Precision machining high-purity copper is notoriously challenging. Compared to standard brass or aluminum alloys, C10100 Oxygen-Free Electronic (OFE) copper is exceptionally soft and "gummy."
If your feeds and speeds are incorrect, or if you select the wrong cutting tool geometry, the material will gall, tear, and weld itself to the cutting edge (Built-Up Edge, or BUE). This destroys surface finishes and compromises the tight tolerances required for advanced electronic components.
However, when approached with the correct strategies, C10100 can be milled and turned to produce flawless, mirror-like surfaces.
Overcoming the "Gummy" Nature of OFE Copper
The very property that makes C10100 so valuable-its 99.99% purity and lack of hardening impurities-is what makes it difficult to machine. It lacks the lead or tellurium additives found in free-machining copper alloys.
Because it is so ductile, C10100 does not form clean chips that break away easily. Instead, it tends to form long, stringy, continuous chips that wrap around tooling. Heat management is critical. While its thermal conductivity is unmatched exceeding 101% IACS, heat must still be evacuated rapidly through the chip, not absorbed into the tool or the workpiece.
Crucial Tooling Selection Guidelines
To successfully machine custom components like RF coaxial backing or high-current busbars from solid C10100 copper plates and sheets, tooling choices must be optimized for soft, non-ferrous metals:
Carbide is King (with the Right Coating): Uncoated, highly polished solid carbide end mills are generally the best choice. If a coating is necessary, opt for TiB2 (Titanium Diboride) or Zirconium Nitride (ZrN). Avoid TiAlN or AlTiN coatings; aluminum has a chemical affinity for copper and will cause severe galling.
Sharp, High-Rake Geometries: Tools must be razor-sharp. A high positive rake angle (often combined with a high relief angle) is essential to slice through the gummy copper cleanly, reducing cutting pressure and minimizing work hardening.
Flute Count Matters: For milling, use 2-flute or 3-flute cutters. They provide the necessary chip clearance to evacuate the long, stringy chips without packing the flutes.
Download GNEE METAL's C10100 Machining Parameter Chart (PDF)
Speeds, Feeds, and Coolant Strategies
When establishing a baseline for CNC milling C10100 plates, start aggressively but monitor heat:
Surface Footage (SFM): Copper machines best at higher speeds. Aim for 400 to 800 SFM (Surface Feet per Minute) with sharp carbide tooling.
Chip Load: Maintain a moderate to heavy chip load to ensure the tool is actually cutting rather than rubbing. Rubbing causes rapid work hardening and catastrophic tool failure.
Flood Coolant is Mandatory: Do not attempt dry machining or minimum quantity lubrication (MQL) on deep cuts. High-pressure flood coolant (using a high-lubricity water-soluble oil) is critical to flush chips away instantly and prevent them from welding to the cutter.
Start with the Best Raw Material (Or Let Us Machine It for You)
The most optimized CNC program will fail if the raw material contains inclusions or inconsistent grain structures. Impurities cause hard spots that destroy tooling predictability.
At GNEE METAL, we eliminate material variables. We supply premium C10100 OFE copper with guaranteed absolute purity (Max 5ppm oxygen). Whether you are sourcing solid billets or specific C10100 copper plates and sheets, our material arrives ready for flawless fabrication. We understand that in ultra-high vacuum (UHV) applications, where issues like hydrogen embrittlement are fatal, component integrity starts with the metal matrix.
However, if managing the complex tooling, high-pressure coolant, and chip evacuation requirements of OFE copper is outside your current production bandwidth, we offer a complete solution.
Beyond supplying raw materials, GNEE METAL specializes in delivering fully finished, print-to-part Custom CNC Machined Parts. From intricate RF coaxial connectors to heavy-duty custom busbars, our in-house machining centers are optimized exclusively for high-purity copper, guaranteeing tight tolerances (±0.1mm) and pristine surface finishes without contamination.
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GNEE METAL Product Range
| Product Type | Shapes Available | Common Grades | Diameter/Thickness Range | Length/Width Range | Applications |
|---|---|---|---|---|---|
| Copper Tubes | Round, Square, Rectangular, Coiled | C10100, C10200, C11000, C12200, C12000 | OD: 0.5mm - 300mm Wall: 0.1mm - 20mm | Up to 6000mm or custom | HVAC, Plumbing, Heat Exchangers, Refrigeration, Hydraulic Lines |
| Copper Plates & Sheets | Flat Sheets, Perforated, Embossed, Tread Plate | C10100, C11000, C12200, C23000, C26000 | Thickness: 0.1mm - 200mm | Width: Up to 2500mm Length: Up to 6000mm | Electrical Busbars, Roofing, Cladding, Gaskets, Transformers |
| Copper Bars & Rods | Round Bar, Square Bar, Hexagonal Bar, Flat Bar | C10100, C11000, C14500, C17200, C18200 | Diameter: 1mm - 300mm | Length: 1000mm - 4000mm | Machined Components, Electrical Contacts, Busbars, Fasteners |
| Copper Wires | Round Wire, Flat Wire, Square Wire, Stranded, Braided | C11000, C11600, C17200, C17510 | Diameter: 0.05mm - 12mm | Coil weights: 1kg - 500kg | Electrical Wiring, Cables, Springs, Mesh, Welding Wire |
| Copper Strips & Coils | Thin Strip, Foil, Slit Coil, Profile Strip | C11000, C12200, C19400, C26000, C26800 | Thickness: 0.03mm - 5mm | Width: 2mm - 1000mm Coil ID: 300mm - 600mm | Transformers, Radiators, Shielding, Terminals, Connectors |
About Our Factory
We operate a full range of production lines including extrusion presses, cold drawing benches, high-speed rolling mills, slitting lines, and precision CNC machining centers, enabling us to produce copper tubes, plates, bars, wires, and strips entirely in-house. For quality assurance, we maintain a dedicated inspection laboratory equipped with spectral analyzers, universal testing machines, hardness testers, surface roughness testers, and optical measuring instruments. Every batch is tested for chemical composition, mechanical properties, and dimensional accuracy before shipment. Our production capacity reaches 500+ tons per month, and we hold ISO 9001:2015 certification with full traceability from raw material to finished product. Whether you need standard mill stock or custom-processed components, we deliver precision copper products with short lead times and complete material certification.
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