In terms of types of heat sealing, there are primarily three categories that may be customized in several ways: constant, impulse, continuous heat sealing.
Types of Heat Sealing: Heat Sealing Technologies
(A) Constant Heat Sealing
Instead of impulsing the use of heat, this heat-sealing technique depends on maintaining a consistent temperature for the seal jaws.
This technique has some benefits over the impulse sealing approach, particularly with laminated or multi-layered materials, but it isn’t always appropriate for all kinds of materials because of the persistent heat. The increased strength and thickness of such material allow for a more rapid processing time. The only parts of these multi-layer materials that are likely to fuse and form a seal are the inner, pressed-together surfaces.
Jaws that are constantly heated might be more sturdy and less complex. With continuous heat tools, more power is necessary to heat the jaw’s bulk and offset the heat loss via the mounting and neighboring machine parts.
(B) Impulse Heat Sealing
A static application finds success when two film layers are held together using two seal jaws. A non-stick coating keeps the heating components in place while the seal jaws shield them from heat and electricity. A heating element, which produces heat as a result of its resistance, carries an electrical current tha heats the film layers. This creates a weld when the layers of film fuse together.
In most cases, after the process of sealing is complete, the film material is cooled down to restore its original features.
To have a strong weld, you have to be cautious around the edges, where the hot and cold materials contact. In the event of a sudden shift, the seal’s effectiveness may diminish. The clamping force applied to the seal jaws also influences the possibility of material extrusion from the seal area, which may have a thinning impact. Reduce the size of this transition zone to the absolute minimum required for a more robust seal.
Cutting and sealing are two areas where the extrusion effects might be useful. Heat is applied to the heating element so that it forces the film material out of the seal area. Consider the use of a pointy ‘V’ form as an example.
As a general idea, the impulse sealing approach provides the most flexible options for getting the job done. However, because of the high speeds of the machines, this might not be practical for many applications. Although heating elements may take on a variety of forms and curves, the resistance must remain constant throughout the contour to provide uniform heating. Typically, they have a straight-line design.
Time Control Impulse Sealing
It may be enough to use a time control when dealing with inexpensive installations or applications that do not need a lot of speed. The real temperature is neither measured nor monitored; instead, a certain current flow is applied to the heating element for a specific amount of time.
The use of an electronic controller provides a much better alternative. These controllers determine the temperature in degrees Celsius by using the heating element’s temperature value and its capability to alter electrical resistance in response to its real temperature. An extra sensor is not necessary with this setup.
An integrated temperature controller ensures a consistent quality sealing seam every time. Because it is possible to maintain a consistent temperature for a certain period while dealing with thick film materials, control of temperature is practically necessary. Longer service life is an additional advantage.
(C) Continuous Heat Sealing
With continuous sealing, you have a lot of choices.
Circulating bands grasp and transport the materials as they pass across two film layers. In order to transfer the material between two seal jaws that heat and clamp down on it, these bands must move in time with the film layers. Moving from the hot zone to the cold zone, the material stays trapped between the bands the whole time. You may adjust it so the substance cools and returns to its original state.
Though this technique works for the majority of materials, there are a few drawbacks: the bands wear out quickly due to friction and wear, and heat has to travel through them to reach the material.
A heated wheel works just as well as heated bands. While this technique does away with the bands, it does not clamp the film material as it cools.
Although there are some challenges to using air to convey heat, the use of the correct technology may lead to good outcomes. There shouldn’t be any resistance because the material isn’t touching the heat generator. To optimize the seal’s quality and function, make sure the material layers contact and apply the correct tension.
This method also allows for a cooling phase to follow the heating phase, allowing for a more faster material cure. Operating speed drops dramatically as material thickness rises for various applications because heat transfer is restricted by a lack of contact pressure.
What type of heat sealing does the tube sealing machine use?
When it comes to tube sealing technology that a tube sealing machine uses, hot-air tube sealing is by far the most common choice. The machine works by creating a vacuum. It then forcing hot air into the plastic or laminate tube through its open end. This heats air to a point where it may pass through the plastic tube wall, softening and pliable the material.
You’re on the right track to finding out more about heat sealing and types of heat sealing. This is Your Ultimate Guide to Tube Sealing Machine to complete your research!