CU · copper alloy
Electrolytic Tough Pitch Copper C11000
Pure copper: gummy, prone to built-up edge and famous for long stringy chips. It is bought for 100% IACS conductivity, not for the way it cuts.
Quoting this material
- Typical lead time
- 10–15 working days
- Condition
- Annealed (soft) or hard drawn
- Achievable finish
- Ra 1.6 µm typical · Ra 0.8 µm best
Machined in-house to your drawing: see the precision CNC machining service and the machine and inspection capability it runs on.
Machinability
Our own 1–10 shop ranking, not a published index: 10 is free-cutting brass C360, 1 is Inconel 718. It ranks how a material behaves on the floor - cycle time, chip control and tool life together. Where a published index exists it is quoted in the note.
Pure copper: gummy, prone to built-up edge and famous for long stringy chips. It is bought for 100% IACS conductivity, not for the way it cuts.
Properties as supplied
| Parameter | Value | Unit |
|---|---|---|
| Tensile strength | 220–340 | MPa |
| Yield strength (0.2%) | 70–330 | MPa |
| Elongation | 40–50 | % |
| Hardness | 45 | HB |
| Thermal conductivity | 388 | W/m·K |
| Modulus of elasticity | 117 | GPa |
Hardness, tensile and thermal figures are typical published values for the condition stated. Actual mill certificates govern; send the specification with the drawing and we confirm against the certificate before the material is cut.
Condition
Annealed (soft) or hard drawn
Heat treatment
Not hardenable by heat treatment. Annealing softens it after cold work; nothing raises its strength other than alloying, which is what the C1xxxx chrome and beryllium coppers are for.
Achievable surface finish
Ra 1.6 µm
Ra 0.8 µm
A polished finish is achievable but it tarnishes quickly; a bright dipped or plated finish is normal for a visible copper part.
Tooling and cutting parameters
Cutting speed
- 150–300 m/min (carbide)
Feed
- 0.10–0.30 mm/rev turning · 0.08–0.20 mm/tooth milling
Tooling
- Sharp uncoated carbide with polished flutes, high positive rake, no coating that increases friction
Coolant
- Flood - copper needs lubrication to stop the chip welding to the edge
Starting points for carbide on a rigid setup, not a guarantee. The right numbers depend on the machine, the toolholder and the fixturing - ask and we will say what we would actually run.
Typical applications
- Busbars and current-carrying hardware
- Heat sinks and thermal spreaders
- Welding electrodes and fixtures
- RF and microwave components
- Vacuum and cryogenic parts
DFM notes for this grade
- Machinability is the price of conductivity: if the design can take a chrome copper or a brass, the part machines far more cheaply
- Long stringy chips are the safety and handling problem - specify a peck cycle on deep holes, and never let a long string of swarf wrap the tool
- It is soft enough to deform under light clamping; a fixture that would be fine for steel will mark a copper part
Questions buyers ask
- When should I use chrome copper instead of pure copper?
- When the part needs strength as well as conductivity. C18200 gives roughly twice the strength of C110 at about 80% of the conductivity, which for a welding electrode or a heavily loaded current-carrying part is usually the right trade.
- Why is copper so difficult to get a good finish on?
- Because it is soft and ductile: the chip tends to weld to the cutting edge and then tear off the finished surface. The cure is sharp uncoated tooling with a high positive rake and enough coolant - a coated insert that helps on steel usually makes copper worse.
Grades we would quote instead
C18200 Chrome Copper
6/10Copper with chromium for strength: roughly 80% of the conductivity of pure copper and about twice the strength, and it machines better than C110 because it is harder.
C26000 Cartridge Brass
8/10The 70/30 brass: excellent cold-forming and good machining, though without the lead it does not break a chip as cleanly as C360.
C17200 Beryllium Copper
5/10Machines like a hard brass in the annealed state and like a tool steel after ageing.