Recently, we’ve started using Delrin as a new manufacturing material for some HFM.Parts products. Understanding when to use specific materials is key to creating high-quality and purposeful products. The positive and negative characteristics of Delrin, as well as its typical applications in the automotive industry are both important factors to consider during product creation and design.
What is Delrin?
Delrin is a branded form of polyoxymethylene (POM), a thermoplastic polyacetal material increasingly used in various engineering applications. A thermoplastic is a type of plastic polymer that can be heated, shaped, and then cooled to solidify. Delrin is made from pure formaldehyde molecules.
The material was first discovered in the 1920s by German chemist Hermann Staudinger and physicist Gustav Mie. Although the discovery was significant, it wasn’t commercially utilised until the 1950s when DuPont began working with and patenting the material, branding it as Delrin.
The chemical formula for Delrin is (CH₂O)n. It is an acetal homopolymer, meaning it is composed of a single type of monomer linked by chemical bonds.
Why is Delrin used?
Delrin is an extremely versatile material due to its exceptional blend of properties, including mechanical, chemical, thermal, and moisture resistance and its ability to act as a strong electrical insulator. Complemented by its ease of processing, Delrin is a popular choice for common manufacturing processes like injection moulding, machining, and 3D printing.
| Property | Value and Notes |
| Tensile Strength | 10,000 psi |
| Flexural Modulus / Stiffness | 410,000 psi |
| Friction Coefficient | 0.1 – 0.3 |
| Elongation at Break | 10% – 40% |
| Fatigue Resistance | Withstands cyclic loading (tensile and compressive) up to 5,000 psi |
| Temperature Range | -40°C to 90°C |
| Performance Beyond 90°C | Tensile Strength: 2,000 psi Flexural Modulus: 180,000 psi |
| Performance Below -40°C | Reduces impact resistance by 20% |
| Water Resistance (at 65°C) | Maintains performance without compromise |
| Chemical Resistance | Resists organic solvents and neutral chemicals, effective up to 70°C |
| Discoloration & UV Resistance | Resists discoloration and UV degradation |
HFM.Parts and Delrin
Our first Delrin part, the Mx-5 door bushing, replaces the soft OEM rubber bushings with more rigid Delrin door bushes. The strength and rigidity of the material help the door as an active chassis support component. As the material is less rigid than metals or aluminium, the NVH (noise, vibration, and harshness) levels are reduced. Finally, due to Delrin’s resistance to chemicals, moisture, and UV degradation, the door bushing is sure to last and perform at its best for a long time to come.
Other thermoplastic alternatives that we examined were either less rigid, less resistant to environmental degradation, or less economical to produce. Aluminium alloys were another great option, but they are 2-3x more expensive and potentially too rigid for this particular application, as they will not dampen the NVH levels as effectively as Delrin.
Delrin’s material characteristics combine strength, resistance, ease of production, and cost-effectiveness that alternative materials could not achieve. By investigating the different types of materials available to us, we can create products that consider the customer’s and product’s best interests. In this case, Delrin will become a regular material in our engineering database when new products require its particular set of characteristics.