Plastic CNC Machining – Types of Plastic for CNC Machining

“Do you think plastics can be precisely machined? Most certainly. Let’s enlighten the modern-day Plastic CNC Machining process with thorough details to comprehend the key challenges faced during components production”

Plastic CNC machining plays a significant role in today’s plastic fabrication industries. It is a renowned method of creating highly tolerant and durable plastic components. While selecting the appropriate plastic material for usage, there are a few considerations that should be followed. For instance, pricing, workability, strength, weight, and stress tolerance level.

This article highlights the essential details of CNC plastic machining, plastic types suitable for CNC machining, and optimal machining processes. Moreover, we’ll examine the industrial applications, merits, and demerits, and discuss achieving the perfect finish.

What is Plastic CNC Machining?

Plastic CNC Machining refers to the process of using computer numerical control (CNC) machines to precisely cut, shape, and form plastic materials into desired shapes and dimensions. To cut these plastics into coveted shapes, certain tools such as drills, mills, lathes, and routers can be used. Moreover, the Computerised Aided Designs added precision, quality, and error-free optimization levels in this process. This method has become indispensable across various industries due to its ability to produce complex parts with tight tolerances, exceptional surface finishes, and rapid turnaround times. 

Plastic CNC Machining

Plastics For CNC Machining

The plastic material widely ranges from thermosetting to thermoplastics. When selecting thermoplastics for CNC machining, it’s essential to understand their differences. 

Thermoplastics Vs. Thermosetting: Thermoplastics are polymers that can be softened through heating without curing (chemical reaction). Moreover, these materials can be remelted and remolded multiple times without any change in their composition. Therefore, they are extensively used for CNC Plastic applications.

On the other hand, thermosetting plastics are polymers that can not be remelted or remolded once they have undergone a chemical reaction. That is why their usage is limited in the machining industry.

Common Types of Plastics Used For CNC Machining

Various types of plastics or polymers can be used to sculpt intricate plastic parts. There’s a range of machining processes for ABS to PET, let’s figure out the optimal machining processes for each plastic type and their applications.

1. Acrylonitrile Butadiene Styrene (ABS)

CNC ABS Plastic Machining

Acrylonitrile Butadiene Styrene or ABS is an engineered thermoplastic polymer. Its lightweight property, adjacent to high strength, machinability, and impact resistance makes it well-suited for CNC machining processes. It can be milled, turned, drilled, and machined with relative ease. Therefore, it is used for the creation of complex parts with intricate details. 

Moreover, ABS offers excellent impact resistance and toughness, making them suitable for functional prototypes and durable end-use parts.

2.  Acrylic (Polymethyl Methacrylate, PMMA)

Acrylic or PMMA is a transparent thermoplastic homopolymer known for its optical clarity and scratch resistance ability. It is more lightweight and cheaper than glass. It can be precisely machined into various shapes without deteriorating its transparency. Moreover, acrylic offers a versatile spectrum of colors and opacities.

Acrylic Sheet CNC Machining

Additionally, parts made with acrylic are more durable and cost-effective. Thus, acrylic can be fashioned into a diverse range of products due to its excellent machinability and mechanical strength. 

3. Nylon 66 (Polyamide)

Nylon plastic CNC machining  

Nylon 66 or polyamide is a durable thermoplastic that offers distinct properties such as high strength, toughness, and resistance to wear, heat, and chemicals. It has a low coefficient of friction which reduces friction between moving parts and minimizes the need for lubrication. Hence, it’s most suitable for machine precision parts like gears, bearings, and bushings.

4. Polycarbonate (PC)

Polycarbonate CNC machined parts

Polycarbonate is a transparent thermoplastic similar to acrylic. It is known for its high impact resistance, excellent optical properties, and dimensional stability. Moreover, it can withstand high temperatures without being melted. Also, polycarbonates can generate UV radiation. This makes them perfect for medical equipment such as goggles, syringes,  etc.

5. Polyethylene (PE)

Polyethylene (PE) is a type of lightweight thermoplastic. In CNC plastic machining its use is integral due to its chemical resistance and low friction properties. PE comes in various grades such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), and ultra-high molecular weight (UHMW).

Polyethylene CNC Machining

• High-Density Polyethylene (HDPE):  HDPE is known for its excellent machinability. It is lightweight, and strong and can be easily cut, drilled, milled, and turned using a CNC machine without generating excessive heat or wear on cutting tools.

• Low-Density Polyethylene (LDPE):  LDPE is a more flexible and less rigid material than HPDE. Moreover, LDPE has a low coefficient of friction, which reduces wear on cutting tools during machining operations.

• Ultra-high molecular weight (UHMW): UHMW exhibits superior mechanical properties than HDPE and LPDE. It offers excellent impact resistance, abrasion resistance, and toughness, making it suitable for applications requiring high durability and wear resistance.

6. Polypropylene (PP) 

Propylene Plastic CNC Machined part

Polypropylene is a cost-effective semi-crystalline thermoplastic known for its high chemical resistance and stiffness. It can be swiftly milled, drilled, turned, and routed to create intricate shapes and precise plastic parts. However, CNC machining of polypropylene can be challenging in most cases as it has a lower melting point than other plastics.
7. POM Machining (Polyoxymethylene)

POM/Delrin machining part

POM, also known as Delrin or acetal. It is a solid and rigid thermoplastic known for its exceptional dimensional stability and low friction properties. Polyoxymethylene is among the best plastics since it is resistant to chemicals, oils, and solvents. 

Moreover, it offers two grades 570 and 150 to design intricate parts with tight tolerances due to its excellent dimensional stability. 

8. PVC (Polyvinyl Chloride)

 PVC Machining Parts

PVC is a pliable and widely used engineered thermoplastic. It comes with two distinct forms plasticized or unplasticized. Mostly unplasticized uPVC is employed by CNC machining experts due to its rigidity. Parts like pipes and fittings are made of uPVC. 

Additionally, its superior resistance to chemical erosion and smooth inner surface allows water to flow smoothly without interruption.  Moreover, uPVC is also resistant to a broader range of temperatures than plasticized PVC. CNC machining manufacturers commonly use it to produce construction materials, pipes, and window profiles. 

9. PEEK (Polyether Ether Ketone)

PEEK CNC Machined parts

PEEK is known as high-performance thermoplastic. It offers exceptional mechanical properties, chemical resistance, and high-temperature stability (up to 260°C(480 F)). Furthermore, it’s lightweight and able to endure harsh environments. It is immiscible in all kinds of solvents as well. On top of that, it is biocompatible and inert, and PEEK’s recyclability makes it useful for sustainable manufacturing solutions. 

But, it’s quite expensive than other plastics, so product designers should use them for specialized projects.

10. PET (Polyethylene Terephthalate)

CNC Machined PET parts

When it comes to plastic machining, Polyethylene Terephthalate can be an excellent option. PET is a strong and lightweight thermoplastic renowned for its excellent dimensional stability and chemical resistance. Moreover, it is a convenient option over other commonly employed plastics like Nylon as it’s easy to machine, and offers FDA-approved CNC machining plastic parts. 

Here is a comprehensive overview of various plastic machining methods and their diverse industry applications. 

Table: Plastic Machining Processes and Applications

Best Machining Methods for Plastic CNC Machining

Plastic CNC machining uses various techniques to cut and shape plastics. The most commonly used approaches are CNC milling, turning, routing, drilling, and engraving. All these techniques use pre-programmed CNC software to control the movements of the machining equipment.

1- Plastic CNC Milling

Milling is among the primary techniques employed in plastic CNC machining. It utilizes rotary cutting tools to subtract material from a plastic workpiece. It enables the creation of intricate shapes and features with remarkable precision. Moreover, Plastic CNC milling is highly versatile, accommodating a wide range of plastic materials, including ABS, acrylic, nylon, polycarbonate, and polypropylene. 

So, CNC milling is extensively used in producing CNC plastic machining prototypes, molds, enclosures, and brackets. Lastly, CNC milling offers unparalleled flexibility and efficiency in manufacturing plastic parts with precise dimensions and smooth surface finishes.

2- Plastic CNC Turning

Another essential method for plastic CNC machining is turning. In this process, the workpiece rotates while a cutting tool removes material to form cylindrical shapes. This technique is particularly well-suited for manufacturing plastic rods, shafts, bushings, and components with rotational symmetry, offering high precision and surface finish.

3- Plastic CNC Routing

CNC Routing involves the use of a rotating cutting tool, or router, to carve specific shapes, profiles, or contours from large, flat plastic sheets or panels. This technique is best for precisely shaped plastics such as acrylic, PVC, and polycarbonate, among others while maintaining tight tolerances and smooth surface finishes. 

Moreover, product designers can achieve high levels of productivity, accuracy, and repeatability in producing custom-designed plastic parts and components to meet the requirements. This method is commonly employed in creating signs, displays, panels, enclosures, and decorative elements due to its efficiency and ability to cut through plastic materials with precision.

4- Plastic CNC Drilling

CNC Drilling focuses on creating holes of precise depths and diameters in plastic-stationed workpieces by the use of drill bits. Drill bits cut and shape holes in a workpiece. It is essential for producing plastic components requiring accurate hole patterns for assembly, fastening, or internal routing of features.

5- Plastic CNC Engraving

Engraving employs specialized tools to engrave designs, logos, or text onto the surface of plastic workpieces. You can use Acrylic, ABS, PVC, and polycarbonate for engraving. This method adds both aesthetic and functional value to plastic components. 

Moreover, it enhances their visual identification. CNC engraving spans branding, labeling, decoration, and customization across various industries.

Advantages of Plastic CNC Machining

• Precision: CNC plastic machining offers unparalleled precision and accuracy, ensuring consistent quality across large production runs. 
• Versatility: It can accommodate various plastic materials, geometries, and part sizes, making it suitable for diverse applications. 
• Efficiency: CNC machining enables rapid prototyping and production, minimizing lead times and optimizing production schedules.
• Complexity: Intricate designs and complex geometries can be achieved with ease, allowing for the creation of highly customized parts. 
• Cost-Effectiveness: Despite initial setup costs, CNC machining offers cost savings in the long run through reduced material wastage, labor costs, and improved efficiency.
• Diverse Range of Plastic Materials: There are numerous types of plastics available for CNC machining, each with its unique properties. This allows manufacturers to choose the most suitable material for their specific application, whether it requires strength, flexibility, heat resistance, or other characteristics.

Read More:

• 6 Types of Plastic Dies: Do You Know Them All?
• CNC Milling for Plastic Parts: Precision in Low-Weight
• Polycarbonate Polishing From Basic to Applications
• What is CNC Machining of PVC
• Engineered Plastic Components: A New Age of Industries
• What is Tooling in Manufacturing?

Make Your Plastic Choice with Pro-lean

Are you confused about which material option is good for you? Consult with Prolean experts. We deal with a wide range of materials from metals to plastics. Our Professional Engineers will provide comprehensive assistance, from plastic material selection to process optimization.

Whether your project demands intricate designs, tight tolerances, or large-scale production, our advanced CNC plastic machining services are meticulously crafted to fulfill your distinctive needs. We ensure quality and outcomes with every iteration.

If you want to explore your options for plastic CNC machining, send us your design today and get an instant quote.

Summing Up

CNC Plastic machining is a renowned manufacturing process widely acceptable and applicable in producing intricate components. With its precision, flexibility, and ability to work with various plastic materials, CNC machining enables the production of custom components, prototypes, and specific parts requiring high tolerance and durability. 

There are several plastic material choices available to you with different specifications and applications. CNC plastic machining is a highly economical process and its products are highly efficient, mechanically strong, and of high quality.

As industries continue to grow and demand for customized, high-quality plastic parts rises, CNC plastic machining will remain a critical manufacturing process due to its driving efficiency, productivity, and innovation across various sectors.

FAQs 

What are the challenges associated with plastic CNC machining?

Challenges of plastic CNC machining include; the selection of the right plastic material, tool wear, chip control, thermal control, achieving desired surface finishes, and the dimensional stability of plastic materials.

What are UV-resistant plastics?

UV-resistant Plastic materials are designed to withstand UV radiation without losing their mechanical characteristics. The most commonly used UV-resistant plastics are ABS (Acrylonitrile Butadiene Styrene).

Why is CNC Machining prioritized for Plastic?

CNC Machining is prioritized for several reasons: 

• It excels at producing intricate parts with tight tolerances.
• CNC machining is suitable for both prototyping and production runs of low to medium-volume.
• CNC machining supports a wide range of plastic materials, such as ABS, acrylic, polycarbonate, nylon, PEEK, and various thermoset plastics.
• It offers easy customization and iterations.
• It does not have significant tooling costs like Injection molding.
• CNC machining can incorporate various secondary operations such as drilling, tapping, milling, and engraving into a single process.

Which country is best at making CNC machining plastic prototypes?

China’s CNC plastic machining is at the forefront of the world for its cost-effective manufacturing solutions and large-scale production capabilities.