The thickness has to be enough; don’t choose something too thin just to save money. Trays made of tinplate are flat, so they’re more likely to have a 'bulging bottom' or 'collapsed edges' under pressure. Industry data suggests that 0.35mm thick tinplate is commonly used for metal trays. If the tray is large or needs to be stacked for transport, thinner material (like 0.23mm) won’t resist deformation well. It’s recommended to judge based on the tray’s length-to-width ratio: the bigger the size, the more you should go above 0.3mm.
The most common problem with shallow trays is 'bottom bulging.' With a large bottom area and short sidewalls, the center of the bottom tends to sag under weight. One way to optimize the structure is to design raised support feet at the bottom edges so stacking pressure is taken by the feet, not the bottom directly. If the supplier’s mold wasn’t originally designed this way, you should ask how they prevent bulging for large flat bottoms.
If the tray is for direct food contact, don’t skimp on the inner coating. If you’re using it for unpackaged cookies, candy, or tea, the inner walls must have a food-grade coating. Tinplate itself can’t be in direct contact with oils or acidic foods long-term. When inspecting, check if the coating is complete, with no bare metal or bubbles. A safer approach is to ask the manufacturer for GB 4806 or FDA testing reports—if they don’t have them, think twice.
Ink color differences are more noticeable on shallow trays. Since trays are flat and for display, the design usually covers the whole bottom and sides, so any color mismatch or misalignment will be very obvious. Good industry color control is ΔE ≤ 3, and high standards can get it under 1.5. Confirm the factory’s color tolerance before ordering and get a sealed sample, treating the sample as the standard for batch production.
Don’t neglect packaging during transport. Trays can easily rub against each other, especially printed surfaces. For single trays, bubble wrap or corrugated dividers are recommended; for bulk stacking, stack them facing the same direction, fix with stretch film, and don’t stack too high to avoid deformation at the bottom. Data shows that with proper protection, deformation during transport can be kept under 1%, while unprotected trays can reach 8%-12%.
