This issue is crucial! The welding process directly determines the cabinet's sealing and corrosion resistance. The core conclusion is that qualified welding must meet "even surface, no defects, secure connection, and proper protection," which can be assessed through direct observation and simple tests.
Direct Observation: Examine Appearance Details
Weld Seam Appearance: Qualified weld seams have even width and consistent height, presenting a smooth scale-like or straight pattern; whereas, unqualified weld seams vary in width and height, and may even have incomplete gaps.
No visible defects: weld seams and surrounding areas are free from pores (small indentation-like bubbles), slag (black residue), cracks (fine or distinct fracture lines), and burn-through (local damage with holes). These defects can lead to water and dirt penetration, accelerating corrosion.
Surface Cleanliness: After welding, sanding is required for qualified products, ensuring smooth welds without burrs, and a natural transition with the cabinet surface; unsanded or poorly sanded surfaces are prone to scratching and accumulating dirt.
Edge Treatment: Cabinet edges and seams are fully welded without any gaps; incomplete welding at corners can become weak structural points, prone to cracking under stress.
Section 2: Simple Test: Verification of Strength and Sealing Integrity
Shake Test: Gently shake the cabinet sides or door while holding them with both hands. A cabinet with qualified welding should not have any looseness or unusual sounds. If there is shaking or displacement at the joints, there may be a problem with the soldering.
Cabinet Door Operation: Repeated opening and closing of the cabinet door results in no deformation at the hinge connection seam, with smooth and effortless operation without any sticking. If there is a pulling sensation or unusual noise during opening and closing at the seam, it indicates insufficient welding strength.
Seal Testing: In damp conditions (such as bathroom models), water should be sprayed at the welds to observe for leakage; no leakage indicates a passable weld; leakage suggests gaps in the weld, indicating poor sealing.
III. Key Judgment Criteria
Welding Density: Full welding is required for critical load-bearing areas (such as cabinet frames, panel connections), and spot welding is not permitted. Spot-welded connections are prone to breakage under stress and have a shorter lifespan.
Corrosion Treatment: The weld joints must undergo the same corrosion treatment as the cabinet surface (such as acid pickling and passivation, sandblasting), with no noticeable color difference; weld joints without corrosion treatment are prone to rusting first.