Material and Surface Treatment Design Guide

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In modern manufacturing, the choice of materials and how they are treated is critical to product quality. CNC machining is widely used in many industries due to its high accuracy and efficiency. But, getting the best results requires deep knowledge of materials and their use in design. In addition, the use of engineering plastics and composites is increasing, and their performance in CNC machining is as important as design considerations. Picking the right materials, smart designs, and good surface treatments can greatly improve part quality. This guide from Yonglihao Machinery covers these key points. They are essential for a successful CNC project.

Properties and applications of different metallic materials

CNC machining commonly uses metal materials. It mainly includes steel, stainless steel, aluminum, copper, and their alloys. These materials play an important role in different applications due to their different properties. Choosing the right material for a specific machining need can improve the part’s performance and life.

Steel and Stainless Steel: Steel and stainless steel are known for their high strength and corrosion resistance. Steel is very hard and strong. It is good for parts that feel high stress. These parts are both structural and mechanical. Stainless steel adds great corrosion resistance to steel. This makes it good for use in harsh places. It is widely used in building structures, machine parts, tool making, and various industrial equipment.

Aluminum: Aluminum and its alloys are favored for their light weight. They are also liked for their ease of processing and high thermal conductivity. Aluminum is less dense than steel. But, alloying and heat treatment can greatly increase its strength. Moreover, the malleability and machinability of aluminum make it suitable for machining a variety of complex shapes. Currently, it is widely used in aerospace and automotive manufacturing. For example, aircraft have structural parts. Cars have bodies and engine parts. Electronic equipment has radiators and heat exchanger parts.

Copper and its alloys: Copper and its alloys are known for their excellent electrical conductivity and corrosion resistance. Copper is second only to silver. It is the most used conductive material in the electrical and electronics industry. Moreover, copper alloys such as brass and bronze also have good mechanical properties and wear resistance. It is now widely used in electrical components, heat exchangers, and piping and in building decoration. Commonly used components include valves, pipe fittings, and musical instruments. They also include bearings, gears, and ship propellers.

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Engineering Plastics and Composites in CNC Machining Applications and Design Considerations

Common Engineering Plastics

ABS: ABS is an engineering plastic that is impact resistant, heat resistant, and easy to machine. It is strong and rigid. It is often used to make car parts, appliance housings, and toys. ABS is easy to CNC machine and has a good surface finish. This makes it suitable for many complex shapes.

Polycarbonate: Polycarbonate (PC) has high strength, high transparency and good impact resistance. It is widely used in electronic equipment shells, optical lenses and safety protection equipment. Polycarbonate is easy to process. But, it deforms at high temperatures. So, the temperature must be controlled when processing it.

Nylon: Nylon (polyamide) has excellent mechanical properties, abrasion resistance and chemical resistance and is commonly used in gears, bearings and industrial machinery parts. Nylon works well in CNC machining. But, due to its high hygroscopicity, it needs to be dried before machining. This drying prevents dimensional changes.

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Composite Materials

Carbon Fiber: Carbon Fiber Reinforced Plastic (CFRP) is extremely strong and rigid while being very lightweight. It is widely used in aerospace, motorsports and sports equipment. Carbon fiber is difficult to machine and usually requires the use of special tools and high precision CNC equipment.

Glass Fiber Reinforced Plastic: Glass Fiber Reinforced Plastic (GFRP) is strong and rigid. It resists corrosion and is widely used in buildings, ships, and wind turbine blades. GFRP is more machinable. But, the machining process makes a lot of fiber dust. This requires effective dust removal measures.

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Design Considerations

Several factors must be considered when selecting engineering plastics and composites for CNC machining. They are needed to meet specific design and application needs. This will result in efficient, high-quality CNC machining.

Machinability: The machinability of a material has a direct impact on machining efficiency and the quality of the final product. Engineered plastics like ABS and polycarbonate are easy to machine. They are good for parts with complex shapes. However, carbon fiber and glass fiber-reinforced plastics need special tooling and methods for machining. This is to ensure machining accuracy and surface quality.

Strength: The mechanical strength of different materials determines the application scenarios for which they are suitable. Carbon fiber-reinforced plastics are very strong. They are good for applications needing strength and lightness, like aerospace and motorsports. Nylon is good for mechanical parts, like gears and bearings, because of its wear resistance and strength.

Chemical resistance: The chemical resistance of a material is critical in some applications. For example, nylon and polycarbonate resist chemicals well. They are suitable for parts exposed to chemicals. ABS may degrade in some chemicals. So, it must be chosen carefully.

Impact of mechanical and thermal properties of materials on design

When selecting the right material, you need to evaluate its mechanical and thermal properties together. This is to ensure that the part works well in its intended use and lasts a long time.

Mechanical Properties

Tensile Strength: Tensile strength is the ability of a material to resist damage under tensile force. Materials with high tensile strength, such as steel and carbon fiber composites, are suitable for structural components that need to withstand high tensile stresses. These materials are widely used in aerospace and construction. They provide the needed strength and durability.

Hardness: Hardness refers to the ability of a material to resist localized deformation, especially scratching or abrasion. Harder materials, like titanium alloys and stainless steel, are common in making mechanical parts and tools. They perform well in high-friction environments. For example, harder materials are suitable for parts such as knives, bearings and gears.

Toughness: Toughness is the ability of a material to absorb energy without fracturing when subjected to impact or rapid loading. Materials with high toughness, such as polycarbonate and certain high-performance plastics, are important in the manufacture of protective equipment and safety components. These materials are effective in protecting internal structures in the event of an accidental impact.

Thermal Properties

Coefficient of Thermal Expansion: The coefficient of thermal expansion is a measure of the change in volume or length of a material in response to a change in temperature. Low coefficient of thermal expansion materials such as carbon fiber composites and ceramics perform well in high-temperature environments because they maintain dimensional stability and are suitable for use in components of electronic equipment and precision instruments.

Thermal Conductivity: Thermal conductivity refers to the ability of a material to transfer heat. Highly thermally conductive materials such as aluminum and copper are very effective in heat dissipation applications and are commonly used in the manufacture of heat sinks, heat exchangers, and electronic device housings. These materials dissipate heat quickly and protect equipment from overheating.

Impact Analysis

Selecting the right material for a specific job needs both mechanical and thermal properties.

Application scenarios: Materials are selected based on specific applications. Aerospace parts need strong, light materials, like carbon fiber composites. Electronic devices need materials with good heat conduction, like aluminum and copper.

Environmental conditions: Consider the temperature and chemical properties of the environment in which it will be used. For example, high temperatures need materials with low thermal expansion and high heat resistance. Corrosive environments need corrosion-resistant materials like stainless steel and titanium.

Machinability: Consider the machinability of the material to ensure cost-effective manufacture of the part. Materials like aluminum and ABS are easy to machine. They are suitable for parts with complex shapes. Harder materials like steel and titanium may need better equipment and techniques.

Material and Surface Treatment Design Guide-Yonglihao Machinery

Design and Manufacturing Tips for Composite Parts

To improve composite parts for high-performance uses. The following involved as well as manufacturing techniques need to be considered.

Design Techniques

Laminate design: The laminate structure is at the core of composite design. Multiple layers of material are stacked to make things stronger and stiffer. The orientation and thickness of each layer of material can be optimized according to design needs. For example, in high-stress areas, we can increase the fiber layer’s thickness. Or we can change the fiber’s orientation to boost strength and durability.

Fiber orientation optimization: Fiber orientation plays a key role in the performance of composites. Fibers are typically aligned in the direction of greatest stress to maximize strength and stiffness. For example, in parts that are mostly loaded in tension, fibers should align with the load. In parts heavily influenced by shear stress, fibers should be staggered for better shear resistance. By optimizing fiber orientation, the performance of a composite part can be significantly improved.

Manufacturing Processes

Vacuum Forming: Vacuum forming is a common way to make composites. It creates high-quality parts by placing prepreg in a mold. Then, it uses a vacuum to remove air and extra resin. This process is suitable for manufacturing large and complex shaped parts with high precision and strength.

Hot Compression Molding: Hot compression molding is a highly efficient way to make composite materials. It works by compacting prepregs into molds at high temperatures and pressures. This allows the composite fibers and resins to bond fully. The parts made this way have excellent mechanical properties. It is commonly used in the aerospace and automotive industries where high performance and strength are required.

Selecting the right CNC machining material for CNC machining zero

Design and manufacture of high-performance plastic parts

By choosing materials and methods wisely, you can design and make plastic parts. They can meet many high-performance needs. The following are the relevant suggestions organized by Yonglihao Machinery:

Material Selection

PEEK (polyether ether ketone): PEEK is a high-performance plastic with excellent mechanical properties and chemical stability. It is strong, stiff, and heat-resistant (up to 260°C). It is used in tough applications in aerospace, automotive, and medical devices. PEEK also resists wear and chemicals, making it a good replacement for metal parts.

PPS (Polyphenylene Sulfide): PPS is an engineering plastic. It has high heat and chemical resistance. It also has good dimensional stability. It keeps high strength and rigidity at high temperatures. It is widely used in car parts, electrical parts, and other fields.

PTFE (Polytetrafluoroethylene): PTFE is known for its excellent chemical resistance, high-temperature resistance, and low coefficient of friction. It is commonly used to make seals. It is also used to make insulating materials and parts that resist corrosion. Due to its non-stick and wear resistance, PTFE is widely used in food processing equipment and medical devices. However, PTFE’s main disadvantage is its low strength. This weakness usually requires it to be mixed with other materials.

Manufacturing Methods

CNC machining: CNC machining is a high-precision method. It is also high-efficiency. It is for making many complex shapes in high-performance plastic. materials such as PEEK, PPS, and PTFE can be CNC machined to achieve precision manufacturing. The parts produced are characterized by high accuracy and repeatability and can meet tight tolerances. This process is also suitable for small-lot and customized production, and can flexibly respond to different design requirements.

Injection molding: Injection molding is a very efficient way to mass-produce plastic parts with complex shapes and high precision. High-performance plastics, like PEEK and PPS, need careful temperature and pressure control during molding. This is to ensure the best material performance. This process is fast and suitable for mass production, but the tooling costs are high and it is usually suitable for projects with long production cycles.

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Surface Treatment Technology Options and Environmental Design

Yonglihao Machinery offers a wide range of surface treatment solutions to meet different needs. Choosing the right surface treatment tech can greatly improve a product. It can boost its performance and looks while extending its life.

Electroplating: Electroplating is the process of plating a thin metal film on a substrate. It is mainly used for protecting against corrosion and for decoration. Electroplating can form a dense protective layer on metal. This layer stops the metal from touching corrosive substances in the environment. It extends the life of parts. For example, galvanizing stops steel from corroding. In addition, electroplating is also used to improve the look of products. For example, chrome plating makes surfaces shiny. It’s common on car parts and home decor. Gold plating is used on jewelry and high-end electronics to make them fancier and more valuable.

Spraying: Spraying is a process. In it, a spray gun or other equipment applies paint evenly to a workpiece surface. People use it for protective coatings and cosmetics. This process forms a dense coating on the workpiece surface. It protects the substrate from the external environment. This includes waterproofing, rustproofing, and UV protection. It is common in industrial equipment to prevent corrosion and wear. It can also be used to improve the appearance of products, through different colors and textures of paint to achieve the beautification effect, The home appliances and furniture industry often use spraying technology to enhance the visual effect and tactile feel of the product.

Anodizing: Anodizing is an electrochemical treatment process. It creates an oxide film on the surface of aluminum and its alloys. This film makes the material more resistant to corrosion. It also makes the material harder and more decorative. Anodizing forms a dense film of aluminum oxide on the surface of aluminum. This film greatly improves the corrosion resistance of aluminum products. It is suitable for outdoor equipment and aluminum parts in marine environments. Also, anodic oxidation hardens the aluminum surface. It improves its abrasion and scratch resistance. People commonly use it in automotive parts, electronic product shells, and so on. Anodized aluminum products can have many colors and textures. They are used in architecture, households, and electronics.

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Designs to optimize surface treatment effects and reduce environmental impacts

Design Considerations

When designing parts for surface treatments, attention needs to be paid to the effects of surface finish and geometry. Surface finish is a key determinant of coating adhesion and final results. Higher surface finishes help to distribute the coating evenly and improve corrosion protection and aesthetics. The desired surface finish can be achieved at the design stage by selecting the appropriate machining method (e.g. precision milling or grinding) .

Geometry has a significant effect on the effectiveness of the surface finish. Complex shapes make it hard for the coating to cover evenly. This is especially true in sharp corners and recessed areas. These areas tend to become weak points for uneven coating thickness, reducing the effectiveness of the protection. For this reason, designs should avoid sharp edges and complex internal corners. They should use rounded corners and smooth transitions. These features ensure that the coating spreads evenly and stays intact.

Environmentally friendly design

In the choice of surface treatment methods, environmental design is particularly important. Low-polluting surface treatments not only minimize the impact on the environment but also reduce a company’s environmental compliance costs. Below are a few common environmentally friendly surface treatments:

Powder Coating: Powder coating is an environmentally friendly surface treatment that is free of volatile organic compounds (VOCs), which reduces environmental pollution. Powder coating is applied to the surface of the workpiece by electrostatic spraying and then cured at high temperatures to form a coating. This method is suitable for both metal and plastic parts and has the advantages of high efficiency, energy saving and environmental protection.

Waterborne Coatings: Compared to traditional solvent-based coatings, waterborne coatings have significantly lower VOC content and are more environmentally friendly. Water-based coatings release fewer harmful substances during the drying process and are suitable for coating a variety of metal and non-metal surfaces. By choosing the right water-based coatings, you can reduce environmental pollution while ensuring coating performance.

Electroplating Recycling Technology: In the electroplating process, metal ions in the plating solution can be recovered and reused by using closed-loop systems and wastewater treatment technologies to reduce the discharge of hazardous wastewater. For example, the use of ion exchange and electrolytic regeneration technology can effectively recover nickel, chromium, and other metals, reducing environmental pollution and resource waste.

Anodizing wastewater treatment: The wastewater produced in the anodizing process contains a large amount of acid and alkali substances and heavy metal ions, through the use of advanced wastewater treatment technology, such as neutralization, precipitation, and filtration, the wastewater can be treated to meet the standard and then discharged or recycled to reduce environmental pollution.

How to choose the right surface treatment to improve part performance

Choosing the right surface treatment can improve part performance. It can protect against corrosion and wear. This ensures their longevity in many uses.

Performance Improvement

Surface treatment technology plays a key role in improving the corrosion and wear resistance of parts. Below is a list of some of the common surface treatment methods and their corresponding performance enhancements, organized by Yonglihao Machinery:

Electroplating: Electroplating techniques that coat the surface of a part with a layer of metal, such as nickel, chromium, or zinc, can significantly improve the part’s corrosion and wear resistance. For example, a galvanized coating effectively prevents steel parts from rusting and is suitable for a variety of outdoor and industrial applications.

Spraying: Spraying technology creates a protective coating on the surface of a part, improving its corrosion and wear resistance. Spray coatings can be applied with a variety of materials, such as epoxy, polyurethane, and powder coatings, depending on the needs of the application. For example, epoxy resin coatings have excellent chemical resistance and mechanical properties and are suitable for the protection of chemical equipment and pipelines.

Anodizing: Anodizing is particularly suitable for aluminum products, and by generating an oxide film on the surface of aluminum, it can significantly improve its corrosion resistance and hardness. The anodized aluminum products not only have excellent anti-corrosion properties but also improve the wear resistance and scratch resistance of the surface.

Application Examples

Galvanization in the automotive industry: In automotive manufacturing, body and chassis parts are often galvanized to improve corrosion resistance. A German automaker we work with applied galvanized steel to the chassis structure of its new SUV. The zinc layer prevents rust. It also greatly extends the vehicle’s service life and safety.

Epoxy coating for chemical equipment: We work with a French chemical equipment manufacturer. They use epoxy resin coating for their storage tanks and piping. The epoxy coating resists chemical corrosion, acid, alkali, and solvents. It ensures the equipment works well for a long time in harsh conditions. Epoxy coating also has excellent mechanical strength and wear resistance, reducing the frequency of maintenance and replacement.

Anodizing electronics housings: An electronics manufacturer uses anodizing technology for its high-end laptop computer housings. Anodizing the aluminum alloy housing makes it look beautiful. It also greatly improves its corrosion and wear resistance. The hard anodized layer is durable. It makes the laptop less prone to scratches and wear during daily use. This boosts the product’s quality and the user’s experience.


Yonglihao Machinery, as a supplier specializing in CNC machining services, understands the importance of material selection and surface treatment technology on the performance and quality of parts. In terms of material selection, steel is suitable for structural and mechanical parts due to its high strength and wear resistance, but it is heavy and prone to rust. Aluminum is widely used in aerospace and electronic equipment because of its lightweight, corrosion resistance, and ease of machining. Copper has excellent electrical and thermal conductivity, making it suitable for electrical components, though at a higher cost. plastics such as ABS and polycarbonate are commonly used in appliances and industrial parts because of their lightweight and chemical resistance.

The choice of surface treatment technology is also critical. Electroplating greatly improves resistance to corrosion and abrasion. It works for both corrosion protection and decoration. Spraying gives a protective coating and looks nice. It’s used a lot for car parts and machines. Anodizing is great for aluminum. It improves its corrosion resistance, hardness, and looks.

If you have questions about material selection or surface treatments, Yonglihao Machinery will be happy to provide professional advice. We will ensure that they meet your processing needs.


Steel has high strength and wear resistance, but is heavy and prone to rust (except for stainless steel) and is suitable for structural and mechanical parts. Aluminum is lightweight, corrosion-resistant, and easy to machine, but not as strong or hard as steel, and is widely used in aerospace and electronic equipment. Copper has excellent electrical and thermal conductivity, is corrosion-resistant but costly, and is commonly used for electrical components and heat exchangers. Plastics such as ABS and polycarbonate are lightweight and chemically resistant, but have poor heat resistance and are used for appliance housings and industrial parts.

When choosing a surface treatment technology, you need to consider the material properties, application environment, aesthetic requirements, and cost. Aluminum is suitable for anodizing, while steel is suitable for plating and spraying. In high-corrosive environments, zinc or nickel plating is ideal; in high-friction environments, sprayed polyurethane coatings are more effective. Chrome plating and high gloss spray coatings are options for parts with high aesthetic requirements. Low-pollution processes such as powder coating and water-based coatings are environmentally friendly and economical options.

Eco-design methods include the use of low-VOC waterborne and powder coatings to minimize environmental pollution. In addition, the use of closed-loop systems and advanced wastewater treatment technologies allow for the recovery and reuse of metal ions in the plating solution and the reduction of hazardous wastewater discharges. For example, ion exchange technology in plating process and neutralization treatment in anodizing can effectively reduce environmental impacts

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