Copper is widely used in electrical, telecommunications, and industrial applications because of its excellent conductivity and thermal performance. However, despite being relatively soft, copper presents several unique machining challenges.
One of the most common issues is burr formation.
In this case study, we share how the Renjie engineering team successfully solved a severe burr problem during a high-volume copper machining project, improving both production efficiency and product quality.
A customer specializing in electrical distribution equipment approached Renjie for the production of precision copper terminals.
The parts would be used in high-current electrical systems where dimensional accuracy and surface quality were critical.
| Item | Requirement |
|---|---|
| Material | C110 Copper |
| Quantity | 5,000 Pieces |
| Tolerance | ±0.03 mm |
| Surface Finish | Ra 0.8 |
| Application | Electrical Power Systems |
The geometry was relatively simple, consisting of:
Multiple drilled holes
Thin wall sections
Several chamfered edges
Precision mounting features
Initially, the project appeared straightforward.
However, production quickly revealed a significant challenge.
During the first production run, the quality inspection team discovered excessive burr formation around several drilled holes and machined edges.
The burrs created several concerns:
Increased manual deburring time
Potential assembly difficulties
Risk of electrical contact issues
Reduced cosmetic appearance
Inspection reports showed that nearly 35% of parts required additional rework.
This significantly reduced production efficiency.
| Quality Item | Requirement | Actual Result |
|---|---|---|
| Hole Edge Burr Height | ≤0.05 mm | 0.15 mm |
| Surface Finish | Ra 0.8 | Ra 0.9 |
| Production Yield | >98% | 65% |
Although the dimensions remained within specification, the excessive burrs made the process unsustainable for large-scale production.
The engineering team immediately launched a root-cause investigation.
The first assumption was tool wear.
Several cutting tools were inspected and replaced.
However, the burr problem persisted.
Next, machine accuracy was verified.
Machine calibration records showed no abnormalities.
Attention then shifted toward the machining process itself.
After reviewing production data, engineers identified three contributing factors.
The original drill geometry had been selected based on previous aluminum projects.
Copper behaves differently.
Because of its softness and ductility, copper tends to deform before shearing cleanly.
This resulted in material being pushed rather than cut.
Production parameters had been optimized for efficiency rather than copper-specific cutting conditions.
The aggressive feed rate increased material deformation around hole exits.
Long continuous chips accumulated near several machining features.
These chips occasionally re-contacted the workpiece surface, creating additional burrs and scratches.
After identifying the root causes, the engineering team implemented several improvements.
The original drill was replaced with a geometry specifically designed for non-ferrous metals.
Benefits included:
Cleaner cutting action
Reduced material deformation
Improved chip formation
The difference became immediately noticeable during testing.
Engineers adjusted:
Spindle speed
Feed rate
Peck drilling cycle
The new parameters reduced cutting pressure while maintaining productivity.
A modified coolant delivery system was introduced.
The improvements included:
Increased coolant flow
Better chip evacuation
Reduced chip recutting
This prevented long chips from damaging finished surfaces.
For critical electrical contact surfaces, a light chamfer operation was added after drilling.
This ensured:
Consistent edge quality
Improved assembly performance
Reduced manual deburring
Although it added several seconds to cycle time, it eliminated substantial downstream rework.
A second pilot batch was produced using the optimized process.
The results exceeded expectations.
| Metric | Original Process | Optimized Process |
|---|---|---|
| Burr Height | 0.15 mm | 0.03 mm |
| Surface Finish | Ra 0.9 | Ra 0.6 |
| Rework Rate | 35% | 2% |
| Production Yield | 65% | 99.2% |
The burr issue was effectively eliminated.
Following process validation, full production began.
| Production Metric | Result |
|---|---|
| Parts Produced | 5,000 |
| Delivery Time | 14 Days |
| Rejected Parts | 0 |
| Customer Complaints | 0 |
| Acceptance Rate | 100% |
The customer reported improved assembly efficiency and later awarded Renjie additional production contracts.
This project highlighted several important principles in copper machining.
Although softer than steel, copper requires specialized machining strategies.
Using tools designed specifically for copper can dramatically improve quality.
Small adjustments to cutting parameters often produce significant improvements.
Eliminating burrs during machining is far more efficient than relying on secondary operations.
Copper components are commonly used in:
Electrical systems
Battery technology
Renewable energy equipment
Telecommunications infrastructure
Industrial automation
Successfully machining these components requires more than advanced machinery.
It requires a deep understanding of:
Material behavior
Tooling technology
Process engineering
Quality control
At Renjie, our engineering team continuously develops optimized machining solutions for challenging manufacturing projects.
Whether you need custom copper connectors, electrical terminals, busbars, or precision conductive components, Renjie can help.
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