CS267043B1 - Grinding wheel - Google Patents

Abstract

A grinding wheel made of synthetic corundum, silicon carbide or their mixtures, consisting of firmly bonded abrasive layers with a binder based on phenol-formaldehyde resins and at least one internal damping layer, this layer having a binder based on butadiene or butadiene-styrene rubber containing abrasive material. Its use achieves a reduction in vibrations and noise levels by 5 to 10 dB and an increase in grinding performance by 10 to 15%.

Description

The invention relates to a grinding wheel with a damping intermediate layer for hand grinders.

Grinding wheels used for roughing operations, grinding and cutting materials using hand grinders are made from a mixture composed of grinding grain, liquid and powdered phenol-formaldehyde resin and fillers. Depending on the working circumferential speed, they are optionally reinforced with fiberglass inserts. Workers working with these discs are at risk from vibrations and increased sound levels.

These shortcomings are eliminated, or at least largely suppressed, by disks produced using a film of anti-vibration material. The film is inserted into the body of the disk during its formation. However, this method does not guarantee a reliable interconnection of the layers, especially in the case of raw wheels, and causes a reduction in the grinding power by 10 to 20%.

These disadvantages are eliminated by a grinding wheel with a binder based on phenol-formaldehyde resins and a grinding material from the group of artificial corundum, silicon carbide or mixtures thereof, with at least one inner damping layer, in that the damping layer consists of a granular binder based on butadiene or butadiene styrene rubber. material. This mixture consists of 15 to 40 parts by weight, parts of butadiene or butadiene styrene rubber, 90 to 140 parts by weight, parts of abrasive grains, 0.4 to 1.5 parts by weight, parts of sulfur, 0.1 to 0.2 parts by weight, parts of antioxidant, 1 to 0.2 parts by weight of accelerator parts and 3.5 to 12.5 parts by weight of filler are incorporated into the disk body as one or more intermediate layers during molding. Its vulcanization takes place simultaneously with the thermal curing of the phenol-formaldehyde binder.

The advantage of wheels, made by composing abrasive and damping layers, is not only the reduction of noise and vibrations in the grinding process, but also the increase of grinding performance.

The wheels produced according to use example I. showed the following values when grinding stainless steel material;

Disc Grinding time in min. Material loss in g Disc loss in g Noise in dB ear, disc 0 180/8 mm 10 215 65 104 - 107 disk according to the invention 10 246 32 94 - 96 disc with damping foil 10 205 59 94 - 96 grinder empty - - - 84 - 86

As can be seen from the table, the actual noise of the disc is reduced by almost 50%, the total by about 10%. At the same time, the grinding power is increased by 14 í, compared to the foil wheel by almost 20%.

Example of use I

FLEX grinding wheel with convex center measuring 180 x 7 x 22.2 mm a) composition of the abrasive layer

100 materials, parts - artificial semi-brittle corundum No. 63 materials, parts - powdered phenol-formaldehyde resin materials, parts - liquid phenol-formaldehyde resin materials, parts - cryolite materials, parts - magnesite

CS 267 043 Bl

b) the composition of the damping layer

100 mass parts - artificial white corundum No. 12 35 mass parts - butadie.nstyrene rubber 8.5 mass parts - kaolin 5 mass parts - butadiene rubber 0.85 mass parts - sulfur 0.15 mass parts - 2-phenylaminonaphthalene 0.15 mass parts - tetramethylthiuram disulfide

c) wheel composition

1. fiberglass fabric impregnated with resin

2. abrasive layer

3 · damping layer

4. fiberglass fabric impregnated with resin

5. abrasive layer.

6. fiberglass fabric impregnated with resin

Example of use II

FLEX grinding wheel with convex center with dimensions 230 x 10 x 22.2 mm a) composition of the abrasive layer

50 wt. 50 wt. parts - tnikrocrys talic corundum No. 80 parts - artificial brown corundum No. 63 8 wt. parts - powdered phenol formaldehyde resin 4 wt. parts - liquid phenol formaldehyde resin 5 hmo t. parts - calcium sulphate

b) the composition of the damping layer

100 materials, parts - artificial brown corundum No. 10 40 masses, parts - butadiene styrene rubber 4 materials, parts - calcium carbonate 2.5 masses, parts - kaolin 0.5 masses, parts - sulfur 0.2 masses, parts - 2-phenylaminonaphthalene 0.1 masses, parts - tetramethylthiuram disulfide

c) wheel composition

1. fiberglass fabric impregnated with resin

2. abrasive layer

3 · fiberglass fabric impregnated with resin

4 · damping layer

5. abrasive layer

6. damping layer

7. fiberglass fabric impregnated with resin

8. abrasive layer

9 · resin-impregnated fiberglass fabric

Claims (2)

OBJECT OF THE INVENTION A grinding wheel with a binder based on phenol-formaldehyde resins and a grinding material from the group of artificial corundum, silicon carbide or mixtures thereof, with at least one internal damping layer, characterized in that the damping layer consists of a granular binder based on butadiene or butadiene styrene rubber and comprising abrasive material. 2. Grinding wheel according to claim 1, characterized in that the inner damping layers are composed of 15 to 40 parts by weight, parts of butadiene or butadiene styrene rubber, 90 to 140 parts by weight, parts of grinding grains, 0.4 to 1.5 parts by weight, of sulfur 0.1 to 0.2 parts by weight of antioxidant, 0.1 to 0.2 parts by weight of accelerator and 3.5 to 12.5 parts by weight of filler.