When looking at different methods of heat sealing it is first important to explain the difference between the two most common heat deliveries used in heat sealer machines. Constant and impulse.
Constant heat sealing is just that, a constant delivery of heat. Essentially the heat is applied onto the packaging film from the sealer bars at an operator set temperature for as long as required. We usually see this method used in handheld machines as it is preferred when sealing heavy duty, multi layered laminate packaging.
The next and most common is impulse heat sealing. Impulse applies heat onto the packaging film from the sealer bars in a timed pulse. This allows for consistency and reproducibility, because the temperature is pre-set and the heat application timed. The packaging weld is optimal with each seal cycle, and less exposed to the operator error that comes with constant.
Methods of heat sealing are also decided by machinery type too.
Different devices, platforms, configurations, and mechanisms of action are all different methods that each suit different types of sealing work.
A continuous band sealer machine will suit high volume pouch sealing work more than a handheld heat sealer will.
Though a hand held, portable machine can seal pouches it is far more suitable for large or awkwardly sized packaging that needs to be easily manoeuvred around. Think 1 tonne bulk bags, FIBC liners, Octabin Packaging, Gaylord Liners and export packaging.
A vacuum sealer machine will both extract the air from packaging and seal in once cycle. The vacuum sealing method is perfect where shelf life and preservation are key drivers.