Comprehensive Guide To Delrin Machining: Benefits, Limitations, Applications, & Tips

In our other post, we discussed how you can use PEEK CNC machining to produce high-performance parts. If you plan to produce thermoplastic components with high tensile strength, excellent dimensional stability, and superior wear resistance, Delrin machining could be the way to go!

This article explores the advantages and drawbacks of machining Delrin. It further highlights the use of machined Delrin components across various industries and provides valuable tips for an efficient machining process.

Table of Content

Understanding Deltrin | Polyoxymethylene(POM)

Delrin is a brand name that refers to a type of thermoplastic material whose polymer chains have both crystalline and amorphous regions. Therefore, it is a semi-crystalline thermoplastic whose chemical name is Polyoxymethylene (POM). Its other names are acetal homopolymer, Polyacetal, or Polyformaldehyde.

In addition to being widely used in rapid prototyping, POM is machined to produce a wide range of parts for different applications.

For Delrin machining processes, you will find the material in different grades to suit different application needs. They are available either in sheets or bar forms.

Learn more on the common Delrin plastic grades here.

Delrin Machining – Advantages and Drawbacks

If your production project requires machined Deltrin components, you can choose manual or precision CNC machining. Whichever POM production approach you choose, there are general benefits and limitations that you must be fully acquainted with. Let’s find out!

Advantages of Deltrin Parts Machining.

lightweight | High Tensile Strength

If your project demands lightweight components with high tensile strength of about 7000 to 9000 PSI, POM thermoplastic is a perfect alternative to metal. Compared to most metals, its superior strength-to-weight ratio makes its machining the most suitable and cost-effective for high-stress application parts.

Suitability for Long-term Applications

Sometimes your production may need a thermoplastic that can withstand long-term operation under stressful conditions such as movements. Because Delrin has excellent fatigue resistance, its machined parts can withstand stressful working conditions for longer with low deformation risks.

Good Insulation Property

POM is also known for its good dielectric properties. This makes Delrin machining highly suitable for the production of some electrical insulators.

Resistant to Wear & Abrasion | Natural Lubricity

Delrin boasts a low coefficient of friction and, therefore, is a perfect material choice if you plan on producing machined moving parts with excellent resistance to wear and abrasion.

The hardness of Delrin gives it excellent abrasion resistance. Delrin machining is therefore suitable if you intend to produce parts that will operate in high-friction environments. Such parts include gears, bearings, and other parts that require high wear resistance.

Natural Lubricity | Resistant to Some Chemicals

Because Delrin material is self-lubricating, using it to produce moving parts will save you from the lubrication requirements that metal parts demand.

This makes it ideal for making parts for use in equipment or machines operating in dry and high-hygienic conditions.

Delrin is also resistant to lubricants and chemicals such as petrol/gasoline, alcohol, and common solvents. Therefore, its parts will still operate optimally when exposed to such environments.

Machining Ease

POM has excellent machinability compared to a wide range of aluminum and brass alloys. With a slow feed rate, you can achieve a higher cutting speed than is possible with most thermoplastics.

Further, Delrin machining does not always require the application of water or oil to facilitate the cutting process.

However, when drilling, use a suitable coolant to avoid excess heat accumulation.

Unparalleled Dimensional Stability

Deltrin is one plastic with high dimensional stability. Therefore, with Delrin, you are confident the machining factors such as pressure or temperature will not adversely impact your part’s shape or dimensions. This, makes Delrin machining suitable for your production of high-precision engineering components.

Resistance to Moisture/Low Hygroscopicity

Derlin is one of the most stable thermoplastics. Exposure of Delrin machined parts to moisture will have little or no impact on their performance.

Delrin machining is, therefore, a perfect option if you intend to produce parts for outdoor applications or use in wet or high-humidity conditions.

Stable Performance Under Different Temperature Ranges

Delrin machining becomes your best choice if your project requires plastic components that can effectively perform under varying temperature ranges. The material can maintain stable performance at temperatures of between -40 to 90 degrees Celsius ( (-40 to 190 degrees Fahrenheit)

Limitations/Drawbacks of Delrin Machining

Despite its colorful benefits, below are a few limitations of machining your project parts using POM plastic:

Low Resistance to Corrosive Chemicals Like Acids

Delrin has low resistance to strong acids, bases, and oxidants. So, if your parts are meant for such extreme conditions, consider other options such as PCTFE machining.

Not Resistant to UV Radiation Exposure.

Over-exposure of machined Delrin parts to UV radiations will, in the long run, affect both its color and mechanical strength. So, if you desire to machine a thermoplastic component for long-term outdoor application, POM machining is not your best option.

Sensitive to High Temperature | Not Self-extinguishing

Even though POM plastic can withstand high temperatures, excess temperatures if not managed can result in your parts’ deformation.

Therefore, if your project requires fire-resistant or self-extinguishing plastic components, Delrin is not your perfect machining material.

Difficult to Bond With Other Materials

Because POM plastic has low surface friction and sensitivity to chemicals, bonding it using most adhesives is difficult as they will easily peel off after drying.

So, you must bond your components to surfaces for their normal operation, you must spend extra bucks on more advanced adhesive solutions.

Valuable Tips for Successful Delrin Machining

So, if you want to adopt POM Machining to produce parts for different industry needs, below are valuable tips to enhance your machining efficiency:

Correct Design for POM Parts Machining

Because POM is a semi-crystalline thermoplastic, it slightly shrinks during the cooling process. Therefore, for uniform cooling and for your parts to maintain dimensional stability, the design of your parts should have uniform thickness.

Wall thickness design considerations

Designs with thin walls tend to warp easily and are not suitable for machining. You should also avoid large component designs. Large workpieces result in uneven cooling after they are exposed to high machining temperatures. This may result in the parts warping.

Delrin Thread Design

If your parts should have threaded parts, choose a design with rounded roots. This helps distribute stress and keep the threads stable. Do not design parts with V-shaped threads as they have a high risk of stripping due to high stress levels.

Support Consideration

To enhance the rigidity of your Delrin parts, consider including ribs in your designs where applicable.

Avoid Sharp Corners | Design for Chamfered Edges

Your designs should also have fillets rather than sharp corners to facilitate uniform and safe stress distribution. Further, Delrin parts should have chamfered edges instead of bevel edges to reduce shipping risks.

Keep Your POM Workpiece Clean

Delrin parts are meant for high-demanding applications where precision and hygiene may be critical.

Therefore, to ensure the production of high-quality and safe products, keep your POM workpiece and cutting tools free from contaminants.

Good sanitation will also ensure your machining tools serve you optimally with no risks of tear and wear caused by abrasive contaminants.

Use of Sharp Tools With a High Clearance Angle

Only use sharp and authentic tools to ensure you produce parts with high-quality surface finishes.

During POM machining, your cutting tool must have a high clearance cutting angle. This helps limit the contacts between the tool and your Delrin workpiece for a smooth cutting operation.

Further, the high angle helps reduce tear and wear on your tools. It also helps in reducing excess heat accumulation during the machining process.

For efficient and long-term Delrin machining, invest in suitable tungsten carbide or Polycrystalline diamond (PCD) cutters.

Avoid ceramic cutters as they generate more heat and do not allow for easy chip removal from your workpiece.

Do Not Over-tighten the Delrin Workpiece.

Machining forces are lower for engineering plastics than for metals and the former deforms more easily if clamped too tightly, clamping pressures shall be reduced.

Machining Delrin parts does not require high cutting force. Therefore, you do not have to tightly clamp your workpiece and risk causing deformation.

All you need is to apply a light clamping force to keep it in a safe and stable machining position.

Maintain Safe Machining Temperature

Temperatures exceeding 121 degrees Celsius (Degrees Fahrenheit) can adversely affect the mechanical integrity of your machined POM component.

Use compressed air instead of liquid coolants to maintain stable temperatures and effectively remove chips for quality cutting.

Industry Application of Delrin Machining Components

Below is a list of some of the most common sectors and industries that rely on Delrin machined parts or components. Some of the applications include:

Industrial Applications

Different industry players, such as manufacturers, factories, and engineering industries, rely on a wide range of Delrin components for the operation of their machines or equipment. Examples of such parts include bushings, bearings, robotic gears, wheels, valves, housings, etc.

Delrin Machining In The Medical/Healthcare Sector

Delrin is also used to produce certain medical parts. It is easy to sterilize, making it suitable for medical and health sector applications.

Examples of the Delrin machining parts commonly used in the medical and health sectors include prosthetics, dose-counting inhalers, auto-injector pens, stent delivery systems, pipe clamps, and tubeless insulin pumps or patch pumps.

Automotive Industry

Delrin machining is also used to produce a wide range of automotive parts, such as car auto-door lock systems, window system parts, motors and gears, etc.

Consumer Sector

In the consumer and electronics sectors, Delrin machining is used to produce a wide range of products, such as drawer latches, gears for domestic tools or equipment, and drawer rollers. Some furniture parts, such as handles or locks, are also machined from Delrin material.

Delrin Machining Parts In the Electronic/Electrical Industry

POM machining is also used to produce a wide range of products within the electronics and electrical industries. Examples of electrical parts you can fabricate through Delrin machining include electrical connectors and insulators.

Conclusion

The impressive properties of Delrin material, such as its resistance to tear and wear, and impressive dimensional stability, make it a perfect material for the production of different machined parts.

There are various grades of Delrin you can choose from based on your project needs.

The quality of your Delrin machined parts is determined by your part’s design, the tools you use, and your machining expertise.

You also must remember that POM material is susceptible to deformation if exposed to temperatures exceeding 121°C (249.8°F). Therefore, having an effective compressed-air cooling system during your machining process is critical.

At HM, we have the expertise, experience, and technology to drive your CNC machining projects using different metals and thermoplastics such as PEEK and Delrin.

If you have inquiries regarding your project or need a partner you can rely on, talk to us!