An ordinary steel plate, through several precision manufacturing steps, ultimately becomes a safe and reliable electrical cabinet. While this process may appear complex, from the perspective of a full‑chain manufacturer, the key stages are actually straightforward and easy to understand. Hunan Electrical Appliance Co., Ltd. As the original manufacturer, we’ll guide you through the entire transformation process—from steel sheet to finished cabinet—quickly and comprehensively.
Step 1: Material Selection and Cutting — A great cabinet starts with high-quality steel sheets.
It all begins with material selection. We choose Aluminum-zinc coated steel sheet This material boasts excellent corrosion resistance and electrical conductivity, making it the preferred choice for manufacturing high‑quality switchgear cabinets such as KYN28, XGN, and HXGN.
CNC cutting The entire steel sheet is fed into a CNC turret punch press or a laser cutting machine, where, under computer program control, the individual components of the cabinet are precisely cut.
Precision Assurance All mounting holes, cooling vents, and cable entry/exit openings are formed in a single stamping operation, with dimensional accuracy of the modular holes maintained within 0.5 mm.
Step 2: Bending and Forming — Giving the Steel Plate a Three-Dimensional Shape
Flat sheet material is bent into three-dimensional components with complex cross-sections using a CNC bending machine.
Multi-bend : The same edge is bent 2–3 times to form a “U‑shaped” or “C‑shaped” cross‑section, significantly enhancing the cabinet’s structural rigidity.
Rebound Control : The preset bending angle compensates for the elastic springback of the steel plate, ensuring accurate bend angles.
Step 3: Assembly and Welding — Frame Formation
Assemble the bent components into a complete cabinet frame.
Modular structure : High-strength bolts and rivet nuts are used for connections, with spot welding employed to reinforce critical areas. The advantage of a modular structure lies in its high parts interchangeability and ease of mass production.
Dimensional Verification During assembly, repeatedly measure the diagonals and verticality to ensure the cabinet is square and free of distortion.
Step 4: Surface Treatment — Applying an Anti-Corrosion Coating
The cabinet frame enters the spray‑painting line for surface treatment.
Pre-processing : Degreasing, rust removal, and phosphating (or silanization) to ensure coating adhesion.
Electrostatic powder coating The powder is uniformly adsorbed under the influence of an electrostatic field, then baked at high temperature to achieve leveling and curing, with the coating thickness controlled within 60–80 μm.
Color customization : Customizable to RAL color chart colors upon customer request.
Step 5: Component Assembly — Primary Circuit Construction
The sprayed cabinet is conveyed to the assembly station for the installation of main circuit components.
Main busbar installation : Grind and polish the copper busbar lapping surfaces, apply conductive grease, and tighten using a torque wrench to the specified torque.
Component fixation : Circuit breakers, instrument transformers, earthing switches, surge arresters, and other equipment shall be installed in accordance with the drawings.
Handcart commissioning : Insert the circuit breaker handcart into the cabinet and test the smoothness of its insertion and withdrawal, as well as the alignment accuracy of the contacts.
Step 6: Secondary Wiring — Formation of the Control Circuit
After the primary components have been installed, proceed with the wiring of the secondary circuits.
Wiring Planning : Route control wiring according to the secondary schematic; separate power and low‑voltage circuits, and ensure all cable runs are straight and level.
Wire numbering designation Each wire has printed identification sleeves at both ends, facilitating identification and maintenance.
Terminal crimping : Use a crimping tool to firmly crimp the cold-pressed terminals, ensuring no copper core is exposed; each terminal may accommodate a maximum of two wires.
Step 7: Factory Inspection — Every unit must pass five rigorous checks.
Before leaving the factory, finished cabinets must undergo rigorous testing in accordance with national standards.
| Test Item | Content Requirements |
|---|---|
| Visual inspection | Coating intact, door lock operates smoothly, markings are clear. |
| Insulation resistance | Phase-to-phase and phase-to-ground insulation resistance of the main circuit ≥ 12 MΩ (for 12 kV switchgear) |
| Power-frequency withstand voltage | 42 kV/1 min without flashover or breakdown |
| Circuit resistance | Main circuit DC resistance ≤ 40 μΩ |
| Mechanical operation | Perform closing and opening operations 5 to 10 times each; operation shall be reliable. |
| Five-Prevention Interlocking | Mandatory testing: each step must meet the requirements. |
| Secondary function | The protective device operates correctly, and the instruments display accurately. |
All test records shall be filed and retained, with the factory test report enclosed in the cabinet.
This step determines : The pass rate and safety of delivered equipment
Step 8: Packaging and Shipping — Safe Arrival at the Site
Switchgear that has passed inspection is affixed with a certificate of conformity and a nameplate before proceeding to the packaging stage.
Moisture-proof packaging : Cabinet body wrapped in plastic film, with desiccant included.
Shockproof protection : Additional corrugated cardboard or wooden frame; cushioning material added to critical areas.
Packing of attachments : Special tools, spare parts, and drawings are supplied with the cabinet.
This step determines : Integrity during product transportation
Why choose a full‑chain manufacturer?
From steel sheet to the finished cabinet, it may seem like “just a few steps,” but each step is a testament to the combined strength of equipment precision, process expertise, and a robust quality management system. Hunan Electrical Appliance Co., Ltd. As an end-to-end manufacturer, we offer the following advantages:
Quality is fully controllable throughout the entire process. From the receipt of raw板材 into the warehouse to the shipment of finished products, every process operates under the same quality management system.
Self-Managed Delivery Schedule Assurance : No reliance on outsourced processing; independent production scheduling; urgent orders can be expedited on a dedicated basis.
Precise cost control : Eliminating intermediaries makes the price more competitive for the same specifications.
Bearing the responsibility on one’s shoulders : If any stage encounters an issue, the customer needs to deal with only one point of contact.
Welcome to our factory for a site visit and witness firsthand the complete transformation process—from steel sheet to finished cabinet. Hunan Electrical Appliance Co., Ltd. — A trusted, reputable manufacturer of electrical cabinets, directly from the source.
