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.
Delrin’s first use was in 1960, and since then, it has become raw material for the production of parts for use in different industries. 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 machining needs. It will introduce delrin plastics, their properties, and their different grades. It will then talk about its use in rapid prototyping and how to select the right grade. Let us dive in.
Delrin Plastic in Rapid Prototyping
Due to the ease of machining POM material, it is an extremely suitable material for 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. Below are two popular delrin rapid prototyping processes.
· CNC Machining
CNC machining is the most common rapid prototyping method used in working with Delrin plastic. It is the right manufacturing method due to the hardness of the plastic. It is also suitable due to the manufacturing process features such as high accuracy, precision, and tolerance.
· Injection Molding
Injection molding involves melting a manufacturing material and pouring it into a mold. The part assumes the shape of the mold on cooling. Delrin is a suitable material for the injection molding process as it can melt and be molded into the right shape.
· 3D Printing
Delrin is an ideal material for 3D printing. Delrin 3D printing filaments are used in this additive manufacturing process to manufacture wear-resistant parts. The process is additive, and it involves creating the product layer by layer.
Delrin Material Properties
Delrin plastic has unique properties that make it one of the common plastic materials used in rapid prototyping. Below are some of its important properties.
· Electrical Characteristics
Delrin has excellent insulating properties. Combined with its excellent mechanical strength, Delrin 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
Delrin has a tensile strength of between 7,000 and 9,000 PSI. Being a plastic, Delrin is less dense than metals. Delrin plastic is also exceptionally hard. This hardness does not mean Delrin is brittle as Delrin also has great toughness.
Delrin is one of the few materials that are exceptionally hard and still retains its toughness. The high strength to weight ratio of Delrin makes it suitable for parts that need to resist great stress while being light.
· Fatigue Resistance
Delrin is an exceedingly tough material. It can withstand a great amount of abuse without failing. Delrin plastics are exceptionally resistant to fatigue failure from –40° to 80°C. In addition, its fatigue resistance capabilities are not impacted significantly by moisture, chemicals, or solvents. This property makes it a material of choice for parts subjected to repeated impact and stress.
· Impact Resistance
Delrin plastic have been found out to be able to endure sudden impact without failing. Delrin polymers have very high toughness compared to other polymers. Grades of Delrin exist which 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, rapid prototyping Delrin is possible because it does not 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.
Pros of Using Delrin in Rapid Prototyping
Delrin is an important plastic in rapid prototyping. Below are a few advantages of using delrin rapid prototyping.
Delrin is exceptionally machinable. Due to its exceptional dimensional stability, it is easy to machine parts made from Delrin to high levels of precision. There is also no need for special equipment and methods when machining Delrin.
Delrin has high tensile strength and endurance, which makes it a suitable material for high-stress applications. Delrin is so strong that it often serves as a replacement material for steel and aluminum alloys.
· Moisture Resistance
Delrin absorbs very little amounts of moisture, even in the dampest conditions. This means it can maintain its structural integrity even when used in underwater applications.
· Creep Resistance
Delrin is an exceptionally tough material that can take loads of stress without failing. This exceptional endurance makes it a material of choice for parts in several industries.
· Electrical Insulation
Delrin serves as an excellent insulator. Its use in a lot of electronics is due to this feature.
Cons of Using Delrin Plastic in Rapid Prototyping
Delrin plastic has many advantages. However, using it can also have some limitations. Below are a few disadvantages of using delrin materials 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. Class A fire extinguishers have to be employed when Delrin materials catch fire.
· Heat Sensitive
Delrin machined parts are not ideal for situations where there is a generation of extreme heat. Although Delrin 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 Delrin parts using adhesive. Most adhesive bonds achieve a strength that is less than 10% of the shear stress of the Delrin. 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 plastic 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
This grade of Delrin is famous for its bettter mechanical properties over other types of acetals. This grade of Delrin 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 the 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 its 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 which function in high-stress level environments.
All grades of Delrin have excellent machinability, which makes Delrin 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. \
Application of Delrin in Rapid Prototyping
Delrin material has applications in a large variety of industries, including the following
· Automobile Industry
Delrin plastic is a popular component in the automotive industry to manufacture parts such as gears for windows and windshield wipers. The excellent load-bearing capacity of Delrin makes it suitable for such applications. Delrin is also a popular component of grills, gas caps, and seatbelt hardware.
· Industrial Equipment
Delrin plastic also has been used in 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. Delrin plastic is a raw material for manufacturing 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 of Delrin for your part.
· Moisture Absorbance
Although most grades of Delrin offer great resistance to moisture, some Delrin grades offer greater water resistance than others. In conditions where it is important to create a tight water seal, some grades of Delrin material are advised to be used. 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 Delrin 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 wears resistance.
· Rapid Prototyping Process
Different delrin plastic has different mechanical properties. Consequently, different rapid prototyping processes will be used. 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 of delrin plastic 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. Delrin 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. Delrin 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 machined part. There are different grades of Delrin plastic available at RapidDirect, along with professionals ready to answer your questions and help you select the best CNC machining material for your specific needs.