3 Parameters for heat-sealing
The 3 parameters are equaly important for a perfect heat-sealing.
Perfection depends upon absolute control over every factor that affects the process. In addition to using a reliable and consistent source of polymeric materials, the sealing or cutting process must be designed to assure absolute repetition of the temperatures, forces, and timing employed. This is easily accomplished if the proper system components and design are employed. It has been well established that the most dependable and precise system of production is the most cost effective.
ROPEX Resistron RES Impulse Heatseal Controllers provide a reliable and consistent heat sealing of polymeric materials for sustainable packaging. Perfect Seals… Every Time.
Temperature - The ideal temperature for sealing and subsequent cooling of a seal depends upon the formulation of the material. Some polymeric materials have a relatively wide window of opportunity for successful sealing or cutting. Other materials may have very narrow seal temperature window. Never the less, every material combination has an optimum Time/Temperature/Force combination that will produce the highest production rate with quality assurance. The challenge, therefore, is to determine the optimum combination of these elements. Skilled system designers at Ropex GmbH. and Jørgen Bork Electronic ApS do this every day.
Sealing Force - Sealing force is one of the key elements in achieving the perfect seal. This too, varies with the nature of the material to be sealed and the optimum balance between time, temperature and force. Some materials are relatively dense and require only moderate force; others such as woven or non-woven fabrics require high forces to compress the material in order to facilitate the required seal or seal/cut.
Time - The old adage applies here. “Time is everything”. Perfect timing is achieved by the use of Ropex Resistron Controllers. The overall full cycle time determines the production rate and must be minimized to minimize production cost. If fifteen (15) milliseconds can be saved in a 1.5 second cycle, the production rate will be increased by 10%.
Using Ropex Impulse Heat-Sealing Technology, the full cycle time is divided between jaw close, seal heat, seal cool, and jaw release. Total cycle time can be minimized by constantly pre-heating the element to a temperature that is slightly below the required cooling temperature. This will minimize the time required to reach the optimum sealing temperature at each cycle, thereby shortening the total cycle time.
Because the temperature of the sealing element is always under absolute control, the heating cycle can be activated during the jaw closing time so that the heating element is at the ideal sealing temperature upon contact. The heat energy stored in the pre-heated element will be immediately discharged into the work piece upon contact, thereby further shortening cycle time. Further, the temperature of the heatseal band can also be monitored to open the jaws and release the work piece when the heatseal band has cooled to the desired release temperature.