If you’re looking for a high-performance thermoplastic polymer to replace metal components, look no further than molded acetal parts. Acetal is the strongest, stiffest thermoplastic resin, and among the best in creep resistance. First introduced in 1956, acetal was specifically developed to compete with zinc and aluminum castings. Today it can be found in plastic zippers, garden hose heads, medical devices, small gears, and mechanical pencils.
Properties of Acetal
Molded acetal parts have high tensile and flexural strength, stiffness, resilience, fatigue endurance, and moderate toughness under repeated impact. They also have high resistance to solvents and chemicals, low friction, excellent dimensional stability, and great abrasion resistance. Additionally, their high deflection temperature and excellent creep resistance make them perfect for close-tolerance, high-performance parts. Good electrical properties give them long-term stability in electrical applications. With low moisture absorption, molded acetal parts can perform reliably in environments that experience humidity changes.
There are some disadvantages to acetal:
- Has poor resistance to acids
- Subject to UV degradation
- Difficult to bond (its high resistance to chemicals means it doesn’t glue well)
Homopolymer Vs. Copolymer Molded Acetal
There are two basic types of acetal: homopolymer and copolymer. While the differences between them aren’t significant, they can impact your decision if a characteristic is critical to your application.
- Stiffer at both room and elevated temperatures
- Slightly harder and more slippery
- Have higher tensile strength
- Have higher impact strength making them less likely to fracture on impact
- Have a slightly higher operation temperature
- Have higher fatigue endurance and withstand repeated cycles of stress
Copolymers, meanwhile have:
- Better dimensional stability
- Are less porous due to shrinkage when extruded
- Have a higher chemical resistance, particularly to high pH solutions (such as bleach)
- Greater resistance to degradation through exposure to hot water, steam, or hot air
Processing Acetal Resins
Acetal can be molded with standard injection molding equipment at conventional production rates. The material can be molded to form parts that require glossy surfaces or different surface textures; parts with undercuts for snap fits; parts requiring metal inserts; and parts that require close tolerances. Whether you need molded acetal parts that are heavy with thick sections or large-area with thin sections, we can create the high-performance parts you need.
Molded acetal parts can be found in:
- Fuel system and seat belt components
- Faucet cartridges
- Conveyor plates
- Bushings, gears and cams
- Watch gears
- Coffee spigots
Molded Acetal Parts from Proto-Cast, Inc.
For over 50 years, Proto-Cast has been helping companies create high-performance plastic parts. Our expertise and strict adherence to ISO 9001-2015 standards ensure you receive high-quality, reliable parts. Call us today at 610-326-1723 to learn more about our plastic injection molding services.