DD238058A1 - GRINDING BODY FOR STRUCTURING METAL SURFACES - Google Patents

Abstract

The invention relates to abrasives which are suitable for structuring metal surfaces. In particular, so jewelry elements on metal surfaces, clock dials, bangles, caskets, writing instruments and the like. Can be designed. The aim of the invention is the development of a Schleifkoerpers that is resistant to wear, has low abrasion and is economically and technically easy to produce. According to the invention, the abrasive body consists of a cellular polyurethane elastomer with a proportion of open cells of 60 to 80%, which contains various known abrasives as filler, wherein the abrasive of the polyol component to 60 to 200 wt .-%, preferably 80 to 120 wt .-% , is mixed.

Description

Field of application of the invention

The invention relates to an abrasive article which is suitable for structuring metal surfaces. In particular, so that Schmuckelenemte on metal surfaces, clock dials, bangles, caskets, caps, writing instruments and the like. Be designed.

Characteristic of the known technical solutions

Structuring of metal surfaces is known to be achieved by grinding. Here are the most diverse abrasives, such as silicon carbide and corundum, which are applied to an abrasive carrier, such as paper, linen, fleece and felt, are used.

However, these abrasives have a low flexibility, so that the processing of curved or ornamented metal surfaces is very difficult and the quality leaves something to be desired. In order to increase labor productivity and improve quality, emery cloth is often backfoamed with hard foam in order to achieve uniform structuring.

The disadvantage of this is that the abrasive removed relatively quickly and thus achieved no structuring more

The production of abrasive bodies has been described many times. The resulting abrasives are not suitable for structuring metal surfaces due to their short life (service life) or their high production costs (costs).

For example, DE 3219567 describes the production of elastic abrasive articles. The disadvantage of these abrasive particles is that they consist of two layers, a hardened binder-abrasive grain mixture layer and an elastic support layer and these are cured under the action of centrifugal force. The production is technologically very complicated.

The "method for producing abrasive tools" described in AS 1303365 has the disadvantage that the compaction of the abrasive particles must be carried out by centrifuging.

OS 2342869 describes the production of abrasive articles by embedding fine-grained abrasive in an elastic binder. This binder consists of a foam plastic with closed cells. These closed cells have a detrimental effect on the grinding action or structuring since broken abrasive grains do not adhere to the surface and are thus lost to the grinding process.

Object of the invention

The aim of the invention is to develop a grinding wheel which is wear-resistant and is suitable for structuring differently shaped metal surfaces in high quality.

Explanation of the essence of the invention

The invention has for its object to find an abrasive article that is economically and technically easy to manufacture and has low downforce.

According to the invention, the object is achieved in that the abrasive body consists of cellular polyurethane elastomer containing as a filler abrasives, wherein the abrasive of the Polyolkomponemtete to 60 to 200 wt .-%, preferably 80 to 120 wt .-%, admixed.

Particularly suitable are cellular polyurethane elastomers based on polyester alcohol (component A) and diphenylmethane diisocyanate (component B), whose proportion of open cells is 60 to 80%. The mixing ratio of component A: B is 1: 0.2 to 1: 0.6. The index is between 102 and 109. Further additives include the substances known for polyurethane elastomers. Depending on the desired surface quality of the metal part to be processed, various known abrasives, such as silicon carbide, boron carbide, garnet, glass flour, inter alia, preferably corundum having different particle sizes up to 0.3 mm, preferably 0.2 to 0.3 mm, are used. The apparent density of the abrasive bodies is in the range of 500 to 1,000 kg / m ³ , preferably between 700 and 800 kg / m ³ .

The processing of the cellular polyurethane elastomer system is carried out according to known technological parameters. The application of the centrifugal force is not necessary. Nevertheless, the abrasive is distributed homogeneously in the grinding wheel. Depending on the shape of the part to be structured, the abrasive shape can be designed. This also makes it possible to structure complicated surface shapes. Particularly suitable is the abrasive body in the form of discs or abrasive belts.

With the abrasive body according to the invention can be metal surfaces of any kind, such as steel, brass, aluminum u.a. work great. The advantages of metal finishing using the abrasive article according to the invention are that differently shaped surfaces can be mechanically structured. The achieved surface quality is far superior to that achievable by manual grinding. There is achieved a material savings in abrasives compared to the known grinding wheels, since the grinding body according to the invention is characterized by low wear and high utilization.

Due to the open-cell surface of the abrasive particles, the abrasive abrasion involved can be retained and further used for grinding.

embodiments example 1

360 g of the polyol component, consisting of a mixture of polyester alcohols, crosslinkers, foam stabilizers, activators and water are intimately mixed with 430 g of corundum with a particle size of 0.2 to 0.3 mm.

For the purpose of reducing the viscosity, the mixture can be heated to 4O ⁰ C.

115 g of isocyanate component are added to this mixture and mixed with a stirrer at 1400 rpm for 10 seconds.

This mixture is poured into a heated to 70 ⁰ C, fixed shape as a disc of 10cm diameter and this closed.

After 10 minutes, the cured molding can be removed. A thermal aftertreatment is not necessary. The bulk density of the molding thus produced is 700 kg / m ³ .

The disk thus produced is mounted on a rotating shaft and used to pattern watch dials.

Example 2

The mixture prepared according to Example 1 for the abrasive article is poured into a cylindrical shape of 15 cm height, in which a Cordband is inserted, and these closed. After a service life of 10 minutes, the cured abrasive belt can be removed. A thermal aftertreatment is not necessary.

The bulk density of the molding thus produced is 750 kg / m ³ . Since the cord tape is inserted in the middle of the mold, the sanding belt can be used on both sides.

The abrasive belt is biased on two shafts, one of which acts as a drive shaft, tensioned and used to pattern writing instruments.

Claims (4)

Invention claim: An abrasive article for structuring metal surfaces, characterized in that the abrasive article is comprised of a cellular polyurethane elastomer having an open cell content of 60 to 80% containing abrasive agents known as a filler, wherein the abrasive of the polyol component is 60 to 200% by weight. , Preferably 80 to 120 wt .-% is added. 2. abrasive article according to item 1, characterized in that the cellular polyurethane elastomer is preferably prepared based on polyester alcohol and diphenylmethane diisocyanate in the mixing ratio of component A to component B1: 0.2 to 1: 0.6 and has a ratio of 102 to 109. 3. abrasive article according to item 1 and 2, characterized in that the bulk density of the abrasive body in the range of 500 to 1000 kg / m ³ , preferably 700 to 800 kg / m ³ , is located. 4. abrasive article according to item 1 to 3, characterized in that the grain sizes of the abrasive to 0.3 mm, preferably 0.2 to 0.3 mm, amount.