Reprinted from Plastics Today – July 2016
Injection-molded oil pump housing to employ PAEK polymer
Led by legendary automotive innovator Matti Holtzberg, the Polimotor 2 project aims to design and manufacture a next-generation, all-plastic engine for competitive racing in 2016. And polymer producer Solvay is a key participant in the project, supplying its AvaSpire AV-651 CF30 polyaryletherketone (PAEK) to form three sections of the Polimotor 2 engine’s external dry sump modular oil pump housing.
“Solvay’s unmatched selection of specialty polymers offered several possible options for replacing the typically aluminum pump components, including its high-performing Ryton PPS and KetaSpire PEEK products,” said Holtzberg, who is also president of Composite Castings, LLC, based in West Palm Beach, FL. “But we found that this particular grade of AvaSpire PAEK delivered the targeted weight reduction with an optimal balance of toughness, dimensional stability and other qualities required to successfully withstand the rigors of the Polimotor 2’s oil pump.”
Each of the three injection molded sections weighs 90 g (0.2 lbs) compared to 0.19 kg (0.42 lbs) for their aluminum counterparts. Overall, replacing the entire metal housing with one molded from AvaSpire PAEK delivered a total weight reduction of 270 g (0.6 lbs) while meeting the desired performance requirements of the oil pump.
A 30 percent carbon fiber-reinforced compound, AvaSpire AV-651 CF30 PAEK delivers higher strength, stiffness and fatigue resistance compared to base AV-651 grades, and enhanced weight reduction vs. glass fiber-reinforced AvaSpire PAEK grades. The material’s long-term thermal oxidative stability approaches that of carbon fiber-reinforced PEEK, but it delivers better dimensional stability and warp resistance during injection molding.
Michigan-based Molding Concepts injection molded the three net shape parts. They were then machined by Allegheny Performance Plastics, LLC, a Pennsylvania-based processor of high-performance thermoplastics. “The excellent machinability of AvaSpire AV-651 CF30 PAEK enabled Allegheny to achieve the extremely tight tolerances necessary for the pump’s gear tip clearance and sealing surfaces, while achieving very good surface finishes,” said Greg Shoup, president of Allegheny Performance Plastics.
AvaSpire AV-651 CF30 PAEK is well-suited to form the structural components of Polimotor 2’s oil pump housing, which will encounter oil temperatures approaching 140°C (284°F) and internal pressures cycling between 2.8 and 5.5 bars. “Like Solvay’s Ryton PPS or KetaSpire PEEK polymers, AvaSpire PAEK is attracting increasing interest for the unique benefits it offers automotive component applications,” said Brian Baleno, global automotive business development manager for Solvay Specialty Polymers. “Specifically, AvaSpire PAEK offers the most optimal balance of toughness and elongation within our specialty polymers portfolio, which is prompting evaluation of these polymers for use as vacuum pump vane tips, bearing cages and cable ties.”
The Polimotor 2 project aims to develop an all-plastic, four-cylinder, double-overhead CAM engine that weighs between 138 to 148 lbs (63-67 kg), or about 90 lbs (41 kg) less than today’s standard production engine. Holtzberg’s ground-breaking program will leverage Solvay’s advanced polymer technologies to develop up to ten engine parts. In addition to the oil pump components, other parts include cam sprockets, fuel assembly components and O-rings, water cooling fixtures, throttle body parts and other high-performance components. Besides AvaSpire PAEK, other Solvay materials targeted for use encompass Amodel polyphthalamide (PPA), KetaSpire polyetheretherketone (PEEK), Radel polyphenylsulfone (PPSU), Ryton polyphenylene sulfide (PPS), Torlon polyamide-imide (PAI) and Tecnoflon fluoropolymer (FKM).