What is Delrin? Delrin, or POM-H (homopolymer acetal), is used in CNC machining, 3D printing and injection moulding to create durable, precise components. This article explores Delrin’s properties and how to get the most out of the material.

Delrin is an engineering thermoplastic that offers low friction, high stiffness and exceptional dimensional stability. It can be used to produce high precision parts thanks to its impressive material properties, such as high strength and wide operating temperature range (-40 to 120 degrees Celsius). Delrin also has excellent mechanical properties and is tougher than ABS.

This article explores the material properties of Delrin and provides tips on how to work with this versatile and robust material. Whether you’re CNC machining, injection moulding or 3D printing custom parts, this resource will help you understand what Delrin is made of and when to use it.

How is Delrin made?

Delrin or POM-H (homopolymer acetal) is part of the POM family of materials, the other POM being copolymer acetal (POM-C). It was first discovered by Hermann Staudinger, a German chemist, in 1920 and was later commercially synthesised by DuPont in 1956.

Delrin is produced by distilling hydrocarbons into fractions. These can be combined with other catalysts through polymerisation to produce a finished plastic. In fact, delrin is the specific version of acetyl resin first produced by DuPont.

How is Delrin used? What can you make with Delrin?

Delrin is favoured by many machinists because it’s easy to work with and can be machined on 3- and 5-axis machines, similar to metal parts. It can also be 3D printed and injection moulded, making it versatile and a viable plastic for a wide range of applications.

You’re likely to find Delrincomponents in the automotive and consumer electronics industries, as well as any sector that requires high performance engineering components. Typical applications for Delrinparts include high performance parts such as gears, housings, bolts, nuts, pump components and more.

Electrical components including connectors, electronic parts, covers and insulators can also be made from Delrin. Delrin can also be used to make automotive parts, including door latches and articulated shells. It is also found in medical products and technologies, such as insulin pens and metered dose inhalers. Delrin is also a good option for replacing metal parts.

What are the benefits of making parts with Delrin?

  • High Strength and Stiffness: Delrinprovides excellent mechanical properties, making it suitable for parts that need to bear loads and resist deformation.
  • Low Friction and Wear Resistance: It has a low coefficient of friction and high wear resistance, which is ideal for applications involving moving parts, such as gears and bearings.
  • Dimensional Stability: Delrinmaintains its shape and size under varying environmental conditions, ensuring precision and reliability in the parts.
  • Chemical Resistance: It is resistant to many chemicals, solvents, and fuels, making it suitable for parts exposed to harsh environments.
  • Ease of Machining: Delri can be easily machined to high tolerances, allowing for the production of intricate and detailed parts.
  • Low Moisture Absorption: Its low water absorption ensures that parts do not swell or lose their mechanical properties in humid or wet conditions.
  • Good Fatigue Resistance: Delri can withstand repeated stress and cyclic loading, making it durable for long-term use in mechanical components.
  • Electrical Insulation: It has good electrical insulating properties, making it suitable for electrical and electronic applications.
  • FDA Compliance: Certain grades of Delri are FDA-compliant, making them suitable for use in food contact applications and medical devices.
  • Cost-Effective: Compared to metals and some other engineering plastics, Delrin offers a good balance of performance and cost.

How do you assemble Delrin parts?

One consideration when choosing a manufacturing material is component assembly. Delri parts can be assembled in a variety of ways. You can use self-tapping screws, snap-fits and press-fits to assemble and disassemble Delri parts, and welding, bonding and riveting are permanent assembly methods.

If you have a large, complex assembly, you can use adhesives for prototypes or small production runs, but they won’t be strong enough for final performance. We recommend the use of bonded joints where performance is critical.

Remember to clean and degrease surfaces with sandpaper or chemicals to improve assembly results.

What are the material properties of Delrin?

  • Excellent dimensional and geometric stability
  • Reliable machinability
  • Resistance to wear and fatigue
  • Good heat and chemical resistances 
  • Shiny surface and opaque white color

What’s the right surface finishing for Delrin?

Delrin parts can be finished in one of two ways, depending on cosmetic requirements and the application of the components. Machined Delri parts are generally good to go, although they will have machine marks and a slightly rough surface. Bead blasting is the other viable option. This gives the part a uniform finish and improves durability.

There are several surface finishing options available to put the finishing touches to Delri parts, including hot stamping, screen printing, painting, laser marking, metallising and pad printing.

If you choose to paint Delri parts, they can be baked at temperatures up to 160 degrees Celsius. Surfaces can also be metallised with copper, chrome and aluminium coatings for improved cosmetics and durability. This parts can be laser marked and pre-treated with mild acid solutions.

Sourcing Simplified – Start Your Next Project With PROTO MFG

Are you looking for a reputable partner for your parts fabrication and machining projects? Look no further. At PROTO MFG, we specialize in CNC machining and related technologies, including sheet metal fabrication, rapid prototyping, etc. Whether it is a project with a simple design or parts with complex geometries, do not hesitate to contact us today!

Let's Get Started