Design Guide for PVC Clamshell Blister Packaging in electronics and electrical: 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 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; full colour printed inserts; gauge 0.30 to 0.80 mm. Materials most often specified are Polypropylene, Polyethylene Terephthalate, Recycled PET, Polyvinyl Chloride, and the choice between them changes stiffness, temperature resistance, chemical behaviour and price.

In the electronics and electrical sector the decision is usually driven by ESD protection and dimensional accuracy, with cleanliness as a secondary requirement. Typical end uses include device inserts, battery packs, component trays.

Key Material Properties

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

Polyvinyl Chloride is frequently the default selection here: PVC can be formulated from rigid pipe compound to soft medical grade by changing plasticiser content.

Design Rules for Thermoformed Parts

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

• 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.
• Use a draft angle of at least 3 degrees per side so the part releases without vacuum locks.
• 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.
• Add ribs, steps or kiss-offs instead of increasing overall gauge to gain stiffness.

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
• Polyvinyl Chloride based: inherently flame retardant
• Recycled PET based: lower carbon footprint than virgin resin
• 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

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

• Vacuum forming
• Twin sheet forming
• Rf sealing
• Die cutting

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

Use this checklist when comparing two or three supplier quotations.

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

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.

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.

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 Polyvinyl Chloride?

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.

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.