Advances in both material and energy efficiencies for vertical form-fill-seal (VFFS) technology are important to consider as we address issues concerning longevity, recyclable content, and practicality. With Ultrasonic Technology Vs. Heat Sealing, ultrasonic sealing technology increases efficiency and decreases the wastefulness of VFFS machines by replacing heat-sealing bars.
Although plastic ultrasonic sealing has been available since the 1960s, the packaging industry began to notice a trend toward ultrasonic film sealing around ten years ago. The potential for this sealing method to expand features in particular domains was a significant draw. Applying ultrasonic sealing to your pouch packing has several excellent advantages:
Ultrasonic Technology Vs. Heat Sealing
Higher Seal Dependability
When conventional heat seals encase liquids, oils, and other residue from some products on sealing surfaces, they become contaminated, leaky, or fail. In order to produce a stronger and more reliable seal, ultrasonic welding vibrates or cuts through any contaminants inside the sealing area before heating the surfaces.
Saving Energy
Due to their need for continuous power and precise temperature regulation, conduction heat-sealing systems are notoriously power-hungry. For instance, consider a factory with two packaging lines that can work nonstop for 16 hours straight and manufacture 100 welds every minute. Four 500-watt cartridge heaters—2,000 watts per hour or 32,000 watts per day—may be necessary to maintain continuous seal-bar temperatures during a conduction heat-sealing procedure.
Multiplying 200 ms for each weld by 100 wpm would give you an approximation of the daily power consumption of a similar ultrasonic welder, which would be roughly 24,000 watts due to the intermittent nature of the power usage. Such a welder would need a power source with a peak power rating of 1,500 watts. These examples show that even while running at full power, the ultrasonic heat-sealing process reduces energy usage by 25%.
Tangible Cost Reductions
In the case of small VFFS snack packs of 6-inch size, two standard heat seals, each measuring 0.500 inches on the top and bottom, occupy almost one inch of the total package length. Even though the net product volume is the same, the total length of the package for two identical ultrasonic welds is only 0.25 inches (0.125 inches on top and bottom). This results in a material savings of 0.75 inches per bat (0.375 inches x 2).
Sustainability
Manufacturers can consider biodegradable packaging materials like polylactic acid (PLA) when designing eco-friendly disposable containers. Commercial-grade sealing using biopolymers like PLA is more complex due to their lower polymer concentration. Packagers increasingly use ultrasonic welds to join such packages because they provide better melt control than heat seals, which only control four critical parameters—temperature, pressure, time, and form. Ultrasonic welding allows precise, programmed, and repeatable control over more than a dozen key welding or sealing parameters. Sealing precision promotes process reliability as well as adaptability.
Ultrasonic or Heat Sealing on VFFS Machines
We’ll walk you through the steps of ultrasonic sealing and help you decide whether it’s right for your products, just as we would for any of our satisfied customers.
Semi-auto Ultrasonic Plastic Sealing Machine MWPF-2
How Ultrasonic Sealing Work?
By using acoustic vibrations to produce molecular-level heat, ultrasonic sealing technology can effectively seal films. A sonotrode and an anvil work together to cause vibrations, which in turn cause the plastic’s molecules to migrate and melt. Cohesive or form-fit unions glue the components together, creating a molecular solid contact.
The absence of heat directly from the VFFS seal jaws, the most unique aspect of this process, protects the material from overheating. In addition, ultrasonic sealing is superior to other packaging methods for fresh fruit and other products that might get trapped in seals.
When it comes to packing, our goal is to discover the optimal answer for every issue. We’ve got you covered if you’re trying to select between ultrasonic film sealing and the more conventional heat sealing process for your pouches, bags, or other products.
Heat Sealing Machine
Sealing Width
When comparing ultrasonic sealing to heat sealing, one common argument is that the seal width disparity is much less with ultrasonic sealing. In fact, some estimates place the gap as much as 75% smaller with ultrasonic sealing. This leads many to believe that ultrasonic sealing is the gold standard in this industry. The difference, however, isn’t always as little as it seems when comparing the lengths of the seals.
The disparity in seal width was reduced to a mere 2 mm in one comparison.
So long as the actual length of the ultrasonic seal is 4 mm, considering the knife gap in both sealing methods, a 6 mm seal would be satisfactory. You may choose the heat seal option, as increasing the BPM rate was more significant than the 2 mm difference.
One benefit of heat sealing is a more secure seal, achieved by having a wider seal width. Conversely, less material waste might result from the smaller ultrasonic seal.
When choosing a seal width, it is also important to consider visual appeal. Some buyers, especially those looking for snack foods, may prefer a thicker seal. However, aesthetics are subjective; what works for one company may not work for another.
Bags Per Minute (BPM) and Overall Equipment Effectiveness (OEE)
When it comes to BPM, heat sealing is now on top. Heat seal technique often experiences gains of 40+ bpm above ultrasonic sealing. Although this rate might vary based on product material, film, equipment, as well as other factors when all else is equal, it exceeds ultrasonic in BPM.
Heat seal can keep up with or surpass bpm rates, even if ultrasonic innovation constantly improves. Consider how many bpm you’d want or need your machine to produce here.
The usage of ultrasonic conversion has enhanced the productivity of several businesses’ manufacturing lines. They highlight a few of these benefits:
- It takes no time for the jaws to become hot.
- After a manufacturing cycle, the jaws are not as hot, which might make them safer for the workers.
- For salads and other similar products, leaks are less of an issue.
Pricing for Ultrasonic Sealing
At first glance, heat sealing with servo-driven seal jaws is much more expensive than ultrasonic sealing technology. Ultrasonic sealing seems to start making up for it with its reduced use of energy and raw material utilization for certain goods and markets when looking at the complete cycle and ROI.
Think about how much money you will need to repair or replace components of the ultrasonic sealing system. It may cost roughly up to $2,000 to replace the jaws in a heat sealer if broken, which often happens during maintenance and changeovers or if they come into touch with hard objects like frozen peas or dry beans.
As new seal jaws may cost three to five times as much, changing the sonotrode that reacts with the anvil. This is to produce molecular friction can be just as expensive. Furthermore, the whole jaw carrier and sonotrode insert replacement cost is around 50% of the system’s overall cost.
Some sectors may find the expenses more than justifiable, but a few stand to gain the most from these changes.
Consumption of Energy
Ultrasonic Technology Vs. Heat Sealing energy consumption. Ultrasonic sealing takes the lead when it comes to lower energy consumption.
In terms of machine speed, the power consumption of ultrasonic sealing is almost insignificant. Ultrasonic sealing only uses energy, except for a few joules needed for the generator’s constant operation. Conduction sealing necessitates the continual heating of the bars. They release energy via convection and radiation even when they aren’t in use, or if nothing is sealed. The energy consumption for conduction sealing is directly proportional to the machine’s speed, which decreases as output rises.
Accordingly, the energy usage comparison improves as production increases. A lower production indicates a more negative trend. Consumption differences might be influenced by film kind as well. Regarding energy usage, ultrasonic technology is head and shoulders above the competition, regardless of the film type or production.
Revolutionizing Ultrasonic Sealing
Ultrasonic Technology Vs. Heat Sealing. One of the many benefits of ultrasonic sealing technology is that it works well with heat-sensitive goods. This may include cheese, chocolate, fruit, and vegetables. However, this may not be the most important issue when we look into it further. To ensure that these delicate goods remain structurally stable even when subjected to high temperatures, some vertical form fill seal machines may be customized with bevel plates. Ultrasonic sealing is finding more and more uses in the fresh fruit and salad industries. This is because it can seal through products.
When it comes to ultrasonic sealing, VFFS machines can switch between several ways. You can go from a heat seal to an ultrasonic seal. Perhaps even the other way around, just by swapping out the jaw.
The specific needs of your product should dictate the sealing method you use. Although being abreast of new developments and trends is critical, nothing is more important than selecting the right solution for the right task.
