Copper Machining & Fabrication Suppliers in San Jose, CA

These three cover most San Jose copper machining and they trade off purity, conductivity, and machinability. C101 is oxygen-free electronic copper (OFE), the highest purity with the best electrical and thermal conductivity, specified for the most demanding RF, electronic, and high-conductivity applications, but it's expensive and gummy to machine. C110 is electrolytic tough pitch copper (ETP), the standard high-conductivity grade for bus bars, heat sinks, and general electrical work, with conductivity just slightly below C101 at lower cost and better availability, though it's still soft and difficult to machine cleanly. Tellurium copper (C145) adds a small amount of tellurium that transforms machinability, allowing clean, fast machining of complex parts, while retaining most of the conductivity. The selection rule: if your part demands absolute maximum conductivity, use C101 or C110; if it's a complex machined part where slightly reduced conductivity is acceptable, tellurium copper gives you a far better part to manufacture and often a lower total cost despite the alloy premium. A good shop will help you weigh conductivity against machinability rather than defaulting to pure copper.

Pure copper grades like C101 and C110 are soft and ductile, and that softness is the problem. Instead of shearing cleanly, copper tends to smear, gall, and form a built-up edge on the tool, producing torn surfaces, burrs, and poor dimensional control. It's the opposite challenge of a hard metal: there's nothing wrong with the strength, the material just doesn't want to cut cleanly. Getting a good finish requires a shop experienced with copper, using very sharp and often polished tooling, appropriate feeds and speeds tuned for a soft gummy material, sometimes specialized geometries and coolants, and care to avoid built-up edge. If your part needs a fine or mirror finish for RF, optical, or sealing reasons, ask the shop specifically whether they've achieved that finish on copper before, because copper finish capability does not automatically follow from aluminum or steel experience. For parts where machinability is critical and maximum conductivity isn't, switching to tellurium copper solves the finish problem at the source. Always discuss surface finish requirements explicitly when quoting copper, since assuming a shop can hit a tight Ra on pure copper is a common and costly mistake.

Most functional copper parts benefit from or require plating, because bare copper oxidizes and tarnishes, which degrades both appearance and surface performance over time. The right plating depends on the function. Nickel plating provides corrosion protection and a durable barrier and is common as an underlayer or standalone finish. Tin plating improves solderability and corrosion resistance and is frequent on electrical contacts and bus bars. Silver plating offers excellent surface conductivity and is used on RF, microwave, and high-current contact surfaces where surface conductivity matters, since high-frequency current travels at the surface. Gold plating provides the best corrosion resistance and reliable low-resistance contacts, used on critical connectors and high-reliability applications, often over a nickel barrier. For San Jose RF and semiconductor work, the plating spec and thickness can be as performance-critical as the machining, so it must be specified precisely and verified. Confirm whether the shop plates in-house or subcontracts, require the plating certification documenting type, thickness, and spec compliance, and make sure copper parts are handled and packaged to prevent oxidation between machining and plating or delivery.

Copper's thermal conductivity is roughly twice that of aluminum, so copper makes sense whenever a part has to move more heat than an aluminum design can handle in the available space. In San Jose's semiconductor and power-electronics work, that situation comes up often: tightly packed components, high heat fluxes, or thermal budgets where every degree matters can force a copper heat sink or cooling block even though copper is heavier and more expensive. The tradeoffs are real, copper weighs more than three times aluminum for the same volume, costs significantly more per pound, and is harder to machine, so it's not a default choice. The right approach is to start from the thermal requirement: if an aluminum heat sink meets the thermal spec with margin, use aluminum for the weight and cost savings; if aluminum can't pull enough heat or the geometry is too constrained, copper earns its premium. Sometimes a hybrid makes sense, copper where the heat concentrates and aluminum elsewhere. A knowledgeable San Jose shop serving thermal applications can help you make this call, and because thermal performance is often validated empirically, sourcing locally lets you iterate quickly if the first design doesn't hit the target.