Acetal Product Comparison

<p>Acetal is a well known thermoplastic material known chemically as “PolyOxyMethylene” or POM for short. Acetal is available in 2 types of resin formats. Copolymer acetal (POM-C), available in numerous tradenames from several raw material manufacturers and Homopolymer acetal (POM-H), known commonly as Delrin®. So what’s the difference you ask?</p><h2>Acetal Copolymer</h2><p>For starters, Acetal copolymer is slightly cheaper than Delrin®. Acetal copolymer is also free of the center line porosity that is inherent in Acetal homopolymer. Acetal copolymer offers excellent dimensional stability and maximum continuous use temperature up to 180°F (80°C). Copolymer acetal grades are FDA, USDA, NSF, and 3-A Dairy compliant and available in wide variety of colors. A few other advantages acetal copolymer has over the homopolymer variety are the following:</p><ul><li>Due to its higher level of cyrstalinity, copolymer has better dimensional stability.</li><li>Better impact and wear resistance (especially in wet environments)</li></ul><h2>Acetal Homopolymer</h2><p>The main difference in Acetal Homopolymer, or Delrin® is the fact that Delrin® comes with an inherent low density center known commonly as “center line porosity”. The larger the cross section, the larger the center line porosity. Delrin® offers slightly higher mechanical properties than acetal copolymer, but most of its mechancial properties come within 10% of acetal copolymer. Another feature worth mentioning is the fact that Delrin® offers lower chemical resistance than acetal copolymer. Delrin® is availabe in natural and black colors. A few advantages Delrin® offers over acetal copolymer are the following:</p><ul><li>Greater tensile and impact strength at room temperatures and below.</li><li>Greater stiffness, with higher flexural modulus at room temperature and elevated temperatures.</li><li>A bit harder, giving Delrin a better coefficient of friction in applications where water and moist environments don’t come in to play.</li></ul><p>So what does all this mean? In most applications, Acetal Copolymer and Delrin® can be used interchangeably due to the fact that most of the material properties fall within 10% of each other. Just keep in mind that when specifying Delrin®, you will always have the center line poroisty issue to deal with which has its pluses and minuses depending on the specific application.</p><p>If you need CNC machined or stamped Acetal or Delrin® parts, give us a call or send us your prints on our <a href="/quote" target="_blank">quick quote</a> form.</p>