To make sealing applications greener, ultrasonic welding offers many advantages compared to traditional heat sealing. Its precise, reliable capabilities and efficiency allow end-users to reduce energy consumption, confidently use biodegradable packaging, minimize product and packaging waste, and improve packaging recyclability and compostability. This sustainable technology can ultimately save energy by up to 25% and reduce carbon footprints by up to 75%.
Ultrasonic welding systems simply use less energy than conduction heat-sealing systems. Ultrasonic welding processes consume energy in short bursts compared to the continuous energy supply that conduction sealing processes require to complete the same production capacity. For example, to complete 100 welds/min over two eight-hour shifts per day, a typical conduction sealing process needs four, 500-watt cartridge heaters (2,000 watts/hour or 32,000 watts/day) to constantly maintain its operating temperature, while an ultrasonic welder of the same capacity would be equipped with a power supply rated at 1,500 watts but would use power in short bursts (e.g., ~200 ms/weld) totaling about 20 seconds/min of total power consumption.
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 biodegradable, single-use packaging and achieve a commercial-grade, hermetic seal. However, the precision and control inherent to ultrasonic welding offers far more capability to manage the narrower processing windows of bio-based resins. (Image 5)
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, also improves material recycling and/or compostability.
In addition to creating a more reliable seal, an ultrasonic weld can reduce packaging material consumption and eliminate seal failures due to contamination. To reduce packaging material consumption, ultrasonic welds require only 0.25-in. of total package length when sealing the ends of small snack bags, while conventional heat seals consume about 1.0-in. Comparably, ultrasonic welding returns 0.75-in. of package length.
To prevent seal failures, the high-frequency, vibratory motion (usually 20, 30, or 40 kHz) of the ultrasonic welding process vibrates potential residue out of the seal area that conventional heated tools often seal in. Because encapsulation of these residues results in contamination, leaks, or failures, the clean weld that ultrasonic welding achieves reduces waste while improving seal quality and repeatability. DW
Filed Under: Packaging