Common Defects in rPET Clamshell Blister Packaging for retail and merchandising and How to Prevent Them

Most quality claims on thermoformed parts trace back to a handful of root causes. Learn to recognise them on the drawing, in the tool and on the finished part.

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; full colour printed inserts. Materials most often specified are Polystyrene, Polyethylene Terephthalate, Polypropylene, Polyvinyl Chloride, and the choice between them changes stiffness, temperature resistance, chemical behaviour and price.

In the retail and merchandising sector the decision is usually driven by shelf presentation and print quality, with stack strength as a secondary requirement. Typical end uses include dump bins, counter displays, pegboard blisters.

Key Material Properties

Typical values for a general purpose grade are listed below; filled, stabilised and speciality compounds will differ.

Recycled PET is frequently the default selection here: Food-grade rPET requires a recognised recycling process plus solid-state polycondensation.

Failure Modes and Prevention

These are the failure modes that generate the majority of complaints.

• hinge cracking after flexing – usually caused by material moisture; prevent it by controlling resin drying.
• weak snap lock – usually caused by melt temperature; prevent it by controlling incoming inspection.
• misalignment after sealing – usually caused by gate position; prevent it by controlling handling and storage.
• haze in thick PET – usually caused by gate position; prevent it by controlling incoming inspection.
• sharp trim edges – usually caused by melt temperature; prevent it by controlling resin drying.

Common Grades and Variants

• Polystyrene based: rigid and glossy
• Polyethylene Terephthalate based: excellent barrier to CO2 and moisture
• Recycled PET based: lower carbon footprint than virgin resin
• Polypropylene based: lowest density among commodity plastics

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.

• Twin sheet forming
• Die cutting
• 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

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

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

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

Frequently Asked Questions

Can you produce clamshell blister packaging in Recycled PET?

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 is the minimum order quantity for clamshell blister packaging?

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.

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 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.

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.