Machining Copper

Copper metals are highly valued for their appearance. Primarily, it is used in everyday art and on utensils. Copper has better material and electrical characteristics as compared to aluminum or aluminium. This makes it essential to produce complex parts. These parts are used in applications such as EDM electrodes.

However, copper is typically challenging to machine. This hardness poses several problems as follows. The additives include aluminum, zinc, silicon, and tin. These combinations result in the formation of alloys such as brass and bronze. Nickel-silver alloys are also produced to meet specific requirements.

Every one of the alloys is thus designed for exact machining applications. Therefore, they play a significant role in many fields. The machining of copper alloy parts becomes more accessible, allowing for more efficient production. This, in turn, enables production to be done more efficiently. Copper is still valuable for all areas because of its versatility. It is even more helpful when combined with other metals. Nevertheless, copper is irreplaceable, and the industry will continue to encounter it in the future.

This article will focus on copper cnc machining methods, essential factors to consider, various uses of copper, and necessary machining services. So, let us help you decode the information you need to make the most of this instrumental metal.

Copper CNC Machining:

When it comes to CNC machining copper, there are two critical factors to keep in mind for optimal results:

1. Optimal Tool Material Selection:

Dealing with raw copper is problematic because the material is very soft, making tools wear out very fast and challenging to remove chips. One of the problems often faced is the creation of a built-up edge, which is a condition where copper particles cling to the tool and produce uneven surfaces. To eliminate these problems, it is necessary to employ cutting tools manufactured from materials like high-speed steel (HSS). HSS tools are specifically famous for cutting copper since it is a soft metal and do not blunt HSS tools quickly while using CNC machines.

2. Setting the Ideal Feed Rate:

The feed rate determines the speed at which the CNC cutting tool travels on the copper workpiece. When it comes to copper machining, it is advised that one should keep the feed rate between moderate and low. High feed rates can produce much heat, which is not preferred in precision machining applications.

One of the critical aspects of controlling the feed rate is that it is vital for precision and surface finish during machining. If higher feed rates are required in your project, then it becomes mandatory to use cutting fluids or coolants because heat has to be taken out for better precision in the machining process.

3. Selecting the Correct Grade of Material

Choosing the correct grade of copper is one of the most critical decisions made during the design of any project. Electrolytic rigid pitch copper (ETPC), also known as pure copper (C101), has a purity of 99%. 99% reliability can be a problem and expensive, particularly regarding mechanical components.

When comparing the two materials, C110 is more conductive than C101, more accessible to machines than C101, and sometimes cheaper. Selecting the correct material grade is crucial to achieving the design necessities in the proper manner.

Manufacturability should be deemed regardless of the type of material incorporated in developing a product. One has to follow the principles of DFM to the letter to get the best outcome. Some recommendations include closely controlling the performance tolerance and dimensional checks. Do not make thin walls with small radii for improved machining. Wall thicknesses should be kept to a minimum of 0.5 mm for structural strength.

For CNC milling, the size limit is 1200mm x 500mm x 152mm, while for CNC turning, it is 152mm x 394mm. Design undercuts with square profiles, full radii, or dovetails to reduce the machining operations. These guidelines are specific to copper components and are essential in enhancing on productivity and quality of the components.

The Copper Alloys For Machining

Copper materials include various commercial metals used in different industries depending on the required properties for a specific application.

1. Pure Copper:

Copper is known to be in the purest form, soft, and can be easily molded. It may contain a small percentage of alloying additions to improve its characteristics, such as improved strength. High-purity copper is used in electrical applications, including wiring, motors, other equipment, and industrial applications such as heat exchangers.

The commercial grades of pure copper are classified by the UNS numbers C10100 to C13000. For applications requiring higher strength and hardness, such as machining beryllium copper, alloying pure copper with beryllium is a common practice.

2. Electrolytic Copper:

Electrolytic tough-pitch copper is obtained from cathode copper, refined by electrolysis, and contains deficient impurities. The most widely used grade is C11000, which offers electrical conductivity of up to 100% IACS and high flexibility, which makes it suitable for electrical applications such as windings, cables, and bus bars.

3. Oxygen-Free Copper:

Due to its shallow oxygen content, oxygen-free copper grades such as C10100 (Oxygen-free electronic) and C10200 (Oxygen-free) are characterized by shallow oxygen content and high electrical conductivity. These coppers are made under non-oxidizing conditions and are used in high vacuum electronics such as transmitter tubes and glass-to-metal seals.

4. Free-Machining Coppers:

These copper base alloys contain nickel, tin, phosphorus, and zinc additions, which aim to improve the machinability. Some well-known alloys include bronze, copper-tin-phosphorus, brass, and copper-zinc, characterized by high hardness, impact strength, workability, and corrosion resistance. It has uses in various machining operations, such as in machining coins, machined electrical parts, gears, bearings, and automotive hydraulic parts.

Techniques of Machining Copper

The following are some of the most efficient ways of machining copper:

Machining copper as a material is a process that is associated with some difficulties due to the material’s flexibility, pliability, and durability. Nevertheless, copper can be alloyed with other elements such as zinc, tin, aluminum, silicon, and nickel, improving the possibility of machining copper. Such alloys are usually easier to cut than materials of similar hardness and typically need lesser cutting force. Below are some commonly employed machining techniques for copper, ensuring precise production in professional copper machining services:

CNC Milling for Copper Alloys

Milling is among the most effective techniques for cutting copper alloys with the help of computer numerical control. This is done automatically with the help of a computer-controlled rotary cutting tool to shape the workpiece to the required size. Copper parts with grooves, contours, holes, pockets, and flat surfaces can be produced through CNC milling.

Critical considerations for CNC milling copper or its alloys include:

• Choosing the suitable cutting material like carbide N10 & N20 or HSS grades.
• Slowing the cutting speeds by approximately 10% improves the tool life.
• Additional reduction of the cutting speeds (by 15% for carbide tools and 20% for HSS tools) when working with cast copper alloys with cast skin.

CNC Turning for Copper

CNC turning is suitable for copper machining because the workpiece rotates while the tool remains stationary and makes the necessary cuts. This technique is used extensively in the manufacturing of mechanical and electronic goods. Below are some of the key recommendations for turning copper and its alloys using the CNC turning process:

• The cutting tool edge angle should be between 70 and 95 degrees.
• For cutting the softer copper types, the edge angle of the cutting tool should be slightly less than 90 degrees to prevent smearing.
• Reduce the cutting tool’s angle and maintain constant cutting depths so the tool will last longer, the cutting rate can be made faster, and the pressure on the tool is reduced.
• The position of the first cutting edge should be controlled to manage the forces and heat that are produced at the time of cutting.

The above methods demonstrate the effectiveness of CNC machining of copper and its alloys in producing parts for various sectors.

Considerations For Surface Finishing for Copper

Surface finish is critical in copper CNC machining to meet the required quality standards for the parts in their respective applications. Based on the above research objectives, the following specific objectives have been developed in the context of the present work with the view of attaining the primary goal of enhancing the Copper CNC machining parameters:

The first strategy of surface finish control is to change the machining parameters. The specific approach to controlling the roughness of the surface is fundamental. Pay particular attention to the nose or tool corner radius: You should also focus a lot on the nose or tool corner radius. Moreover;

• Reduce the nose radius for the softer copper alloys, and do not polish a rough surface.
• Wiper inserts are more suitable for providing the desired clean-cut surface while maintaining the feed rate.

Post-Processing Options for Brass CNC Finishing

In addition to optimizing machining techniques, post-processing methods should be considered to achieve desired surface finishes. Besides improving the machining strategies, it is also necessary to consider the post-processing needs to get the desired surface finish.

• Hand polishing: This is quite time-consuming but efficient in giving the surface texture that is smooth and shiny.
• Media Blasting: It gives a matt finish and is good at hiding slight surface irregularities.
• Electropolishing: Suitable for copper because it improves conductivity, hence the brightness and appearance, giving it that polished look.

These techniques make the copper machined products not only helpful but also to have the correct appearance and to perform the required function. Go to Bronze machining page to know more.

Diverse Applications of Copper CNC Machining

Machining of copper is used in different fields, and it has advantages in the characteristics of the material and opportunities. Here are some key sectors where machined copper parts are integral; Copper in mechanical applications has very high thermal conductivity and high corrosion resistance. It is widely used in: Here is how it is used:

• HVAC (Heating, Ventilation, and Air Conditioning) systems for heat exchangers are used to confirm optimum heat exchange.
• The automotive industry for radiators is due to the strength and efficiency of heat transfer in enhancing the performance of the car’s engine.
• Electricity is used in bearings production where, due to the non-stick nature of copper, the machines last longer and have less friction.
• High levels of accuracy in finishing the gas welding nozzles which is very vital in the process of welding.
• Plumbing industry for products that are not affected by corrosion and thus can provide the guarantee of plumbing accessories.
• In the electrical and electronics industries, copper’s superior electrical conductivity is highly valued.
• Electrical equipment for bus bars is manufactured for use in the distribution of current in the distribution systems.
• Motors and windings for the electronics sector, where copper’s conductivity is preferred, and terminals.
• Among the common uses of wiring in homes, offices, and factories, copper wiring is used for its efficiency and security.

Besides these uses, because of its non-magnetic characteristics and flexibility, copper has been used in various ways in different industries:

• Copper machining is applied in the manufacturing industries mainly to create precise parts used in the machinery and equipment sectors.
• Copper is applied in the aerospace industry for those products that are most likely to be relied on and expected to perform optimally, such as aircraft electronics and parts.
• Machined copper is also used in the automobile industry in the electrical systems and parts of the engines to increase their performance and energy.
• Renewable energy technologies include solar panels, wind turbines, and other machines that use copper due to their conductivity, enhancing energy generation and transmission.

These examples prove the versatility and the need for copper machining in various fields because it serves the intended function needed to achieve the technical and functional specifications required to deliver the necessary dependability, productivity and performance in several uses.

Explore copper machining Services at CNM.

CNC-machined copper parts are commonly applied in numerous industries in contemporary society. However, high-quality copper machining services must meet the exact design specifications and product requirements.

CNM Tech is one of the top 10 CNC machining servcies in the world, we have staff with adequate experience to offer you the best CNC milling and turning services based on your designs. Whether you have a complicated geometry in your application or tight tolerance requirements in industrial components, we are committed to providing you with more than your expectations. Contact CNM now to get professional help with fine-quality copper machining services.