The Ultimate Guide to CNC Copper Milling
Copper is one of the oldest metal materials with exceptional isentropic properties. More specifically, copper is used in various electronic components for heat dissipation and electrical conductivity.
CNC machining of copper is challenging due to its ductile nature. It is one of the most challenging materials to machine precisely since it generates heat during the CNC machining process and enhances isentropic properties. That’s why the copper materials are slowly machined to get desired geometry.
Computerized numerical control (CNC) machines are very efficient and effective among other manufacturing technologies, due to their high speed, accuracy, and compatibility with different materials such as:
- Copper
- Brass
- Bronze
- Copper-nickel alloys, and many more.
Now, let’s take a look at what CNC copper milling is all about and key aspects to consider before you choose your next CNC machining services provider.
What is CNC Copper Milling?
CNC milling is an automated machining service in which the workpiece is stationary and the spindle moves across the surface of a material. The CNC machining of copper is a steady process due to its high flexibility, toughness, and plasticity.
The different grades of copper used in CNC machining are as follows:
- Pure copper: is most suitable for manufacturing electrical components because these are usually soft and malleable.
- Electrolytic copper: It is tough in nature, so the CNC machining of electrolytic copper offers only finishing touch.
- Free machining coppers: Comprises various alloying elements, which increase the machinability of copper parts. Some of the copper machined parts are:
- Bearings
- Electrical equipment
- Gears
- Automotive hydraulics
- Heat exchangers
The advantages of CNC copper milling are:
- High ductility
- Great impact strength and hardness
- Corrosion resistant
- Easy weldability
- Thermal and electrical conductivity
- High Formability in both hot and cold processes
- CNC machined copper parts offer cost-effective surface finish
Properties of copper alloys
Copper is commonly combined with different elements to form copper alloys, which enhances different properties. The most preferred alloying element is zinc in excessive amounts. The name of the copper alloy depends on the element which is added.
The types and different properties of copper alloys are given as follows:
- High copper alloy: It contains 96% to 99.3% of copper. It gains the properties of alloying elements but maintains high electrical and thermal conductivity due to excessive copper content. It is mostly used in casting applications. High copper alloys include:
- Cadmium copper alloy
- Beryllium copper alloy
- Chromium copper alloy
- Zirconium copper alloy
- Bronze: It is a combination of tin and aluminum. As the percentage of copper is high so properties of bronze are much similar to copper. Bronze offers high strength, low friction, corrosion resistance, ductility, and thermal conduction. Some common types of bronze are:
- Nickel silver
- Phosphor bronze
- Silicon bronze
- Copper-nickel
- Brass: It is prepared by adding 15% of zinc to copper. To increase the machinability of brass, lead is also added in a small amount and can act as a lubricant. It is strong, machinable, conductive, and corrosion-resistant. Different types of brass are listed below:
- Engraving brass
- High tensile brass
- Free-cutting brass
The above-mentioned copper alloys offer:
- Fast machining
- Smaller chip formation
- Longer tool life
- High-quality surface finish
Surface finish for copper milling
At the post-processing stage of machining the part, it is necessary to perform a surface finish. There are three types of surface finish techniques and these are as follows:
- Polishing
- Blasting
- Passivation
Polishing
To deal with surface roughness, different chemicals are used for polishing the part. The polished CNC part has good reflection and a smooth surface profile. This surface finish service is mainly used in the precision machinery industry. The increase in wall thickness of the part is very minute after the polishing process. The different types of polishing processes are given below:
- Mechanical polishing
- Chemical polishing
- Electrolytic polishing
Blasting
Blasting is another technique used for removing abrasive media from the machined part. This process is done by using a spinning wheel that accelerates centrifugally and blasts pressurized chemicals against a surface. It is usually applied to larger and more complex parts. The different types of blasting processes are:
- Shot blasting
- Sandblasting
- Media blasting
- Copper slag blasting
Some benefits of copper slag blasting are listed below:
- High cleaning speed
- Low dust level
- Recyclable
- Lower abrasiveness
- Less than 1% of crystalline silica is used
- Reduces slag consumption rate
- Increases blasting productivity
Passivation
Passivation is a process used to finish metal surfaces with special chemicals. The passivation of copper is also called decontamination. This process creates a protective layer to improve corrosion resistance and also makes parts shiny and attractive. In this way, the surface will be preserved for a long period. It also removes free iron or other contaminants from the surface of a workpiece while at the same time it forms a dense oxide layer over the surface.
Some of the methods used for passivation are given as follows:
- Nitric acid passivation
- Citric acid passivation
- CitriSurf passivation
- Alkaline-acid-alkaline passivation
Copper CNC machining tips
CNC copper milling is much easier than other metals of the same isentropic properties. Today, CNC machining on different grades of copper is processed successfully. To achieve optimum results. some key aspects regarding copper milling are listed below:
- Choose the right material grade
- Must verify your design
- High-speed steel and carbide-cutting tools are preferred
- Maintain the sharpness of the cutter and inspect the profile of the cutting edge
- Follow recommended feed rate and spindle RPM
- Use of coolant (cutting fluid)
- Keep the parameters of tolerancing on the lean side
- Keep the work area clean
- Try cold plastic deformation
Conclusion
To summarize, I hope this article delivered key concepts to enhance your knowledge of CNC copper milling. With the demand for copper machined parts on the rise, CNC copper machining units help a lot in modernizing the world. It is just building the base of CNC copper milling on customer needs and strengthening your clustering in the market as well.
Worthy Hardware is a CNC manufacturing and sheet metal fabrication company,including CNC machining services,CNC milling services, CNC turning services, laser cutting services and stamping services.Call us +86-76989919645 or email us [email protected] for more discounts for your projects.