Delrin is the brand name of an acetal polymer used extensively in CNC machining for its exceptional structural integrity, durability, and strength. The material, also called POM (Polyoxymethylene) or Delrin plastic, is further machinable via other processes such as injection molding and 3D printing.
There are different grades of Delrin available, each with a varying mix of properties. Consequently, choosing the right material might be challenging. This write-up will work to avert that as it will serve as a guide to choosing the right grade of Delrin for your needs.
Delrin’s Properties Ideal in Rapid Prototyping
Since rapid prototyping requires the fast creation of parts, it needs to be done using a material that is stable and has a great machinability rating. Delrin material satisfies both of these conditions, so it is an extremely suitable material for CNC machining, injection molding, and even 3D printing.
Below are some of its important properties.
· Electrical Characteristics
Delrin has excellent insulating properties. Combined with its excellent mechanical strength, it is a very good material for use in electrical components.
The plastic can also withstand large quantities of electrical stress, making it suitable for use as a high-voltage insulator. Its low moisture absorbance also makes it a great material to keep electrical components dry.
· Mechanical Strength
Being plastic, Delrin’s tensile strength of between 7,000 and 9,000 PSI is less dense than metals. It is one of the few materials that are exceptionally hard and still retain its toughness. The high strength-to-weight ratio makes it suitable for parts that need to resist great stress while being light.
· Fatigue Resistance
Delrin plastics are exceptionally resistant to fatigue failure from –40° to 80°C. Its fatigue resistance capabilities are not impacted significantly by moisture, chemicals, or solvents. This property makes it a great choice for parts subjected to repeated impact and stress.
· Impact Resistance
Delrin can endure sudden impacts without failing. It has very high toughness compared to other polymers, so it can undergo treatment to provide even higher resistance to sudden impact.
· Good Dimensional Stability
Dimensional stability measures a material’s ability to retain its normal dimensions after undergoing subjection to pressure, temperature, and other conditions during machining. Therefore, it won’t lose its shape when machining. Machining Delrin is significantly easier than machining other materials due to this property.
· Frictional Properties
Moving machine parts usually undergo lubrication to reduce the friction generated when they rub against each other. Parts machined out of Delrin do not, however, need lubrication as they are innately slippery. This property can serve as parts of machines such as food processors where external lubricators may contaminate the produce.
Cons of Using Delrin Plastic in Rapid Prototyping
Delrin has many advantages. However, using it can also have some limitations. Below are a few disadvantages of using Delrin material in the rapid prototyping process.
When a part machined out of Delrin starts burning, it continues to do so until it loses the supply of oxygen. Thus, it’s advisable to use Class A fire extinguishers when it catches fire.
· Heat Sensitive
Delrin machined parts are not ideal for situations where there is a generation of extreme heat. Although it has some measure of heat resistance, it will deform and can even melt if the temperature gets too high.
Delrin is resistant to chemicals, and this makes it extremely difficult to join parts using adhesive. Most adhesive bonds achieve a strength that is less than 10% of the shear stress of the Delrin material. To bond Delrin surfaces, the surface has to be roughened before the application of the adhesive.
Delrin material is less stiff than metals. This means parts with large spans must be extra thick or supported at regular intervals to prevent deflection.
Different Grades of Delrin in Rapid Prototyping
Choosing Delrin plastics as the right plastic for rapid prototyping comes with an understanding that it has many grades. Each grade has its mechanical properties and is suitable for different purposes and machinable by different processes. Below are a few Delrin plastic grades you could consider.
· Delrin 150
Delrin 150 is famous for its better mechanical properties than other types of acetals. It offers exceptional strength and rigidity and has exceptional resistance to warpage even when subjected to high temperatures.
The lubricity of Delrin 150 gives it good resistance to wear and tear, making it suitable for long-term applications. This makes it a material of choice for parts that must withstand high-stress levels in the automotive and construction industries.
· Delrin AF 100 (13% PTFE Filled)
This Delrin plastic is exceptionally durable and resistant to wear. The addition of PTFE makes it stronger and improves its lubricity. It is a great replacement material for metal in situations that require exceptional durability and endurance. PTFE-filled Delrin plastic has natural lubrication and doesn’t require the addition of external lubricants to reduce friction between moving parts. This natural lubricity makes it ideal for situations where grease and other chemical lubricants are not suitable.
· Delrin (30% Glass Filled)
Glass-filled Delrin plastic is a component for parts that are subjected to high constant stress. This is due to the exceptional impact resistance of this grade of Delrin material. Glass-filled Delrin has great resistance to creep and deformation. It has high resistance to warpage and great endurance.
· Delrin AF DE588
This grade of Delrin contains 20% PTFE fibers. This gives it exceptional rigidity, strength, and durability. It is a component approved by the US Navy for use in submarine parts. This Delrin variant is useful for fast-moving parts that function in high-stress-level environments.
All grades of Delrin have excellent machinability, which makes it a great choice as a material for rapid prototyping. However, they all have different material features which make them suitable for use in individual applications. At RapidDirect, we are experts at machining pom material and can advise you on what grade of Delrin to use based on your specific use case.
We also have a large variety of other machining materials, which you can be advised to use in cases where Delrin plastic is not the best choice. Do you want the best machining service? Contact RapidDirect today to get a quote.
Applications of Delrin in Rapid Prototyping
Delrin material has applications in a large variety of industries. Read on.
· Automobile Industry
Delrin plastic is a popular component in the automotive industry to manufacture parts such as gears for windows and windshield wipers. Its excellent load-bearing capacity makes it suitable for such applications. It is also a popular component of grills, gas caps, and seatbelt hardware.
· Industrial Equipment
Delrin is suitable for manufacturing gears, bearings, fan blades, farm equipment, as well as many other industrial components.
· Consumer Appliances
Delrin parts are present on a wide array of consumer goods, like handles of appliances, clips, zippers, valves, etc.
· Electrical Appliances
Delrin plastics can function as housings for electrical appliances, switches, platforms for cartridges, forms for holding coils, etc.
How to Choose the Right Delrin Material
Delrin has a great blend of characteristics that make it suitable for use in situations where other plastics and even metals cannot be used. The following is a Delrin material guide to help you select the right grade for your part.
· Moisture Absorbance
Although most grades of Delrin offer great resistance to moisture, some of them offer greater water resistance than others. In conditions where it is important to create a tight water seal, it’s suggested to use some of its grades. Delrin 150, for example, is a grade of Delrin that offers excellent protection against moisture.
· Wear Characteristics
Materials with high lubricity often exhibit greater resistance to wear and tear. Some grades also contain other materials that make them tougher. Delrin AF 100 is a great choice for moving parts as it also contains PTFE fiber which increases its toughness and wear resistance.
· Rapid Prototyping Process
Different Delrin plastic has different mechanical properties, thus being applied in different manufacturing processes. For example, for the hard Delrin plastic grades, CNC machining is the most common method.
Choosing the right grade comes with understanding the different properties of Delrin plastics and their relatedness to their uses. For example, certain grades have certifications for use in food processing. This means they are safe for use as food containers and parts that come in contact with food.
Parts manufactured from Delrin can be exceedingly difficult to glue. This is due to the chemical resistance and natural lubricity of Delrin. It is naturally slippery, and this, therefore, makes it difficult for the glue to adhere to the surface of the plastic.
Delrin Plastic has certifications from the FDA as a food-grade plastic. This means it is perfectly safe for you to use it in a food production appliance. The NSF also certifies it alongside the USDA, which allows it to be employed in the packaging of dairy products.
Delrin plastic has many great properties that make it suitable for use in different industries, from the automotive industry to the food industry. It is also one material that can substitute for various applications due to its excellent strength and lightweight. Different grades of Delrin, however, exist all with different strengths and weaknesses.
This write-up provides you with the properties of the various grades of Delrin, which will help you make an informed decision on the grade of Delrin that is perfect for your part. What’s more, there are different grades of Delrin plastic available at RapidDirect, along with professionals ready to answer your questions and help you select the best material for your prototyping needs.