Copper CNC Machining

Copper is, after silver, the best electrical and thermal conductor. With a thermal conductivity of 390 W/mK and an electrical conductivity of 58 MS/m, it is irreplaceable for many applications in electrical and thermal engineering.

In CNC machining, copper poses special challenges: its high ductility leads to long continuous chips, and its excellent thermal conductivity quickly transfers process heat into the workpiece — which can cause thermal deformation.

Copper requires an adapted strategy:

• Sharp tools — Polished solid carbide end mills with sharp edges (rake angle 15–20°). Dull tools = material smearing
• High cutting speed — v_c 200–400 m/min for milling, 150–300 m/min for turning
• Chip breakers — Choose geometries with positive rake angle so the long continuous chip breaks in a controlled manner
• Coolant — Generous emulsion needed as copper quickly transfers heat into the workpiece
• Clamping — Caution with thin walls: copper deforms easily under clamping forces

Pro tip: For better machinability, use alloys like CuCrZr or CuTeP (tellurium copper) — they produce shorter chips than pure E-Cu.

• Electrical Engineering — Bus bars, contacts, PCB heat sinks
• Thermal Engineering — Heat sinks, heat exchangers, EDM electrodes
• Welding Technology — Electrode holders, spot welding caps
• Research — Vacuum chambers (OF-Cu), particle accelerators