New ultrasonic cross direction module – to weld ultrasonic cross seams for pull-ups even faster
Good to know: The trend towards training pants is increasing; especially in the Asian markets where training pants are almost solely being sold. In the Western part of the world, pull-ups are gaining popularity. The worldwide demand for incontinence products cannot be underestimated either. In this segment, the training pants are part of the clothing and any adhesives or hard weld areas are undesirable. The main benefit of ultrasonics is that no adhesives are used.
This makes the production process clean and controllable, leaving the potential for skin irritation is practically ruled out. The seal softness and visual appearance achieved with the ultrasonic welding of nonwovens layers is unrivalled, one of the major reasons almost all manufacturers are opting for ultrasonics with regard to side seams in training pants, also referred to as “cross seam”.
At IDEA ultrasonic welding specialist introduces an innovation for ultrasonic cross direction for which three patent applications have been filed. The new inline process ensures higher production speeds required by the markets, producing standard deviation rates of almost zero between the first and second seals, even with multi-layer changes.
The engineers have developed a new ultrasonic module designed for intermittent cross seal applications with a primary focus on training pant diapers. This system has become more rigid overall; with optimized control of the amplitude peaks, frequency shifts and with finite measuring and control technology. Due to new software and modifications within the generator and the controller, the process can now be optimized even more and the force can be controlled more accurately.
To put it plainly, the system now knows exactly when to expect the cross seal. All these aspects result in significant reduction of problematic deviations from standards between the first and second seal. Deviations often represent a loss in quality. Another contribution to the improved parameters can be attributed to the modified anvil drum design.
In field tests and initial customer test installations, the new ultrasonic module has proved to be robust, meeting the requirements below:
• Machine speeds > 250 m/min
• Consistent seal strength
• Welding of multi-layer materials with varying layers (4 - 8)
• Attractive visual appearance and softness
Overall the new Herrmann Ultraschall process, known as “Cross Direction” is stable, repeatable and has become significantly faster. Hygiene manufacturers can now opt for a cost-effective machine with profitable speeds. At IDEA Herrmann Ultrasonics shows various ultrasonic processes at booth 1621.