What is Delrin (POM-H): Определяющее руководство

If you work with plastics in manufacturing, engineering, or product design, you might have heard of Delrin. And you might ask– what is Delrin plastic? Or what kind of plastic is Delrin?

Let’s answer those questions, including where you can use Delrin and what methods can be done to make Delrin parts. Start reading!

What is Delrin Plastic?

Delrin is a strong plastic that slides easily, stays in shape, and doesn’t wear out quickly. You can use it to make very precise parts because it’s tough, works in extreme temperatures (-40 to 120℃), and is even stronger than ABS plastic.

What is Delrin Made Of?

Delrin, also called POM-H (homopolymer acetal), is part of the POM plastic family.

The other type is POM-C (copolymer acetal). A German chemist named Hermann Staudinger first discovered it in 1920, and DuPont started making it commercially in 1956.

Delrin is made by breaking down hydrocarbons into smaller parts. These parts are mixed with other chemicals to create plastic through a process called polymerization. Delrin is actually a special type of acetal resin that DuPont originally developed.

How to Manufacture Delrin Parts?

Most Delrin parts are made using injection molding or Обработка на станках с ЧПУ, but 3D printing is also an option. Each of these methods has its own advantages.

Here’s what you need to know about each method:

Injection Molding Delrin

Injection molding is a fast and efficient way to mass-produce parts. It works by melting plastic pellets and injecting the liquid plastic into a mold under high pressure.

The plastic then cools and hardens into the final shape. This process is great for making parts with smooth surfaces.

Delrin works well with standard injection molding machines, but to get the best results, follow these tips:

• Use the lowest possible back pressure and keep hold pressure between 60-110 MPa, depending on the Delrin type.
• Set the material temperature at 215±5℃ (or 205±5℃ for tougher grades).
• Keep the mold temperature between 80-100℃, but for highly precise parts, use up to 120℃.
• Dry the material before molding if it has absorbed too much moisture (more than 0.2%).

CNC Machining Delrin

CNC machining removes material from a solid block to create custom parts. This method is perfect for small and medium production runs, as well as for making highly precise parts.

Delrin is easy to machine and holds its shape well, meaning you can achieve tight tolerances of ±0.005 without the material warping. However, since Delrin softens at high temperatures (above 90℃), it’s important to use a cooling method:

• Air-based coolants work best to keep the surface smooth.
• Always use dedicated tools for Delrin to avoid contamination from metals or other plastics.
• A fast cutting speed and slow feed rate produce the best results.

3D Printing Delrin

While Delrin is mostly injection molded or machined, you can also 3D print it, though it’s not the easiest material to work with. When 3D printing, you’re usually working with POM filaments rather than the Delrin brand specifically.

To get better results when printing POM:

• Use a heated bed (between 100-130℃) to help the first layer stick.
• Try using a cellulose or wood-based platform, tape, or adhesives for better adhesion.
• Set the printing temperature between 210-220℃ and, if possible, use a heated chamber to reduce warping.
• Print in a well-ventilated area and keep the temperature below 230℃ to avoid releasing harmful fumes.

What is Delrin Used For?

You’ll often see Delrin used in cars, electronics, and other industries that need strong, high-quality parts. Some common uses include:

Mechanical parts - gears, housing, screws, nuts, and pump components.

Electrical parts - connectors, covers, and insulators.

Car parts - door locks and moving components.

Медицинские изделия - insulin pens and inhalers.

Properties of Delrin

You can evaluate Delrin plastic by looking at these properties:

Химические свойства

• Resists many chemicals and organic solvents, especially below 70℃.
• Does not easily discolor.
• Some newer types have better UV resistance.

Механические свойства

• Very strong (tensile strength of 10,000 psi at room temperature).
• Stiff and rigid (flexural modulus of 410,000 psi).
• Can stretch 10-40% before breaking.
• Handles repeated stress well (fatigue resistance of 5,000 psi)
• Low friction (slides smoothly against steel with a friction rating of 0.1-0.3).
• Resistant to wear, impact, and bending over time.
• Does not absorb much water, making it great for humid or wet conditions.

Тепловые свойства

• Works in temperatures from -40℃ to 90℃.
• Stays strong at high temperatures, holding 2,000 psi tensile strength at 90℃.
• At -40℃, it only loses 20% of its impact resistance but does not become too brittle.
• Can handle water up to 65℃ without losing performance.

Электрические свойства

• Excellent electrical insulator, even in heat and moisture.
• Low energy loss, making it a great insulating material.
• Flammable, with a UL94 rating of HB (horizontal burning).

Advantages of Using Delrin for CNC Machining

Delrin plastic has many benefits for CNC machining, and these are as follows:

• Strong and tough, holding its shape well
• Can handle shocks and stress without breaking
• Resists damage from chemicals
• Has a smooth, glossy surface
• Low friction, making machining easier
• Safe for food and water in many cases (FDA & NSF approved)
• Can replace metal parts made with die-casting

Disadvantages of Using Delrin for CNC Machining

Though there are many benefits, there are still some drawbacks when CNC machining Delrin parts, such as the following:

• Hard to glue or bond to other materials
• Doesn’t hold up well against acids and bases
• Can break down in sunlight and release gases at high temperatures
• Become brittle in very cold conditions

Why Choose Delrin?

Delrin can be a great choice for your parts and projects. Sometimes, the benefits are clear–like in a race car example. Other times, it takes more thought. We help you compare Delrin with other materials so you can make the best choice.

Delrin Plastics vs Metals

When choosing between plastic and metal, think about the balance between cost and benefits. If you made a part from metal, test an engineering-grade plastic like Delrin with the same shape and design.

Even though plastics and metals have different strengths, switching could improve performance and lower costs–especially if the metal design wasn’t ideal.

Molded plastics allow for more complex shapes, built-in colors, and fewer parts in an assembly. This can make manufacturing easier and reduce extra steps, saving time and money.

Sometimes, the best choice is using both. You can add metal inserts to plastic parts for stronger threads, wiring, fluid or gas channels, or better heat control while keeping costs low.

Delrin Plastics vs Other Plastics

Delrin is stronger and more durable than many other plastics. It holds its shape well and doesn’t absorb much moisture, making it better than Nylon, which can swell in humid conditions.

It also has a low-friction surface, so it moves smoothly without sticking. This makes it a great choice for gears, bearings, and moving parts, where other plastics like PVS or ABS might wear out faster or need lubrication.

Delrin is also highly resistant to chemicals, including fuels, oils, and solvents, while plastics like Polycarbonate or ABS can break down when exposed to harsh substances.

It handles higher temperatures than some common plastics, but it is not as heat-resistant as PTFE (Teflon) or PEEK.

If you need a material that is easy to machine, Delrin is a great option because it cuts cleanly and holds precise shapes better than Polyethylene or Acrylic, which can be too soft or brittle.

How Do Geometric Tolerances Behave for Large Delrin Parts?

Delrin is easy to work with and machine, and it stays stable, so you can get precise measurements. But if you’re making large parts, they might shrink a little–about ±0.05mm.

How to Choose the Right Delrin Material？

Delrin comes in different grades– 100, 500, 900, and 1700. These numbers show how easily the plastic melts and flows. Grade 100 is the thickest, while 1700 flows the most. Your choice depends on how you need to fill molds and what the part will be used for.

The table below shows different types of Delrin and what they are best for.

Заключение

Delrin is a strong, smooth, and reliable plastic that works well in many industries. You can machine, mold, or even 3D print it to create precise parts that last.

DEK specializes in CNC machining, injection molding, and 3D printing to deliver high-quality, precise Delrin components. Get a free quote when you contact us.

Вопросы и ответы

What type of plastic is Delrin?

Delrin is an engineering-grade thermoplastic known as Polyoxymethylene (POM). You might also hear it called acetal, polyacetal, or polytrioxane, and you choose it for its strength and low friction.

What is Delrin 150?

Delrin 150 is a strong, general-purpose plastic made from pure Delrin (POM homopolymer). It is highly durable, wear-resistant, and absorbs very little moisture.

What’s the best way to assemble Delrin parts?

Delrin parts can be joined in different ways. You can use self-tapping screws, snap-fits, and press-fits for easy assembly and disassembly. For a permanent hold, you can use welding, adhesives, or rivets

If you’re working on a prototype or small production run, adhesives can work, but they may not be strong enough for long-term use. For critical parts, we recommend using bonded joints for better performance.

Before assembly, clean and degrease surfaces using a sandpaper or chemicals to get the best results.

How do Delrin and acetal differ?

Delrin (POM-H) is tougher, has better wear resistance, and lower friction, making it great for high-performance parts. Acetal (POM-C) is easier to work with and still good for low-friction applications, but it’s not as strong or stiff as Delrin

What’s the best surface finish for Delrin?

You can finish Delrin parts in two main ways, depending on their look and function. As-machined parts are ready to use but may have visible machine marks, while bead blasting creates a smoother, more durable surface

For extra customization, you can add hot stamping, silk screen printing, painting, laser marking, metalizing, or pad printing.

If you choose to paint Delrin, you can bake it at up to 160℃, while metalizing with copper chrome or aluminum improves durability and appearance.

Laser marking also works well after treating the surface with a mild acid solution.

What’s the cost of machining Delrin parts?

Delrin is one of the easiest plastics to machine, making it more expensive than some others–but it’s worth the cost. It stays strong and keeps its shape during machining, and because it’s so rigid, it’s less likely to break.