Mercedes-Benz Aktiengesellschaft

Ewald Eissler

Rolf Schumacher

A method attaches small plastic parts securely in a defined position on compression molded parts consisting substantially of bonded or synthetic resin bound natural fibers or chips. The parts are compression molded into the desired shape in a compression mold from a preformed, loose layer of a mixture of at least one of natural fibers and chips and of binder introduced into the compression mold, while undergoing a setting reaction of the binder and a volume reduction of the layer. During the compression molding operation, at least one clearance or thin portion, smaller than the small plastic part, is formed in the wall of the compression molded part at the fastening point of the small plastic part on the compression molded part. Thereafter, a direct form-fitting injection molding of the small plastic part or parts onto the wall of the compression molded part at the fastening point is carried out. The finished compression molded part is placed in a defined position with the fastening point in a split injection mold for molding on the small plastic part, each mold half of the injection mold coming snugly into contact on the near side and the far side of the wall of the compression molded part. The plastic for forming the small plastic part is injected from one side of a mold half into the injection mold and, within the injection mold, completely fills the clearance of the compression molded part. The plastic reaches the mold half opposite the injection side through the clearance or the thin portion which breaks open under the pressure of the plastic injected therein.

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Hildrizhausen, Germany

Ewald Eissler