Blister packaging is an efficient, economical, and protective form of solid dosage packaging. The process covers five core steps: forming, filling, sealing, coding and cutting, each of which needs to be precisely controlled to ensure the quality and stability of the final product. Through advanced online testing technology and strict quality control systems, blister packaging can ensure that health supplements maintain good safety and efficacy during storage and use.
5 Core Steps of Blister Packaging Process
Step 1: Forming
The first step in the blister packaging process is the formation of the pharmaceutical cavity, or “blister”. In the production line, the forming material (e.g. PVC, PVDC-coated PVC or cold-formed aluminum) is fed into a heating unit. In the thermoforming process, the plastic film is heated to 110-140°C and then formed into regular grooves by means of a mold with negative pressure. In the case of cold-formed aluminum, no heating is required, but it is shaped directly by high-pressure stamping. The molding quality of the blister directly determines the stability of the pharmaceutical and health supplement package, so the temperature, molding pressure and time need to be precisely controlled to ensure that the blister has a uniform shape and precise dimensions.
Step 2: Filling
Once the molding is complete, the bulk supplements are precisely placed into the blister. Tablets, capsules or micro tablets are conveyed through an automatic feeding device and calibrated by a sensor or camera inspection system to ensure that each blister is filled completely. If missing tablets, overlaps or breakage are detected, the system automatically rejects the non-conforming product. In order to ensure the integrity of the supplement product, the filling process needs to avoid dust contamination and control static electricity to prevent the drug from sticking to the conveyor belt and affecting the feeding accuracy.
Step 3: Sealing
The sealing process follows after the bulk supplements have been filled. The cover material usually consists of an aluminum foil or laminate film with a special heat-sealable coating. When the foil and blister material enter the heat-sealing area, they are firmly bonded at 180-250°C and under the right pressure to form a hermetically sealed package. The quality of the seal is critical, as too loose a seal may lead to moisture in the health supplement product, while too tight a seal may damage the blister structure. Therefore, the temperature, pressure and sealing time must be strictly controlled, and the integrity of the seal must be verified by peel and seal tests.
Step 4: Coding
The batch number, production date and validity period of the health supplement products must be printed on the sealed blister packaging for quality traceability. Commonly used coding methods include inkjet and embossing. The ink coding process requires the ink to dry quickly and wiping resistant, while the imprinting method uses a mold to press characters to ensure clarity. The coding process needs to keep the font clear, avoid blur or misprinting, and ensure that the information is readable.
Step 5: Cutting
The batch number, production date and validity period of the health supplement products must be printed on the sealed blister packaging for quality traceability. Commonly used coding methods include inkjet and embossing. The ink coding process requires the ink to dry quickly and wiping resistant, while the imprinting method uses a mold to press characters to ensure clarity. The coding process needs to keep the font clear, avoid blur or misprinting, and ensure that the information is readable.Step 5: Cutting
Finally, the sealed blister package enters the cutting process. The cutting tool cuts the blister sheet into single or multiple packaging units according to the preset dimensions to meet the needs of different packaging specifications. The cutting accuracy should be controlled within ±0.2mm to ensure that each piece of blister is of the same size, which facilitates subsequent cartoning and distribution. If the cutting error is too large, it may affect the adaptability of the automatic packaging equipment, or even lead to product scrap.
Comparison of 3 Forming Methords of Blister Pack
| Forming Method | Thermoforming | Cold Forming | Thermo-Cold Composite Forming |
| Core Process | Heat plastic films (e.g., PVC, PET) to a softened state, then form grooves using pressure or vacuum. | Directly press and form aluminum foil composite films in the mold. | First form a transparent layer via thermoforming, then overlay a cold-formed layer.using pressure or vacuum. |
| Applicable Materials | PVC, PET and other plastic films | Aluminum foil composite films | Plastic films + aluminum foil composite films |
| Applicable Products | Small-sized products (e.g., tablets) | High-sensitivity products (e.g., pharmaceuticals) | High-value, high-sensitivity pharmaceutical products |
| Core Advantages | 1. High production efficiency; 2. High packaging transparency, enhancing product display effect. | 1. Excellent protective performance (moisture resistance, light resistance, oxygen barrier); 2. Strong protection effect. | 1. Combines transparent visibility (from thermoforming) and high barrier protection (from cold forming); 2. Meets dual needs of visibility and long-term storage. |
| Main Disadvantages | Relatively weak protective performance (e.g., moisture resistance, oxygen barrier). | 1. Opaque packaging; 2. Large space occupation, affecting packaging compactness. | 1. Relatively complex process; 2. Usually higher cost. |
| Workshop Operating Points | 1. Control material preheating temperature to ensure uniform film softening and avoid local overheating/damage; 2. Adjust forming pressure/vacuum to match groove size with products (error ≤ ±0.1mm); 3. Cool and shape promptly after forming to prevent film rebound. | 1. Check flatness of aluminum foil composite films before mold feeding (use only if no wrinkles/scratches); 2. Maintain stable mold pressure during pressing to avoid aluminum foil rupture/edge leakage; 3. Sample 5 pieces per batch to test barrier properties (moisture resistance, light resistance). | 1. Aluminum foil rupture/edge leakage: Reduce mold pressure and check for sharp mold edges; 2. Substandard barrier performance: Replace with qualified aluminum foil films and check for foreign objects at seals; 3. Film wrinkles: Stretch films flat before mold feeding and adjust film feeding speed. |
| Common Problems & Solutions | 1. Local film damage: Reduce preheating temperature and check for local overheating of heating tubes; 2. Groove size deviation: Recalibrate pressure/vacuum parameters and check for mold wear; 3. Film rebound: Extend cooling time and lower cooling air temperature. | 1. Produce the transparent layer per thermoforming standards (overlay cold-formed layer only if no bubbles/deformation); 2. Control lamination pressure/temperature during composite forming to ensure no interlayer gaps and firm adhesion; 3. Inspect transparency clarity and seal integrity for every 10 products. | 1. Interlayer gaps: Increase lamination pressure and raise temperature (not exceeding material tolerance); 2. Bubbles in transparent layer: Improve vacuum during thermoforming to expel air under the film; 3. Incomplete seal: Check composite mold sealing performance and replace aging sealing rubber strips. |
Quality control and process monitoring
During the entire blister packaging process, GMP needs to be strictly followed for quality monitoring. Key parameters such as blister molding quality, drug filling status, sealing integrity and cutting accuracy must be tested and recorded online.
Common detection methods include:
Conclusions
From being a “safety armor” that preserves the activity of pharmaceuticals and health supplements to a “portable container” that enhances food freshness, blister packaging continues to meet the rigorous packaging demands of modern industry, thanks to its core advantages of sealability and precise dosage control. In the future, with breakthroughs in eco-friendly material technologies and the integration of intelligent designs, it will no longer be merely a protective carrier. Instead, it will evolve into a crucial link connecting products, users, and sustainable development, continuously empowering industrial upgrading and consumer experience in every detail.