Design Guide for PP Clamshell Blister Packaging in industrial equipment: 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 clamshell blister packaging 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 tamper evident tear strips; hinged single piece designs; gauge 0.30 to 0.80 mm. Materials most often specified are Polyethylene Terephthalate, Recycled PET, Polystyrene, Polyvinyl Chloride, and the choice between them changes stiffness, temperature resistance, chemical behaviour and price.

In the industrial equipment sector the decision is usually driven by thick gauge capability and flare and fire rating, with paintability as a secondary requirement. Typical end uses include twin sheet panels, protective guards, kiosk shells.

Key Material Properties

These figures are typical for commercial grades and should be confirmed against the supplier's certificate for your specific lot.

Polypropylene is frequently the default selection here: PP is the lightest mainstream packaging resin and keeps its shape under repeated flexing.

Design Rules for Thermoformed Parts

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

• Make corner radii at least equal to the sheet thickness; sharp corners are where holes start.
• Add ribs, steps or kiss-offs instead of increasing overall gauge to gain stiffness.
• Design uniform wall thickness by avoiding abrupt depth changes in the same cavity.
• Avoid undercuts unless the tool has moving sections, which adds cost to every cycle.
• Confirm the trim method early: steel rule die, CNC router or press tool each have different tolerances.
• Leave a flat sealing flange of at least 6 mm when the pack has to be heat sealed or lidded.

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 based: excellent barrier to CO2 and moisture
• Polypropylene based: lowest density among commodity plastics
• Recycled PET based: lower carbon footprint than virgin resin
• Polyvinyl Chloride based: inherently flame retardant

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.

• Die cutting
• Twin sheet forming
• Vacuum forming
• 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 Clamshell blister packaging Correctly

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

1. check the pack passes the retail drop test
2. avoid sharp internal corners at the hinge
3. specify the closure type and tamper evidence level
4. confirm the trim method to avoid sharp edges
5. test the hinge for at least 20 open-close cycles

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

Frequently Asked Questions

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 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.

Can you produce clamshell blister packaging in Polypropylene?

Yes. {mat1} is one of our regular materials for this item, and we can supply virgin, modified and certified grades with full traceability. Material certificates and test reports are issued per batch.

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.

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.

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.