Advanced Machine Vision System Ensures 100% Quality of Food Packaging Using 53 Digital Cameras
Packaging is an extremely important part of food products for the consumer market, as it fulfills a number of functions. Most importantly, proper packaging is essential for the preservation of perishable goods and the protection of consumer safety and health. Additionally, malfunction in packaging can lead to inaccurate filling – for example by reducing the volume of a cup. The packaging carries important information for the consumer but also for the supply chain and retailers, such as bar codes, best-before-dates, etc. Last but not least, the packaging is what consumers see first on the supermarket’s shelves. It is a brand ambassador, conveys an implicit message on the value of the product and differentiates it from its competitors. No wonder that the food industry and its packaging suppliers pay a lot of attention to high quality standards of their cups, boxes and lids.
Based in Taastrup, Denmark, Superfos a/s is Europe’s largest manufacturer of injection-molded plastic packaging, supplying high-quality packaging for food, non-food and healthcare markets. In order to ensure a 100% quality assurance of their products, Superfos partnered with TriVision a/s, a leading Danish machine vision solution provider, to implement an advanced machine vision inspection system on their Randers, Denmark production lines dedicated to containers for butter and other dairy products.
Meeting both quality and economic goals
Evolving in the competitive environment of fast moving consumer goods, Superfos faced the challenge of ensuring a reliable, 100% quality inspection and optimizing costs. “Of course, the primary goal of a machine vision inspection system is to ensure high quality standards”, says Stig Skovbo Sørensen, Project Engineer at Superfos. “However, we also expected economic benefits from the system: we wanted to ensure that all products leaving the production line be good, but also that all products rejected be bad, meaning reducing waste through mistakenly rejected good products”. Another economic challenge for the inspection system was to perform quality checks at the full speed of the production line, to avoid impacting productivity.
Zero Error: TriVision Packaging Inspector
TriVision’s Packaging Inspector is a state-of-the art optical inspection system specially designed for 100% inspection in the packaging industry. It can detect defects such as overmolding in injection-molded plastic containers and check printed labels. TriVision Packaging Inspector is a modular system that can be adapted to the products to be inspected and the tasks to be performed.
The system implemented at Superfos includes several inspection stages ensuring a 100% inspection of all containers and all lids leaving the production lines. The plastic cups are inspected from up to three different viewing angles using digital cameras from Allied Vision Technologies.
TriVision’s Packaging Inspector is extremely flexible and can be taught new container models within seconds. Besides, it includes a statistical analysis which allocates each defect to the specific injection molding cavity tool. That way, the operator can quickly react and alert maintenance if a tool produces too much waste. Using the graphical interface, the user can also modify tolerances for each inspection criteria according to the requested quality standards.
Another unique feature of Packaging Inspector is the high level of support it offers: TriVision has remote access to all installations via a virtual private network (VPN) and can diagnostic and fix problems extremely rapidly.
Best ingredient for success: AVT FireWire Cameras
Alone at Superfos’ Randers factory, a total of 53 digital cameras are in operation as part of the TriVision Packaging Inspector systems. All of them are digital FireWire cameras from Allied Vision Technologies.
For the inspection of square butter boxes, TriVision selected Stingray F-046B cameras to control material defects: Two cameras are positioned below a conveyor belt and inspect the inside surface of the box as it passes above them. Simultaneously, an AVT Stingray F-201B inspects the printed artwork from above to check the correct position of the label, barcode, etc. The lids used to seal the containers are controlled on separate lines using Stingray F-201C color cameras.
The Stingray is a highly flexible industrial camera combining a fast IEEE 1394b interface with advanced image optimization functions (AVT smart features). The Stingray F-046 and F-201 feature a 0.4 Megapixel and 2 Megapixel CCD-sensor respectively.
Round cream cups are checked using a combination of Stingray F-146B and Marlin F-145C cameras. The Stingray F-146B camera inspects the inside surface of the cup as it passes below it on a conveyor belt, while a lateral Marlin F-145C camera checks the presence of the label on the outside surface.
The Stingray F-146B is a 1.4 Megapixel monochrome camera delivering up to 15 frames per second at full resolution. The Marlin F-145C is a robust 1.4 Megapixel color cameras with a IEEE 1394a interface.
The lids for the round cups are controlled by AVT Guppy F-146B ultra-compact IEEE 1394a monochrome cameras with 1.4 Megapixels resolution.
Switch to AVT Pays Off
“We started up eleven years ago with digital cameras from another manufacturer”, recalls Ole K. Neckelmann, Managing Director of TriVision. “However, those cameras did not work reliably enough. Besides, they did not offer enough possibilities for fine tuning in order to optimize the image quality for our software”. After four years, TriVision decided to replace all cameras with AVT models. “Advanced systems need advanced cameras. Our Packaging Inspector system detects the smallest defect but this requires a very fine tuning of the camera settings with the image processing software. AVT Stingray cameras offer a wide scope of settings for image optimization and camera control that help us to make the most out of every single image”, says Neckelmann.
In seven years working with AVT, TriVision has implemented several generations of cameras and gained valuable experience. Key to the successful relationship was also the local support by Parameter AB, Allied Vision Technologies’ partner in Denmark and the Nordic countries.
Today, TriVision’s Packaging Inspector is a success both for TriVision and for Superfos. “The key factors of success for the Packaging Inspector are its extremely high accuracy and its reliability. Selecting AVT cameras was the right choice to achieve both”, says Ole K. Neckelmann. Superfos’ Stig Skovbo Sørensen is also delighted with TriVision’s Packaging Inspector: “We feel we have purchased a very efficient product. I feel great comfort in the systems we have now”, he says.
Building on this success, TriVision is planning several similar projects at other packaging manufacturers.