The success of a CNC machining project depends on many factors, one of which is the choice of material. This key factor determines the durability and performance of the final product. There are many materials to choose from for CNC machining projects. Therefore, you must understand the advantages and disadvantages of each material in order to find the most suitable material. In this guide, we will take a deep look at the different types of CNC machining materials available and how to choose the right material for your project.
CNC machining wide range of material compatibility and application areas: opening the treasure door of industrial manufacturing
CNC precision machining is suitable for a variety of materials, including high-performance metals and engineering plastics and special composite materials, etc., which can provide flexibility for different industries, help companies customize high-precision parts and enhance market competitiveness. In the treasure house of industrial manufacturing, various different materials are like shining treasures, with a wide variety and each with its own characteristics. And CNC machining technology is the magic key to open this treasure door. It can be used for the processing of a variety of materials according to different processing requirements. These materials have their own characteristics and play different roles in different engineering projects. The correct selection of the right material is essential for the performance, precision and durability of the parts. CNC machining technology can be perfectly combined with various materials, which is the basis for supporting the efficient operation of the entire modern industrial system. The wonderful encounter between CNC machining and different materials is like a carefully choreographed industrial concerto, playing a beautiful movement of efficiency, precision and innovation on the broad stage of modern manufacturing. Each material blooms with unique brilliance under the carving of CNC machining, contributing indispensable power to the development of human science and technology and the improvement of life.
Types of metal materials for CNC machining
CNC machining is widely used in many industries due to its high precision and high efficiency. Different types of metals are suitable for CNC machining. However, each metal has its unique properties, strength and performance, which are suitable for different metal CNC projects. The following are the types of metals commonly used in CNC machining projects.
Aluminum
Aluminum is a common metal known for its lightweight and corrosion-resistant properties. Due to its good machinability, it is an ideal material choice for CNC machining parts. The most common types of aluminum alloys are 6062 and 7075. Due to their high strength-to-weight ratio, they are widely used in automobiles, aerospace and consumer products. Aluminum also has good electrical and thermal conductivity. It is an affordable and high-performance material choice. Another important benefit of this CNC machined metal is that you can easily coat it for enhanced surface protection.
Copper
Copper is a material that conducts heat and electricity very well, which makes it a great choice for many applications. However, copper is difficult to machine due to its soft texture. During machining, the material tends to stick to the tool, making the process difficult. However, copper can be machined well with the right machining strategy and tool. Copper is ideal for medical applications due to its antimicrobial properties. It has a reddish color, which is good for aesthetics.
Bronze
Bronze is an easy-to-machine alloy made of tin and copper. It is durable and corrosion-resistant, making it ideal for producing complex parts such as bearings and gears. In addition, this material is also weather-resistant, making it an excellent choice for demanding applications such as marine and aerospace.
While bronze is not as popular a choice for CNC metal machining parts as aluminum, it has high strength and wear resistance. You can use bronze for parts with high friction.
Copper
Copper, known as pure copper, is highly regarded for its excellent conductivity and toughness. Its surface is rosy red, and its electrical and thermal conductivity are among the best in metals, second only to silver. Because of this, copper is widely used in making electrical and thermal conductive equipment. At the same time, its excellent corrosion resistance also makes it a place in the chemical industry.
Steel
Steel is a durable metal with high tensile strength and corrosion resistance. There are different types and grades of steel, including carbon steel, tool steel, and mild steel. Therefore, steel is a reliable material that can be used to make automotive parts, medical equipment, and heavy components. Compared with materials such as titanium, steel is a more economical alternative for manufacturing parts. In addition, steel is also easy to weld. Since steel is corrosion-resistant, no additional coating or treatment is required. The grade or type of steel you are processing will determine its machinability. Some steels are easier to process, while others may be difficult to process.
Stainless steel
Stainless steel contains chromium, which makes it corrosion-resistant. This material is strong and durable. However, unlike ordinary steel, stainless steel is more difficult to process because of its strong toughness. Common materials such as 316 or 304 are used in the manufacture of food processing equipment and medical devices. CNC machined stainless steel is popular for its high performance and long life. Stainless steel surfaces are not reactive, making them ideal for applications where cleanliness is a concern.
Magnesium
Magnesium is a lightweight metal that is easy to machine. Although it has a low density, magnesium has a high strength-to-weight ratio. Therefore, magnesium is a good material choice for applications where lightweighting is important. For example, manufacturers like to use magnesium to produce automotive parts and aerospace components. You must be very careful when machining metals such as magnesium because powdered magnesium is highly flammable.General CNC machining manufacturers do not usually undertake projects with magnesium materials. Choose Xtproto.
Titanium
Titanium is a hard metal with good biocompatibility and corrosion resistance. It is often used to manufacture aerospace components, high-performance engineering parts, and medical implants. Therefore, titanium is a highly reliable material that maintains its performance regardless of temperature fluctuations. Titanium alloys are corrosion-resistant and are ideal for marine applications. However, machining this material requires high-performance tools and extensive experience. Titanium can withstand any harsh conditions due to its toughness.
Mild steel
Mild steel, also known as low carbon steel, refers to steel with a carbon content of less than 0.25%. Compared with general materials, mild steel has low strength and hardness. Strong ductility, low tensile strength, wear resistance, low cost, easy processing and welding make mild steel widely used. Using CNC processing technology, mild steel can be used in industry for parts with high ductility requirements.
Tool steel
Tool steel is known for its excellent hardness and wear resistance and is designed for the manufacture of tools such as molds, stamps and knives. D2 alloy stands out for its excellent wear resistance and can maintain its original hardness at high temperatures of 425℃. This makes it ideal for tool and mold manufacturing. A2 air-hardening general-purpose tool steel, on the other hand, shows good toughness and dimensional stability in high temperature environments, making it ideal for manufacturing injection molds.
Monel
The demand for CNC machined monel alloy parts is unprecedentedly high. It is mainly used in applications that are exposed to corrosive environments and require higher strength. There are few CNC machining shops that specialize in monel alloy machining because the machining is difficult and requires a high level of experience. It is widely used in aerospace, marine, high-end musical instruments and other fields.
Inconel
It is a nickel-based high-temperature alloy that has become popular in recent years due to its many beneficial properties. Inconel parts are suitable for environments that may be subject to water corrosion or oxidation. It is also very suitable for applications where parts may be subjected to extreme pressure and heat. It is widely used in aviation, aerospace, petrochemical and other fields.
Types of plastic materials for CNC machining
Plastics have become one of the most commonly used CNC machining materials in the field of precision manufacturing due to their excellent properties. Plastics themselves have corrosion-resistant properties. There are many types of these lightweight CNC machining materials, each of which has different mechanical and chemical properties. When it comes to CNC machining, you must understand the characteristics of each plastic. This will help you choose the plastic that best meets the requirements of your CNC machining project. The following is a list of CNC materials.
ABS (Acrylonitrile Butadiene Styrene)
ABS is an affordable and food-resistant plastic. This tough plastic is easy to process, making it ideal for prototyping consumer products. ABS does not perform well in applications exposed to extreme heat and UV rays.
PC (Polycarbonate)
Polycarbonate is able to withstand shock and vibration. This plastic is optically clear and heat resistant, so you can consider it a good choice for electronic components and automotive parts. Polycarbonate is easy to process, but it is prone to cracking when exposed to heat. Therefore, you need to ensure that it is sufficiently cooled during processing.
PMMA (Acrylic)
Acrylic is known for its smooth surface and durability. Due to its high optical clarity, this plastic can be a good alternative to glass. This material is versatile and easy to process, making it ideal for CNC machining. However, acrylic tends to crack when subjected to stress.
POM (Polyoxymethylene, also known as Acetal or Delrin)
This plastic has excellent properties such as low friction, dimensional stability, and high strength. POM is a good material for manufacturing automotive parts such as bearings and gears. In addition, it performs well in humid and corrosive environments.
PA (Nylon)
Nylon is a flexible and impact-resistant plastic with a wide range of uses. Due to its excellent wear resistance and surface lubricity, nylon is used to make parts that rub, such as gears, sliding surfaces, and bushings. However, nylon has low dimensional stability because it absorbs moisture from the air.
PE (Polyethylene)
Polyethylene is an easy-to-process and chemically resistant material. Polyethylene is divided into low-density polyethylene (LDPE) and high-density polyethylene. Generally, polyethylene is used to make wear-resistant parts such as liners and containers. Due to its soft texture, it can be difficult to process.
PEEK (Polyetheretherketone)
This is a thermoplastic with excellent thermal stability. PEEK is resistant to high temperatures, making it ideal for parts in the medical, aerospace, and automotive industries. With its mechanical and chemical properties, it is able to survive in high-pressure environments. In some applications, you can use them to replace certain metals.
PP (Polypropylene)
Polypropylene is a common CNC machining material used to produce piping systems and medical devices. It has good moisture and chemical resistance, making it ideal for applications exposed to corrosive environments. However, this plastic is very soft and difficult to process.
HDPE (High-density polyethylene)
High-density polyethylene (HDPE) has properties such as a high strength-to-density ratio and good chemical resistance. Due to its low coefficient of friction, this plastic is ideal for making moving or sliding parts. However, since HDPE easily deforms, it requires extra care when processing it.
HIPS (High-impact polystyrene)
The structural properties of HIPS make it very easy to process. Although this plastic is not as strong as other plastics, it is impact-resistant. It is a low-cost material, so it can be used for packaging and prototyping.
LDPE (Low-density polyethylene)
LDPE is very soft and flexible. You can use it to produce tubes, caps, and foils. However, due to its softness and flexibility, this material presents some challenges during processing.
PBT (Polybutylene terephthalate)
PBT has good dimensional stability and mechanical strength. Due to its mechanical properties, this plastic is easy to process. PBT is a good plastic choice for making parts for automobiles, electronics, and medical devices.
PPA (Polyphthalamide)
This is a nylon with chemical resistance. It is a reliable choice for producing engine parts in the automotive and electronics industries. PPA has superior mechanical and thermal properties than regular nylon. You can use PPA for high-temperature CNC machining.
PAI (Polyamide-imide)
PAI is a very strong thermoplastic with excellent dimensional stability. This plastic is able to withstand extreme temperatures and mechanical stress. You can use them to make aerospace components and high-speed mechanical parts. However, due to its high strength, this thermoplastic is difficult to process.
PET (Polyethylene terephthalate)
PET is a common type of plastic used in food and beverage packaging. This plastic has good wear resistance and dimensional stability. Since PET is lightweight, it is easy to machine and can achieve a smooth surface.
PPS (Polyphenylene sulfide)
PPS is an easy-to-machine plastic with excellent mechanical strength and chemical resistance. In addition, PPS CNC machined plastic parts can withstand harsh conditions without performance degradation, making them ideal for manufacturing chemical processing equipment and electrical insulators.
PS (Polystyrene)
Polystyrene is widely used in the food and packaging industries to make disposable cutlery, cups, and packaging. This plastic is not impact-resistant, so it can crack or break easily. Polystyrene has a smooth surface after processing, which makes it ideal for prototyping.
PVC (Polyvinyl Chloride)
PVC is an affordable and flame-retardant plastic material. This material is strong, making it ideal for valves, pipes, and building components. It is also resistant to chemicals and high impact. You can use it to make housings, chemical tanks, walkways, and custom fittings.
PTFE (Teflon)
PTFE is a common plastic that has non-stick and low-friction properties. This makes it ideal for producing moving and sliding parts such as seals and bushings. However, due to its softness, this material cannot achieve tight tolerances. PTFE performs well in applications that come into contact with chemicals.
UPE (Ultra-High Molecular Weight Polyethylene)
UPE, also known as ultra-high molecular weight polyethylene (UHMW-PE), is a strong plastic material that is wear-resistant and impact-resistant. It also has low friction properties, which is critical for manufacturing moving parts such as gaskets and conveyor systems. Due to its soft texture, the material is challenging to machine.
Bakelite (Phenolic Resin)
Bakelite is a strong plastic known for its heat resistance and electrical insulation properties. However, due to its brittleness, this plastic is difficult to machine. It remains one of the oldest and most reliable plastic CNC machining materials.
FR-4 (Fiberglass Reinforced Epoxy Laminate)
FR-4 is a high-strength plastic made of epoxy resin and woven fiberglass cloth. This material has electrical insulating and flame-retardant properties and is often used in the production of printed circuit boards. Extra care is required when machining FR-4. This is because an important component of FR-4 – the fiberglass – is abrasive and can wear down cutting tools.
Other Types of Materials that Can Be Machined with CNC Machining
While plastics and metals are the materials commonly used for CNC machining, the CNC machining process is also compatible with other materials. CNC machines can process different materials while providing smooth surfaces and precise results. Here are some other materials that can be machined using CNC.
Graphite
Graphite is a common material used to make electro-discharge machining (EDM) dies for metal casting. Graphite is a soft material that is a good conductor of electricity due to its resistance to high temperatures.You can achieve tight tolerances when machining with graphite. However, since graphite produces fine dust, proper containment is required during machining. Graphite is resistant to thermal shock, making it a good choice for applications with extreme temperatures.
Wood
This is another material that can be easily machinedmaterial that is not difficult to machine. There are many types of wood, including softwood, hardwood, and engineered wood. With a CNC milling machine, you can create intricate designs with wood. You can use it to make furniture parts, cabinets, and carvings with great precision. One of the great things about wood is that it is easy to machine. However, due to its high moisture content, wood is dimensionally unstable, which can cause some problems during machining. If machined properly, wood is great for architectural and artistic applications.
Silicone
This material looks similar to rubber and has similar flexibility. Rubber is great for making molds, seals, and gaskets used in automotive parts and medical devices. Silicone, which is soft, is not suitable for machining. Therefore, CNC machining is suitable for harder silicones, such as high-durometer silicone. You need specialized CNC tools to achieve the best results. Silicone is suitable for use in environments with high temperatures and chemicals.
Rubber
Rubber has elasticity, which makes it difficult to machine. However, you can machine harder rubber products, such as vulcanized rubber sheets. They are ideal for making industrial parts. The best way to machine rubber is to use CNC water jet cutting. This CNC machining method prevents the rubber from deforming. Rubber is impact resistant, so it is ideal for vibrating applications.
Ceramics
Ceramics are extremely strong CNC machining materials that are thermally stable. In addition, ceramics such as zirconium oxide and aluminum oxide also provide excellent results when machining. However, machining ceramics requires special processes and tools. Due to the high hardness of ceramics, low feed speeds and diamond tools are required when machining.
Ceramics are often used in the aerospace, medical, and electronics industries. They are not prone to corrosion and wear, making them suitable for manufacturing parts used in harsh conditions.
Phenolic resins
Phenolic resins are a glass- or paper-reinforced thermosetting plastic. It is a machinable material with excellent mechanical strength and electrical insulation. You can use phenolic resins to manufacture mechanical fixtures and electrical housings. Although phenolic resins are abrasive in themselves, a clean surface can be obtained with the right tools. However, phenolic resins can wear tools, so they need to be handled with care during machining.
Stones
Stones can be natural or man-made. You can machine this material for artistic or architectural purposes. The best methods for machining stone are CNC water jets and CNC milling cutters. These machines can cut stone with precision and provide a clean surface. Stones such as marble or granite are great for making intricate designs such as plaques and countertops. However, the hardness of stone makes it difficult to machine. Therefore, you must use the right tools and coolant system to prevent wear. Diamond tools can help you maintain precision and improve the results of stone machining.
Foam
There are many types of foam, such as polyurethane and high-density modeling foam. These foams are mainly used for packaging inserts, composite molds, and prototypes. Foam is a lightweight material that is easy to machine. It is an affordable option for making large, lightweight parts. However, foams usually produce dust during machining.
Epoxy Resins
Manufacturers use epoxy resins to make composite parts and molds. Epoxy resins are strong and heat-resistant after curing. These materials are ideal for making master molds for prototypes in the aerospace and automotive industries. Tight tolerances can be easily achieved using resins. This makes them ideal for applications that require repeatable precision.
Carbon Fiber
Carbon fiber is a hard, strong material with good thermal stability. In most cases, carbon fiber fabric stock usually requires the addition of resin to make it easy to machine. When machining carbon fiber, special tools are required to achieve the desired results. Additionally, carbon fiber is abrasive and tends to generate dust. Therefore, proper dust management is a must when machining this material.
Plaster
Gypsum is ideal for artistic and architectural applications. You will find that drywall and plaster of Paris (POP) are easy to machine. These materials are very soft and brittle. With CNC machining, you can create intricate designs and shapes with plaster. In addition, plaster is suitable for making decorations, roofs, and theatrical props.
Important Factors to Consider When Selecting CNC Machining Materials
Choosing the best material for your CNC machining is more than just choosing a plastic or metal. Whatever material you choose affects everything, including appearance, cost, life, and performance. Here are the main factors to consider when choosing the most appropriate material for your CNC machining project.
Part Design: Before selecting a material, it is important to understand the material requirements of the part you are manufacturing. Can it work under high stress, withstand extremely heavy loads, and operate in harsh or extreme temperatures? The expected strength, performance, and dimensional stability of the part greatly influence the choice of material. For example, aerospace parts require lightweight CNC materials with high strength, while food-grade CNC machined parts must be non-toxic and corrosion-resistant.
Weight control: Weight plays a very important role in several industries such as robotics, automotive, and aerospace. If you need lightweight parts without sacrificing strength, it is recommended to choose magnesium, aluminum, or plastics such as nylon and PEEK. In addition, if weight is your concern and durability is your priority, titanium or stainless steel will be the best choice. Be sure to consider the strength-to-weight ratio of the application you are using.
Corrosion resistance: Corrosion can significantly shorten the service life of parts, especially in areas exposed to salt, chemicals, or humid environments. For applications in food processing, medical, or marine industries, it is crucial to use corrosion-resistant materials. Titanium, stainless steel, and a variety of high-performance plastics such as PEEK and PTFE all have excellent corrosion resistance, ensuring that parts are safe and functional for a long time.
Part application scenario: The use of the part will largely affect your choice. For example, electronic products require materials with excellent insulation properties, such as phenolic resin or FR-4. Medical devices may require biocompatible materials such as PEEK or titanium. Additionally, automotive parts may require heat-resistant metals such as steel, or high-performance plastics such as PPS. Fully understanding the functional needs of the part and the operating environment is critical to avoiding performance failures.
Cost: Material costs can vary. Metals such as aluminum are generally more affordable, while high-performance materials such as engineered plastics or titanium are much more expensive. You need to balance performance needs with budget, especially in high-volume production. In addition, you should also consider processing costs; these costs include processing cycle time and tool wear, which can be affected by the machinability and hardness of the material.
Machinability: Some materials are not easy to machine. Some softer materials, such as aluminum, are cheaper to machine and can be completed quickly; however, they may not have the durability or strength required for certain applications. In addition, harder materials such as titanium require special tools and longer processing times, which increases production costs. Good machinability can help shorten lead times and reduce overall costs, especially for complex parts.
Environmental impact: Sustainability is a growing concern across industries. Some materials are more environmentally friendly than others, such as aluminum, which is highly recyclable. Choosing materials with a lower environmental footprint will help green manufacturing initiatives. Also, check whether the material releases harmful byproducts during processing, such as polyvinyl chloride (PVC) fumes, and ensure that effective environmental and safety measures are in place.
Material properties: Mechanical properties such as elasticity, hardness, and tensile strength must match the performance requirements of the part. For example, high tensile strength is critical for load-bearing components. Elasticity may also be required for parts that absorb shock. Depending on the application, chemical resistance, electrical insulation, and thermal conductivity are also important properties to consider.
Availability: Some high-performance materials may be difficult to source in the required quantities or sizes, resulting in increased costs and possible delays in the manufacturing process. Standard CNC machining materials such as ABS, aluminum, and stainless steel are often available in different grades and shapes. Always check the global or local availability of a material before using it in your design.
Tolerance and precision of the part: Some materials have tighter tolerances than others. For example, aluminum has excellent dimensional stability. Additionally, softer plastics, such as polypropylene, can deform during or after processing. If the design requires very tight tolerances, especially for multiple parts in a fluid system or mechanical assembly, choose a material that remains stable even under environmental changes and processing stress.
Thermal expansion: Thermal expansion refers to the degree to which a material changes in size when the temperature fluctuates. In precision applications such as optical devices and engine parts, it is better to use materials with lower coefficients of thermal expansion, such as certain ceramics.Plastics tend to expand more than metals, which can cause alignment or installation problems in environments with temperature changes. This is critical for high-precision projects that are highly sensitive to temperature.
Product aesthetics: In some cases, the appearance of a part and how it operates are very important. For consumer products, visible machine parts should look nice and neat. Materials such as acrylic provide optical clarity, while anodized aluminum provides a modern, stylish surface.Some metals and plastics can also be polished, dyed, or coated to achieve a certain aesthetic effect. When choosing, factors such as surface treatment compatibility, color selection, and surface texture should be considered.
Surface treatment type: The surface finish you choose will not only affect the appearance of the part, but also its performance in terms of wear, sealing and friction. Some materials have a better and smoother finish after machining than others. For example, aluminum and brass generally have a better finish than rough materials such as fiberglass or cast iron composites. In addition, certain surface treatments, such as electroplating, painting, etc., may only be compatible with certain materials. Finally, be sure to consider your post-processing requirements when choosing your preferred substrate.
Contact Xtproto Now for CNC Machining Material Recommendations
Are you ready to complete your CNC machining project? Then contact Xtproto! Our team of engineers will immediately provide you with material options that meet your needs. Whatever your plan is, optimizing cost, surface finish, weight or strength, we are a professional CNC machining supplier with a reliable system to guide you to choose the best material for your part. Whether it is high-grade plastics or metals, we have a variety of options and professionals to meet your various project needs. Don’t think about it anymore; Xtproto provides you with an easy and convenient manufacturing process to meet your on-demand CNC machined parts needs and provide accurate material guidance. Send your design now and get an online CNC quote to help you achieve better CNC manufacturing!
Conclusion
Choosing the right CNC machining material is essential to achieve the best performance, cost-effectiveness and durability. Understanding the characteristics of each material and its impact on CNC machining, you can make informed decisions and create better products. Whether you are machining composites, plastics or metals, choosing the right material for your product needs can help you achieve reliable machining results.