Material Description

Acetal (polyoxymethylene) is a semi-crystalline thermoplastic that is available in both copolymer and homopolymer grades (Delrin®), in addition to several filled Delrin® grades.  Acetal is easy to machine and offers good dimensional stability, high strength, and stiffness.

As a semi-crystalline material, Acetal is also characterized by a low coefficient of friction and good wear properties-especially in wet environments.

Because Acetal absorbs minimal amounts of moisture, its physical properties remain constant in a variety of environments.  Low moisture absorption results in excellent dimensional stability for close-tolerance machined parts.  In high moisture or submerged application, Acetal bearings outperform nylon 4 to 1.  Acetal is ideally suited for close tolerance mechanical parts and electrical insulators which require strength and stiffness.  It also offers resistance to a wide range of chemicals including many solvents.

With its high strength and dimensional stability, Acetal has many applications in the automotive industry, including its use in bearings, and other mechanical components. Its low coefficient of friction also makes it a popular choice for conveyor system parts and industrial equipment.

PMI machines both homopolymer and copolymer grades of Acetal including enhanced bearing grade materials. Acetron® GP POM-C Acetal is porosity-free and is an excellent choice for general purpose grade. For slightly higher mechanical properties we offer and machine the homopolymer Acetal machined parts. For improved frictional properties, PTFE-enhanced Acetron® AF products are offered.

Notable Material Features

  • High mechanical strength, dimensional stability, and rigidity
  • Very low moisture absorption
  • Good wear and abrasion resistance
  • Wide range of chemical resistance (including hydrocarbons, neutral chemicals, and many solvents)
  • Natural lubricity

Grades Of Acetal

Acetal Copolymer (unfilled)

The copolymer grade offers excellent performance at a slightly lower cost than Delrin®.  Acetal copolymer may exhibit center line porosity, but porosity-free material is available.  Certain grades are FDA, USDA, NSF, Canada AG and 3-A Dairy compliant.  Low stress levels and high strength assure flatness and dimensional stability up to a maximum continuous service temperature of 180°F.

You can find a wide range of Acetal machined parts at Plastics Machining Inc. Do you have any further questions? Contact our team today to learn more about our custom parts and how they can fit your business.

Also See:

Delrin® Plastic Machined Parts

Applications

  • Problem: Dairy nickel and stainless blades were costly and expensive to fabricate.
  • Solution: Acetron GP POM-C porosity free POM-C plate is machined into scraper blades used in commercial ice cream manufacture.
  • Benefits: The porosity free Acetron ® GP POM-C blades are easily cleaned and do not entrap dirt or bacteria. The low stress level of Acetron® GP POM-C means parts that machined flat, stay flat.
  • Problem: Specialty metals and low-tech plastics don’t perform well in some moist environments.
  • Solution: Acetron® AF Blend POM-H excels in moist applications and offers longer part life.
  • Benefit: Acetron® AF Blend POM-H has a lower coefficient of friction than unfilled Acetal and lasts longer in most applications. It offers good stability and chemical resistance.
  • Problem: Clean in Place (CIP) equipment cleaning is a challenge for many metal gears.
  • Solution: Acetron® GP POM-C’s gears are easily fabricated and stand up to repeated cleaning cycles.
  • Benefits: Acetron® GP POM-C’s excellent chemical resistance, low internal stress and dimensional stability add up to better performance particularly in food processing and packaging applications.
  • Problem: Metal rollers in cargo truck lifts were being damaged in use.
  • Solution: Impact resistant Acetron® GP POM-C rollers absorb collisions with loading docks without deforming and causing the system to fail.
  • Benefits: Lighter weight and an ability to bounce –back made tight tolerance Acetron® GP POM-C rollers a better choice that other materials.

Tech Notes:

In general, Acetal does not perform as well in abrasive wear applications as nylons   Compensation for moisture related growth generally allows Nylatron®  nylons to be used for wet, abrasive applications. If your application requires dimensional consistency in an abrasive, high humidity or submerged environment, Ertalytye,® PET-P will often offer improved performance.

Delrin® is a registered trademark of E. I. du Pont de Nemours and Company.