Maximum Efficiency in Quality Control: Two-Stage Inspection System for Aluminium Trays
Novelis Inc. is a global leader in the manufacture of innovative aluminium products and in the provision of services as well as in aluminium recycling. In order to automate the quality control of aluminium trays, which had previously only been carried out manually on a random sample basis, ISW (Industrielle Sensorsysteme Wichmann), in cooperation with STEMMER IMAGING, was commissioned to implement a two-stage inspection system to check the quality of the trays.
The task
Component selection and design support to realise an automated quality inspection system in the aluminium tray production.
The challenge
Ensuring 100% inline quality control at high cycle speeds and with a wide variety of shapes and sizes.
The solution
Together with ISW, STEMMER IMAGING designed a two-stage inspection system individually adapted to the variety of shapes and sizes of the aluminium trays. Carefully selected components guarantee optimum interaction throughout the entire production line.
- Two inspection stations for checking contours and holes
- Designed for high production speeds
- Maximum flexibility for product variants
- High process reliability
- Increased profitability
The challenge of 100% quality control: Aluminium tray inspection at maximum speed
Whether on aeroplanes, at takeaways or in supermarkets – aluminium trays used as containers for food are present everywhere. With approximately 50 presses at its Plettenberg site in Sauerland, Novelis Deutschland GmbH manufactures countless types of trays. Due to the high cycle speeds and the huge quantities previously only manual checks could be carried out on a random sample basis, so Novelis decided to invest in an automated inspection system.
The requirements were high – in addition to the high cycle speeds, the system also had to be designed to accommodate the huge variety of different shapes and sizes enabling 100% reliable inline inspection. An experienced system integrator, ISW (Industrielle Sensorsysteme Wichmann GmbH), was selected to design and implement the systems based on the high-quality vision components from STEMMER IMAGING.
The Machine vision solution from ISW and STEMMER IMAGING
The containers are checked in a two-stage system, which inspects 100% of the trays for any leaks or contour defects. The system is individually adapted to the variety of shapes and sizes of the aluminium trays. STEMMER IMAGING's main task was to select the optimum components for perfect interaction of the entire production line.
Machine vision station No. 1 – Contour inspection
Two high-resolution cameras are used in the first machine vision station to inspect the trays' contours. The two Line Scan Bars (LSB) from Mitsubishi Electric have a sensor width of approx. 400 mm and detect target deviations of +/- 100 µm. This station detects geometry errors such as so-called noses or chads on the containers. The tolerance for checking the contours can be parametrised. Each LSB is illuminated by a CCS line light, which is fitted above the containers passing by as background lighting.
Machine vision station No. 2 – Hole inspection
At the second machine vision system, directly after the contour inspection station, the trays are checked for leaks. Images are taken at this point by four Genie Nano area scan cameras supplied by Teledyne DALSA, each capturing one half of the trays. To detect leaks it is best to work with background lighting, as with a material thickness between 40 and 180 µm any light shining through can be reliably detected and identified as a defect. Containers which have leak points are sorted and fed to a recycling process.
"STEMMER IMAGING is our key supplier for machine vision. Regardless of which industry we have operated in over recent years, we have always been able to rely on their technical competence and good support.“
Stefan Tukac, ISW
The key success factors of the two-stage inspection system
The system implemented by IWS and STEMMER IMAGING was individually adapted to the requirements of the aluminium tray production at Novelis in order to use the most suitable components in each application area. The previous manual quality control method, which used a random sample basis, could be replaced by a reliable automated 100% inspection.
Customised solution
When putting together the various components for the inspection system, STEMMER IMAGING made full use of its advantage as a manufacturer-independent provider of machine vision technology and was able to select the optimum products for each task to meet Novalis' specific requirements.
Increased profitability
When putting together the various components for the inspection system, STEMMER IMAGING made full use of its advantage as a manufacturer-independent provider of machine vision technology and was able to select the optimum products for each task to meet Novalis' specific requirements.
Maximum flexibility to handle product variants
The components used in the inspection system have been designed to allow all sizes and shapes of aluminium trays to be inspected without any changeover adjustment. To convert a press line to other types of trays it is sufficient to show the system ten good parts and confirm these, after which it is possible to start the production and inspection of new containers.
User-friendly operation
A monitor is used to check and visualise the inspection results with image analysis from both machine vision systems combined into a single view. Based on this, good/bad decisions made by the system can be tracked and necessary settings corrected if required.
High level of process reliability
After selecting the components, STEMMER IMAGING's experts carried out intensive feasibility studies to ensure the process reliability of the individual products. For example, with the Line Scan Bars, which were originally developed for a completely different concept.
Cooperative partners at eye level
ISW (Industrielle Sensorsysteme Wichmann) and STEMMER IMAGING have a close cooperative partnership in a wide range of industries for many years. As a best-solution partner, STEMMER IMAGING has been supplying the optimum vision components for ISW's customised solutions for almost two decades.
“Due to the high production speeds, without this system, it would have been impossible to replace the former random checks with a reliable 100% inspection of the contours while simultaneously checking for leaks, thus increasing the cost-effectiveness of our processes to the current higher level.”
Julian Schmidt, Production Engineer at Novelis
Other successful projects from the packaging industry
Improving the quality of pharmaceutical packaging components
Millions of components such as rubber stoppers and plungers for pharmaceutical vials and syringes are used in the pharmaceutical industry. These parts must be one hundred percent free of defects. To meet this requirement, the Dutch company Simac Masic has designed a reliable inspection system utilising high-speed vision solutions, developed in conjunction with the experts from STEMMER IMAGING.
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