multiples of the diamond abrasive grain. In such way, a grinding wheel, never causing a grinding burn and a grinding crack even if a grind-difficult material of titanium nitride system cermet or the like is dry ground, reduces also the resistance applied to the abrasive grain layer, enabling the continuous grinding without performing dressing work further improving the 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 bound together by 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 starts grinding, the abrasive grains gradually cut into the workpiece material, but until the force acting on the abrasive grains and the workpiece material exceeds a certain value, The workpiece material is not cut but remains elastically deformed. At this time, the abrasive grains slide on the workpiece material, generating grinding heat.

For example, if the workpiece material is cemented carbide, its thermal conductivity is approximately a
19 Cal, /cIIL86c' (: and relatively high ita af>, co (7) Grinding heat is removed through the workpiece material itself or by chips. However, when the workpiece material is a titanium nitride-based cermet, In the case of There was a problem that the flank wear progressed quickly and grinding cracks occurred.Therefore, conventionally, wet grinding was used to grind difficult-to-grind materials such as those mentioned above.However, wet grinding Wet grinding also had the disadvantage that grinding heat could not be sufficiently dissipated, and continuous grinding was not possible without constant dressing work.In addition, wet grinding requires cleaning the workpiece material after grinding and removing dirt from the machine. , it was necessary to replenish the grinding fluid, and the workability was extremely poor.

The present invention solves the above conventional problems by pulverizing an abrasive grain body made of abrasive grains bound by a binder and holding it by a polyurethane rubber bond.
To provide a grinding wheel which can prevent grinding burn and grinding cracks because the generation of grinding heat is suppressed by the intervention of a polyurethane rubber bond, and which can continuously carry out dry grinding of difficult-to-grind materials even when dressing work is performed. With the goal.

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
An annular groove 1b is formed in a with its center aligned with the center of the base metal 1. Then, the abrasive grain body 2 formed by bonding diamond abrasive grains with a binder is finely crushed to a required size, and the polyurethane rubber bond 3
The abrasive grain layer 4 of a predetermined thickness is formed by being held by and adhesively fixed in the groove ib.

Here, it is preferable that the abrasive grain body 2 is crushed into pieces about 10 times the size of diamond abrasive grains. The above-mentioned binder is a well-known one such as a resinoid binder or a metal bond, and the above-mentioned polyurethane rubber bond 3 is made by polymerizing a prepolymer produced from diisocyanates and cross-linking with a cross-linking agent such as glycols or diamines. This is a room temperature curable polyurethane rubber produced by

In addition, when manufacturing the above-mentioned grinding wheel, first, a cup-shaped base metal 1 is manufactured, and an annular groove 1b of a predetermined depth is formed in the upper surface 1a of the base metal 1. As shown in FIG. 3(a), finely crushed abrasive grains 2 are dispersed into the grooves ib, and a liquid polyurethane rubber bod 3 is poured into the grooves ib, which is then hardened to form an abrasive grain layer 4. After that, Figure 3 (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 4 is removed from the base metal 1.
What is necessary is just to make it protrude from the upper surface 1a by a predetermined thickness.

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 dry grinding of difficult-to-grind materials is performed using a conventional grinding wheel, the grinding heat becomes high and problems such as grinding burns occur, but with the grinding wheel of the present invention, the polyurethane rubber bond 3 is used to dry grind materials. This is because since the grains 2 are held and bonded to the base metal 1, the generation of grinding heat is suppressed to a low level, and grinding burns and the like are prevented.

That is, in the grinding wheel of the present invention, since the holding force of the abrasive grain body 2 is weak and the elasticity is high, the diamond abrasive grains in this abrasive grain body 2 contact the workpiece material and the workpiece material is elastically deformed. During grinding, the force applied to the diamond abrasive grains is dispersed appropriately, and as a result, the generation of grinding heat is kept low.

In addition, in the grinding wheel of the present invention, since the abrasive grain body 2 is finely crushed, the contact area between the abrasive grain body 2 and the workpiece material is small, and the polyurethane rubber bond 3 has elastic force. , the resistance between the abrasive grain layer 4 and the workpiece material is reduced. As a result, the sharpness is improved and the ground surface is better than before, 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. t to 0.01 mm
These are the test results of dry grinding of titanium nitride-based cermet.

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. Furthermore, the grinding wheel of the present invention has a higher grinding ratio than the conventional grinding wheel, 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 @41J, or of course may be of other shapes. Furthermore, various types of abrasive grains other than diamond, such as cubic boron nitride, can be used. Further, in the above, the base metal 1 is used, but in some cases, the grinding wheel may be constructed by simply crushing the abrasive grains 2 into small pieces and holding them with the polyurethane rubber bond 3 without using the base metal 1. . Furthermore, the elasticity of the polyurethane rubber bond 3 can be appropriately adjusted by incorporating an appropriate amount of filler such as an inorganic substance into the polyurethane rubber bond 3.

As described above, according to the present invention, the abrasive grain body made of abrasive grains bound by a binder is finely crushed and held by a polyurethane rubber bond, so that difficult-to-grind materials such as titanium nitride cermets can be processed using a dry grinder. Even when grinding, grinding burn or grinding cracks do not occur due to grinding heat, and the resistance acting on the abrasive grain layer is reduced, allowing continuous grinding without dressing work and improving the grinding ratio. It is possible to provide a highly practical grinding wheel.

[Brief explanation of the drawing]

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. Further, FIGS. 6(a) and 6(b) are cross-sectional views for explaining a method of manufacturing a grinding wheel, and FIG. 4 is a cross-sectional view of a grinding wheel having a different shape. 1... Base metal, 2... Curved abrasive grain body, 3... Polyurethane rubber bond, 4... Abrasive grain layer. Figure 3 (a) 4th eye

Claims (1)

[Claims] A grinding wheel characterized in that an abrasive grain body consisting of abrasive grains bonded by a binder is finely crushed and held by a polyurethane rubber bond.