Copper Machining and Fabrication for Electronics and Automotive in Anderson, SC

C101 oxygen-free electronic copper (OFE) carries the highest purity specification in the commercial copper family — 99.99 percent minimum copper by ASTM B170 — and is specified when maximum electrical conductivity (101 percent IACS minimum) and minimum oxygen content (less than 0.001 percent) are both required. Oxygen-free copper is critical for electronic and electrical components where hydrogen embrittlement in hydrogen atmospheres during brazing or annealing would cause intergranular cracking in oxygen-containing grades. C101 is the material of choice for vacuum-tight electronic feedthroughs, high-frequency waveguide components, and precision bus bar assemblies where any resistance increase from impurities would generate heat that compromises system reliability. Anderson's electronics manufacturing base uses C101 for high-reliability interconnects in power conversion equipment, sensor housings, and precision conductor assemblies. Machining C101 requires understanding its behavior: unlike steel, copper does not produce predictable chip breakage, tending instead to generate long, stringy, ductile chips that wrap around tools and create chip management challenges. Anderson CNC operators running C101 use sharp positive-rake uncoated carbide or polycrystalline diamond (PCD) inserts, chip breaker geometries designed for non-ferrous metals, and higher surface speeds — 500 to 1,000 surface feet per minute — to promote chip segmentation. Through-spindle coolant helps with chip evacuation in deep-hole drilling operations through C101 bar stock. Surface roughness after machining C101 is typically very good due to the metal's ductile plastic deformation during cutting, but burrs on edges and in cross-holes are an inherent challenge — copper's softness means it deforms around tool edges rather than fracturing cleanly. Anderson shops producing C101 precision parts budget deburring time into their operations and use specially designed deburring tools for cross-hole intersections in bus bar blanks.

C110 (ETP copper) is the most widely produced and commercially available copper alloy, accounting for the majority of copper products in service globally. With 99.9 percent minimum copper content and oxygen levels of 0.02 to 0.04 percent, C110 achieves 100 percent IACS conductivity and serves all electrical and thermal applications that do not require the strict oxygen-free specification of C101. The oxygen content makes C110 susceptible to hydrogen embrittlement, which eliminates it from applications involving hydrogen brazing or reduction atmospheres, but for the vast majority of Anderson's electrical and thermal copper applications — bus bars, lugs, heat sinks, terminal blocks — C110 is fully adequate at a lower cost than C101. Anderson fabricators cut C110 flat bar, round bar, sheet, and strip on plasma tables, laser cutters, band saws, and CNC mills for bus bar blanks, electrical enclosure components, and formed terminals. Sheet forming of C110 on press brakes requires noting that copper's bend radius requirements are similar to stainless — minimum bend radius of 1 to 2 times material thickness to avoid cracking — and that copper springback is lower than spring steel but not negligible. Press brake operators in Anderson programming copper bending operations adjust for springback by overbending slightly and allowing the part to spring back to the target angle. Tin plating C110 copper is standard practice for Anderson's automotive electrical connector and terminal suppliers. Tin plating provides a solderable, oxidation-resistant surface that prevents the green copper oxide patina that would otherwise build up at contact surfaces and increase contact resistance over time. Electroless tin, hot dip tin, and electroplated tin are all available through regional plating shops, with electroplated matte tin being most common for connector terminals in the 0.0001 to 0.0003 inch thickness range.

Tellurium copper (C145) adds 0.4 to 0.7 percent tellurium to pure copper, which dramatically improves machinability by promoting chip-breaking behavior without significantly reducing electrical conductivity — C145 achieves approximately 93 to 95 percent IACS conductivity compared to 100 percent for C110. The tellurium creates a dispersed second phase that interrupts the ductile chip continuity that makes pure copper gummy on CNC equipment. The result is a copper alloy that machines with free-cutting, controllable chips similar to free-machining brass or aluminum, enabling higher production throughput on turned and milled copper components. Anderson CNC shops producing high-volume precision copper components — electrical connectors, contacts, rotor bars, collector rings, and threaded fittings for electrical equipment — specify C145 when machinability and production rate matter as much as maximum conductivity. The modest conductivity reduction from 100 percent to 93 percent IACS is acceptable in most electrical applications unless the design is at the absolute limit of conductor cross-section. Tellurium copper is available in round bar, hex bar, and flat bar forms from service centers, making it practical for CNC turning and milling without special sourcing. Weldability of C145 is limited by the tellurium content — tellurium segregates to grain boundaries at welding temperatures and can cause cracking in fusion welds. For copper assemblies requiring welding, C110 or C101 are better choices. Anderson shops building copper assemblies that require both high machinability for individual components and weld joining should consider designing for mechanical assembly (pressed, brazed, or bolted joints) using C145 machined parts rather than attempting fusion welding of tellurium copper.