Have you ever wondered which type of CNC plastic is the perfect match for your project? With options like ABS, acrylic, or POM, each offering unique benefits, choosing the right one can feel overwhelming. The right plastic can boost your project’s durability, precision, and performance. Let’s dive into the world of CNC plastics and uncover how to find the ideal material for your machining needs.
Why Use Plastic for CNC Machining
Plastic is widely used because of its convenience, flexibility, durability, and cheapness when manufacturing through CNC milling, turning, drilling, and other processes. This helps with regard to weight loss on components for example in the automotive or aerospace industries. Because, you know plastic is light in weight and easy to use.
Moreover plastic does not require much work when it comes to manufacturing. You can design it accurately without harming any cutting tools like some metals would. On the other hand, plastic does not corrode or have chemical reactions when exposed to harsh environmental conditions. Thus, you can use it in medical food and even industrial use.
If required, you can use plastic in various types such as ABS, acrylic, or even nylon that serve the requirements of strength insulation or even transparency. Let’s explore different types of plastics for CNC technology in the next section.
Types of CNC Plastics
CNC machining is compatible with a wide range of plastics, from soft Polyethylene (PE) to hard POM and PC. The main difference from metal machining is the tooling and process variables like cutting speed and depth.
“You can see the comprehensive details of plastic CNC machining services from RapidDirect for compatible plastics with the list below, including their properties, machining characteristics, and surface finishing options”
Now, let’s discuss each CNC plastic in detail;
ABS
An abbreviation for Acrylonitrile Butadiene Styrene, ABS is one of the popular synthetic polymers. ABS CNC Part is often used in three-dimensional printing for material’s machining easiness and decent dimensional stability.
ABS is robust, lightweight, able to resist impact, and inexpensive to mold, making it a go-to for automotive parts, toys, and consumer electronics. However, It has a low resistance to UV which results in discoloration and breakdown when in contact with sunlight. Additionally, compared to other CNC plastics, it has relatively low heat resistance.
- Where Is It Used:
This CNC plastic machine is used in various automotive parts and consumer electronics. It’s also included in household equipment and rapid prototypes due to its strength and multi-purpose ability.
PC
Being a transparent and tough polymer, it is able to withstand harsh impact strength and temperature as well. Polycarbonate(PC) is rather light and has great optical clarity.
In the fields of safety glasses, electronics, and compact discs, the PC is a far more popular choice owing to its durability and capacity to endure impact while being transparent. Although considered superior, it is still vulnerable to scratches and has a higher price tag compared to other plastics. It should not be treated with UV, it can face degradation over a certain time.
- Where Is It Used:
Protective glasses, light units of automobiles, helmets, and casings of electronic devices all use PC. Additionally, it is commonly employed in architectural structures, such as skylights and bulletproof windows.
Acrylic, PMMA
Acrylic, or PMMA which stands for Polymethyl Methacrylate is a glass substitutive plastic of very low weight with brilliant weather resistance properties.
For signage, lenses, and aquariums that are weatherproof ideal as well as have great optical transparency, PMMA would suit best as it is also shatterproof. It is brittle when faced with force and is also quite easy to scratch making it not the best option when aiming to look for something tougher.
- Where Is It Used:
Acrylic is a major component in the making of signage, cases for light sources, display cases, and aquariums. Its great transparency allows its use for lenses and windows.
POM
POM, also known as Polyoxymethylene, is an adamant plastic that can easily withstand wear and relies on low friction for good performance. However, POM has poor resistance to UV rays and flammability. Moreover, strong acids or chlorine can also lead to degradation.
- Where Is It Used:
You will find it in gears, bearings, fasteners, and automotive parts. POM is useful for precise and sturdy parts.
Nylon (PA)
Nylon is an important polymer characterized by high elasticity and great strength. It is highly resistant to wear and chemicals. Due to the bulkiness and fatness of amino complex, there is high water absorption which can affect the dimensional stability. Also becomes brittle under low temperatures.
- Where Is It Used:
Nylon polymers are common in gears, bushings, conveyor belts, and other mechanical components. Moreover, you can find it in textiles, automotive components, and sporting goods.
PE (HDPE & LDPE)
Polyethylene (PE) is a relatively low-density polymer that is available in both low and High-density Polyethylene forms (HDPE and LDPE). HDPE is stiff and impact-resistant while, LDPE is tough but light in weight. They have low international thermal resistance and are prone to ultraviolet deterioration in the absence of specific additives.
- Where Is It Used:
You can use HDPE in making pipes, certain containers, and cutting boards. While, LDPE is common in making packages, bags, and tubing.
PEEK
The Term PEEK stands for Polyether Ether Ketone. It is a high-performance thermoplastic polymer that is famous for its strength, chemical resistance, and heat resistance. It is very costly and takes a lot of techniques and implementations in comparison to other CNC plastics.
- Where Is It Used:
PEEK is applicable in the aerospace industry, medical implants, and the automotive industry which require high performance in stressful conditions.
PP
Polypropylene (PP) is a tough, lightweight plastic that is well known for its amazing flexibility and its being chemically resistant. It can be UV sensitive and hence rot easily. Moreover, it can turn brittle under low-temperature exposure. Also has some heat exposure limits.
- Where Is It Used:
Today, you will find PP in food containers, parts for vehicles, medicine, and other fabrics. Due to material properties, PP is easily used in several applications.
PBT
Polybutylene Terephthalate (PBT) is yet another strong polymer. It has substantially more heat resistance along with electrical insulation. It provides good chemical resistance and stability to dimensions and is best suited for electrical parts. PBT is brittle in cold temperatures, radiation, and prolonged UV exposure.
- Where Is It Used:
PBT is applied for electrical connectors, automotive components, and domestic appliances because of its toughness and reliability.
PEI
Polyetherimide (PEI) is a tough plastic that contains a great deal of heat resistance. It provides remarkable properties and stability. But, it has high prices and scarce resources on the market. Moreover, it can develop stress cracks.
- Where Is It Used:
Polyetherimide finds application mainly in areas of aerospace, medical equipment manufacturing, and electronics. You can say found in devices requiring great resistance to heat.
PS
Polystyrene (PS) is also called a foamy polystyrene. It is a lightweight and strong polystyrene that is available in solid and foam form. Cheap and easy to fabricate. But the weak point is that it is breakable, non-biodegradable, and poor resistant to impact. It is also flammable with no heat resistance.
- Where Is It Used:
Based on versatility and cost, Polystyrene is popular in packing, packing cups, insulation, and model kits.
PVC
The word polyvinyl chloride also referred to as PVC plastic is one of the most durable and stable kinds of material. It has a strong resistance to chemicals. It is also economical and fire retardant because of the inclusion of additives. But, PVC is no more eco-friendly than any other product and releases harmful gases on burning. Some formulations of it may become brittle with age.
- Where Is It Used:
Polyvinyl Chloride is utilized for piping, windows, floorboards, and electrical wavelengths. Its uses range from construction to windows due to its strength.
PTFE (Teflon)
PTFE or Teflon is known to many as a nonstick fabric that is elastic but heat resistant. Moreover, it is chemically and electrically conductive material. Unluckily, it is quite complex to process and is expensive. It can undergo degradation with high energy radiation or impacts.
- Where Is It Used:
PTFE is used to coat cookware, gaskets, seals, and including electric insulation. It’s also widespread in industrial processes where there is a need for low friction.
A Quick View of the Plastic Machinability Chart
CNC Plastic Type | Machinability | Key Characteristics |
ABS | Excellent | Easy to machine, low cost, good impact resistance, and can be easily thermoformed. |
PC (Polycarbonate) | Fair to Good | Tough and impact-resistant but can be prone to cracking under certain conditions. |
Acrylic (PMMA) | Excellent | Easy to machine, produces smooth finishes, but brittle, and can crack under stress. |
POM (Acetal) | Excellent | Low friction, high stiffness, excellent dimensional stability, ideal for gears and bearings. |
Nylon (PA) | Fair to Good | Excellent wear resistance, but can absorb moisture, which may affect machining quality. |
PE (HDPE & LDPE) | Excellent | Soft and easy to machine, low friction, but can deform if not supported properly. |
PEEK | Fair | High-performance, heat-resistant plastic, but challenging to machine due to high hardness. |
PP (Polypropylene) | Excellent | Easy to machine, low cost, but can be difficult to bond or paint. |
PBT | Fair | Good heat and chemical resistance, but can be brittle and tough to machine. |
PEI (Polyetherimide) | Fair to Poor | High-performance material, tough to machine due to its high rigidity. |
PET | Good | Good dimensional stability, easy to machine, but can warp under stress. |
PS (Polystyrene) | Excellent | Easy to machine, can achieve smooth finishes, but brittle and prone to cracking. |
PVC | Fair | Can be tough to machine, especially with softer formulations, and may produce toxic fumes. |
PTFE (Teflon) | Excellent | Very easy to machine, has low friction, and excellent chemical resistance, but can be hard to bond. |
How to Choose the Right Plastic for Your CNC Machining Project
While choosing the right engineering plastic for your project, you should have the following factors in mind;
Mechanical Properties
It is important to know the mechanical properties of the plastic to be used in a CNC machining project. For example, polymers such as PEEK and nylon offer high strength as well as good wear resistance and can be used for load-bearing elements.
On the other hand, acrylic is a polymer that is designed for flexibility and transparency rather than thumb resistance for example. Hence select the material that aligns with the mechanical requirements of the application.
Corrosion Resistance
If your project involves chemicals moisture or extreme conditions then it is advisable to use highly corrosion-resistant CNC plastics. Chemicals are best handled with PTFE (Teflon) and PVC plastic while HDPE works best with high moisture areas. Using the right selection guarantees dependability and function through the years.
Thermal Expansion
Let us examine the behavior of the plastic in question when exposed to a change in temperature. For instance, PEEK material possesses low thermal expansion making it suitable for high heat applications.
On the other hand, however, certain CNC materials, for example, PP, may expand more than desired due to temperature changes.
Cost and Availability
Often the cost and the material’s availability are important aspects affecting the decision. Generic plastics like ABS and PP are cheaper and readily available. Whereas, specialized materials like PEI or PEEK are more expensive but have specific advantages. A good trade-off between performance and budget is important.
Surface Finish Requirements
When looking at anything visually, it is crucial to take into account if aesthetics and surface quality are of paramount importance.
For ease of use, high tensile strength materials like POM are suitable for applications with an ease of requirement. The final result must be harmonized in such a way that it matches in function and aesthetics.
Tips for Working with CNC Plastic Machine
Sharp Tools, High Feed, Low RPM
The cutting tools should be sharp as they are effective in preventing the tearing of the plastic to be CNC machined. A balance of high feed and low RPM must be employed to prevent the heating and melting of the material.
Clamp carefully
Most CNC plastics tend to deform under pressure. So, utilize air pads or soft pads to distribute the pressure and avoid clamping the machine too tightly. Additionally, at the same time avoid the use of a vacuum table that may lead to destruction while the machine is in operation.
Avoid Coolants
The majority of cut plastics do not require the addition of coolant. However, it can be employed to prevent the cracking of the material. Instead, proper anticipation and control of the tool speed is essential in preventing the overheating of the material.
Oversize Cuts for Soft CNC Plastics
For soft plastics like LDPE, allow oversized cuts as required. It means making cuts near the edges and adjustments to prevent warping, especially during the finishing of the operations.
Take Big, Deep Cuts
When working on plastics such as POM or Nylon, deep cuts are recommended. You know such cuts guarantee that the material does not warp while retaining its original properties. Choose the depth of cut by considering tool size, tool coating, speed, and feed.
Adequate Chip Clearance
Guarantee a clean-up through an air blast or use of vacuum systems a blast or point blank. Apart from this, install over the material being machined tool such that it never allows the buildup of chips to affect the cut being performed.
Moreover, it is also essential to Match Design Complexity with Machine Capability, not all machines can craft the complex features of CNC plastic workpieces. For example, only 3-, 4-, and 5-axis CNC machines can make complex curved surfaces and overhang features.
CNC Machining Techniques for Plastic Parts
CNC machines make plastic parts through machining processes. These techniques remove material to form them in a particular shape that would suit the design requirements. Depending on the complexity and the kind of material to be used, a number of machining techniques can be applied in order to get the desired output.
CNC Turning
This method uses a cutting tool over a cylindrical plastic workpiece and rotates it to make a plastic part. The majority of the time, cutting tools bring negative back rake angles to avoid contact and rubbing of the tool. Moreover, they alter relief angles according to the material.
The tool being made requires a smooth finish which can be achieved through polishing it. It requires a lower rate of feed 0.015 IPR for a Rough cut and 0.005 IPR for a finished cut being applied. Improved angle changes tend to enhance extraspinal accuracy and finished smoothness.
CNC Milling
A complex part is made by cutting a workpiece using rotating cutters and removing material from it through plastic milling. Cutting tools that are used for reinforcing plastics can be rounded on the inner corners for improved results.
High spindle speed and proper clamping boost efficiency. Moreover, there is a sufficient cooling system to prevent the spindles and machine from warping.
CNC Drilling
This specialized CNC plastics machining process entails the creation of holes within thermoplastics with certain drill bits placed at angles ranging from 90-150 degrees. The procedure further employs the use of cooling systems to dissipate any heat created as a result of the drilling. It is also to enhance chip removal. Keep the drilling depth no more than 3-4 times the drill diameter and reduce the feed rate near the exit to avoid damage.
CNC Routing
Plastic materials that need to be shaped and are either flat or curved are also cut about in a controlled fashion through the use of CNC routers. All these processes and optimal speeds provide smooth and accurate results across the board.
Industrial Applications of CNC Plastic Parts
With the guarantee of accuracy and robustness, CNC-plastics machined parts across industries have become easy with the advent of CNC machining.
- Medical Industry: The need for the production of surgical tools, severe prosthetics, medical tools, and so on is transcended with the use of plastic machining. The methods also guarantee safety compliance with stringent requirements while being able to produce engraved detailing.
- Automotive Components: You can machine plastic parts such as dashboards and air holes through computer numerical control. As a result, it decreases the weight of an automobile’s body and improves the performance of machined parts.
- Aerospace Parts: Prototypes, interiors, and components of the structure that are heat resistant and not heavy so in regards to aeronautics plastic is the material used. This process is crucial as details CNC machined plastics through these methods are under enormous stress and require utmost accuracy.
- Electronic Industry: Within electronics, machined plastic components are used like connectors, casings, and keypads. Over-molding connectors together with plastic enhances the insulation and sturdiness of delicate systems.
Get Started with RapidDirect Plastic CNC Machining Services Today
CNC plastic machining is a reliable means of making precise CNC plastic parts with moral tolerances and good quality specifications. It is in expansion due to its accuracy, quickness, and adaptability in the line of duty.
In order to select an appropriate technique and the right material, working with a service provider like RapidDirect will help you a lot. We offer custom CNC plastics machining to meet the requirements of prototypes and productions.
The machinable plastic materials we use are not arbitrary but have been examined to meet the targets. Moreover, the engineering department gives advice on the best material and design to adopt. Uploading your design grants you instant quotes, free-of-charge Design for Manufacturing (DfM) analysis, and competitive rates.
For more details, download our Plastic Materials eBook to learn more about the plastic material and how to take advantage of it when it comes to precise CNC plastic machined parts for your project!
FAQs
Whichever project you are pursuing, it averages that ABS or POM is better for common usage. But if the need is high performance, have a look at PEEK or Nylon which offer high strength and good durability.
That depends on the material, on how complex the part you need is, and on what machine settings you selected. As a rule of thumb, cutting soft items takes a minute; higher complexity parts can take hours.
