Copper CNC Machining
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Copper CNC Machining
Copper is listed as Cu (atomic number 29) on the periodic table and is an excellent conductor of electricity and heat, second only to silver. Commercially available copper is typically more than 99% pure. The remaining 1% is usually impurities such as oxygen, lead, or silver.
Copper is well known for its electrical and thermal conductivity. It is very resistant to corrosion and is also inherently antimicrobial. The power, automotive, medical, and aerospace industries make use of copper specifically for these properties. Select Copper CNC machining in the Xometry Instant Quoting Engine℠.
Copper 101
Copper C101, or oxygen-free copper, is the name to an extremely pure metal that comes in at about 99.99% Cu. This high purity level gives it exceptional conductivity, so it is often referred to as HC (high conductivity) copper. It also serves as the base material for brass and bronze alloys. Its high conductivity makes it ideal for busbars, waveguides, and coaxial cables.
| Tensile Strength, Yield (MPa) | Fatigue Strength (MPa) | Elongation at Break (%) | Hardness (Brinell) | Density (g/cm^3) |
|---|---|---|---|---|
Tensile Strength, Yield (MPa) 69 to 365 | Fatigue Strength (MPa) 90 | Elongation at Break (%) 55 | Hardness (Brinell) 81 | Density (g/cm^3) 8.89 to 8.94 |
Copper C110
Copper C110, or Electrolytic Tough Pitch (ETP) Copper, is another highly pure option. It is not as pure as copper 101, however, instead weighing in at 99.90% Cu. It is the most widely used copper alloy because it is more cost-effective and suitable for most electrical applications. This grade is also easier to machine than copper 101.
| Tensile Strength, Yield (MPa) | Fatigue Strength (MPa) | Elongation at Break (%) | Hardness (Brinell) | Density (g/cm^3) |
|---|---|---|---|---|
Tensile Strength, Yield (MPa) 76 | Fatigue Strength (MPa) 76 | Elongation at Break (%) 45 | Hardness (Brinell) 57 | Density (g/cm^3) 8.89 |
Finishes and Post-Processing Options
In general, copper is used for its thermal and electrical conductivity. As such, many surface finishes used on other machined metals are not suitable as they will hinder these properties. Listed below are some applicable surface finishes for copper.
Electropolishing: Copper can be electropolished to achieve an extremely smooth and shiny surface. This process removes a minuscule layer of material off the surface - typically between 0.0001” (0.00254 mm) and 0.0025” (0.0635 mm). Electropolishing can further improve corrosion resistance but does not affect conductivity.
Electroplating: Metal plating of copper is frequently used to help prevent oxidation of its outer surface while maintaining electrical and thermal conductivity. In particular, precious metal plating like silver or gold plating can provide low contact resistance to maintain excellent conductivity and solderability.
Cost-saving Design Tips
Copper is a very costly material to use, so part design optimization is recommended.
Only use where required: Only use copper components where necessary. Manufacturing an entire part out of copper is prohibitively expensive if only a small portion needs its unique properties.
Choose the right grade: Attempting to use ultra-pure copper, such as 99.99% pure C101, for a purely mechanical part is not cost-effective. However, if exceptional conductivity is not required and a lot of material is machined, C110 is likely a better choice.
