Delrin: Is It Just Another Plastic or Something More?
If you do not work in the plastic manufacturing industry, you may not have even heard of Delrin. If you do, you are probably tired of keeping track of all the different plastic materials out there. Regardless, Delrin has been a reliable material in the production of countless different products and components since 1960.
But what exactly is Delrin material? What does it bring to the table? And how does it differ from other plastic materials?
If you do not know the answers to these questions, do not worry. Even the most established plastic fabrication companies struggle to choose materials for their projects. This article covers some of the basics around Delrin, so you can become a plastic materials connoisseur.
What Is Delrin Material?
Delrin is a plastic material more commonly recognized as an acetal homopolymer. This semi-crystalline thermoplastic offers exceptional impact and wear resistance as well as electrical insulation properties. It is an ideal choice for several machining applications and is often used to replace metal parts.
Some other Delrin characteristics include high tensile strength, stiffness, creep resistance, and fatigue resistance. All these mechanical properties allow plastic manufacturers to create thin, lightweight parts in a quick and cost-efficient way. In short, Delrin is an affordable, durable material that is easy to machine for all types of plastic components.
One frustration that can arise is choosing Delrin among others in its class. Delrin is really just a brand name for a specific acetal homopolymer and is interchangeable with many others of the same type.
Now, that’s a lot of fancy words, and honestly, I’m not even convinced the experts know what they mean. However, we must soldier on for the sake of knowledge and learning. So, what is the difference between Delrin and other acetal polymers?
Acetal vs Delrin
Acetal plastics, also known as polyoxymethylene, are a class of thermoplastics that come in several different forms and specific brands. Whether copolymers or homopolymers, these plastics do share many overlapping characteristics with slight variance. Overall, they are typically lightweight, wear-resistant, and low-friction.
There are also metal-detectable acetals, which include metal additives. This allows machinery to find broken fragments during production using metal detectors. These are often colored blue to make them easier to find and extract, especially in applications involving food.
So What’s the Difference?
The central difference between Delrin vs other acetal materials is due to its status as a homopolymer. Rather than having several different subunits, this material’s crystalline structure is entirely uniform. This improves properties such as stiffness and resistance to flex fatigue. It also increases overall mechanical durability.
A downside of choosing Delrin over other acetal thermoplastic materials is centerline porosity. This is an abnormality caused by gas escaping while the plastic cools. If the center is drilled out, this is a non-issue. If not, however, it can increase the risk of bacterial growth in food and medical applications.
In conclusion, Delrin is somewhat unique, but it is not that much different from other acetal plastics. In most cases, it can be exchanged for other materials depending on your application and budget.
Delrin Properties & Applications
Delrin’s properties make it a good choice for several high-capacity mechanical applications, and with its moisture resistance, it is also useful in damp environments. Here is an overview of Delrin properties and applications:
Delrin Material Properties
High fatigue resistance
High creep resistance
High tensile strength and stiffness
Excellent dimensional stability
Wide operating temperature range
Resistance to hydrocarbons, solvents, & neutral chemicals
Machinable to tight tolerances
Ideal for light, thin part design
Reduced part production costs
Friction, fatigue, and abrasion resistance
Low moisture absorbance
Useful electrical properties
Compliant with FDA & USDA
Medical delivery devices
Pistons and valves
Electrical insulator parts
Food product forming dies
Gears, bearings, & bushings
Delrin Machining Methods
There are many ways to create components with Delrin. The most common methods include plastic injection molding and CNC machining Delrin.
Injection molding is used for both plastic and rubber materials. This process involves injecting melted plastic into a pressurized metal die cavity where it will cool down and take shape.
It can create a large volume of parts in a relatively short amount of time, so it is a good choice if you work on a tight schedule. In fact, a single molding cycle can create a complete part in as quick as a few seconds!
Alternatively, CNC machining is a method that devices to perform various production tasks. In contrast to injection molding, CNC machining does not work with melted plastic. This technology takes a solid block of material and meticulously shaves away layers until it creates a predetermined shape.
The machinery gets its directions from a CAD or other digital file. The instructions are then processed and converted into mechanical actions by the automated milling machines. A significant advantage of this process is that the files can be edited between each cycle, allowing for quick adjustments to be made mid-production.
However, Delrin is not the only material used to create parts with these production methods. Want to learn more about other plastic materials? Check out this article on ABS plastic.