Blister retail packs are produced by a number of different thermoformers, with significant variation in quality.
Plastic Ingenuity supplies high-quality blister packs for customers who are very conscious of the effect low-quality packaging can have on their brand appeal and image.
Design Considerations for Blister Packs
The primary consideration for the design of blister packs relies on the customer's need for strength and consistency within the part.
For strength, male parts are stronger at the top of the part for protection, and inconsistent at the flange. Female blister packs have strength at the flange for consistency—it is important for the bottom of the cavity to have this increased strength. A consistent flange makes the package easier to seal.
One of the most critical areas of the design process is the trim tolerance. Plastic Ingenuity requires a +/- 1/32" trim variation because of tooling shifts during the thermoforming process.
The shape of the part and layout of that shape determine tool spacing. Because of the changes in shape and layout, material distribution can fluctuate from the middle of the part to the edges. The overall gauge of the part will be determined through a collaboration of Plastic Ingenuity and the customer.
PI usually suggests that the draft of the sidewalls on the blister packs be 10 degrees to aid in the de-nesting of the part. Variance from this would be based on a need and would require stacking lugs to help de-nest the parts.
Thermoforming Considerations for Blister Packs
Material distribution is determined by plugs and process sequence. Process sequence would be vacuum, form air, tool temperature, and the timing of all of those three.
Undercuts make the parts difficult to remove from the tool, to de-nest from each other, and to process parts on a heat sealer.
Plastic Ingenuity uses a "trim in place" blister machine to produce blister packs without undercuts. This machine allows PI to stay competitive within the blister packaging market.
Points to Consider for Blister Packs
- Are very inexpensive to produce.
- Can be custom fit to help sell/promote products.
- Can have multiple products in a common blister.
- Protect and hold the product securely.
- Come in a variety of sizes, from small unit-dose pills to large suitcase-sized blisters.
- Allow products to be seen, but not touched.
- Nicely frame the product's visual presentation on the shelves/pegs.
- Often require some type of a card to seal the blister.
- Require heat sealing the blister pack to the card.