DE29711063U1 - Grinding wheel - Google Patents

Description

Patent Attorney
Dlpl.-lng. R. Lieb®8t

BaJlindaram 15 · Tal. 32 47 07
20096 b

Winker CVD Technik GmbH 24 June 1997

King's Greek Coin 14 45/45 Li/Sch

22609 Hamburg

grinding wheels;

Description:

The innovation relates to an abrasive body for grinding optical glass, precious stones, marble or other materials such as wood, metal, plastic or the like. In particular, the innovation relates to abrasive bodies in the form of a ductile, thin-surface base body equipped with an abrasive material for grinding optical lenses, in particular spectacle lenses. Therefore, the following will mainly refer to

of spectacle lenses, without this implying any restriction on the use of grinding wheels ¹ .

Metal foils with a thickness of 0.1 to 0.5 mm ^{and diamond} particles are used to grind optical glass. These metal foils are generally made of a low-alloy bronze with ^{a tin} content of less than 10%. Such foils are therefore ductile and can be easily pressed to the given radius of the optical fine grinding machine. These foils can be used as grinding media ^on both sides, since they are completely permeated with diamond in the appropriate concentration. The diamond particles have a grain size of preferably 5 to 30 pm. During the grinding process, the grinding media wear out and a mixture of glass dust, heavy metal powder and diamond powder is produced as grinding residue. It is obvious that the disposal of such residue, particularly because of the heavy metal, causes considerable problems.

The innovation is based on the task of creating an abrasive

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per for the above-mentioned purposes in such a way that the problem of disposal is avoided.

According to the innovation, this task is solved by making the base body of the grinding body out of a carbon fiber fabric or knit or a graphite foil, on which a diamond or boron nitride coating is arranged as a grinding layer. This has the advantage that the only grinding residues are diamond powder, carbon or graphite dust and dust from the material of the object to be ground, e.g. glass dust, which can be disposed ^{of in} an environmentally friendly manner. Recycling the glass dust together with the diamond powder and carbon and graphite dust is easily possible. The grinding bodies produced using the new base bodies, which can have the same thickness of 0.1 to 0.5 mm as the usual bronze foils, have the further advantage that they ^can be used as replacement products for the known metallic grinding bodies. The carbon fiber fabrics or knitted fabrics or the graphite foils are in

same; j way elastic as metal foils, since the

Diamond or boron nitride layer is deposited on the fibers of the fabric or knitted fabric or the surface of the graphite ^foil and thus allows it to be deformed accordingly.

The diamond or boron nitride coating is preferably applied to the base body by gas phase deposition, optionally ^on both sides. This process, also known as CVD (Chemical Vapor Deposition), can produce a very thin and homogeneous layer. For example, it can be provided that the coating has a thickness of 5 to 50 μm on ^one or both sides.

To improve the adhesion of the diamond or boron nitride coating to the material of the base body, an intermediate layer of precious metal, such as gold, silver, platinum or iridium, preferably applied electroplated, can be provided between the base body and the diamond coating.

The shape of the grinding wheels is basically arbitrary and

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depends essentially on the shape of the machine tool for the grinding tool and the workpiece to be machined. For example, the grinding tool for machining precious stones or marble can be a ring.

The base bodies of the grinding wheels can be made from commercially available carbon fiber fabrics or knits or rolled graphite foil in any shape ^to suit the respective requirements. At least one surface of the finished base body is ^then provided with a thin diamond or boron nitride ^layer , for example using the CVD process. Before the diamond or boron nitride layer is applied to the surface of the base body that is to receive the diamond or boron nitride layer, a precious metal layer can be applied by electroplating as an adhesion promoter and to equalize the tension between the base body and the diamond layer. The coated grinding wheels are attached to the grinding disc in the usual way, e.g. glued. The coated grinding wheels can also be used ^like sandpaper without being attached to a support body, e.g. grinding disc.

During the grinding process, the thin diamond coating wears away in the usual way, so that the base body is ^exposed . After this, the workpiece can no longer be ground, which also shows the wear of the grinding body. The grinding bodies must then be replaced. The waste product: the used grinding body then ^only consists of graphite foil or carbon fibers and can be disposed of ^with normal waste. ^This not only eliminates the costly heavy metal disposal of the known grinding bodies made of metal foil, but also eliminates the need for environmentally harmful chemical disposal processes. The used base bodies can also be coated repeatedly. Waste products in the quantities that would have accrued with the state of the art are therefore avoided.

Examples of the innovation are explained in more detail below using the schematic drawings.

Show it:

Ffg. Ij fin cut an abrasive body,

Fig. 2: for cutting a grinding wheel with a circular grinding body,

Fig. 3: Cross-section of a sanding film with a sanding body attached to the front surface.

The grinding body shown in Fig. 1 has a base body 3 made of a carbon fiber fabric or knitted fabric or a graphite foil. The base body 3 has been provided with a thin diamond layer 1 on both sides using the CVD process. A precious metal intermediate layer 2 is provided between the diamond layer 1 and the base body 3 as an adhesion promoter. These grinding bodies can be attached to a support body (not shown), e.g. a grinding disc for optical glasses, or can also be used like a normal sandpaper.

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In the grinding wheel shown in Fig. 2 and preferably intended for working on precious stones ^, an annular grinding body is attached via an adhesive layer ¹⁴ to the edge of a metal plate ⁵ held on a rotatable spindle (not shown ¹ ). The grinding body comprises an inner base body 3 made of carbon fiber fabric or knitted fabric or graphite foil, on which a precious metal intermediate layer 2 is galvanically deposited on both sides. The surface of the base body 3 facing away from the metal plate 5 has a diamond coating 1 applied using the CVD process.

Fig. 3 shows ¹ a metallic grinding roller 5, the outer surface of which has an adhesive layer ¹⁴ on which an innovative grinding body is held ^1. The grinding body itself ¹ consists of a base body 3, made of a carbon fiber fabric or knitted fabric or a graphite foil and has been galvanically coated with a precious metal intermediate layer 2. The surface of the base body 3 facing away from the metallic grinding roller 5 has ¹ a nitride layer 1 applied using the GVD process.

The innovation ^is not limited to the embodiment shown and described. It includes modifications familiar to the person skilled in ^the art. In particular, several ring-shaped grinding bodies, between which diamond impregnations are provided, ^can be arranged on a grinding wheel. The edge area of the grinding wheel can also have the diamond impregnation, which is adjoined by ring-shaped grinding bodies towards the center of the wheel. The ring-shaped grinding bodies can also be held on the edge of cup-shaped grinding wheels or grinding wheels, whereby the surface of the grinding bodies which receives the diamond coating can be curved.

Claims (5)

Shooting sayings 1. Grinding body for grinding optical glass, precious stones, marble or other materials such as wood, metal, plastic or the like in the form of a ductile base body equipped with an abrasive material, characterized ⁱⁿ that the base body (3) consists of a carbon fiber fabric or knitted fabric or a graphite foil, on which a diamond or boron nitride coating (1) is arranged as a grinding layer ( ¹ ). 2. Grinding body according to claim 1, characterized in that the ^diamond or boron nitride coating (1) is applied to the base body (3) by gas phase deposition. 3. Abrasive body according to one of claims 1 or 2, characterized in that the diamond or boron nitride coating (1) has a thickness of 5 to 50 pm ¹ . 4. Grinding body according to one of claims 1 to 3, characterized in that between the base body: (3) and the diamond or boron nitride coating (1) is provided with an intermediate plate (2) made of precious metal such as gold, silver, platinum, iridium or the like ¹ . 5. Grinding body according to claim 4, characterized in that an intermediate layer (2) made of precious metal is applied galvanically to the base body (3).