Why Copolymer Acetal and Dupont Delrin Sheet and Rod Outperform Other Plastics

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Acetal Copolymer Rod and Dupont Delrin® Homopolymer Acetal Sheet Are Favorite Plastics for Machining. POM-C and POM-H are the resin call outs from resin manufacturers.

One of the most popular Performance Plastics is Acetal. There are two main versions of the Acetal resin, the POM-H which is a Homopolymer Acetal and it is produced by Dupont under the brand name Dupont Delrin®. The other resin is POM-C and is a Copolymer Acetal which is produced by several resin manufacturers.

Many clients assume that Delrin® rod and Acetal rod is the same thing. This is not quite true. Yes, all Delrin rod is Acetal rod, but not all Acetal rod is Delrin® rod. Delrin® is a trade name for Homo-Polymer Acetal made by Dupont. This is the most recognized of all Acetal materials, but far from the only available Acetal material.

The Copolymer Acetal is produced by a wide variety of large plastic resin manufacturers, with BASF being probably one of the largest and best known. Some main resin names are: BASF Ultraform® H4320, Kepital® F10-02, or Hostaform® M25.

While Delrin® is a wonderful material, in larger cross sections or larger diameters, the Delrin® brand Homo-Polymer can exhibit center line porosity. This can sometimes be seen with the naked eye and is a darker white in a normally milky white natural colored material. This center line porosity can cause problems in some applications. This porosity may allow leakage of fluid or air if under pressure at the ‘soft centers’ of the Delrin® Rod and Delrin® Sheet.


Many machine shops prefer the Delrin® brand rod and sheet for small machined parts. This is due to the increase in a few key properties, and of course brand recognition. However, the Acetal Copolymer is much more popular due to the price savings and availability.

The Acetal family of plastic resins are excellent for wear resistance, great mechanical strength, and superior machining properties. It is available in a huge range of sizes and shapes. Click here for more details on Acetal – Delrin Rod, and sometimes referred to as plastic dowel. Several of our manufactures have the capacity to supply colored Acetal – Delrin rod; click here from more details on the colored Acetal material. Most Plastic Sheet and Rod suppliers carry some of this material. The large Performance Plastic suppliers carry a wide range of sheet and rod sizes in stock, check with your preferred supplier for details.

The wide range of available items in the Acetal product line, the excellent machinability and highly rated physical properties make the Acetal product line an excellent choice for machinable finished parts. Acetal material is favorably compared to Nylon, PET and Noryl for machined parts in both the machinability and the raw material cost.

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