With high hopes for the beverage consumer industry Xolution, a German think tank company, has introduced a new resealable opening mechanism for cans.
Beverage manufacturers can now offer resealable containers with a tremendous increase in convenience for consumers. The complete lid is assembled by the Austrian company Alpla, who use the ultrasonic systems by Herrmann Ultraschall for the ultrasonic process steps.
The can is sealed with a slider functioning as tamper-proof opening. It can be easily opened and, due to a special seal insert on the bottom side of the lid, resealed completely tight. For an economic assembly process of these types of lids, high counts must be produced.
To connect the plastic slider on the inside with the plastic slider on the outside of the can through the aluminum end, it was required to find a fast and precise joining technology. In ultrasonic welding, the molecules are heated up and joined extremely fast due to ultrasonic vibrations. A heat-up phase of the tool is not required and the cool-down times for the parts are shorter than with any other thermal joining process, thus reducing the cycle times. Process cycles, including hold times, are often less than half a second. Another advantage of this technology is the accuracy of process control realized by means of the ultrasonic generator. It is possible to precisely define the energy for generation of the melt in terms of duration and location and to transfer it accurately. In this way, the four small pin domes are staked fast and tightly in the first process step. In the second process step, staking of the tamper-proof opening is performed.
Carbonated beverages develop high pressure and thus present high quality demands for connection of the plastic seal parts. In ultrasonic welding, the software-controlled generator technology allows for precise monitoring and adjustment of the process window. The inevitable but low degree of heat-up of the weld tool at high cycle rates can be monitored and compensated by the generator. During pre-commercial development, the speed of action of the manufacturing environment and the cycle rates were simulated, and the zero-tolerance quality of the welded staking domes, suitable for the high pressure inside the can, was proved in the ultrasonic lab. Pressure stability of the can is more than 7 bars if unopened and more than 5 bars if resealed.
Marc von Rettberg, CEO Xolution, is content with the implementation of the innovative design and with the selection of project partners. He welcomes collaboration with Alpla and Hermann Ultraschall and considers it positive and promising. But there is another fact important to him: packers can buy the pre-assembled can lids with opening mechanism and process them in their existing filling lines. This means that, in fact, no large investments in machinery are required, just the unpacking of the sleeves will have to upgraded if needed. Xolution was founded in 2003 and provides innovative beverage packaging.