Blister packing can preserve food items, protect electronics, or even hygiene items like toothbrushes. Whether you’re a manufacturer or packaging company looking for a more efficient packaging method, keep reading this article to discover what blister packing is and how you can apply it to your business.
What is Blister Packing, and How Does it Work?
Blister packing involves enclosing your product in a plastic cavity covered with an aluminum, plastic, or paperboard backing. These ‘blisters’ protect the product from environmental conditions, offer easy consumer viewing, and ensure tamper-proof integrity. Blister packing is used across various industries, including pharmaceuticals, food, electronics, etc.
It comes in various types, each tailored to suit your product.
- Plastic-Paper
Here, a plastic cavity is lined by a paperboard backing. The lid is heat-sealed onto the plastic and may be slid open, perforated for easy product removal, or have the cavity trapped between two cards.
- Plastic-Plastic
This is known as clamshell packaging. A plastic material is formed and sealed onto another plastic. In some cases, one end is hinged so that the package opens like an actual clam. Clamshell packaging is usually employed for heavier products and gives a full view.
- Plastic-Aluminum
In this type, the plastic is effectively sealed onto an aluminum backing, which may be pushed through to release the product within.
- Aluminum-Aluminum
This is commonly used for high-heat- and moisture-sensitive products due to its strong barrier properties. The downside is the absence of visibility.
The Blister Packaging Manufacturing Process: A Step-by-Step Breakdown
- Design and Prototyping: The manufacturing process begins with a comprehensive analysis where engineers collaborate to determine the optimal configuration for the specific product to be packaged.
- Material Selection and Preparation: After finalizing a design, the most suitable materials are chosen.
Polyvinyl chloride (PVC) is a prevalent choice due to its clarity, chemical resistance, and good barrier properties. However, it may hurt sustainability as it can degrade during production. So, approved stabilizers must be added during production to mitigate this issue.
Polyethylene is a potential alternative to PVC due to its strong, lightweight, and versatile properties. The plastic is durable and easily recyclable. However, it’s less useful in pharmaceuticals due to its high water permeability in comparison to PVC.
Polyvinylidene chloride (PVDC) is used in blister packing but not as a film-forming material. This is because this material blocks oxygen and water so effectively that it works very well as a coating on PVC or aluminum films. They enhance material properties, offering heat-sealable, flexible, and transparent coatings, though they can suffer thermal degradation.
Some other materials that may be used in blister packing are aluminum, cyclic olefin copolymers (COC), polypropylene (PP), polychlorotrifluoroethylene (PCTFE), etc.
- Blister Forming: Here, a negative die serves as a mold for thermoformed or cold-formed packing.
- Thermoforming: A design is created to suit the specific products, and a mold is made. A suitable plastic material (PVC, PET, PVDC, etc.) is then heated at a temperature of 300°C to make it soft and pliable. Using vacuum and compressed air, the material is stretched over the die and shaped.
- Cold forming: This method is peculiar to aluminum blisters, which are used for more sensitive products. After designing, a positive die is created to mechanically press the foil into the mold cavity. The aluminum may be made into soft or hard blisters depending on your product needs.
- Product Loading: Products are inserted into cells manually or automatically, with high-volume production using machines equipped with vibratory/gravity-fed hoppers, rotating brushes, and alignment paddles for efficiency.
- Lidding Material Application: The backing is often printed with relevant information like custom branding, batch codes, or expiration dates. They are then fed into a heat-sealing press where they’re aligned with the formed blisters and sealed onto them. Heat, pressure, and sealing resin bond the backing to the blisters, creating a permanent, tamper-evident seal.
The sealed blister packs are then passed through a cooling station to stabilize the seal.
- Perforation and Die-Cutting: Once the product integrity is ensured, the packs pass through a die-cutting station where the sheets are cut into cards. Precision machinery cuts the sheets into cards, allowing for custom features like child-resistant or easy-peel functionality, or tamper-proof seals.
- Inspection and Stacking: Defective packs are detected by a visual inspection system and automatically separated from the finished output. The finished blister packs are then transported to robot-picking arms that stack and pack the products in cartons or shipping materials.
Essential Equipment for Blister Pack Manufacturing
Blister Forming and Sealing Machines
These machines are central to creating blister packs and may be thermoforming or cold-forming.
As previously mentioned, thermoforming blister packing machines use pressure and heat with molds to form cavities, which are then filled and sealed. They’re suitable for tablets, capsules, batteries, and consumer goods. They are available as manual, semi-automatic, or fully automatic.
Cold-forming machines mechanically press laminated aluminum into cavities without heat. The subsequent steps are similar to thermoforming. They are suitable for highly sensitive products and are opaque in nature. The machines are mostly semi- to fully automatic.
Ancillary Equipment
These are some machines beyond the main ones that aid blister-packing manufacturing.
- Chillers: They cool formed plastic and seals for dimensional stability.
- Air Compressors: Provide compressed air for pneumatic functions essential for automated machine operation. u
- Vacuum Pumps: Create the vacuum necessary for thermoforming blister cavities.
- Feeding Systems: Accurately load products into blisters. Types include vibratory, brush, gravity, and robotic pick-and-place systems.
- Printing Units: Apply data (batch codes, expiry dates) and branding to lidding materials using inkjet or thermal transfer technologies.
Blister Packing Production Costs: What to Expect
The material type, production volume, and other factors affect the costs associated with blister pack production. Bulk production is typically cheaper, but custom designs and printing increase costs. Of the two materials that make up a blister pack, the thermoformed cavity is the major cost driver.
Small productions of 1-10 units can be as expensive as $4-$5 per pack; medium-scale productions of about 10,000 to 50,000 units would drop significantly to $0.08-$0.11 each, and large-scale productions have even lower per-unit costs between $0.05 and $0.07.
Custom-made sealing trays can also add $200 to $250 per tray, and tooling costs for molds can start at $600 with the potential of reaching $5,500.
How to Ensure Quality Control in Blister Packaging
- Material Quality Checks: Verify raw materials for correct thickness, barrier properties, and absence of defects (e.g., tears, uneven coating).
- In-Process Quality Monitoring: At every stage of production, monitor cavity integrity and uniformity and check for seal strength and delamination. Ensure clean, precise cuts without damaging the pack or product.
- Product Integrity Checks: Examine that the correct product is placed in each cavity at the accurate number and with no foreign materials.
- Visual Inspection Systems: Utilize automated vision systems for high-speed detection. These will identify defects like missing products, misprints, damaged seals, foreign material contamination. The machine will then automatically reject non-conforming packs.
Top 5 Blister Packing Companies and Suppliers in the Market
We are a prominent manufacturer of diverse packaging machinery, notably offering automatic hot-sealing blister packing machines for products like capsules and tablets. Our range supports diverse automation needs for blister production.
- Uhlmann Pac-Systeme
This company provides packaging for pharmaceuticals in blisters, trays, bottles and cartons. Their machines have a strong focus on precision and sustainability.
- Romaco Pharmatechnik GmbH
Romaco manufactures packaging for the pharmaceutical, cosmetic, and food industries. They offer blister packaging machines with compact footprints and precision.
- Constantia Flexibles
This company provides high-quality materials and eco-friendly packaging options, including advanced blister foils and films. They also supply high-barrier materials essential for sensitive products.
- Amcor PLC
Amcor manufactures environmentally friendly packaging for sectors like pharmaceuticals. They offer various blister packaging materials, focusing on high-quality and sustainable options.
Conclusion
Blister packing provides protection for products across many industries. For manufacturers and packaging companies, this guide has covered its various types, the detailed step-by-step manufacturing process, essential equipment needed, typical production costs, and quality control measures. You can now implement efficient and reliable blister packing to ensure your products remain safe, well-preserved, and ready for the market.
