Design Guide for PS / HIPS Thermoformed Medical Device 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.

Everything here can be checked on a real sample before you commit to a production order.

Product Overview

This category covers a family of products rather than a single item. In practice a buyer defines thermoformed medical device 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 gamma, ETO and steam options; rigid and semi rigid designs; gauge 0.40 to 1.50 mm. Materials most often specified are Polyethylene Terephthalate, Polyethylene Terephthalate Glycol, Polystyrene, Polypropylene, 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 pharmaceutical blisters, surgical kit trays, IV and catheter kits.

Key Material Properties

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

Polystyrene is frequently the default selection here: HIPS is the default thermoforming sheet for food packaging and appliance liners.

Design Rules for Thermoformed Parts

Thermoforming rewards designs that respect how the sheet stretches. These rules prevent most tooling rework.

• Leave a flat sealing flange of at least 6 mm when the pack has to be heat sealed or lidded.
• Make corner radii at least equal to the sheet thickness; sharp corners are where holes start.
• 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.
• 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

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

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

Each step below has its own control points, and skipping one of them is where most defects start.

• Tyvek lidding
• Validation sealing
• Cleanroom thermoforming
• Pressure forming

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 Thermoformed medical device trays Correctly

Work through these points in order and most specification mistakes disappear.

1. run peel strength testing on every production lot
2. control tooling wear to avoid trim burrs
3. validate the seal process to ISO 11607
4. confirm the sterilisation method with the material
5. specify particle and cleanliness requirements

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

Frequently Asked Questions

What is the minimum order quantity for thermoformed medical device trays?

For standard sizes and colours the minimum is usually one pallet or one production run; for custom tooling the economic minimum depends on the tooling cost amortised over the expected volume. Send us your annual volume and we will calculate the break even point.

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.

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.

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.

Conclusion

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