Researchers in Germany have developed a new inspection system that can detect extremely small defects in sealed packaging while products are still moving through the production line.
The technology could help manufacturers reduce waste, improve product safety, and ensure that food, medical supplies, and other sensitive products remain securely sealed.
Billions of products around the world are packaged in sealed plastic film every year.
For industries such as food and healthcare, these seals must be completely airtight to prevent contamination, spoilage, or leaks.
Even tiny holes or poorly sealed areas can reduce product quality or create safety risks.
To tackle this problem, researchers at the Fraunhofer Institute for Ceramic Technologies and Systems (Fraunhofer IKTS) have created a new quality control system as part of the OCTInline project.
The system uses a technique called optical coherence tomography, or OCT, to inspect seals without opening or damaging the package.
OCT is an imaging technology that uses harmless near-infrared light to look beneath the surface of materials.
It was originally developed for examining the human eye, but researchers have adapted it for industrial use. The system sends light into the packaging material and measures the light that reflects back, allowing it to create detailed three-dimensional images of the seal’s internal structure.
This makes it possible to reveal tiny air pockets, weak seals, or other hidden defects that would otherwise be difficult to detect.
One of the biggest achievements of the project was integrating the OCT system directly into a commercial packaging machine. Instead of inspecting products after they are packaged, the system checks every seal continuously as the packaging line operates at speeds of up to 25 meters per minute.
Despite these high production speeds, the technology can identify defects as small as eight micrometers, roughly one-tenth the width of a human hair.
Developing the system was not simple. Detecting such tiny flaws while the packaging film is constantly moving required researchers to carefully balance image quality, scanning speed, and machine vibrations. Even slight movement of the film could interfere with the measurements, so the team had to fine-tune the system to achieve reliable results in real manufacturing conditions.
The new technology is becoming especially important as manufacturers move toward more environmentally friendly packaging. Many companies are replacing traditional multilayer plastic films with recyclable mono-material films. While these newer materials are easier to recycle, they are also more likely to develop sealing defects, making continuous inspection even more valuable.
The system offers benefits beyond simply finding faulty packages. By analyzing the seal quality over time, it can also detect problems with the packaging equipment itself. Changes in pressure, temperature, or worn sealing tools can gradually reduce seal quality, and the OCT system can identify these issues before they lead to large numbers of defective products.
A demonstration version of the system has been operating since July 2026 at packaging machine manufacturer Kallfass Verpackungsmaschinen GmbH in Germany, where it is being showcased to potential customers.
Although the first application focuses on packaging, the researchers believe the technology has much broader potential.
Because it can inspect transparent and semi-transparent materials without causing damage, it could also be used to examine functional coatings, ceramic components, medical devices, and parts produced by industrial 3D printing.
Anywhere that tiny internal defects or thin material layers need to be inspected with high precision, OCT could become an important tool for quality control.
