Table of Contents

delrin machining

Machining Delrin: A Complete Guide to Delrin CNC Machining

Recently, there has been a great demand for plastics of high tensile strength, low friction coefficient, and high wearing resistance. The aim is to replace metals as the only manufacturing product with high strength and rigidity. Today, technological advancement offers Machined Delrin, a lightweight polymer that replaces metals in product manufacturing companies.

Delrin part are now the versatile option in all attempts to make a tremendous high-tensile thermoplastic material as a consumer product. It is considered the most economical plastic due to its excellent machinability properties and lower cost.

In this Delrin machining guide, you will learn the basics of Machined Delrin. We’ll guide you through what Delrin is, the benefits of machining Delrin, and every other thing you need to know. Let’s get right to it!

What is Delrin?

Delrin, also known as Polyoxymethylene (POM) or acetal homopolymer, is a semi-crystalline engineering thermoplastic.

what is delrin

It is characterized by its low coefficient of friction, high tensile strength, high wearing resistance, and flexural modulus properties. It is generally manufactured using CNC machining or injection molding.

Delrin is a brand name for acetal homopolymer mainly used in CNC machines for its structural integrity, mechanical strength, and durability. It is naturally opaque and is available in many colors.

You’ll mostly find the Delrin plastic in its semi-crystalline state at high melting temperatures. However, Delrin is also available in sheets and extruded bars forms. These forms are most suitable for machining processes like milling and cutting.

It also works well with high-end cutting tools like laser cutting and other cutting tools. Delrin in granulated form is suitable for injection molding and plastic extrusion.

Also, its excellent mechanical and high-strength thermoplastic properties make it useful industrially for high-load mechanical applications. These applications include door restraint, conveyor belts, gears, scraper blades, and other essential products and parts.

Advantages of Machining Delrin Material

Delrin is a popular semi-crystalline engineering thermoplastic for custom machining because of its excellent mechanical properties, machinability, and material properties.

Machining Delrin for industrial purposes and consumer use has many advantages. Some of the benefits include the following:

Excellent Machinability

Delrin is a free-cut plastic that offers excellent machinability properties, making it ideal for parts that require complex geometrics or tight tolerances.

advantages of machining delrin material

Due to its superior dimensional stability and good creep resistance, plastic CNC machining works perfectly with Delrin plastics. It is easy to cut or machine parts made from Delrin with a high level of precision.

There is no need for special machines to ensure appropriate cutting when machining Delrin for parts that involve complex geometrics.

Excellent Dimensional Stability

A material’s dimensional stability implies its ability to retain its original dimensions after undergoing subjection to stress. The stress could be in the form of pressure, temperature, and other conditions during the machining processes.

excellent dimensional stability

This specific property of Delrin ensures it does not deform in size or lose its shape when machining Delrin.

As a result, Machining Delrin is remarkably easier to machine than other materials due to this excellent dimensional stability property.

Low Weight

Machined Delrin is light compared to metals. However, Delrin has a high tensile strength-to-weight ratio compared to most metals.

This property makes Delrin suitable as a part that can withstand immense stress while being lightweight.

High Mechanical Strength and Rigidity

Although Delrin is less heavy than metal, it has a high impact strength. Its tensile strength values range between 7000 and 9000 PSI.

The rigidity of Delrin does not make it liable to breakage; it is exceptionally tough and hard to break.

Delrin products are made of acetal homopolymer that is fatigue-resistant. Its rigidity, high stiffness, impact resistance, and mechanical strength make it suitable for high performance.

Delrin is highly durable with high tensile strength. Thus, machining Delrin is for high-stress processes.

Low Moisture Absorption

low moisture absorption

Delrin has little or no affinity for moisture, even in the dampest condition. As a result, it absorbs very little moisture compared to other engineering thermoplastics, making it suitable for wet environments.

The moisture resistance property of Delrin helps to retain its structural integrity even in underwater applications. Machined Delrin materials are the most advisable for use in conditions where there is a need to create a tight water seal.

Good Wear and Abrasion Properties

Parts of a machine that are always in motion require lubrication to reduce the friction generated between parts. This is especially the case for parts machined with metal materials.

Machined Delrin parts do not require lubrication due to their superior friction resistance property to all other plastic.

Wide End-Use and Temperature range

cnc machined pom parts

Delrin parts have a broad range of applications in several industries. As mentioned earlier, this material has excellent mechanical strength, and moisture resistance, and is lightweight.

In addition, Delrin has good creep resistance and can be resistant to high temperatures. However, care should be taken to prevent machining Delrin at a temperature above its melting point.

Delrin parts also have excellent resistance to fatigue failure with a wide temperature range from -40oC to 80OC. Thus, they fit perfectly into many different applications.

Some of the applications include:

  • Mechanical Gears, Bearings, Bushings
  • Medical Equipment
  • Subsea Equipment
  • Automotive parts
  • Consumer electronics
  • Valves, seals, handles, and more

Finishes of Machined Delrin Parts

There are two finishes for the Machined Delrin (POM) plastics parts. The finish you choose will depend on the application of your component and other aesthetic requirements.

The surface finishing options include the following:

As Machined Finish

img 4664

Some applications may require you to leave your Delrin part as it is after machining. As-machined Delrin tends to have a relatively rough or textured surface. This increases friction for parts intended for use in mechanical purposes. Such components can withstand friction and other intensive applications.

Bead Blast Finish

pom parts bead blast finish 2

Another essential finish for Delrin parts is the bead blast finish. Bead blasting gives uniform surface finishing, and you won’t have to worry about the part’s dimension. It is not aggressive, and it works perfectly with Delrin.

This surface finish is also ideal for hiding defects of parts manufactured with this material. Manufacturers choose bead blast finish to improve components’ durability. The flexibility of this finishing process allows it to fit into many manufacturing processes. 

Cost-Saving Design Tips of CNC Machining Delrin

Suppose you desire to save costs while obtaining a product or part corresponding to your final part goals through Delrin machining processes. In that case, you must bear in mind one important rule – the longer a part takes to machine, the more costly it will be.

From this critical rule, other factors affect costs. These factors include your material choice (easily machined materials are less expensive) and part design.

Here, we will focus on how part design can reduce Delrin machining costs.

1. Incorporate internal radii

When producing or designing parts, it is advisable to incorporate internal radii instead 90 degrees angles at the corners to save machining time and cost.

Designing parts with internal radii instead of sharp corners helps streamline the production process.

CNC milling machines are cylindrical. Due to their cylindrical nature, they intrinsically have curves or radii when they create corners inside parts.

In addition, an increase in internal radius corresponds to a larger milling machine for use and the higher machining time.

2. Avoid tight tolerances

You should use tight tolerances in machining parts only when required. This reduces costs more efficiently because high tolerances vastly increase machining time.

 Although CNC machines can achieve some of the tight tolerances in the manufacturing process, not all parts require it. The CNC machining service will implement its standard tolerance if a part is submitted without specified tolerances or industry standards.

3. Avoid thin walls, deep cavities, and thread

Suppose manufacturing a cost-saving product is a driving factor for your company. In that case, it is advisable to thicken the walls where possible during the machining of parts. This is because machining a thin wall can damage parts through vibration if done too quickly.

Machining thin walls require repetition of low cutting depth, which adds more time to the machining process. Therefore, incorporating thicker walls in parts lowers machining time and saves costs.

Another cost-saving tip for CNC machining is to avoid deep cavities and threads.

Firstly, the higher the cavity depth, the longer the time required to cut the material. In addition, cavities with a diameter 4 times greater than the machine may require other specialized machining processes and increase production.

Also, it is essential to keep thread depth low to reduce machining cost unless it is critical to the part.

It is advisable to keep depth thread size below 3 times the diameter of the hole as deeper thread drives up machining time and depth.  


1. What is stronger, acetal, or nylon?

Nylon provides high strength and offers great stiffness. It is also stable at high temperatures. On the other hand, acetal (Delrin) is better in impact resistance and moisture absorption.

2. Is Delrin same as POM?

Delrin is a brand name for POM; it is an ideal polymer for metal replacement.

3. Is Acetal food safe?

Not all acetal are safe for food packaging, but certain polyacetal formulations are food safe.

4. What is Delrin good for?

Delrin is majorly for industrial applications as a replacement for metal. Its main applications are gears, bearings, bushings, automotive parts, pumps, and valve component rollers, fittings, consumer electronics parts, etc.


Delrin has many excellent properties that make it the most suitable replacement for metals. It is a versatile material, making it useful in many industries, ranging from automotive to food, aerospace industry.

In general, endeavor to follow all the cost-saving tips highlighted in this article for Delrin machining to significantly minimize production cost.

If you have any questions about Delrin machining, our team of experts is always ready to support and present more optimization tips. AT Machining professionals boast in-depth knowledge of various machining technologies. Our Delrin machining capabilities help us to meet and surpass your expectations to ensure the success of your project.

Contact us today to receive an instant quote.

photo 2

Hey there, I’m Sam!

From AT-Machining, I’m a CNC Machining Expert in this field for more than 20 years.  We offer cost-effective machining services from China. Ask for a quote for your ongoing or upcoming projects now!

Best Regards, Sam, Co-Founder

AT Machining

On-demand CNC Machining With Custom Finishes. You Design It, We'll Make It.