Hollow Bodies with Demanding Inner Geometries at Small Series Scale
Rapid product manufacturing (rpm) GmbH in Helmstedt, Germany, has worked out several mold concepts that fit the specific demands of the NylonMold process. Yielding lot sizes of between one and 10,000 items, the company thus follows the trend towards made-to-order products in serial production. The molding process thermally activates polymerization in the closed mold, which is mostly made of silicone. This way, highly crystalline polyamide components are obtained.
Combined to the fusible core technique, rpm has recently introduced a process that makes it possible to produce small series of complex one-piece seamless hollow bodies from polyamide with almost any inner and outer geometry desired. The fusible core technique is a special injection molding process used for large series. Applying this method, a core is molded from a low-melting metal alloy inside a core mold in a reproducible process. This metal core forms the complex inner structure of the component, and is overmolded with a plastic material in the injection mold. In a subsequent production step it is then fused locally. While standard alloys fail to meet the requirements of small scale production, rpm developed its own material formulation to reduce the time required to make and remove the core as well as diminish energy consumption. According to manufacturer information, the material cost of the solid core is 77 % lower than that of the material hitherto used.
An inquiry concerning the small scale series production of a 2-level V8 suction unit coming from the United States boosted development. When creating the small-series molds, the designers considered manufacturing information obtained from prototype construction referring to possible difficulties in certain areas. It is crucial, for instance, to take into account the position, i.e. slope and tilt angle, of the mold while casting the monomer blend, since it determines the final quality of the hollow body. After the component was deflashed, it is submitted to weighing and endoscopic examination, in order to determine channel diameters free of residues. The nylon mold process is able to reproduce sudden changes in wall thicknesses without the need to change the production process. As a result, the user is able to produce in one single mold a standard outer geometry combined to various inner geometries.
rpm rapid product manufacturing GmbH
Patents encourage innovation: Stay on the ball with the latest innovations in the plastics industry in our patents section.
Would you like to subscribe to our Newsletters on plastics technology and profit from the latest information?
You know the trade name but want to know the material manufacturer, type of polymer and delivery form? Search here!