Polyplastics Co., Ltd., a leading global supplier of engineering thermoplastics, has completed an extensive study which confirms the viability of polyphenylene sulfide (PPS) for bump-off molding of automotive engine cooling systems. Polyplastics’ linear DURAFIDE (R) PPS, which already offers superior performance over rivals like nylon 66, now has bump-off molding capabilities to eliminate deburring.

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Bump-off molding results in an undercut that “bumps” in two directions and ejects from the mold without using a sliding structure. The parting line (mold lip) goes away, allowing for a burr-less mold. Previously, PPS had limited use in bump-off molding of engineering parts due to its fragility.

Polyplastics found that materials with high bending-fracture strain in high-temperature environments (150C for PPS) are suited for bump-offs in terms of both damage and deformation. The company also observed that improvements in fracture strain in high-temperature environments are possible by reducing filler, adding elastomer, and utilizing high-molecular-weight PPS.

Polyplastics has shown that linear PPS exhibits greater fracture strain than cross-linked PPS and is more conducive to bump-off molding. Polyplastics’ DURAFIDE PPS appears to be suited for bump-offs from the standpoint of toughness in high-temperature environments. Among DURAFIDE PPS materials, high-molecular-weight 1130A1 (GF30%) and 1140A1 (GF40%) appear to be useful for bump-offs.

Polyplastics believes that DURAFIDE PPS boosts product reliability, and that bump-offs reduce the deburring process and facilitate greater design freedom. DURAFIDE PPS also delivers high heat resistance with a continuous service temperature of 200C to 240C. It also offers greater chemical resistance versus fluoropolymers, and greater dimensional stability and reduced hydrolysis/water absorption compared to nylon 66.

For more information, visit https://www.polyplastics.com/en/product/lines/pps_bump-off/index.vm

DURAFIDE (R) is a registered trademark of Polyplastics in Japan and other countries.

About Polyplastics

Polyplastics Co., Ltd. is a global leader in the development and production of engineering thermoplastic solutions. The company’s broad product portfolio includes POM, polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), and liquid crystal polymer (LCP). The company has the largest global market share of POM. With more than 50 years of experience, the company is backed by a strong global network of R&D, production, and sales resources capable of creating advanced solutions for an ever-changing global marketplace.