Mold design for the assembly injection molding of a solid housing with integrated dynamic seal

Currently, it is not state-of-the-art to mold a hard housing with integrated dynamic seal, without any postprocessing. Usually, separately processed rubber seals need to be mounted into the housing in an additional assembly step, which is time-consuming and costly. The article deals with the mold design for the efficient manufacturing of a hard housing with an integrated dynamic soft seal, as well as the influence of processing parameters in assembly injection molding on the bonding strength, soft component properties, and sealing lip contour. Selected gating types were used to manufacture demonstrator parts and perform bond strength tests and morphological analyses. Additionally, the mechanical properties of the seal component as a function of the processing temperature were investigated. Furthermore, the contour of the injection molded seal lip was analyzed. The developed design concept allows an automatized manufacturing process of such a hybrid structure consisting of a hard and soft component. The feasibility study on the manufacturability of a demonstrator part proves a good adhesive bonding between the hard and soft component as well as a precise shape of the seal contour. A contrary dependency between bond strength and mechanical material properties of the soft component was detected. POLYM. ENG. SCI., 58:545-551, 2018. (c) 2017 Society of Plastics Engineers