Design and Manufacturing of the Injection Mold for Metal-Inserted Rubber Parts Using CAD/CAM/CAE Technologies: A Case Study of the Engine Mounting

Abstract

In general, rubber parts used in automotive applications are designed and manufactured without any inserts; it is significant, however, that for certain parts, such as an engine mounting that, the metal core must be used to increase the compressive strength of products. With the lack of numerical tools used to predict the rubber flow characteristics and the interaction between rubber and metal insert during the molding process, mold designers must rely on their experience and the trial-and-error method to design molds. Therefore, in this research, an application of CAD/CAM/CAE on the design and manufacturing of an injection mold for the engine mounting rubber made of a blend of Natural Rubber (NR) and AcryloNitrile-Butadiene Rubber (NBR) is performed. A CAD model of the part is constructed and then a two-cavity mold as well as various runner patterns and gate positions are designed and further analyzed using CAE. Subsequently, with use of the CAM system, a metal-inserted mold and related components are manufactured and used to produce the rubber engine mounts on the vertical rubber injection machine. The empirical and numerical resulting parameters, including part geometry, injection pressure, and part temperature at various injection stages, correlate well. This information provides mold designers and manufacturers a better understanding of the rubber behavior during curing in the metal-inserted rubber molding process so that various mold components can properly designed and effectively used. Consequently, better mold and product quality with less defects as well as reduced production time can be obtained.