No abstract

Combining a soft thermoplastic elastomer with a hard polymeric material by multi‐component injection molding provides a novel and sophisticated alternative for mounting a vulcanized dynamic elastomeric seal part into a rigid housing. Such assembly injection molding is new and challenging, but promises several economic advantages. The main issue within such a development is the assurance of sufficient bond strength between soft and hard component, in order to withstand the service load conditions safely. This paper studies certain process influences on the interface condition between the materials. The strength of the adhesive bond of composite test specimens consisting of a hard outer ring and a soft inner ring with integrated rotary seal lip are evaluated. The injection molded and investigated composite parts consist of glass fiber reinforced polybutylene terephthalate (PBT‐GF30) as hard component and a thermoplastic polyurethane (TPU) as soft component. The required force to reach delamination between hard and soft component is monitored and correlated with the surface structure and properties of differently plasma pre‐treated hard components. Supposed a material combination and the contact temperature are defined the surface conditions of the hard component play the major role with respect to the adhesion bond strength.

The manufacture of a rotational shaft seal (soft component) adhesively bonded to a polymeric housing (hard component) is not state of the art. The paper approaches the feasibility to shape such hard-soft composite employing assembly injection molding technique.

The present paper approaches possible advantages of hybrid constructions compared to monolithic design. Hybrid constructions represent multi-material composites where each of the materials employed are optimally utilized. Therefore, materials consumption decreases which leads to material, energy and cost efficiency and finally contributes to sustainability.The investigations targets on a possible substitution of a heavy iron casted pump housing by a metal-polymer hybrid light weight construction and on the achievable total mass reduction. Multi-material composites are prerequisite for lightweight design and promise a huge mass reduction potential.

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. © 2017 Society of Plastics Engineers