Design Guide for PC Returnable and Reusable Thermoformed Trays in food and beverage: Draft, Radii and Draw Ratio

Thermoforming rewards designs that respect how a heated sheet stretches. These rules prevent most tooling rework and most thickness complaints.

Use it as a working checklist when you write your next enquiry.

Product Overview

This category covers a family of products rather than a single item. In practice a buyer defines returnable and reusable thermoformed trays by three things: the base resin, the format or dimension, and the performance or certification level it has to meet. Typical options in this category include washable designs; gauge 1.5 to 6.0 mm; stack and nest configurations. Materials most often specified are High Density Polyethylene, Polycarbonate, Acrylonitrile Butadiene Styrene, Polypropylene, and the choice between them changes stiffness, temperature resistance, chemical behaviour and price.

In the food and beverage sector the decision is usually driven by food contact compliance and migration limits, with seal integrity as a secondary requirement. Typical end uses include bakery inserts, takeaway containers, ready meal trays.

Key Material Properties

The table below summarises the values that usually decide the material choice.

Polycarbonate is frequently the default selection here: PC replaces glass where impact safety matters, but it needs a hard coat for abrasion resistance.

Design Rules for Thermoformed Parts

A few geometry decisions made on the drawing save weeks of tooling adjustment later.

• Keep the draw ratio moderate: deep cavities thin the sheet and force you to start with a thicker gauge.
• Avoid undercuts unless the tool has moving sections, which adds cost to every cycle.
• Design uniform wall thickness by avoiding abrupt depth changes in the same cavity.
• Add ribs, steps or kiss-offs instead of increasing overall gauge to gain stiffness.
• Use a draft angle of at least 3 degrees per side so the part releases without vacuum locks.
• Make corner radii at least equal to the sheet thickness; sharp corners are where holes start.

Send these rules to your designer together with the sheet gauge and the target cycle time; most tooling modifications come from ignoring draft and corner radii.

Common Grades and Variants

• Acrylonitrile Butadiene Styrene based: high impact toughness
• Polyethylene Terephthalate based: excellent barrier to CO2 and moisture
• Polypropylene based: lowest density among commodity plastics
• High Density Polyethylene based: high impact strength even at low temperature

Beyond the base resin, most suppliers offer UV stabilised, food contact, flame retardant, anti-static and recycled content versions of the same product. Ask which additive package is included, because it is often the difference between a part that lasts three years and one that lasts ten.

Processing and Finishing Options

The route below is the one most factories use for this type of part.

• Thick gauge forming
• Twin sheet forming
• Welding
• Cnc trimming

Secondary operations such as printing, welding, machining and assembly are often cheaper to do in the same factory, and they reduce the risk of mismatch between components.

How to Specify Returnable and reusable thermoformed trays Correctly

Use this checklist when comparing two or three supplier quotations.

1. specify identification method for tracking
2. define the expected number of trips and the payback
3. validate stack height over the full pool size
4. check washing temperature compatibility
5. plan a repair and replacement policy

Send this list to your supplier with the drawing and you will receive comparable quotations from every factory you contact.

Frequently Asked Questions

How long does tooling and sampling take?

A new tool typically takes 25 to 45 days depending on cavity count and complexity, followed by T1 samples within one week. Existing tools can usually start production within 10 to 15 days of order confirmation.

What tolerance can be achieved?

Standard production tolerance follows the relevant ISO or DIN tolerance class for the process; tighter tolerances are possible after machining or grinding, but they add cost. Define the tolerance only on the functional dimensions.

Which certifications can you provide?

We can provide ISO 9001 quality system documentation, material certificates, RoHS and REACH statements, and where applicable food contact, flame retardancy or drinking water approvals. Tell us your target market and we will match the document set.

How do you control colour consistency?

Colour is controlled with a masterbatch reference approved by the customer, and every production lot is checked against the approved sample under standard lighting before shipment.

Do you offer samples?

Yes. Standard samples are normally free of charge and shipped within three working days; custom samples are charged at cost and credited against the first production order.

Conclusion

Share your specification and quantity with us and we will recommend the most cost effective material, tooling route and packing method for your market.