WO1998010895A1

WO1998010895A1 - Abrasive cutting and grinding wheel

Info

Publication number: WO1998010895A1
Application number: PCT/SI1997/000025
Authority: WO
Inventors: s^¿tefan NEMES^¿
Original assignee: Comet, Umetni Brusi In Nekovine D.D.
Priority date: 1996-09-16
Filing date: 1997-09-08
Publication date: 1998-03-19
Also published as: HUP9901885A2; AU4325097A; PL326649A1; BG102544A; TR199800861T1; HUP9901885A3; UA48200C2; SI9600276A; CZ187898A3

Abstract

Abrasive cutting and grinding wheels which are resin bonded and reinforced with glass fiber nets, and which obligatory contain one part of abrasive in the form of abrasive lumps obtained by cold treatment of remains of resin bonded grinding wheels with dry mechanical procedure of crushing, sieving and airing, resolve the ecological problem of resin bonded grinding wheels waste in a simple, inexpensive and effective way. At the same time, resin bonded cutting and grinding wheels of higher quality are produced, i.e. grinding wheels with smaller specific gravity, more flexible structure and better grinding effects.

Description

ABRASIVE CUTTING AND GRINDING WHEEL

The subject of the innovation is a thin abrasive cutting and grinding disc wheel which is rasin bonded and reinforced with glass fiber nets into which the abrasive is incorporated in form of lumps

The invention resolves technical problems of grinding industry products, particularly those of cutting and grinding rasin bonded product range

The technical problem resolved with this invention is such composition and manufacture of rasin bonded abrasive cutting and grinding wheels which gives them smaller specific gravity and higher grinding effects in comparison with those manufactured so far In addition, the manufacturing procedure for these wheels also resolves the ecological problem of rasin bonded abrasives, because the abrasives are incorporated form of lumps obtained with the reprocessing of remains of rasin bonded abrasive wheels

Both the form and composition of the to date produced rasin bonded cutting and grinding wheels, and their manufacturing procedure, have been known for tens of years and have not changed substantially Only the procedures for the reuse of rasin bonded abrasive refuse have not long ago been introduced, following the endeavours resulting from higher ecological awareness

The so far manufactured abrasive cutting and grinding wheels have been basically composed of abrasive crushed corundum (AI₂O₃) and silicon carbide (SiC), mineral powdered fillers and reinforcement nets of glass fibers

All that has been filled up and stuck together with bakehte-rasm bond, pressed in a mold to the form of a disc wheel and burnt in an oven at 180° Disc wheels are divided according to their

- field of application (for metal and non-metal),

- form (flat for cutting and bulged for grinding),

- size (of larger or smaller diameter and thicker or thinner wheels),

- mode of application (on handy portable or stationary machines)

So far the following solutions have been known for the recycling of remains from rasin bonded grinding wheels

- Simple incineration of rasin bonded grinding wheels, with this procedure the bonding mass, 1 e the rasin burns and the rest, 1 e abrasive lumps, glass fiber and filler material remain Abrasive lumps obtained in this way can be reused and built in new rasin bonded grinding wheels The lumps obtained in this way are normally very dirty, covered with nonmelted fillers and soot therefore they can be used only for products of lower quality The process is inexpensive, but ecologically unsuitable

- Chemical wet treatment is used to disconnect the remains of rasin bonded grinding wheels by means of sulfuπc acid With this procedure abrasives are obtained in clear form of hard lumps, but the treatment is very expensive and rather burdensome for the environment, since it is polluting water

-Through pyrohidrolytic procedure rasin bonded grinding wheels are dissolved by means of overheated steam A patent application has been filed for this procedure So far, this procedure has provided the purest regenerated abrasive which can be applied for repeated incoφoration into grinding wheels In terms of technology this procedure is excellent, but technically very demanding and dangerous in case of any mistake, because hydrogen also appears in the process, although it is a closed one Therefore the procedure is expensive and has not given expected results in practice The characteristic feature of the above described recycling procedures is the obtaining of abrasives for repeated use in new grinding wheels and, at the same time, the resolution of ecological problems in the environment, because in this way the remains of rasin bonded grinding wheels are not deposited in open-air dumps The characteristic feature of rasin bonded cutting and grinding wheels is the fact that their cutting and grinding effect increases in proportion with increased peripheral speed of the disc wheel Connected with this fact is the potential increase of the centrifugal bursting force which, however, also depends on weight portion of the abrasive used, 1 e of the specific gravity of the abrasive component from the above mentioned characteristics and technical knowledge stem continued aspirations for the development and production of such rasin bonded cutting and grinding wheels which will be safer in use, more effective cutting and grinding, and less burdensome for the environment

The present invention offers the simplest, least expensive and most effective solution to these development aspirations known to date

The use of the invention will make it possible to manufacture rasin bonded cutting and grinding wheels which will be lighter and therefore cheaper, they will also be safer in use and will give better cutting and grinding results

The essential quality of the invention is illustrated by the two following production examples

1 The remains of baked cutting and grinding discs and wheels are crushed into lumps, I e into such a form and size and purity of abrasive as suitable fo reuse and reinstallation into rasin bonded cutting and grinding abrasive wheels In average, the surface hardness of these wheels is 200 kg per cm² While being crushed, disc wheels break and fall apart on their weakest links This is the reason why the average surface firmness of the lumps thereby obtained is higher than that of the wheels from which the lumps actually origin Therefore the repeated use of these lumps which are built into new cutting and grinding wheels guarantees products with higher average surface hardness

2 Before the abrasive bits are used again and built into new wheels, they are again wetted with fresh rasin In this way, according to the invention, in newly manufactured cutting and grinding disc wheels more bonding rasin is incoφorated than it was the case in the to date standard production method of these wheels

'I he products manufactured according to this method have smaller specific gravity and are, at the same time, more flexible and less hard

Claims

PATENT CLAIMS

1 The process of production of abrasive cutting and grinding disc wheels which are ras - bakelite bonded and reinforced with glass fiber nets

is denoted by

adding one part of the abrasive in the form of lumps obtained from the remains of rasin bonded wheels in the way that, when preparing the compound, the abrasive lumps are rasin wetted first and then other components are added according to already known procedure In this way we get a product of more flexible structure, higher grinding efficiency and smaller weight

2 The process of recycling of remains of abrasive cutting and grinding disc wheels which are rasin - bakelite bonded and reinforced or not reinforced with glass fiber nets

is denoted by

obtaining abrasive from remains of rasin bonded abrasive cutting and grinding wheels with a dry mechanical process - by crushing, sieving and aiπng - m form of abrasive lumps which are harder than the wheel from which they have been obtained, in addition their specific gravity is smaller and their binding ability with rasms is better than could otherwise be achieved by using standard abrasive lumps