ACETAL/DELRIN PLASTIC MATERIALS & MACHINING

Acetal as a copolymer, or Delrin as a homopolymer, has excellent mechanical, electrical, and wear properties, as well as good dimensional stability with low creep.

This is a great material for bearing applications because it has a low coefficient of friction and wears well in both wet and dry plastic machined applications.

In addition, it has low moisture absorption and high dielectric strength, hence finding many uses in electrical products. With a high melting point, acetal machined parts can be used in continuous exposure to temperatures up to 185°F and burst exposure to 200°F.

It has good resistance to solvents, though strong acids and bases should be avoided. For a list of which chemicals to avoid, see our chart.

When it comes to material shapes, Acetal and Delrin both have good stiffness and toughness grades. However, Delrin has slightly higher mechanical properties. Yet it should be known that the extrusion process for Delrin suffers from centerline porosity in sheets. Generally, Delrin sheet products are not watertight. Other notable properties are good hydrolytic stability and resiliency.

Due to its low moisture absorption and low friction, we find that acetal/Delrin is a fit material for bushings, gears, bearings, and other moving parts.

Most have witnessed the excellent machinability the materials has as well. Able to work with tight tolerances and be formed into complex shapes, most machinists find it easy to work with acetal without much issue.

Moreover, acetal is available in many colors and varieties, allowing aesthetic choices for consideration when making.

Limitations & Considerations

While it's important to note that while acetal is a good material overall, it does have some limitations.

1. Acetal can be sensitive to UV radiation and degrade the material quicker if left to prolonged sunlight exposure.
2. It can be susceptible to stress cracking when in contact with certain materials. To see which, visit our chart here.

Plastic Machining with Acetal/Delrin Plastic transcript