Types of Plastic for CNC Machining

ABS is the best plastic for CNC machining due to its versatility, ease of machining, and ability to produce durable parts with excellent dimensional stability. CNC machining is widely used to manufacture plastic components for industries like aerospace, automotive, medical, and electronics. Each type of plastic has unique properties that make it suitable for specific applications.

This article explores the different types of plastics used in CNC machining, their characteristics, and how to choose the right material for your project. Yijin Hardware provides expert CNC machining services, offering precision and reliability for all your plastic machining needs.

Key Takeaways

• ABS is the most versatile plastic for CNC machining.
• PEEK offers high heat resistance for demanding applications.
• Nylon provides excellent wear resistance for moving parts.
• Acrylic is ideal for transparent and visually appealing components.
• Material selection depends on mechanical, chemical, and cost considerations.

Common Types of Plastics for CNC Machining

CNC machining works with a variety of plastics, each offering specific benefits depending on the application. Below are the most commonly used plastics in CNC machining.

ABS (Acrylonitrile Butadiene Styrene)

ABS is one of the most versatile plastics for CNC milling and routing. It is easy to machine and produces smooth finishes. ABS is widely used due to its affordability and ability to withstand impact without cracking. It offers:

• High impact strength, making it suitable for parts that require durability
• Excellent dimensional stability, ensuring precise components
• Easy post-processing options like painting or plating
• Low cost compared to other engineering plastics

Applications include automotive interior parts, consumer electronics housings, and prototypes.

PC (Polycarbonate)

Polycarbonate is a strong plastic known for its toughness and transparency. It’s an excellent choice for applications requiring high-impact resistance and optical clarity. PC can withstand moderate heat and provides electrical insulation properties. However, it can be prone to cracking under stress during machining. Common uses include:

• Automotive light covers
• Aerospace components requiring transparency
• Medical equipment housings
• Electrical connectors

Acrylic (PMMA)

Acrylic is ideal when optical clarity and UV resistance are required. It machines easily but can be brittle if not handled carefully during the machining process. Acrylic is commonly used in applications such as:

• Display cases
• Light fixtures
• Signage panels
• Transparent prototype models

Its ability to achieve smooth finishes makes it a popular choice for visually appealing components.

POM (Acetal/Delrin)

POM is an engineering plastic with exceptional machinability due to its low friction and high stiffness. It’s widely used in mechanical applications where wear resistance is critical. POM (Acetal/Delrin) offers:

• High stiffness and rigidity, making it suitable for precision parts
• Excellent dimensional stability even under stress
• Low coefficient of friction, ideal for moving parts like gears and bearings

Applications include automotive gear systems, conveyor belts, bushings, and mechanical prototypes. According to the National Library of Medicine, Acetal and Delrin have powerful dimensional stability, making them great options for complex parts that require tight tolerances.

Nylon (PA)

Nylon is a durable engineering plastic with excellent wear resistance. It’s commonly used in applications requiring moving parts or components exposed to friction. Nylon provides:

• High impact strength for demanding environments
• Good chemical resistance against oils and solvents
• Low coefficient of friction for smooth operation in mechanical systems

Applications include gears, bearings, bushings, and industrial machine components.

HDPE (High-Density Polyethylene)

HDPE is a lightweight yet strong plastic that offers good chemical resistance and durability. It’s easy to machine but requires proper support during the process to prevent deformation. HDPE is commonly used in:

• Outdoor applications like piping systems
• Chemical storage containers due to their resistance to corrosive substances
• Food processing equipment as it is FDA-approved
• Marine components exposed to moisture

PEEK (Polyether Ether Ketone)

PEEK is a high-performance engineering plastic known for its exceptional heat resistance and chemical stability. It’s challenging to machine due to its high hardness but delivers unmatched performance in demanding environments. PEEK is often chosen for:

• Aerospace components requiring high-temperature resistance
• Medical implants due to biocompatibility
• Automotive parts exposed to heat and chemicals
• Industrial applications needing strength-to-weight optimization

Factors to Consider When Choosing Plastics for CNC Machining

Choosing the right plastic material ensures your project meets performance requirements while staying within budget. Here are key factors to consider:

Mechanical Properties

Mechanical properties determine how well a material performs under stress or load. For example:

• Strength: Materials like PEEK offer high strength-to-weight ratios.
• Stiffness: Nylon provides rigidity while maintaining flexibility.
• Impact resistance: ABS handles impacts without cracking.

Ensure the selected material aligns with your application needs.

Chemical Resistance

Chemical exposure can degrade certain plastics over time. Consider materials that resist:

• Solvents like alcohols or acetone (e.g., POM)
• Acids or bases (e.g., HDPE)

For chemical storage containers or harsh environments, choose plastics with good chemical stability.

Temperature Resistance

Temperature affects plastic performance during operation or machining processes. Factors include:

• Heat deflection temperature: PEEK withstands high temperatures without deforming.
• Coefficient of thermal expansion: Materials like PC remain dimensionally stable under heat.

For high-temperature applications like aerospace or automotive parts, opt for heat-resistant plastics.

Machinability

Some plastics are easier to machine than others. Key considerations include:

• Chip formation: Materials like ABS produce clean chips during milling.
• Tool wear: Softer plastics reduce tool wear compared to harder materials like PEEK.

Easier machinability reduces production costs while ensuring precision.

Cost

Material cost influences overall project expenses. ABS offers low-cost solutions for prototypes, while PEEK may be more expensive but necessary for specialized applications. Balancing cost with performance ensures optimal results.

Applications of CNC Machined Plastics

CNC-machined plastics are widely used across industries due to their versatility and performance.

Aerospace Applications

Aerospace requires lightweight yet strong materials capable of withstanding extreme conditions. Plastics like PEEK offer:

• Weight reduction compared to metals
• High strength-to-weight ratio for structural integrity
• Resistance to chemicals like jet fuels

Applications include aircraft interiors, engine components, and insulation panels.

Automotive Applications

The automotive industry relies on CNC machined plastics for durable yet lightweight components, such as:

• Interior trims made from ABS
• Under-the-hood parts using nylon or POM

Prototypes are often machined from acrylic or HDPE before mass production via injection molding.

Medical Applications

Medical devices benefit from biocompatible plastics like PEEK or UHMW polyethylene due to their chemical stability and durability. Common uses include:

• Surgical instruments requiring precision machining
• Diagnostic equipment housings made from PC

Plastics ensure sterility while meeting regulatory standards.

Electronics Applications

Plastics play a crucial role in electronics by providing insulation and structural support. Popular choices include:

• ABS housings for consumer electronics
• PC connectors offering optical clarity

CNC-machined plastics ensure reliable performance in sensitive electronic systems.

Comparison of Common CNC Machining Plastics

This table highlights key differences between commonly used plastics in CNC machining.

Yijin Hardware: Premium Plastic Machining

Yijin Hardware specializes in precision CNC machining services tailored to your needs. We work with the best plastic for CNC machining, including high-performance materials like PEEK and nylon. Our expertise ensures consistent quality across prototypes and production runs. Contact us today for reliable CNC plastic machining solutions!

Best Plastic For Machining FAQs

What is the cheapest plastic to CNC?

The cheapest plastic for CNC machining depends on the application and manufacturing process. ABS is often the best plastic for CNC milling due to its low cost and machinability. HDPE is the best plastic for CNC routing, offering affordability and ease of cutting. Both materials provide cost-effective solutions for producing plastic parts with good durability.

Is plastic CNC machining worthwhile?

Yes, CNC machining is a great option for producing machined plastic parts with precision. Delrin is an excellent choice for CNC plastic machining parts due to its strength and stability. The removal during machining is efficient, reducing waste and improving production speed. Plastic machining is worthwhile for prototypes, machine parts, and specialized components.

What makes a plastic millable?

Plastics that resist melting and deformation are ideal for milling with high-speed cutting tools. Delrin, acrylic, and nylon are among the top choices in the guide to the best millable plastics for CNC machining. The material must balance toughness and machinability to produce high-quality machine parts. Choosing the right plastic ensures accuracy, efficiency, and cost-effectiveness in CNC machining.

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