If your high-precision C10100 components are warping after they come off the CNC mill, you are likely dealing with residual internal stresses. Because C10100 Oxygen-Free Electronic copper is extremely ductile and "sticky," the mechanical forces of heavy milling or deep drilling can introduce significant tension into the metal lattice.
For engineers working with sub-micron tolerances in semiconductor tools or high-frequency waveguides, a final stress-relieving heat treatment is not an option-it is a requirement. Without it, the 99.99% pure copper part will "relax" over time, leading to dimensional drift that can ruin the alignment of a complex assembly.
Why do precision C10100 parts warp after machining?
Every piece of C10100 Round, Square & Flat Bar arrives with some level of residual stress from the extrusion or rolling process. When you remove material during machining, the balance of these internal forces is disrupted.
Furthermore, if your C10100 machining speeds and feeds are not optimized, the cutting tool can "push" the metal rather than shear it, creating new surface stresses. This is particularly problematic for thin-walled parts or long, slender conductive rods where even a 0.05mm deviation is a failure.
The Optimal Stress Relieving Cycle for OFE Copper
The goal of stress relieving is to allow the copper atoms to rearrange into a lower-energy state without triggering recrystallization or changing the hardness of the material. Unlike the full annealing process we covered in C10100 annealing and grain size, stress relieving happens at much lower temperatures.
Temperature Range: 150°C to 250°C (300°F - 480°F).
Soak Time: 1 to 2 hours per inch of thickness.
Cooling: Slow furnace cooling is preferred to prevent new thermal stresses.
Performing this cycle ensures that your 101% IACS conductivity is maintained while the physical dimensions of the part remain locked in place.
Consult GNEE Engineers: How to Prevent Warping in C10100 Parts
Troubleshooting Dimensional Drift in C10100 Components
| Symptom | Primary Cause | Corrective Action |
| Bowing after milling | Unbalanced residual stress | Stress relieve after roughing, before finishing |
| Hole ovality | Tool heat / Dull drill bit | Use sharp, polished tools and high-pressure coolant |
| Spring-back after cut | Work hardening from dull tools | Audit tool life; use Half-Hard (H02) temper |
| Long-term drift | Ambient temperature cycling | Use low-temp stress relief (150°C) |
Strategic Sequencing for Custom CNC Machined Parts
When we produce Custom CNC Machined Parts, we often employ a "Rough-Stress Relieve-Finish" sequence. This is the only way to guarantee that the final critical dimensions meet the +/- 0.005mm tolerances required for aerospace and scientific research.
By removing 90% of the material, then stress-relieving the "blank" at 200°C, we ensure that the final finishing pass is performed on a stable, relaxed piece of 99.99% pure copper. This also prevents the "Virtual Leaks" often caused by microscopic cracks that can form when highly stressed copper is subjected to vacuum bake-outs.
Sourcing high-purity C10100 is only the first step; maintaining its shape through the manufacturing process is what defines a professional-grade component. By implementing a dedicated stress-relieving cycle, you protect your investment and ensure that your high-conductivity assemblies perform exactly as designed. GNEE METAL provides certified Grade 1 material and the engineering support to help you achieve the ultimate in dimensional stability.
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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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