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Sustainability in the packaging industry is a key aspect of the fight against plastic waste and, ultimately, climate change. The challenges that this presents require flexible and powerful automation technology. OMRON, a global leader in industrial automation, presents some of the changes and technologies that offer solutions.

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Automation technology for sustainable packagingThere is no question that too much plastic is produced and disposed of worldwide. Plastic production has increased exponentially in recent years – from 2.3-million tonnes in 1950 to 448-million tonnes in 2015, and this figure is expected to double again by 2050. Plastics often contain additives to make them stronger, more flexible and durable, and many of these extend the life of the material, driving up estimated decomposition times to over 400 years.

The packaging industry is one of the main contributors to this plastic glut and faces the mammoth task of developing sustainable alternatives, which minimise waste while saving energy and making better use of alternative energy sources.

The following strategies are currently seen as key to achieving more sustainable packaging:

Reducing packaging material use: Not only in terms of virgin plastics used for primary packaging, but also in the amount of protective secondary and final packaging used. Another driver is the elimination of the use of single-use packaging. Some strategies to tackle this issue include increasing the use and scaling of reusable and refillable systems; and redesigning packaging using alternative materials that facilitate recycling – by using materials that are biodegradable, compostable or have a lower impact on the environment if they end up in landfill.

Packaging made from mono-materials is another strategy attracting increasing interest in the packaging industry. These have better recyclability, but migrating to them can be a challenging process that requires strict process control. Packaging equipment often needs to be adapted or customised to achieve advanced form, fill and seal processes that ensure equivalent package quality and performance.

All efforts to realise more sustainable packaging need to be accompanied by a waste collecting infrastructure that enables a waste-free or low-waste future along with an urgent behaviour change from consumers, industry, retailers and the entire circular economy.

New requirements for production facilities: Another key tactic for reducing the amount of plastic used in packaging is to shift from rigid to flexible packaging. Thinner walls, smaller sizes, narrower seams and lighter weights are a good way to reduce the amount of virgin plastic used in primary containers. Added to this is the use of mono-materials – paper based and biopolymers – as well as an increase in the proportion of recycled material in the primary, secondary and final packaging.

This has implications for processes and technologies on the factory floor that need to be revisited. For example, companies need to check the compatibility of their equipment and adjust settings if necessary. Lines need to be flexible to change over to new materials. Linking and managing new machine-to-machine information is required, while it is also necessary to control the performance of the machines under the new conditions to avoid rejects and material waste.

Ensure quality and safety of new materials: If more sustainable materials are used in packaging, it is still of the highest importance to ensure the quality of the product. On manufacturing lines, therefore, changing to more sustainable materials should be coupled with avoiding typical problems, such as material jams or tears, poor quality seals or incorrect labelling.

Traditional materials have different tear and puncture resistances, which implies that more precise control is needed during package forming, while shrink film made from recycled plastic has very different shrink properties compared to film made from virgin materials. These differences demand versatility, with accurate shrinking temperature control.

There are also aspects to consider in secondary packaging; reducing the melting points of adhesives when assembling and sealing cartons; adopting material reduction strategies such as lightweight corrugated materials; or unpacking and repacking the contents of a pallet with cartons made from more sustainable cardboard and other alternative materials.

Using automation to future-proof packaging

All these strategies require careful analysis to identify exactly what needs to be updated to ensure the ongoing quality and safety of the product. Ultimately, we need to future-proof manufacturing with automation and robotics technology that can work flexibly with different materials.

The following examples show some of the challenges companies may experience, along with the solutions already available from OMRON.

Film jamming: Thinner, recycled films are more sustainable, but can also tangle more quickly. Even slight changes in film thickness lead to uneven winding and unwinding and uneven tension on the film. This causes defects during pouch forming or sealing, such as curling, ripping, folding or sideways shifting and misalignment.

Correct handling with maximum throughput and minimum film consumption is key to overall OEE (original equipment effectiveness). Therefore, if creases are forming in the seal, operators should check for machine errors that are contributing to the film not being fed correctly. Examples include misaligned rollers, different feeding devices or sticky rollers that do not rotate freely.

OMRON’s Film Tension Control System provides synchronised control of tension, feed and cut. This is complemented by (colour) mark detection for film compensation through motion control to ensure optimal unwinding of the roll. The OMROM Packaging Library offers a wide range of function blocks for film processing in vertical form, fill and sealing (VFFS) machines.

Film sealing: Thinner film materials offer lower costs and improved aesthetics. However, these materials are more sensitive to heat and susceptible to burn through when using traditional adhesives and sealing technologies. The actual sealing temperature must therefore be constantly and precisely controlled and automatically adjusted to avoid losing productivity or creating sealing defects that result in rejects and waste.

OMRON addresses this challenge with an AI-based temperature control algorithm synchronised with machine movement, and sensor technology that can be placed closer to the sealing bar. Noise is compensated for by an automatic filter adjustment function.

Quality control of packaging and labelling: Re-closable packaging or pouches with nozzles are increasingly replacing rigid plastic containers. Flexible packaging with new elements such as resealable closures place different demands on packaging integrity and quality testing. Thinner films, bio-based materials or those with a higher recycled content have a different thermal, elongation and puncture resistance profile. These differences can lead to irregularities in the shape and edges during forming and cutting.

More sustainable materials such as non-laminated or mono-materials also change shape and can reduce the fidelity or performance of label printing. Reading, checking or verifying label information on packaging is difficult when the shape is inconsistent or the print quality changes.

OMRON addresses this with its high-speed inspection system, a simple and scalable system suitable for multiple lines and transparent integration with robotic systems. OMRON’s inspection system offers a multi-camera platform with a single controller for multiple-image capture at high speed to reliably detect potential defects. Advanced algorithms help to detect difficult-to-read characters, in variable light conditions and at high speeds.

New adhesives and glueing techniques: Eliminating tape and minimising adhesive use increases the recyclability of cartons. Removing the need for a silicone strip makes for 100% recyclable and biodegradable mono-material. To produce and seal cartons, companies are increasingly relying on reduced strategic application of adhesives. This requires a high level of precision and continuous quality control.

With its automated visual inspection system, OMRON supports accurate detection of glue patterns. The high resolution and brightness settings allow low-contrast defects to be detected, even in the toughest light conditions or when applied to difficult to detect materials.

Multi-material handling: Cardboard boxes made of recycled fibres have higher porosity and are more flexible. This makes it tricky to use traditional machines for manually unpacking and repacking boxes made of recycled cardboard without damaging them.

On the other hand, traditional palletising solutions are complicated to adapt and program, they take up a lot of space and cannot be relocated to another part of the plant. It is therefore advisable to have an integrated collaborative robot (cobot) solution with dedicated grippers, which can safely handle a wide range of irregular shapes and delicate objects with varying porosity levels.

OMRON offers a complete solution for sustainable packaging line automation that helps companies become more efficient and greener, utilising their machines for new recyclable materials and ensuring product quality.

And controlling the whole packaging sealing and labelling process is OMRON’s Sysmac, an integrated automation platform that provides complete control and management of automated plants. At the core of this platform, OMRON’s Machine Controller series supports synchronous control of all machine devices and offers advanced features such as motion, robotics and database connectivity.

This multidisciplinary concept allows the solution architecture to be simplified, reducing programming effort and optimising productivity, further contributing to advancing sustainability in the packaging industry.

www.industrial.omron.co.za

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