Tethered Caps: From Regulation to Implementation

In July of this year, EU Directive 2019/904 on Single Use Plastics will finally come into force. One of the consequences of this directive is the widespread introduction of tethered caps in the European Union. We spoke to Marius Pötting, our Product Manager Caps and Closures, and asked him: What impact will the directive have on the industry in general and on inspection systems for closures in particular?

EU Directive 2019/904 comes into force on 3 July. In your opinion, what are the main objectives of this directive?

Marius Pötting:

In general, the directive aims to reduce the impact of certain plastic products on the environment. The focus here is on reducing plastic waste, improving the recycling loop, reducing material consumption as well as using resources more sustainable. The introduction of tethered caps (plastic closures that must remain permanently attached to the packaging) is also intended to prevent the careless disposal of closures in the environment. All these measures obviously have a huge impact on the plastics and packaging industry.

So what exactly does the directive mean for the packaging industry?

The effects on the packaging industry are diverse and require adjustments to the entire process chain. In order to meet the requirements of EU Directive 2019/904, considerable investment in research and development was and still is required. However, the directive also offers opportunities for companies that can position themselves as pioneers for sustainable packaging solutions.

In concrete terms, the introduction of the directive means that adjustments have to be made at various points in the manufacturing process: For example, to the injection molding machine tool, the injection speed and injection pressure, as well as the inspection system all the way to the filling line.

You mention that these changes will also have an impact on the inspection of objects. Can you tell us what exactly is changing for inspection systems?

The introduction of tethered caps has ensured that new, asymmetrical geometries and designs have been established on the market. As a result, both the feeding and the handling of the inspection system had to be adapted. In addition, material savings mean that closures are becoming thinner and thinner and are therefore more vulnerable to process-related defects. Accordingly, the feeding system must be carefully adapted to the thinner material thickness.

One example of this is the INTRAVIS form-fit star wheel separation, which ensures perfect positioning of the closures thanks to its lateral movement. The star wheel separation does not exert any pressure on the closures and there is no friction compared to conventional separation methods.

In addition, the introduction of the new tethered caps has changed the inspection approach, which means that the software must also be adapted. INTRAVIS has implemented a holistic software solution based on Deep Learning: It does not require time-consuming "screening" and “teaching” of different defect patterns. With the new approach, you can train the system on the basis of a few good parts in a quick and intuitive process. Deviations from the defined “good” closures are automatically ejected based on the sensitivity settings you choose. The inspection system thus ensures that even minimal defects are detected and only flawless products find their way to the end consumer.

Talking about the inspection approach: More and more suppliers in the mechanical engineering sector are now offering their systems with the addition of Artificial Intelligence. Can you tell us what customers can expect from INTRAVIS? Many customers are certainly afraid that their data will disappear into a black box and that they cannot understand what exactly is being verified.

At INTRAVIS, the customer always retains full control over the inspection system. As already mentioned, the AI is the foundation for empowering our customers to teach the system which product should be accepted as a good part and which should not. Intuitive reference creation allows the customer to define inspection areas in which all defect criteria are inspected. The customer uses tolerance values to independently define which closure he wants to evaluate as a good or bad part. Based on a large number of successfully completed projects, INTRAVIS has already gained extensive experience of typical defects (such as flashes or short shots at the warranty band) that can occur during tethered cap production. This allows the best possible, customized solution to be found for each project. The cavity-related data analysis enables precise monitoring and analysis in order to be able to react to potential problems at an early stage. This means that our customers always retain full control over their production quality.

INTRAVIS was one of the first providers to offer an inspection system that is “Tethered Caps Ready”. How much experience have you gained in this area in the meantime?

For many years now, INTRAVIS has been actively involved in CETIE (International Technical Center for Bottling and related Packaging), making a significant contribution to the further development of tethered caps and, thus, supporting the optimization of safety and sustainability standards in the packaging industry. Since then, we have dedicated ourselves intensively to the inspection of tethered caps and have successfully adapted to meet the new requirements. By using the latest image processing technologies and machine learning algorithms, we are able to inspect tethered caps quickly and precisely - regardless of whether they are produced using the injection molding or compression molding process. As a leading provider of image processing solutions in the packaging industry, we are proud to have already successfully implemented a large number of inspection systems for closures on the market, and to be able to offer our customers high-quality and reliable solutions for tethered caps.

Finally, let's imagine a customer who wants to convert his existing line to tethered caps. He has already updated everything and is now confronted with the final task of adapting his inspection. How complicated will this be for the customer?

Of course, I cannot speak for other providers on this issue, but INTRAVIS took all the necessary measures early on when developing and refining the CapWatcher. So, an uncomplicated and rapid changeover is definitely possible. It is advisable to involve the inspection system provider in the changeover as early as possible. If you are interested, you can contact us at any time. We will be happy to support you with the transition of your production.

Find out more on our Tethered Caps Webpage!