CNC Plastic Machining

CNC Plastics Machining Selection Guide


Plastic CNC machining stands as a precision-driven process, expertly carving, shaping, and refining plastic materials into desired forms with unmatched accuracy. Starting with a solid block of plastic, CNC machines, guided by computer-generated designs, meticulously cut away excess material. Consequently, this process unveils intricate parts and components tailored to specific industry needs.

Furthermore, the versatility of CNC machining allows for a wide array of plastics, such as Acetal, Nylon, and Polycarbonate, to be transformed with precision. Notably, the adaptability of this method extends to various sectors, including aerospace, healthcare, and electronics, showcasing its crucial role in modern manufacturing.

Moreover, the integration of CNC technology promises efficiency and precision, ensuring that each piece meets stringent quality standards. Ultimately, plastic CNC machining not only accelerates production timelines but also elevates the quality and performance of the final products.

CNC Plastic Machining

1. What is Plastic CNC Machining?

Plastic CNC machining emerges as a groundbreaking process in the manufacturing sector, skillfully transforming plastic materials into meticulously designed parts and components. This advanced method utilizes computer numerical control (CNC) machinery to interpret and execute designs with supreme accuracy and efficiency. Initially, engineers develop precise digital models, which serve as the blueprint for the machining process. Following this, CNC machines spring into action, expertly cutting through plastic blocks to sculpt the final product, adhering to the exact dimensions specified in the digital design.

Moreover, the versatility of this technique is noteworthy. It adeptly processes a vast array of plastic materials, including durable Acetal, robust Nylon, and clear Polycarbonate, making it indispensable across diverse industries. From aerospace to healthcare, and even consumer electronics, plastic CNC machining ensures components are produced with unparalleled precision, meeting the specific needs of each application.

Additionally, the precision offered by CNC machining not only guarantees that each piece fits perfectly into its designated role but also significantly reduces material waste. Consequently, this contributes to more environmentally friendly manufacturing practices. In essence, plastic CNC machining stands as a beacon of innovation, marrying digital design with physical creation to deliver high-quality, precise components across various sectors.

2. Can Plastics Be CNC Machined?

Plastics can undergo CNC machining with remarkable success. This process allows for precise cutting, shaping, and drilling of various plastic materials to create detailed and complex parts. Furthermore, the versatility of CNC machining shines through its compatibility with a wide range of plastics, from soft and flexible options like TPE to hard and durable ones like Polycarbonate.

Consequently, industries from aerospace to medical devices leverage this capability to produce components that meet stringent specifications and quality standards. Moreover, the precision of CNC machining ensures minimal waste, making it a cost-effective and environmentally friendly option for manufacturing plastic parts.

3. Type of Plastic Machining

Plastic machining encompasses a variety of processes, each with its unique applications and advantages. Understanding these methods is crucial for selecting the most appropriate technique for any given project.


Overview: Cutting involves slicing through plastic materials to shape or size them using various tools, such as saws or lasers.

Applications: This method is widely used for creating flat components, trimming excess material, or preparing blanks for further machining. It’s essential in fabricating large sheets or blocks of plastic into smaller, more manageable pieces.


Process Explanation: Turning utilizes a lathe to rotate plastic workpieces against a cutting tool, shaving off material to achieve the desired shape and size.

Typical Uses: It’s ideal for creating cylindrical or round components, such as rollers, bushings, and precision shafts. Turning is prized for its ability to produce parts with high dimensional accuracy and smooth surface finishes.

Milling / Routing

Details: Milling and routing involve removing material from a workpiece using rotating tools. While milling can be performed on various machines, routing is typically used for softer plastics and more intricate designs.

Applications: These processes are perfect for producing complex shapes, slots, cavities, and 3D contours. They're commonly applied in making prototypes, mechanical parts, and decorative items.


Process: Drilling creates holes in plastic materials using drill bits. The process varies in speed and drill bit type depending on the plastic’s hardness and the hole’s required precision.

Advantages: It’s a straightforward, efficient method for adding fastening points or channels for wires and fluids.

Common Applications: Drilling is utilized across numerous applications, including creating mounting holes, ventilation channels, and alignment pins in parts and assemblies.

Grinding / Lapping

Introduction: These are finishing processes used to achieve very smooth surface finishes or extremely precise dimensions. Grinding removes excess material with an abrasive wheel, while lapping uses a gentler action with an abrasive slurry to polish surfaces.

Applications: Grinding and lapping are typically reserved for final finishing touches on parts that require a high degree of surface smoothness or dimensional accuracy, such as optical components, seals, and bearing surfaces.

Plastic Machining Materials

4. Common Materials for Plastic Machining

Plastic machining processes have opened up a world of possibilities for creating high-precision parts and components. Below, we explore the most commonly used materials in plastic CNC machining, each offering unique properties and advantages for various applications.

Delrin/POM CNC Machining

Delrin, also known as Polyoxymethylene (POM), is renowned for its high strength, stiffness, and dimensional stability. It excels in applications requiring precise tolerances and low friction. Delrin is commonly used in gears, bushings, and automotive components due to its durability and resistance to wear and moisture.

Acrylic CNC Machining

Acrylic is favored for its outstanding clarity, making it an ideal choice for optical applications and any project requiring transparent components. It's widely used in signs, displays, and light fixtures. Despite its brittleness compared to other plastics, acrylic can be machined to produce parts with a high-gloss finish and excellent aesthetic qualities.

ABS Plastic CNC Machining

ABS plastic combines strength, flexibility, and thermal resistance, making it a versatile choice for a wide range of applications. Its ability to be easily machined and finished makes it perfect for prototypes, enclosures, and consumer goods. ABS is particularly valued for its toughness and impact resistance.

HDPE CNC Machining

High-Density Polyethylene (HDPE) is known for its high strength-to-density ratio, making it suitable for parts that must withstand harsh environments. It is resistant to many chemicals and is often used in tanks, wear strips, and outdoor equipment. HDPE's low friction and resistance to abrasion also make it ideal for sliding components.

Nylon CNC Machining

Nylon is a strong, wear-resistant material that offers excellent chemical resistance and a lower coefficient of friction. This makes it suitable for bearings, rollers, and gears. Its versatility extends to automotive parts, industrial machinery, and consumer products, where durability and performance are critical.

Polycarbonate CNC Machining

Polycarbonate is prized for its incredible impact resistance and optical clarity. It's the material of choice for bulletproof glass, protective gear, and other safety-related components. Despite its toughness, polycarbonate can be machined to produce parts with precision and clarity.

PEEK CNC Machining

PEEK (Polyether Ether Ketone) stands out for its exceptional heat resistance, chemical resistance, and mechanical properties. It is used in demanding applications such as aerospace components, medical implants, and electrical connectors. PEEK's ability to maintain its properties at high temperatures makes it invaluable in high-performance environments.

Plastic Machining Parts
CNC machined-plastic-parts

5. Plastic Machining Considerations

When engaging in plastic machining, several crucial considerations come into play to ensure the success and efficiency of the process.

Choosing the Right Type of Plastic Material is paramount. Different plastics possess unique properties, affecting their suitability for specific applications. For instance, while Delrin offers excellent dimensional stability for precision parts, Acrylic might be the go-to for transparent applications. Thus, understanding the material's strengths and weaknesses becomes a critical first step.

Structural Support During Machining also demands attention. Plastics, varying in rigidity and flexibility, may require specialized fixtures or supports to maintain shape and accuracy during the machining process. This ensures the final product meets the desired specifications without warping or other deformities.

Temperature Management emerges as another vital consideration. Due to their lower melting points compared to metals, plastics need careful monitoring and control of cutting speeds and feeds to prevent melting or burning. Implementing cooling systems or choosing the correct cutting tools can mitigate heat generation.

Lastly, exploring Available Finishing Processes can enhance the product's appearance and performance. Techniques like grinding, lapping, or polishing not only improve the aesthetic appeal but can also contribute to the functionality of the machined part, such as reducing friction or increasing transparency.

6. Applications of Plastic CNC Machining

Aerospace Parts: Aerospace industries rely heavily on plastic CNC machining for creating lightweight, durable components essential for aircraft. From intricate cabin parts to critical control systems, this process ensures precision and reliability in high-stakes environments, significantly enhancing safety and performance.

Analytical Equipment Parts: In the realm of scientific research, accuracy is paramount. Plastic CNC machining crafts precise components for analytical equipment, such as spectrometers and chromatographs, ensuring exact measurements and reliable results in various scientific investigations.

Food Processing Components: Hygiene and durability guide the food processing industry's requirements. CNC machined plastics, known for their resistance to contamination and ease of cleaning, form essential parts of machinery that process, package, and handle food, ensuring safety and efficiency in food production.

Gas and Oil System Components: The gas and oil sectors demand components that can withstand harsh conditions. Plastic CNC machining delivers robust, corrosion-resistant parts for valves, seals, and pipelines, enhancing the reliability and longevity of systems exposed to aggressive environments.

Healthcare Devices: Precision and biocompatibility are crucial in healthcare. CNC machining facilitates the production of medical devices and components, such as surgical instruments and implants, offering patients safer and more effective treatment options.

Marine Components and Equipment: Durability in saline environments is a must for marine applications. Plastic CNC machining provides corrosion-resistant parts for boats and marine equipment, ensuring longevity and performance in the challenging marine setting.

Semiconductor Equipment: The semiconductor industry benefits from the precision of plastic CNC machining in creating components for cleanroom environments, such as wafer handling tools and casings, which are critical for the production of semiconductors, maintaining purity and precision in the manufacturing process.

7. How to Choose the Right Plastic For Your CNC Project?

Choosing the right plastic for your CNC project hinges on understanding the specific requirements of your application. Firstly, consider the mechanical properties needed, such as strength, flexibility, and heat resistance. For instance, if durability is key, Acetal or Nylon might be your best bet. Secondly, evaluate the environmental conditions the part will face. For outdoor applications, UV-resistant plastics like Polycarbonate are ideal. Moreover, for parts in contact with food or medical supplies, ensure the plastic complies with regulatory standards for safety.

Additionally, think about the finish and aesthetic qualities you desire. Acrylic offers a clear, glass-like finish, perfect for transparent components, while ABS can be easily colored for aesthetic parts. Lastly, cost plays a pivotal role. Compare material costs and machining requirements to find a balance between budget and performance. By carefully weighing these factors, you can select the most suitable plastic material for your CNC machining project, ensuring success and efficiency.

POM CNC Machined Plastic Parts
PC machined plastic part
CNC Plastic Components

8. CNC Plastic Manufacturing at RALLY

At RALLY, we stand at the forefront of plastic CNC machining, showcasing a profound expertise and a broad spectrum of high-performance solutions. Our dedication to quality is unwavering, as we harness state-of-the-art technology to craft precision-machined plastics that meet and exceed our clients' expectations. Furthermore, we understand the essence of time in business. Hence, we pride ourselves on our ability to deliver your projects on schedule, ensuring that your operations run smoothly and efficiently.

Moreover, our commitment extends beyond quality and speed; we also focus on making our services affordable. By optimizing our processes and leveraging our expertise, we ensure that you receive the best value without compromising on the quality or timeliness of your CNC machined plastic components.

Ready to take your project to the next level? Contact RALLY today to learn more about our plastic CNC machining capabilities. We invite you to request a quote and discover how we can contribute to the success of your project with our customized solutions. Join us in forging a future where precision, efficiency, and affordability converge.



In conclusion, the journey through the world of plastic CNC machining reveals a process characterized by precision, versatility, and a wide array of applications. From aerospace to healthcare, the ability to machine various plastics like Delrin, Acrylic, and PEEK into complex shapes and parts underscores its vital role in modern manufacturing. Key considerations such as material choice and machining technique play a crucial role in achieving optimal results.

With RALLY's commitment to quality, efficiency, and affordability, businesses can leverage plastic CNC machining to meet their needs effectively. This guide underscores the transformative potential of CNC machining in crafting the future of manufacturing across industries.

Frequently Asked Questions (FAQs) on Plastic for CNC Machining

1. What types of plastics are suitable for CNC machining?

Various plastics are amenable to CNC machining, including Acetal, Delrin (POM), Acrylic, ABS, HDPE, Nylon, Polycarbonate, and PEEK. Each offers unique properties like strength, durability, and resistance to chemicals and heat, making them suitable for different applications.

2. Can CNC machining be used for complex plastic parts?

Yes, CNC machining excels at producing complex and precise parts. Thanks to its high accuracy and the ability to use computer-aided designs, CNC machines can create intricate details and geometries that would be challenging or impossible with traditional manufacturing methods.

3. What are the main advantages of using CNC machining for plastic parts?

CNC machining offers precision, versatility, and repeatability. It's capable of producing parts with tight tolerances and complex shapes. Additionally, it's a relatively fast process for small to medium production runs and allows for easy modifications to the design.

4. How does CNC machining compare to 3D printing for plastic parts?

CNC machining and 3D printing are complementary technologies. CNC machining is preferred for its precision and the strength of the parts it produces, making it ideal for functional prototypes and end-use parts. On the other hand, 3D printing offers greater design flexibility and is more cost-effective for highly complex or unique, one-off designs. The choice between the two depends on the specific requirements of the project, including the desired material, accuracy, and production volume.

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