Custom Sheet Metal Enclosures for Indoor & Outdoor Waterproof Dustproof Electrical Junction Boxes
Project Background
As industrial electrical systems and outdoor infrastructure expand rapidly, a leading electrical equipment provider launched a 2026 large‑scale customization project for waterproof and dustproof electrical junction box enclosures. These enclosures protect wiring terminals, control modules, and circuit components in harsh and stable environments alike.
Key requirements included:
- IP65 waterproof and dustproof protection
- Dimensional tolerance ≤±0.03mm
- High structural rigidity and deformation resistance
- Corrosion resistance for long‑term use
- Compatibility with standard electrical interfaces
- Stable mass production quality
- Distinct surface finishes for indoor and outdoor environments
Sanjun Hardware was selected for its precision sheet metal capabilities, professional sealing structure design, and mature dual‑environment surface treatment technology.
Manufacturing Process of Core Components
The electrical junction box consists of the main enclosure, sealed door panel, cable entry ports, and mounting base. All production follows ISO 9001 quality standards and industrial electrical enclosure specifications.
1. Material Selection & Pre‑treatment
- Main enclosure and door panel: 1.2mm galvanized steel sheet for high structural strength and corrosion resistance.
- Pre‑treatment: Fully automated ultrasonic degreasing, derusting, and phosphating to create a clean, high‑adhesion surface base ideal for powder coating.
2. Core Manufacturing Craftsmanship
- Precision Laser Cutting: 8000W fiber laser cutter with ±0.02mm tolerance, using nitrogen assist gas to minimize heat distortion and maintain material integrity.
- CNC Bending & Forming: 9‑axis CNC bending machine with custom jigs, ensuring springback ≤0.02mm and consistent sealing‑groove dimensions.
- Sealing Structure: Precision‑milled sealing grooves for waterproof gaskets, standardized cable entry holes, and mounting positions.
- Indoor & Outdoor Electrostatic Powder Coating
- Assembly & Sealing: High‑density waterproof silicone gaskets embedded into precision grooves; automated alignment ensures tight, gap‑free fitting.
3. Quality Control & Testing
- Dimensional inspection: CMM measurement to confirm tolerance ≤±0.03mm.
- IP65 protection test: Dust and water spray testing per IEC 60529.
- Salt spray test: Verifies corrosion resistance for indoor and outdoor versions.
- Powder coating adhesion & hardness test: Ensures no peeling, cracking, or fading.
- Full functional inspection: 100% inspection before delivery for zero defects.
Project Challenges & Solutions
1. Challenge: Stable IP65 Sealing in Mass Production
Inconsistent bending or sealing grooves often cause sealing failure.
Solution: Optimized sealing groove design + high‑precision CNC bending + customized waterproof gaskets + online sealing testing.
2. Challenge: Distinct Performance for Indoor & Outdoor Environments
Indoor requires clean aesthetics; outdoor requires weather and UV resistance.
Solution:
3. Challenge: Structural Strength vs. Lightweight Design
The enclosure must be lightweight for installation yet rigid enough against impact.
Solution: FEA‑optimized internal reinforcing ribs improve structural strength by 25% without extra weight.
4. Challenge: High Batch Consistency
Customer required uniform appearance, size, and performance across 6,000 units.
Solution: Automated production lines + SPC real‑time monitoring + sampling inspection per 100 units.
Project Outcomes
- Delivery: 6,000 units completed and delivered 5 days ahead of the 45‑day schedule, with 100% pass rate in all tests.
- Performance: Enclosures operate stably in both indoor distribution systems and outdoor engineering sites with no water ingress, dust buildup, or coating failure.
- Partnership: The client signed a 3‑year strategic cooperation agreement, appointing Sanjun Hardware as the exclusive sheet metal supplier for its full series of electrical junction boxes.
