Visual inspection of Tetra Pak packaging
is a crucial step in ensuring packaging quality. It primarily relies on high-precision industrial cameras and image processing software to automatically identify various defects on the production line. The table below summarizes the main inspection items and core technologies to help you quickly grasp the key points.
| Inspection Items | Specific Defect Types | Core Technologies/Methods |
| Packaging Material Quality | Aluminum loss, plastic leakage, scratches, ink splatter, misregistration, missing holes/burrs, etc. | Machine vision online inspection system, with different lighting and imaging schemes for printing and lamination processes. |
| Packaging Integrity | Improper lid fit, glue defects, poor sealing, etc | Vision system monitors glue position and integrity, combined with motion control system (such as Beckhoff XTS) for real-time compensation and correction |
| Marking and Coding | Missing, blurry, or incorrect coding information such as production date and shelf life | OCR (Optical Character Recognition) vision inspection system, capturing images and comparing them with standard character features |
| External Contamination/Foreign Objects | Stains, foreign objects, etc., on the packaging surface | Surface defect online inspection system |
Key Technologies for Achieving Accurate Inspection
High-performance cameras alone are not enough; to ensure stable and accurate inspection, a series of engineering challenges need to be addressed. Modern intelligent inspection equipment typically employs the following technologies:
Dynamic Stabilization Technology: Due to the soft texture of Tetra Pak cartons, they are prone to shaking or shifting on high-speed conveyor belts, affecting imaging. Advanced systems employ negative pressure adsorption technology, using ventilation holes on the conveyor belt to firmly adhere the packaging to the belt, suppressing vibration and ensuring consistent shooting position each time.
For complex curved surfaces and blind spots: Fixed-angle cameras may have blind spots for complex structures such as packaging edges, bottom corners, and lids. The solution is to use multi-degree-of-freedom, adjustable-angle detection units, allowing the probe to adaptively deflect, covering traditional blind spots and achieving omnidirectional, blind-spot-free detection.
Environmental interference resistance: Changes in ambient light in the production environment can mask subtle defects. Inspection stations are typically equipped with anti-exposure shields to block stray light and dedicated light sources for directional illumination, thereby improving the signal-to-noise ratio of the image and making defects impossible to miss.
System integration and real-time feedback: On high-speed production lines (e.g., 20,000 packages per hour), the inspection system needs to seamlessly coordinate with the production line control system (e.g., PLC) and actuators (e.g., rejection robotic arms). This often involves the conversion of different industrial communication protocols (such as EtherNet/IP and PROFINET). Deploying dedicated protocol gateways ensures that the inspection results from the vision system can trigger sorting actions in real time.
The Value of Vision Inspection
Deploying an efficient vision inspection system can bring significant benefits to enterprises:
Improved Product Quality: Real-time online inspection can promptly detect and remove defective products, preventing continuous scrap and ensuring the quality of outgoing products.
Increased Production Efficiency: Automated inspection speeds far exceed the limits of the human eye, matching high-speed production lines (up to 170 times per minute or even higher), significantly increasing production capacity.
Reduced Overall Costs: Although there is an initial investment, the system can significantly reduce manual re-inspection positions (some cases report up to 70%), saving a significant amount of material waste caused by packaging defects each year.
Quality Traceability: Data generated by the inspection system can be integrated into the factory management system, enabling digital management and full traceability of production quality.
