The Big Three
By Andres Abreu and Mark Densley
Three ways to make packaging lines more sustainable with pneumatics and ultrasonic welding technologies
Sustainability is a high priority for today’s consumer packaged goods (CPG) companies. Driven by environmental responsibility, government regulations and customer preferences, CPG companies are actively seeking ways to decarbonize their packaging lines and use eco-friendly packaging materials.
Many have started monitoring the energy consumption of their equipment in real time and have upgraded critical areas of their packaging processes using two key technologies: pneumatics and ultrasonic welding.
While companies have long relied on the proven performance of pneumatic technologies in their packaging lines, the latest pneumatic devices feature specialized capabilities and connectivity that can help optimize energy use, improve overall equipment efficiency (OEE,) and maximize performance.
At the same time, ultrasonic welding offers greater precision, reliability and efficiency than traditional heat sealing, helping to minimize waste, improve packaging compostability and reduce energy consumption.
Here are three ways that CPG companies can incorporate these sustainability technologies to reduce the environmental impact, and boost the OEEof their packaging lines.
#1. OPTIMIZING COMPRESSED AIR USE
Compressed air is used to help operate equipment and power processes throughout packaging lines, including bottle production. While the prevalence of compressed air increases the potential for energy loss, certain tools can be used to optimize its use.
Not long ago, there was no reliable way to evaluate compressed air consumption, but the digital transformation of pneumatics has changed that.
Today’s smart pneumatic devices provide a more complete picture of pneumatic system performance, as well as actionable insights that give companies the ability to better understand and effectively control the energy use of their packaging lines.
Smart sensors, combined with an edge computing device, can continuously monitor system airflow and capture real-time flow, pressure and actuator speed.
When properly understood using edge analytics, this data can help companies detect leaks and optimize compressed airflow. The data can also help operators see the relationship between air pressure, flow and the speed of the actuator more clearly. By better understanding the true nature of this relationship, operators can determine the optimal point at which compressed air is used for their packaging processes.
If the analyzed incoming pressure is higher than the process requires, and more compressed air is being used than needed, operators can reduce the pressure and modulate airflow while maintaining the same cylinder cycle time.
By optimizing the amount of compressed air to meet operational requirements without affecting production, companies can minimize energy use.
In addition to optimizing compressed air use, monitoring software can also help operators detect leaks in near real time.
Once it detects a leak, the system sends an alert to maintenance personnel, who can then investigate the equipment in question.
This way, operators can address compressed air leaks much sooner, preventing compressed air loss and reducing emissions.
Companies that have implemented pneumatic solutions for early leak detection and optimized air consumption improve OEE and typically reduce their compressed air energy costs by ten to 20 per cent—shrinking their carbon footprint by up to ten per cent.
System monitoring can help reduce downtime as well. Companies no longer need to plan downtime and have technicians test each machine for leaks, making sure the leaks are sealed before they can cause fluctuations in system pressure.
Leak-related fluctuations can make machines cycle more than necessary, and this extra work wastes energy, prematurely wears equipment and components, and increases maintenance.
#2. PERFECTING PET BOTTLE PRODUCTION
The polyethylene terephthalate (PET) bottle is the most widely used bottling product in the world. It is so popular that about 3,500 stretch blow-moulding (SBM) systems are built and deployed annually to meet demand.
The latest systems combine the SBM (stretch blow moulding) process with the bottling process in one continuous production flow. This production system makes packaging lines more compact and reduces a bottler’s carbon footprint by eliminating the shipping step that occurs between bottle production and filling.
Pneumatic technology is a key part of the construction of SBM systems—powering several key areas of SBM machines.
Pneumatic air preparation systems improve efficiency and offer better control of the low- and high-pressure air that preform actuators and stretch blow bottle expansion steps use. And compact, high-performance blowing blocks provide bottle volume growth control through pre-blow, blow, recycling and exhaust functions.
Some suppliers have advanced SBM pneumatic performance, and sustainability, even further.
For example, one supplier offers a proportional control valve developed for the pre-blow expansion step in PET production that replaces an on/off high-pressure flow and revolutionizes this bottle production step. Whereas the previous on/off high-pressure flow set a uniform flow rate throughout the blow process, the new control modulates the flow to fine-tune each bottle’s expansion within the mould.
This advanced proportional valve technology combines a specially designed proportional valve, control electronics and software, which can either store the blowing sequence set points in the valve or respond to control directions from the programmable logic controller (PLC) that directs the blowing process.
The resulting bottle growth is intelligently modulated, giving end users the ability to perfect how the heated bottle expands within the mold.
The system can also capture feedback results for the quality of each blow, providing critical data needed by bottle manufacturers to perfect the process and minimize the number of rejected, wasted bottles.
It also provides condition monitoring data to support routine and preventive maintenance programs.
Proportional technology for PET blowing moves pneumatics to a whole new level of sustainability for this process.
It offers the potential to reduce material consumption with the capability to finetune bottle wall and shape formation, enabling thinner, more lightweight containers.
It also saves energy by potentially reducing blow air pressure required for high-quality bottle formation and by reducing the heating temperature in the pre-blow oven.
In addition to its energy saving benefits, proportional technology for PET blowing also enables the high throughput production of more complex bottle shapes, which is a critical marketing goal for bottlers.
It also increases manufacturing flexibility, since the process can be easily changed via software/PLC formula specific to each blowing station on the machine and fine-tuned for further improvement without stopping production.
#3. IMPLEMENTING ULTRASONIC WELDING
To make sealing applications greener, ultrasonic welding offers many advantages compared to traditional heat sealing.
It is precise, reliable and efficient—allowing users to reduce energy consumption, minimize product and packaging waste, and improve packaging recyclability and compostability. It also can be used confidently to seal biodegradable materials.
This sustainable technology can ultimately cut energy use by up to 25 per cent and reduce carbon footprints by up to 75 per cent.
Ultrasonic welding systems simply use less energy than conduction heat-sealing systems by consuming energy in short bursts rather than continuously, like conduction sealing processes.
For example, to complete 100 welds per minute over two eight-hour shifts per day, a typical conduction-sealing system needs four 500-watt cartridge heaters (2,000 watts per hour or 32,000 watts per day) to constantly maintain its operating temperature.
On the other hand, an ultrasonic welder performing the same operations would be equipped with a power supply rated at just 1,500 watts and is only energized in short bursts (e.g. 200 ms per weld), consuming power for just 20 seconds out of each minute of production.
Ultrasonic welding is also more compatible with bio-based materials, such as polylactic acid (PLA), than traditional heat sealing.
Because biopolymers contain significantly less polymer content, it can be difficult for the simple time, temperature and pressure settings of a heat sealer to reliably bond this type of material and achieve a commercial-grade hermetic seal.
The precision and control characteristics of ultrasonic welding make this technology far more capable of managing the narrower processing windows of bio-based resins.
Ultrasonic welding produces high-quality, consistent package seals without adhesives or consumables.
The plastic-to-plastic bond it creates not only simplifies package design, but, since there is no contamination within the seal surface, it also improves material recycling and/or compostability.
In addition to creating a more reliable seal, an ultrasonic weld can reduce packaging material consumption as well as eliminate seal failures due to contamination.
Ultrasonic welds require only 0.25-inch of total package length when sealing the ends of small snack bags, while conventional heat seals consume about one inch. In this way, ultrasonic welding uses 0.75-inch less of material to complete a high-quality seal than heat sealing.
Ultrasonic welding also prevents seal failures due to contamination at the seal interface by package-fill residue.
The high-frequency, vibratory motion (usually 20, 30 or 40 kHz) of the ultrasonic welder actually drives residue out of the seal area.
Conventional heated tools, in contrast, often encapsulate these residues, making leaks or failures more likely.
Consumer packaged goods companies have long counted on pneumatics for effective, reliable production of packaging as diverse as soda bottles, cereal boxes, single-serve snack pouches, and pharmaceutical blister packs.
And the latest advances in pneumatics, including the digital transformation of the packaging line, promise even greater benefits.
At the same time, ultrasonic welding is making the sealing process substantially greener.
The right technology will power more compact and environmentally friendly packaging lines.
However, it is important that CPG companies work with an automation expert that understands these new, smart pneumatic and ultrasonic technologies if they want to achieve their most ambitious sustainability and performance goal of significantly reducing their carbon footprint—all while considerably improving OEE.
Andres Abreu is packaging business development manager for assembly and welding, and Mark Densley is director of business development of factory automation at Emerson, a global technology and engineering company providing innovative solutions for customers in industrial, commercial and residential markets.
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