1. Customer Background & Project Overview

A power system industry customer required a customized sheet metal manufacturing solution for non-standard electrical distribution cabinet enclosures. The project was characterized by high product variety and low batch volume, involving a total of 18 different structural models.

All cabinet enclosures were made of 2.0mm cold-rolled steel sheet, with a planned monthly output of approximately 480 units.

The final products were required to meet the following key performance requirements:

· Structural strength compliance for industrial electrical applications

· Surface flatness without deformation after assembly

· Protection level: IP54 dustproof and splash-proof standard

· Stable delivery under tight production schedules

BSD Machinery was responsible for the full manufacturing scope, including sheet metal fabrication, surface treatment, and final assembly.

2. Key Technical Challenges

During project evaluation, several manufacturing challenges were identified:

2.1 High Mix, Frequent Changeover Complexity

The project included 18 different cabinet structures, requiring frequent production switching. Traditional stamping tooling methods would result in:

· High tooling cost

· Long changeover time

· Low production flexibility

2.2 Large Sheet Metal Deformation Risk

Cabinet enclosures involve large panels and multi-bending structures, leading to:

· Welding-induced deformation

· Accumulated dimensional deviation

· Difficulty in maintaining assembly squareness

Required tolerance was controlled within ±0.5mm, making deformation management critical.

2.3 IP54 Sealing Requirement

All enclosure joints required:

· Dust-proof sealing

· Water splash resistance

· Stable long-term environmental protection performance

2.4 Production Scheduling Pressure

Orders were distributed in multiple small batches, requiring:

· Flexible production planning

· Fast model switching

· On-time delivery assurance

3. Engineering Analysis & Manufacturing Strategy

After reviewing customer drawings, our engineering team implemented a full DFM-based manufacturing strategy:

3.1 Structural Decomposition

The cabinet was decomposed into:

· Top panel

· Side panels

· Door assembly

· Base frame

A complete BOM structure and process routing system was established for all 18 models.

3.2 Process Strategy Optimization

Instead of traditional stamping tooling, we adopted a flexible manufacturing approach:

· Laser cutting + CNC bending + robotic-assisted welding

· No dedicated molds required

· Program-based model switching

3.3 Material Control

All materials were strictly controlled:

· Standard cold-rolled steel sheets

· Incoming inspection for flatness and surface defects

· Batch traceability ensured

4. Manufacturing Process Implementation

Step 1: Laser Cutting (Precision Blank Preparation)

· Equipment: 20kW fiber laser cutting system

· Automatic CNC programming import

· Cutting tolerance: ±0.1mm

· One-time forming of holes and cutouts

· Full first-piece inspection + batch sampling

Step 2: Sheet Leveling & Deburring

· Stress-relief flattening to eliminate internal stress

· Edge deburring and chamfering

· Prevents coating damage and assembly scratches

Step 3: CNC Bending Forming (Core Process Control)

· Model-based bending program selection

· Multi-step bending for large structures

· Key control standards:

• Angle tolerance ≤ ±0.5°

• Controlled springback compensation

• Improved squareness accuracy

Step 4: Welding & Deformation Control

· CO₂ gas-shielded welding for the main frame

· Spot welding for auxiliary structures

· Segmented welding to reduce heat distortion

· Post-weld grinding for surface leveling

· Strict inspection of diagonal accuracy and frame flatness

Step 5: Surface Treatment & Powder Coating

· Degreasing → acid washing → phosphating → electrostatic cleaning

· Industrial-grade electrostatic powder coating

· High-temperature curing process ensures:

• Corrosion resistance

• Uniform coating thickness

• Outdoor durability

Step 6: Final Assembly & Inspection

· Installation of sealing rubber strips

· Hardware assembly (hinges, locks, brackets)

· Final inspection covering:

• Dimensional accuracy

• Surface quality

• Door opening performance

• IP54 sealing verification (sampling test)

Qualified products were labeled, packed, and shipped according to customer delivery plans.

5. Quality Control & Process Optimization

During production, several key improvements were implemented:

5.1 Bending Springback Optimization

· Adjusted bending bottom dead point parameters

· Introduced pre-bending process

· Added fixture positioning
→ Effectively eliminated springback deviation issues

5.2 First Article Inspection System Upgrade

A strict three-level inspection system was implemented:

· Operator self-check

· Team mutual inspection

· Quality department verification

Only after approval could mass production proceed.

5.3 Anti-Mix Control System

· Separate storage zones for different models

· Clear labeling system

· Full process traceability cards

→ Eliminated cross-model mixing risk

6. Project Results

The optimized manufacturing solution achieved the following results:

· Changeover efficiency: First-piece release within 5 hours for new models

· On-time delivery rate: 100%

· Monthly output stability: 480 units

· First-pass yield rate: 99.2%

· Customer feedback: Zero quality complaints

7. Conclusion

This project demonstrates BSD Machinery’s capability in handling high-mix, low-volume sheet metal manufacturing with strict precision and sealing requirements.

By combining:

· Flexible CNC-based production

· Advanced deformation control techniques

· Structured quality inspection system

We achieved stable mass production performance under complex multi-model conditions.

The project has established a strong foundation for long-term cooperation in the field of electrical cabinet enclosures, industrial control cabinets, and sheet metal housing systems.