Copper Manufacturers & Suppliers

C110 electrolytic tough pitch copper gums up cutting tools — its ductility and tendency to form long stringy chips make it one of the more frustrating materials to CNC turn at high volume. Tellurium copper (C14500) adds 0.4-0.7% tellurium, which forms copper telluride inclusions that act as chip breakers and internal lubricants, dramatically shortening chips and reducing built-up edge on carbide inserts. Electrical conductivity drops only marginally — typically 93-96% IACS versus 100% for C110 — which is acceptable for contacts, terminals, and connector pins. For high-volume Swiss screw machine production of small electrical components, tellurium copper's improved tool life easily justifies its cost premium over C110.

Pure copper's extreme ductility and low hardness (Brinell hardness around 40-50 HB) create three problems: gummy chips that wrap around tooling, tendency to smear rather than cut cleanly, and work hardening that can cause chatter on interrupted cuts. Best practices include sharp, polished high-rake carbide or PCD tooling with positive rake angles of 10-15 degrees, high surface speeds (600-1000 SFM), light chip loads, and flood coolant or misting. Climb milling rather than conventional milling reduces the tendency to pull and smear. Annealing work-hardened stock before finish machining helps achieve the best surface finish. For intricate copper EDM work, the material's excellent electrical conductivity and low melting point make it an extremely efficient EDM electrode material.

Copper is weldable but challenging due to its extremely high thermal conductivity — heat dissipates so rapidly that preheating to 400-600°F is required for sections above 1/8" to prevent lack-of-fusion. Oxygen content in the base metal matters critically: C110 (tough pitch) contains 200-400 ppm oxygen that forms steam pockets when hydrogen from the welding atmosphere reacts with it, causing porosity and embrittlement. C101 oxygen-free copper eliminates this problem. TIG welding with ERCu filler and argon-helium shielding is the preferred process for quality copper joints. For production brazing of copper assemblies — heat exchangers, refrigeration components — silver-copper brazing alloys (BAg series) at 1100-1500°F produce joints stronger than the base copper.