BS 7442 is a series on rubber or plastic-covered rollers. Rubber or plastic-covered rollers are designed to convey lightweight loads. BS 7442-4.2 provides a system of classifying rubber covered or plastics covered rollers according to the surface finish, determined either by the type of surface treatment or by the surface roughness. A test method for the determination of surface roughness is included.
BS 7442-4.2 on the classification of rubber covered or plastics covered rollers is useful for:
Rubber or plastics covered rollers are a machine part that is composed of an inner round shaft or tube covered by an outer layer of elastomer compounds. BS 7442-4.2 shows the principal methods of surface treatment, which are used to classify the roller surfaces. These are described in BS 7442-4.2. The type of surface finish and the structure or texture that can be achieved depending on the roller cover's hardness and composition. The surface finish of a roller cover is dictated by the intended use and is characterized either as a type of surface treatment or as the maximum value of surface roughness. The surface structures described for types 1 to 4 are produced by regular treatments and have a roughness without preferential direction.
Type 1 is known as polished finish. In soft rubbers, the surface is velvet-like; in hard rubber, ebonite, or hard plastics, it is smooth. Grinding marks and scratches are not visible to the naked eye. Sporadic grinding blemishes are permissible. Type 2 is known as a fine grinding finish which states that slight grinding and feed marks are visible to the naked eye but are not noticeable to the touch. Type 3 is called a standard grinding finish. In type 3 grinding marks and grinding feed are visible and just noticeable to the touch. Type 4 is known as a turned finish. The surface is solely turned, with as little feed of the turning tool as practicable. Turning grooves are visible and noticeable to the touch. Type 5: unground finish. The surface of the roller is without any treatment or dressing, for example, a cloth-marked roller surface as it comes from the vulcanization process or a rough-cast plastics covered roller. Using BS 7442-4.2 you can provide a system of classification of rubber covered or plastics covered rollers according to the surface finish, determined either by the type of surface treatment or by the surface roughness.
ISO 6123-2:1988