Impulse sealing is a way to heat seal thermoplastic. In fact, this process is only one of the many different methods that can be used to heat seal plastic. The term impulse sealing comes from the method that is used to generate heat. A plastic layer is placed on a large fixed coil. A burst of heat is generated and then followed with a burst of cool. This immediately seals and cools the thermoplastic to create a bond that is long-lasting.
In comparison to other materials, bonding plastic is usually much easier. The reason for this may be due to the fact that plastic features a greater degree of uniformity. Therefore, one area on a piece of plastic is difficult to distinguish from a different area on the same piece.
This means that when impulse sealing plastic, the material is basically melted onto itself. Because the area that is melted bonds to itself, it typically becomes more like a solid piece than a bonded joint.
With the majority of plastics, the preferred method of bonding is with heat. Often times, if chemical bonding agents are used it creates toxic fumes and does not work as well. Using heat is easier because it is simple to generate and will not produce any harmful waste. Because heat is so common, a number of methods using it have been developed to bond plastics.
Why Impulse Sealing is Best
When it is included in the process of assembly, there are a few common heat sealer types. A continuous heat sealer is an area that remains very hot throughout the assembly process. As plastics move across this area, they are heated and become bonded. While this method of heat sealing requires little oversight as a no frills technique, there is no guarantee that it will work correctly.
Spot sealing is another common heat sealing method that is commonly used at a manufacturing level. With this technique, a metal rod is kept continuously hot. As the plastic parts move by, they are touched in a specific area with the rod. Although this method is more accurate than continuous sealing, it is only possible to cover small areas at a time.
Impulse sealing is typically used in the final production process. This technique is used when manufacturers require several sheets of thermoplastic to be fused together. In some cases, the plastic sheets will contain additional substances that will be sealed into the layers. Regardless, impulse sealing seals an entire area all at once.