Choosing CNC Materials: Your 8-Item Checklist

CNC machining is a popular and versatile process in the industrial sector, with applications in aerospace, medical, automotive, and other industries. One of the advantages of CNC machining is its ability to work with a wide range of materials. However, selecting the right material for CNC machining is crucial for achieving desired part quality and meeting production demands. In this article, we will provide an 8-item checklist to help you navigate CNC material selection confidently. We will focus on different categories of materials, including metal and plastic options, and discuss their properties, applications, and machining considerations.

Key Takeaways

  • Choosing the right material is crucial for CNC machining success.
  • Consider the properties and applications of different metal and plastic materials.
  • Key factors for material selection include mechanical and thermal properties, cost, and surface finish requirements.
  • Follow tips for machining different materials to achieve optimal results.
  • Use the Protolabs Network’s guidelines to optimize CNC material selection.

Different Categories of Material in CNC Machining

CNC machining is a versatile process that allows for the use of various materials. In this section, we will focus on the two main categories of materials commonly used in CNC machining: metal and plastic. These materials offer diverse properties and applications across different industries. By understanding the characteristics of each material category, you can make informed decisions when selecting the right material for your CNC machining projects.

Metal Materials

Metals are widely used in CNC machining due to their excellent strength, durability, and thermal conductivity. They are commonly found in industries such as aerospace, automotive, and electronics. Metal materials can range from aluminum and steel to exotic alloys like titanium and magnesium. Each metal material has its own set of properties and machining considerations, making it important to choose the right one for your specific project requirements.

Plastic Materials

Plastics are another popular choice for CNC machining due to their versatility, lightweight nature, and wide range of physical properties. They find applications in industries such as consumer goods, healthcare, and electronics. Common plastic materials used in CNC machining include acrylic, nylon, ABS, and polycarbonate, each with its own unique characteristics and considerations. Understanding the properties and capabilities of plastic materials will enable you to select the most suitable option for your CNC machining projects.

Metal Materials Plastic Materials
Aluminum Acrylic
Stainless Steel Nylon
Carbon Steel ABS
Copper and Alloys Polycarbonate

Types of Metal Materials for CNC Machining and Examples

Metal materials are essential in CNC machining due to their exceptional strength, thermal resistance, and hardness. In this section, we will explore some common metal materials used for CNC machining, including aluminum, stainless steel, carbon steel and its alloys, copper and its alloys, titanium, and magnesium. By understanding the properties, applications, and machining considerations of each material, you can make informed decisions when selecting the right metal for your CNC machining projects.

1. Aluminum

Aluminum is a versatile metal material used extensively in CNC machining. It offers excellent corrosion resistance, high strength-to-weight ratio, and good machinability. Aluminum is commonly found in aerospace, automotive, and electronics industries.

2. Stainless Steel

Stainless steel is known for its exceptional corrosion resistance and durability. It is widely used in CNC machining projects that require high strength and resistance to heat and chemicals. Stainless steel is commonly used in medical devices, kitchen equipment, and architectural applications.

3. Carbon Steel and its Alloys

Carbon steel and its alloys are favored in CNC machining for their high stiffness and wear resistance. These materials are commonly used in industrial machinery, automotive parts, and construction projects due to their strength and affordability.

4. Copper and its Alloys

Copper and its alloys are known for their excellent conductivity and corrosion resistance. They are widely used in electrical components, heat exchangers, and plumbing fixtures in CNC machining projects that require conductivity, durability, and thermal performance.

5. Titanium

Titanium offers exceptional strength-to-weight ratio, heat resistance, and corrosion resistance. It is commonly used in aerospace, automotive, and medical industries for critical components that require lightweight yet high-strength materials.

6. Magnesium

Magnesium is a lightweight metal with excellent machinability. It offers high strength and good thermal conductivity. Magnesium is commonly used in CNC machining for applications in the automotive, aerospace, and electronics industries.

Properties and Applications of Common Metal Materials for CNC Machining

Material Properties Applications
Aluminum – Lightweight – Aerospace and automotive parts
– High strength-to-weight ratio – Electronics and consumer products
– Good machinability – Machine components and architectural structures
Stainless Steel – Corrosion resistance – Medical devices and surgical instruments
– Durability and strength – Kitchen equipment and industrial machinery
Carbon Steel – High stiffness and wear resistance – Automotive and industrial machinery
– Affordability – Construction and structural applications
Copper – Excellent conductivity – Electrical components and heat exchangers
– Corrosion resistance – Plumbing fixtures and marine applications
Titanium – High strength-to-weight ratio – Aerospace and automotive components
– Heat and corrosion resistance – Medical implants and sporting goods
Magnesium – Lightweight – Automotive parts and electronic housings
– High strength and good thermal conductivity – Aerospace structures and consumer electronics

Types of Plastic Materials for CNC Machining and Examples

Plastic materials are highly valued in CNC machining for their versatility and wide range of physical properties. Different plastic materials offer unique advantages and are suitable for various applications in CNC machining projects. In this section, we will explore some common types of plastic materials used in CNC machining, their properties, applications, and machining considerations. Let’s dive in!

1. Acrylic

Acrylic, also known as PMMA (polymethyl methacrylate), is a transparent thermoplastic that exhibits excellent optical clarity, high impact strength, and good weatherability. It is commonly used in CNC machining for signages, display cases, lighting fixtures, and automotive parts that require transparency and durability.

2. Polypropylene

Polypropylene is a lightweight thermoplastic with excellent chemical resistance, low moisture absorption, and high fatigue resistance. It is widely used in CNC machining for automotive components, food containers, medical devices, and consumer products.

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3. Acetal

Acetal, also known as POM (polyoxymethylene), is a versatile thermoplastic known for its high stiffness, low friction, and excellent dimensional stability. It is suitable for CNC machining applications that require precise parts such as gears, bearings, and valve components.

4. Nylon

Nylon is a strong and durable thermoplastic with excellent mechanical properties, including high tensile strength and impact resistance. It is commonly used in CNC machining for engineering components, gears, pulleys, and bearings.

5. ABS

ABS (acrylonitrile butadiene styrene) is a versatile thermoplastic known for its high impact resistance, strength, and heat resistance. It is widely used in CNC machining for automotive parts, electronic enclosures, consumer products, and prototypes.


UHMW-PE (ultra-high-molecular-weight polyethylene) is a lightweight, self-lubricating thermoplastic with excellent wear resistance and low friction properties. It finds applications in CNC machining for conveyor components, wear strips, and sliding parts.

7. Polycarbonate

Polycarbonate is a transparent thermoplastic with high impact resistance and excellent thermal stability. It is commonly used in CNC machining for safety glasses, riot shields, automotive components, and electrical insulators.

8. Polyetheretherketone (PEEK)

PEEK is a high-performance thermoplastic known for its exceptional mechanical properties, chemical resistance, and excellent thermal stability. It is widely used in CNC machining for aerospace components, medical implants, and other applications that require high-performance materials.

These plastic materials offer a glimpse into the diverse options available for CNC machining projects. Each material has its own unique properties and applications, enabling manufacturers to select the most suitable material based on their specific project requirements. By understanding the properties and considerations of these plastic materials, you can make informed decisions when choosing the right material for your CNC machining projects.

Types of Plastic Materials for CNC Machining

Key Factors for CNC Machining Materials Selection

When it comes to CNC machining, selecting the right materials is essential for achieving optimal results in your projects. Consideration of key factors plays a vital role in making informed decisions for material selection. Below, we will discuss these factors in detail to help you choose the perfect CNC machining materials.

Mechanical and Thermal Properties

The mechanical and thermal properties of materials greatly impact their performance in CNC machining. Factors such as strength, stiffness, hardness, and thermal conductivity need to be taken into account. For example, if you’re machining a part that requires high strength, selecting a material like stainless steel or titanium would be appropriate. Understanding the mechanical and thermal requirements of your project will guide you in choosing the ideal material.


Cost is another crucial factor to consider when selecting CNC machining materials. Different materials have varying costs, depending on factors such as availability, processing difficulty, and market demand. It’s important to balance the cost of materials with the required performance to ensure efficient budget allocation for your CNC projects.

Surface Finish Requirements

The surface finish of your CNC machined parts contributes to their overall quality and appearance. Certain materials, such as aluminum alloys, can achieve smooth surface finishes with ease. On the other hand, materials like ABS or nylon might require additional post-processing steps to achieve the desired surface finish. Evaluating your surface finish requirements will guide you in selecting materials that meet your specific needs.

Environmental Considerations

Considering environmental factors when selecting CNC machining materials is crucial, especially when your parts will be exposed to extreme conditions or specific environments. Factors such as chemical resistance, corrosion resistance, and temperature resistance should be taken into account. For example, if your project requires parts to be exposed to harsh chemicals, selecting a chemically resistant material like PEEK (polyetheretherketone) would be suitable.


When selecting materials for CNC machining, consider the mechanical and thermal properties, cost, surface finish requirements, and environmental factors to make the best choice for your projects. By understanding the impact of these key factors, you can ensure the optimal performance of your CNC machined parts.

Now that we’ve explored the key factors for CNC machining materials selection, let’s move on to the next section where we will provide valuable tips for machining different materials using CNC processes.

Tips When Using CNC Processes to Machine Different Materials

Machining different materials using CNC processes requires specific techniques and considerations. To achieve optimal machining results and prolong tool life, here are some helpful tips:

  1. Proper Tool Selection: Choose the right cutting tools based on the material properties and machining requirements. Consider factors such as tool material, geometry, and coatings.
  2. Feed and Speed Optimization: Adjust the cutting speed (RPM) and feed rate to optimize material removal while avoiding excessive heat buildup. Refer to machining guides or consult with tooling experts for recommended feed and speed values.
  3. Coolant Usage: Use coolant or lubricants to dissipate heat, reduce friction, and improve chip evacuation. Choose the appropriate coolant based on the material being machined and consider environmental and safety regulations.
  4. Toolpath Strategies: Optimize toolpaths to minimize vibrations, maximize cutting efficiency, and reduce tool wear. Consider factors such as tool engagement, direction changes, and cutting order.

By following these tips, you can enhance your CNC machining process and achieve excellent results when working with different materials.

Tips When Using CNC Processes to Machine Different Materials

Material Tips
Metal Use appropriate cutting tools for specific metal types. Consider cooling methods for heat-sensitive materials.
Plastic Optimize tooling, feed, and speed to prevent melting and material deformation. Consider using coolant or air-blast to remove chips efficiently.
Composite Choose tools with specialized geometries designed for composite materials. Optimize toolpath to minimize delamination.
Ceramic Use high-quality diamond or cubic boron nitride (CBN) tools for machining ceramics. Apply coolant to manage heat buildup and prevent fracturing.

Get the Right CNC Machining Material for Your Projects

Choosing the right CNC machining material is crucial for ensuring the quality of your parts and meeting the demands of your production projects. To help you navigate the material selection process effectively, we have prepared a step-by-step guide. Follow these key steps to identify the most suitable CNC machining material for your specific projects:

  1. Define your material requirements: Start by clearly defining the specific requirements for your project. Consider factors such as mechanical properties, thermal characteristics, chemical resistance, and surface finish requirements. This will help you narrow down the options and focus on materials that meet your project’s unique needs.
  2. Identify candidate materials: Once you have defined your material requirements, research and identify a list of candidate materials that possess the desired properties. Consider both metals and plastics, as each category offers different advantages and applications in CNC machining.
  3. Evaluate material properties: Analyze the properties of each candidate material, including strength, hardness, machinability, and temperature resistance. This evaluation will help you understand how each material will perform during the machining process and in the final product.
  4. Consider material availability and cost: Assess the availability and cost of each material. Factors such as material sourcing, lead times, and price can impact both the feasibility and cost-effectiveness of your CNC machining projects.
  5. Consult material guides and expert recommendations: Utilize material guides provided by reputable sources, such as manufacturers or industry experts, to further inform your decision-making process. These guides offer valuable insights into the performance, applications, and machining considerations of different materials.
  6. Test and validate: Before proceeding with full-scale production, consider testing and validating your selected material. This can involve creating prototypes and conducting feasibility studies to ensure that the material meets your project’s requirements.
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By following this step-by-step guide, you can confidently select the optimal CNC machining material for your specific projects. Remember to consider the unique characteristics of each material, the requirements of your project, and seek guidance from industry experts when needed.

Optimizing CNC Material Selection with Protolabs Network’s Guidelines

When it comes to CNC material selection, optimizing your choices can significantly impact the success of your machining projects. Protolabs Network, a leading provider of CNC machining services, offers comprehensive guidelines to help you make informed decisions. These guidelines consider important factors such as mechanical strength, machinability, cost, hardness, and temperature resistance.

By following Protolabs Network’s guidelines, you can optimize your CNC material selection process, ensuring that you choose the most suitable materials for your specific machining projects. Let’s take a closer look at some of the key aspects covered in these guidelines:

Consider Mechanical Strength

Understanding the required mechanical strength of your CNC machined parts is crucial for material selection. Protolabs Network’s guidelines outline the mechanical properties of different materials, enabling you to find the optimal balance between strength and weight for your specific application.

Evaluate Machinability

Protolabs Network emphasizes the importance of considering the machinability of materials during the selection process. Certain materials may be more difficult or time-consuming to machine, which can impact production timelines and costs. By selecting materials with excellent machinability, you can enhance the efficiency and quality of your CNC machining projects.

Assess Cost

Budget is a significant consideration when choosing CNC materials. Protolabs Network’s guidelines provide insights into the cost variations between different materials, helping you make cost-effective material selections without compromising on performance or quality.

Analyze Hardness and Temperature Resistance

The hardness and temperature resistance of CNC materials play a crucial role in determining their suitability for specific applications. Protolabs Network’s guidelines provide valuable information on these properties, enabling you to select materials that can withstand the required environmental conditions and maintain their structural integrity.

By leveraging Protolabs Network’s guidelines for optimizing CNC material selection, you can make informed decisions that lead to successful machining projects. Whether you are working on aerospace components, medical devices, automotive parts, or other industry-specific applications, keep in mind the importance of material optimization in achieving your desired outcomes.

Next, we will delve into the details of specific materials commonly used in CNC machining, exploring their properties, applications, and machining considerations. Stay tuned!

What is Aluminum? The Robust, Economical Alloy

Aluminum is a widely used metal alloy in CNC machining due to its exceptional properties and versatility. Known for its excellent strength-to-weight ratio, thermal conductivity, and corrosion resistance, aluminum offers numerous advantages for various applications. In this section, we will delve into different grades of aluminum, including 6061, 7075, and 5083, exploring their unique characteristics, widespread applications, and essential considerations for CNC machining.

Properties of Aluminum Alloys

Aluminum alloys possess remarkable strength and durability while being significantly lighter than many other metal alloys. This lightweight nature makes aluminum an ideal choice for industries seeking to minimize weight in their designs. Additionally, aluminum alloys showcase excellent thermal conductivity, allowing for efficient heat dissipation during CNC machining processes. Moreover, aluminum exhibits superior resistance to corrosion, enhancing its lifespan and making it suitable for diverse environments.

Applications of Aluminum in CNC Machining

The versatility of aluminum alloys makes them highly sought after in various CNC machining applications. From aerospace and automotive industries to electronics and consumer goods, aluminum is used to create a wide range of components, including aircraft parts, automotive structures, heat sinks, electronic enclosures, and more. Its exceptional strength and lightweight properties make aluminum alloys particularly beneficial for structural applications where weight reduction is crucial.

Machining Considerations for Aluminum

When it comes to CNC machining aluminum, certain considerations must be taken into account. Due to its high thermal conductivity, proper cooling and the use of appropriate cutting fluids are essential to prevent overheating during the machining process. Moreover, aluminum alloys tend to have a higher level of ductility compared to other materials, necessitating the selection of suitable cutting tools and toolpath strategies. By managing these factors effectively, CNC machinists can achieve precise and efficient machining results with aluminum alloys.

Aluminum Grade Properties Applications
6061 Excellent strength, good corrosion resistance, weldable Aerospace components, automotive parts, structural frames
7075 High strength, good fatigue resistance, machinable Aircraft structures, bicycle components, sporting goods
5083 Good weldability, high corrosion resistance, marine-grade Shipbuilding, marine structures, offshore equipment

Common Plastic Materials for CNC Machining

Plastic materials are widely used in CNC machining due to their versatility and a wide range of physical properties. Understanding the characteristics of common plastic materials is crucial for selecting the right material for your CNC machining projects.

One commonly used plastic material in CNC machining is ABS (Acrylonitrile Butadiene Styrene). ABS offers excellent impact resistance, good mechanical strength, and is easily machinable. It is often used in applications that require durability and a smooth surface finish, such as automotive parts, consumer electronics, and prototypes.

Nylon is another popular plastic material choice for CNC machining. It has a high strength-to-weight ratio, good chemical resistance, and excellent wear resistance. Nylon is commonly used in applications that require toughness, such as gears, bearings, and structural components.

PMMA acrylic, also known as Plexiglas or Lucite, is a transparent plastic material that offers high optical clarity. It is often used for applications that require transparency, such as display panels, lenses, and light covers. PMMA acrylic is easy to machine and provides a polished appearance.

Other common plastic materials for CNC machining include POM (Polyoxymethylene), PTFE (Polytetrafluoroethylene), HDPE (High-Density Polyethylene), and PEEK (Polyetheretherketone). Each material has its unique properties and applications, allowing for a wide range of CNC machining possibilities.

By considering the properties, applications, and machining considerations of common plastic materials, you can confidently select the right material for your CNC machining projects, ensuring optimal performance and quality.