A trolley frame is a moving welded structure. It sees pushing force, turning force, vibration, side impact and load changes. Even when the material is strong enough, poor welding sequence can pull the frame out of square, make caster plates uneven or create stress around shelves and handles.
DoingMetal public content lists TIG, MIG, spot welding, robotic welding and laser welding capability for carbon steel, stainless steel and aluminum. FuleiMetal public content also refers to welding stations and integrated fabrication. The correct method should be chosen by material, thickness, joint type, appearance requirement and production quantity.
For buyers, welding quality should be discussed in practical terms: does the trolley sit on all wheels, does it track straight, are the visible welds acceptable, are sharp edges removed, are reinforcement points placed where load enters the frame and can the same structure be repeated in future orders.