POM CNC parts, Delrin Gears and bearings, POM-H sliding block, POM-C sensor parts, Acetal Machined Parts

POM is an engineering plastic with excellent properties, well-known for its high rigidity, high strength, and outstanding wear resistance. It is often called "super steel" because it can replace metal in many precision components. Differences and Relationships Between POM, POM-C, POM-H, Delrin, and Acetal The relationship between these terms can be summarized as follows: Acetal is the general name for this category of materials. It is primarily divided into two main types: Homopolymer (POM-H) and Copolymer (POM-C). Delrin is the famous brand name for the homopolymer acetal (POM-H) produced by the American company DuPont (now Celanese).The distinctions for each type are explained in detail below:

1. Acetal 

● Definition: This is a chemical class name referring to all thermoplastic materials polymerized from formaldehyde. It is an umbrella term that encompasses both homopolymers and copolymers.

● Usage: In colloquial and industry terminology, "Acetal" is often used to refer to POM materials in general.

2. POM (Polyoxymethylene) 

● Definition: This is the abbreviation for "Polyoxymethylene." It is a synonym for "Acetal" and the common name for this category of materials. In most everyday contexts, POM and Acetal are used interchangeably.

3. POM-H (Homopolymer Acetal) 

● Definition: A polymer consisting of pure formaldehyde chains. Its molecular chain structure is very regular.

● Characteristics: 

Higher mechanical strength, hardness, and stiffness.

Better creep resistance and wear resistance.

Higher continuous service temperature (approximately 90°C vs. POM-C's approx. 82°C).

● Disadvantages: More sensitive to alkaline degradation, slightly poorer thermal stability, and a narrower molding temperature range.

4. POM-C (Copolymer Acetal) 

● Definition: A polymer where small amounts (typically 1-3%) of other comonomers (such as ethylene oxide) are randomly incorporated into the formaldehyde backbone. This disrupts the regularity of the molecular chain.

● Characteristics: 

Better thermal and chemical stability, particularly stronger resistance to alkalis.

Wider processing window, making injection molding easier.

Better long-term resistance to hydrolysis (more stable in hot water).

● Disadvantages: Slightly lower mechanical strength, rigidity, and wear resistance compared to POM-H (though still excellent).

5. Delrin 

● Definition: This is the registered trademark used by DuPont (now part of Celanese) for their homopolymer acetal (POM-H). It was one of the first commercialized and most famous POM brands, so it is often used as a synonym for homopolymer acetal.

● Simply put: Delrin is a type of POM-H, and POM-H is a type of Acetal.