System Integration & Control Systems Design

The role of ‘green’ packaging in sustainable manufacturing

April 2022 System Integration & Control Systems Design

In these times of increasing sustainability efforts, it is essential to find ways to develop more environmentally-friendly packaging, conserve resources and rely on smart and more efficient production lines. Holistic concepts are needed for effective implementation of these efforts.

There 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. Another problem is that plastics often contain additives that make them stronger, more flexible and durable. However, many of these additives extend the life of products when they become waste, with some estimates of at least 400 years until decomposition.

In this context, the packaging industry is one of the main contributors to this plastic glut, which urgently needs to be minimised. The industry faces the mammoth task of developing sustainable alternatives, as well as minimising waste while saving energy and using alternative energy sources.

Five pillars of sustainable packaging

The first key point to consider for more sustainable packaging is the reduction of packaging material, not only in terms of virgin plastic content in primary packaging, but also in the amount of protective secondary and final packaging.

Another point to work on is to eliminate the need for single-use packaging. Some strategies to tackle this issue start with increasing the use of reusable and refillable systems, and redesigning packages with alternative materials that facilitate recycling, are biodegradable, compostable, or have less of an impact on the environment if they end up in a landfill.

Packaging made from mono-materials is another strategy attracting increasing interest within the packaging industry. They have better recyclability but migrating to them could be a challenging process that requires strict process control, since in many cases packaging equipment needs to be adapted or customised to achieve an advanced form, fill and seal process that ensures the same package quality and performance.

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

New requirements for production facilities

As mentioned, one of the strategies for more sustainability in the packaging industry is to reduce the amount of plastic, especially if it is virgin (in other words, containing no recycled material). A key tactic is to shift away from rigid to flexible packaging. Thinner walls, smaller sizes, narrower seams and lighter weights are good ways to reduce the amount of virgin plastic used in the primary container.

Additional to this is the use of mono-materials (paper-based and biopolymers) as well as an increase in the proportion of recycled material in main packaging, protective and transport packaging (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 and linking and managing of new machine-to-machine information is required. It is also necessary to control the performance of the machines under the new conditions and to avoid waste as much as possible.

Switch to new materials, ensure quality and safety

If more sustainable materials are used in packaging, it is still of the highest importance to ensure the quality of the product. At the manufacturing line, changing to more sustainable materials means avoiding typical problems in the primary package, like material jams or tears, poor-quality sealing or incorrect labelling. Paper-based materials have a different tear and puncture resistance, which implies more precise control in package forming. Shrink film made from recycled plastic has very different properties compared to film made from virgin materials, demanding versatile but accurate shrinking temperature control.

There are other aspects to consider in secondary packaging that are achieving more traction lately. Reducing the melting points of adhesives when erecting and sealing cartons, implementing material reduction strategies (including lightweight corrugated materials), or unpacking and repacking the contents of a pallet with cartons made from more sustainable cardboard and alternative materials, are some of these aspects.

All these strategies to make the packaging more sustainable require careful analysis to identify the point(s) along the line that would need to be updated to ensure the quality and safety of the product. What is needed is future-proof manufacturing with automation and robotics technology that can work flexibly with different materials. The following points describe specific challenges that companies should look for.

1. 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 increase the tension on the film. Uneven tension, in turn, causes defects during pouch forming or sealing, such as curling, ripping, folding, or sideways shifting or 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 stuck 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 Omron Packaging Library offers a wide range of function blocks for film processing in VFFS (vertical form, fill and sealing) machines.

2. 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 productivity declines or sealing defects that will generate 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.

3. 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 proportion of 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: this simple and scalable system is suitable for multiple lines and transparent integration with robotic systems. It 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.

4. New adhesives and gluing techniques

Eliminating tapes and minimising adhesives increases the recyclability of cartons. Removing the need for a silicone strip makes it 100% recyclable and biodegradable. To produce and seal cartons, companies are increasingly relying on strategic and reduced 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 with difficult-to-detect materials.

5. Multi-material handling

Cardboard boxes made of recycled fibres have higher porosity and are more flexible. Using traditional machines or unpacking and repacking manually, the handling of boxes made of recycled cardboard can be tricky in terms of avoiding damaging them. Traditional palletising solutions are complicated to adapt and program, they take up a lot of space and cannot be relocated to other parts of the plant when needed. It is therefore advisable to have an integrated collaborative robot (cobot) solution with dedicated grippers to safely handle a wide range of irregular shapes, porosity levels and delicate objects.

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. Sysmac is an integrated automation platform that provides complete control and management of the automation plant. At the core of this platform, the 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 users to simplify the solution architecture, reduce programming effort and optimise productivity.


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