New System Detects Tiny Defects in Packaging Seals
Researchers have developed an optical coherence tomography system capable of non-destructively inspecting packaging seals in real-time, identifying defects as small as eight micrometers.
Billions of products are sealed annually in film packaging, requiring reliable leakproofness, especially for medical and food industries. Within the OCTInline project, scientists at the Fraunhofer Institute for Ceramic Technologies and Systems (IKTS) have created an innovative testing system. This system utilizes optical coherence tomography (OCT) to detect defects in seals non-destructively and in real-time during the packaging process, achieving micrometer-range resolution.
OCT operates by directing near-infrared light into the material and analyzing the reflected signals. This process generates high-resolution, three-dimensional images of the subsurface structure, revealing irregularities like material defects, air pockets, or incomplete seals without damaging the packaging or its contents. The Fraunhofer IKTS team integrated this OCT technology directly into a packaging machine, enabling continuous quality testing at production speeds of up to 25 meters per minute.
"We can detect and visualize various pores in the seal down to a size of eight micrometers," stated Ralf Schallert, manager of the Characterization Technologies Group at Fraunhofer IKTS. The primary challenge was merging this high resolution with high production rates, as smaller defects necessitate more data collection and analysis. Integrating the system into an active industrial process also presented difficulties, with even minor film vibrations impacting measurements, requiring a balance between depth of field, exposure time, and film movement.
The increasing demand for sustainable packaging, particularly recyclable mono-material films, highlights the importance of reliable seal integrity. While environmentally advantageous, these mono-material films are more susceptible to seal defects, underscoring the need for continuous monitoring. The real-time testing offers manufacturers benefits such as reduced scrap and material consumption through faster defect detection. Furthermore, the system provides insights into the condition of machinery and tooling, identifying issues like unoptimized pressure or temperature, or tool wear, allowing for early intervention.
A demonstration system has been operational since July 2026 at project partner Kallfass Verpackungsmaschinen GmbH, where it is also presented to prospective clients. The technology's adaptability extends beyond packaging, with potential applications in functional coatings, ceramic components, and even parts produced by additive manufacturing, wherever thin layers, internal structures, or minute defects require reliable detection.
This development in OCT integration for real-time seal inspection is significant for quality assurance in packaging, especially with the rise of defect-prone recyclable materials. The ability to detect sub-micrometer defects at production speeds addresses a critical need for waste reduction and process control. This technology's potential application to additive manufacturing parts highlights the broader trend of using advanced non-destructive testing for quality control in complex, layered structures.
Edited by the news editor with AI from the original report — please refer to the original source.