Factory Tour

How Sushi Boxes Are Made: From Sheet to Tray

Line 1 at our Shantou facility — sheet feeding, thermoforming, trimming and stacking, filmed during a production run.

Most buyers see a sushi box as a finished product with a price. We see it as the last step of a process that starts as a flat roll of plastic sheet. This article walks through that process on our own line, so you know exactly what you are buying — and what to ask any supplier who claims to make it.

1. The material: food-grade PS and OPS sheet

The tray starts as polystyrene (PS) or oriented PS (OPS) sheet, fed from a roll into the machine. The choice of material decides most of what the finished box can do:

• PS — the standard for sushi trays. Stiff, inexpensive, holds its shape at chilled temperatures, and takes printing well.
• OPS — a oriented, higher-clarity sheet used for lids, where you want the customer to see the contents through a glossy, crack-resistant surface.
• Kraft / paper board — the eco-positioning option, used for our kraft sushi and lunch boxes.

Whatever the material, it has to pass food-contact rules for the market it ships to. Our key products are tested by SGS against US FDA 21 CFR 177.1640 and EU Regulation (EC) No 1935/2004 with (EU) No 10/2011, with LFGB reports and heavy-metal screening available for the paper series. If you sell into the EU, ask for these reports by name — a supplier who cannot produce them is guessing.

2. Thermoforming: sheet becomes a tray

The sheet passes through a heating section until it is pliable, then a multi-cavity mold presses it into shape. Two things matter here, and both are invisible on the finished product:

• Cavity count. One press cycle produces as many trays as the tool has cavities. Higher cavity counts mean lower unit cost — which is why MOQ and unit price move together.
• Wall thickness distribution. A well-made tool distributes material evenly, so the tray does not warp or crack at the corners when it is stacked and shipped.

This is also where customization happens. Custom sizes and compartment layouts need a dedicated tool, which is what sets a minimum order quantity. Our standard FP-00 to FP-11 sizes use existing tools, so they carry no tooling charge and a much lower MOQ.

3. Trimming and stacking

After forming, the web is trimmed to separate the trays, then stacked automatically. Two quality signals worth checking on any supplier's line:

• Is trimming in-line (part of the same machine) or a separate manual step? In-line trimming is faster and produces far less burr.
• Are trays stacked automatically or by hand? Manual stacking is where dust and deformation enter.

4. Quality control and certification

Our line runs incoming material checks, in-process wall-thickness sampling, and a final visual and dimensional check before packing. Reports are issued with the shipment rather than on request after the fact.

Standard	Applies to
FDA 21 CFR 177.1640	US market — PS food-contact articles
EU 1935/2004 + 10/2011	EU market — food-contact materials and articles
LFGB	German market — paper series, heavy-metal screening

5. What this means for your order

Understanding the process tells you which questions actually move price and lead time:

1. Which standard do you need? Determines material and testing, not the box shape.
2. Standard size or custom? Custom means a tool, an MOQ and extra lead time.
3. How many cavities can you fill? Sets your unit price.
4. Which market are you shipping to? Determines documentation and packing.

Answer those four and we can quote the same day. See the sushi box range, the lunch box range, or the full FAQ for sizes and MOQs. To see the same line filmed from the floor, see inside our workshop.