Solar PV Junction Box Copper Terminal
Integrated Stamping & CNC Finishing Precision Manufacturing
Project Overview
Client Requirements
- High-volume production capacity (500,000+ units/month)
- Excellent electrical conductivity (>98% IACS)
- Precise dimensional tolerances (±0.02mm)
- Cost-effective unit pricing for mass production
- Consistent quality across large batches
Our Solution
- Integrated stamping + CNC finishing process
- High-speed progressive stamping for base form
- CNC machining for critical contact surfaces
- Automated quality inspection systems
- Optimized material utilization (>95% yield)
Key Results
- Unit cost reduced by 35% vs. full CNC
- Production cycle time reduced by 60%
- Zero defects in 500,000+ production run
- 98.5% IACS conductivity achieved
- On-time delivery: 100% over 12 months
Technical Specifications
Material Specifications
| Material Grade | C11000 ETP (Electrolytic Tough Pitch Copper) |
| Purity | 99.9% Cu minimum |
| Electrical Conductivity | 98.5% IACS minimum |
| Thermal Conductivity | 401 W/m·K at 20°C |
| Tensile Strength | 220-250 MPa (stamped condition) |
| Hardness | 75-85 HRF |
| Surface Plating | Tin plating 3-5μm (optional for corrosion resistance) |
Dimensional Tolerances
| Stamping Dimensions | ±0.05mm |
| CNC Machined Features | ±0.02mm |
| Contact Surface Flatness | 0.03mm TIR maximum |
| Hole Diameter Tolerance | ±0.015mm for M6 and larger |
| Thickness Tolerance | ±0.03mm |
| Positional Tolerance | ±0.03mm for critical features |
| Surface Finish | Ra 1.6μm (machined surfaces), Ra 3.2μm (stamped) |
Manufacturing Process
Material Preparation & Slitting
High-purity C11000 copper coils are precision-slit to required width (25-100mm typical). Material thickness ranges from 0.5mm to 3.0mm depending on terminal design. Strict material traceability is maintained throughout production.
Key Control: Material certification verification, surface inspection, and dimensional accuracy of slit strips
Progressive Stamping
High-speed progressive stamping (150-300 strokes/min) forms the basic terminal geometry in multiple stations. The stamping process creates mounting holes, basic contours, and pre-forms for CNC finishing. Progressive die ensures consistent quality at high volume.
Key Control: Die wear monitoring, stamping force verification (50-200 tons), and periodic dimensional inspection
CNC Precision Finishing
Critical contact surfaces and features are CNC-machined to achieve tight tolerances (±0.02mm) required for reliable electrical connections. Multi-axis CNC centers ensure precise flatness, surface finish, and dimensional accuracy on contact interfaces.
Key Control: Tool wear compensation, in-process gauging, and surface finish verification (Ra 1.6μm)
Deburring & Cleaning
Automated deburring removes sharp edges and stamping burrs. Parts undergo precision cleaning to remove oils, metal particles, and contaminants. Ultrasonic cleaning ensures pristine surface condition for subsequent plating or direct assembly.
Key Control: Burr height inspection (<0.05mm), cleanliness testing (mil-spec level), and surface integrity verification
Surface Treatment (Optional)
Tin plating (3-5μm) is applied for enhanced corrosion resistance and solderability. Selective plating options are available to plate only contact surfaces. Alternative finishes include silver plating or nickel underplate for specialized applications.
Key Control: Plating thickness measurement (XRF), adhesion testing, and solderability verification
Quality Inspection & Packaging
100% visual inspection and dimensional sampling (AQL 0.65) ensures zero defects. Automated optical inspection (AOI) systems detect surface defects. Conductivity testing verifies electrical performance. Parts are packaged in moisture-proof bags with desiccant.
Key Control: First article inspection, in-process sampling, final inspection, and certificate of conformance
Results & Benefits
Performance Improvements
Business Benefits
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35% Cost Reduction
Hybrid stamping+CNC process significantly lowers unit cost compared to full CNC machining
-
High-Volume Capability
Production capacity exceeds 500,000 units/month with consistent quality
-
Zero Defect Record
500,000+ units delivered without quality rejects over 12-month period
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100% On-Time Delivery
Reliable supply chain with consistent delivery performance over 1 year
"Sinbo Precision's integrated stamping and CNC finishing solution transformed our copper terminal supply chain. The 35% cost reduction combined with exceptional quality and reliable delivery has been instrumental in scaling our solar PV junction box production.
- SolarPower Manufacturing Co., USA
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