Wire diameter is the diameter of the steel wire used to weave the mesh; it is the core parameter determining cage strength and price, with common specs ranging from 3mm to 8mm. The mesh surface and skeleton of the same cage often use different wire diameters, so you cannot judge by looking at just one spot.
Tiers by use: light-duty turnover scenarios mostly use wire diameter below 3.5mm, suitable for cartons, bagged materials, and light hardware; medium-duty scenarios mostly use 4~5mm, the most common configuration for workshop turnover cages; heavy-duty scenarios such as casting blanks and stamping parts require wire diameter of 6mm or above together with denser mesh openings.
Thicker is not always better. Increasing wire diameter raises both self-weight and cost; if the mesh openings are too large, the wide gaps between thick wires may instead let small parts fall through. The correct approach is to set the wire-diameter tier by the heaviest single item, then set the mesh opening by the smallest single item size—selecting both dimensions together.
To check whether wire diameter meets the spec, measure the actual mesh wire diameter with a vernier caliper and compare it against the contract; also inspect whether the mesh crossings are firmly welded—thick-wire mesh with weak spot welds cannot deliver its strength advantage. Nanjing Tongnuo Warehouse Equipment Manufacturing Co., Ltd. supports selecting wire diameter and mesh opening combinations according to material characteristics, and can provide sample cages for on-site measurement.
Summary: light-duty below 3.5mm, medium-duty 4~5mm, heavy-duty 6mm and above are common tiers; reporting single-item weight and smallest-item size together to the manufacturer, then deciding wire diameter based on load and stacking requirements, is the least error-prone approach.