CNC machining is a pivotal practice in manufacturing. It presents accurate and precise processes that blow manual machining methods out of the water, boosting productivity while preventing human error.
So, when combined with copper, a versatile, sustainable and conductive material, it can only improve.
Why use copper?
Copper is a well-known material in the manufacturing industry. Due to its ductility, electrical and thermal conductivity, low melting point and range of other desirable properties, it’s become a popular option across multiple sectors.
With an assortment of grades and surface finishes, copper materials present a range of properties and compositions that suit specific projects. Different industries and sectors can choose the ideal type of copper and surface finish for their needs. CNC machining processes make these components repeatable and consistent in large and small batches.
Applications
Different industries and applications require different components made of different materials. Copper is frequently used across several sectors, including transport, electrical, construction, and consumer goods.
Copper is commonly used to manufacture electrical connectors, motors, generators, radiators, pipes, valves, and fittings. It’s also popular in constructing heat exchangers and fuel systems for automotive and aerospace vehicles. Copper can even be used in the defence and medical industries for everything from ammunition components to orthopaedic implants.
Grades
Copper grades are defined by their properties, which help determine which grade is best suited to certain applications. You must pick the right copper grade for your needs; otherwise, you might end up with unusable components.
- Pure Copper: Typically soft and malleable, pure copper materials are ideal for constructing electrical components due to their high conductivity. However, their softness can prove a challenge during the machining process — for better toughness and other desirable properties, pure copper can be combined with different elements and materials to form new alloys.
- Electrolytic Copper: Electrolytic copper is highly pure due to the electrolysis process, where copper compounds are placed into a solution and purified with sufficient electricity. This kind of copper has excellent electrical and thermal conductivity and ductility, making it the material of choice for heat exchangers, wiring, busbars, windings, and cables.
- Oxygen-Free Copper: As the name suggests, oxygen-free copper has little to no oxygen content. This not only means it has high purity and a low risk of hydrogen embrittlement, but it also makes it perfect for forming electrical copper parts, top-quality audiovisual equipment, and high-vacuum electronics.
- Free-Machining Copper: Free-machining copper materials, like brass and bronze, include different alloying elements. Common alloying elements include zinc, tin, nickel and lead, all of which elevate copper’s properties. Adding these elements makes copper more workable, machinable and corrosion-resistant, meaning it better suits various applications.
Surface finishes
Multiple surface finishes are available for copper-turned parts. These finishes boost the material’s aesthetic value and functionality for parts with minimal flaws and added protection.
Surface finishes are added through different processes. Media blasting, for example, disguises copper’s flaws and defects, ensuring a subtle and durable finish. While electroplating includes adding a protective layer to the copper that prevents oxidation and ensures longer lifespans without sacrificing electrical and thermal conductivity, electropolishing removes a microscopic layer from the copper’s surface. Not only does this create a sleek and shiny finish, but it also limits the risk of corrosion while the part is in use.
Why are CNC machining and copper such a good match?
Due to their high thermal and electrical conductivity, copper and its alloys are perfect for various applications. Copper parts can exhibit excellent corrosion resistance, ductility, and machinability depending on the material grade and surface finish. For accuracy and precision, CNC machining methods — like drilling, milling, and turning — produce components that meet exact standards, tight tolerances, and high demands.
After providing the appropriate design, CNC machines are told how to craft components using a specific G-code. These computer-automated instructions relay how cutting pieces should move to create the required design. This lets the machine quickly form the part by cutting material from the copper workpiece. This process results in intricate detailing and complex geometries that can be repeated over large batches for copper turned parts that are the same every time.
The pros and cons of copper CNC machining
Like most other metals, machining copper can offer a range of pros and cons. Whether it’s the properties of the material or an issue presented to the machining process itself, it’s always wise to weigh both the positive and the negative before manufacturing begins — this way, you can adequately decide whether the copper CNC machining is suitable for your project and plan accordingly to avoid any potential bumps on the road.
Advantages of copper CNC machining
There are plenty of reasons why copper CNC machining is a popular method of manufacturing copper parts. One is its ability to accurately and repeatedly manufacture complex shapes to tight tolerances and specific dimensions. Another is its excellent electrical and thermal conductivity, impact strength, ductility, and machinability.
Not only is copper endlessly versatile with its different material grades and surface finishes, but it also offers good formability in both hot and cold machining processes. It’s a sustainable option, too, as it can be recycled after use without losing its properties.
Why copper CNC machining might not be the right option
While the drawbacks of copper CNC machining don’t necessarily outweigh the benefits, there are still some things you should think about.
As mentioned earlier, certain copper materials offer less machinability, ductility and corrosion resistance. You’ll want to ensure you choose the most appropriate kind of copper for your application and your elected machining process. For example, CNC milling is often used for cutting copper alloys, which are more likely to withstand environments with reactive and corrosive substances.
Throughout the machining process, copper materials can be prone to work hardening. This can affect tool life, causing them to wear, resulting in chipping and manufacturers having to replace cutting tools frequently. Thermal expansion can also present this issue, as copper materials heat up while machining. Thankfully, problems like these can be prevented.
To achieve the most successful CNC copper parts, consider:
- Using the appropriate copper grade: Copper parts should be machined using the best material for the intended application. Factors such as machinability, corrosion resistance, and cost-effectiveness should all be considered.
- Setting the proper feed rate: Since the feed rate refers to the cutting tool’s speed at the workpiece, you should ensure it’s set to the appropriate speed for copper components. This will dictate certain surface finishes and the components’ lifespan and quality while preventing tool wear against the heat copper creates.
- Employing the best tool material: It’s crucial to ensure it is suitable for machining the copper material in question. Since pure copper is soft, it might result in a built-up edge, leading to chipping and poor surface finishing. The recommended tools for copper parts include ones made of carbide or steel that move at high speeds with sharp edges to avoid wearing.
You’ll want to consider costs, too, since different material grades of copper can be sold at various prices. Costs can increase with intricate and complex designs as they take more time to machine, and tools can be expensive to replace where required.
An overview
CNC machining and copper materials make a great pair. They offer easy and precise manufacturing processes and create CNC copper parts that are durable, thermally and electrically conductive.
With several copper grades available, there’s always a material for your project. These grades can be given various surface finishes through media blasting, electroplating and electropolishing to boost aesthetic value and functionality for multiple applications and industries, from electronics and aerospace to automotive and medical applications.
While copper materials have their advantages, they also have their drawbacks. There are specific grades with less machinability, ductility and corrosion resistance. They can also be subject to work hardening and tool wear, so it’s best to consider what grade of copper, feed rate and tool material is best for your project.
Supporting UK businesses
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