Design Guide for PETG Cleanroom Thermoformed Trays in medical and pharmaceutical: 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.

The notes below come from day to day production and export work with overseas buyers.

Product Overview

This category covers a family of products rather than a single item. In practice a buyer defines cleanroom 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 double bagged packing; laser marked identification; gauge 0.40 to 1.50 mm. Materials most often specified are Polypropylene, Polycarbonate, Polyethylene Terephthalate, Polyethylene Terephthalate Glycol, and the choice between them changes stiffness, temperature resistance, chemical behaviour and price.

In the medical and pharmaceutical sector the decision is usually driven by validated sealing and sterilisation compatibility, with traceability as a secondary requirement. Typical end uses include diagnostic packs, IV and catheter kits, pharmaceutical blisters.

Key Material Properties

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

Polyethylene Terephthalate Glycol is frequently the default selection here: PETG forms at lower temperatures and holds detail well, which is why it dominates medical trays.

Design Rules for Thermoformed Parts

Apply these points before the tool is cut; after that every change costs tooling and time.

• Leave a flat sealing flange of at least 6 mm when the pack has to be heat sealed or lidded.
• Use a draft angle of at least 3 degrees per side so the part releases without vacuum locks.
• Add ribs, steps or kiss-offs instead of increasing overall gauge to gain stiffness.
• Avoid undercuts unless the tool has moving sections, which adds cost to every cycle.
• Make corner radii at least equal to the sheet thickness; sharp corners are where holes start.
• Keep the draw ratio moderate: deep cavities thin the sheet and force you to start with a thicker gauge.

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

• Polypropylene based: lowest density among commodity plastics
• Polyethylene Terephthalate based: excellent barrier to CO2 and moisture
• Polyethylene Terephthalate Glycol based: excellent clarity with no stress whitening
• Polycarbonate based: outstanding impact strength (250x glass)

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.

• Particle testing
• Cleanroom washing
• Packing
• Cleanroom thermoforming

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 Cleanroom thermoformed trays Correctly

These are the criteria that actually predict whether the part will perform in service.

1. confirm washing and drying process
2. validate outgassing for vacuum applications
3. state the cleanroom class needed for production and packing
4. avoid paper based packing inside the clean bag
5. request particle count test data

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

Frequently Asked Questions

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.

What packing and shipping options are available?

Standard packing is export cartons on fumigation-free pallets, with custom labelling, barcode and retail packing available. We also handle consolidated containers and door to door delivery.

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.

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.

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.

Conclusion

Our team supplies cleanroom thermoformed trays to medical and pharmaceutical customers worldwide, with samples, material certificates and full inspection reports available before mass production.