What is an impulse sealer used for

Posted by Damian Roberti on

What is an impulse sealer used for

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What is an impulse sealer used for

Understanding the fundamentals of sealing, including the distinctions between sealing with continuous heat, ultrasonic heat, and impulse heat

Sealing coated papers, film and foil laminates, MIL spec barrier bags, and other materials that are thick or made up of multiple layers are the primary uses for constant heat sealers. The sealer seen in the image has an upper sealing jaw that is both temperature regulated and heated continuously. The heated seal jaw has a shield placed over it for your protection. These sealers produce seals that are either wide, flat, or serrated, and they are designed to be used on bag materials that do not require chilling while the bag is under pressure. 


 

 




What is an impulse sealer used for



Sealing systems that use impulse heat bar sealers are by far the most frequent type. They are exceptionally risk-free and perform admirably with a wide range of substrates. During the heat cycle, the heating element that is located on the top and/or bottom of the sealing bar is heated for a preset amount of time or to a predetermined temperature. Following the conclusion of the heat cycle, the beginning of the cooling cycle will occur.

 

 

 

In this position, the jaws provide pressure on the seal in order to maintain it while the material regains its strength and shape. Impulse heat bar sealers are well-known for their capacity to make hermetic seals that are uniform and consistent even in the poly films that are most frequently utilized. (Demonstrated: Impulse Heat Bar Vacuum Sealer by Packaging Aids)


 

 

What is an impulse sealer used for


In order to satisfy the growing demand in the flexible packaging business, manufacturers have been producing an increasingly diverse range of heat sealers in recent years. There are just three typical ways for heat sealing: impulse sealing, direct or steady heat sealing, and ultrasonic sealing. While there is a wide selection of highly specialized sealing devices from which to pick, there is a far smaller selection of heat sealing methods. To assist the customer in making the decision that is optimal for their specific use case, it is important for them to have a solid understanding of the many benefits and potential pitfalls associated with each technique.


What is an impulse sealer used for

Sealing by impulse heating

 

 


Impulse heat sealing is a technique that is frequently utilized for the purpose of combining thermoplastic materials such as polyethylene and polyurethane, both of which need to be heated to a relatively low degree in order to form an effective seal. This adaptable approach can also be used to seal Mylar and Tyvek® bags, pouches, and tubes, in addition to a broad variety of other bag, pouch, and tube materials. Impulse sealing is a common method that is utilized in the process of securing the seal on multi-layer, metalized, and oxygen barrier pouches and bags. An impulse heat sealer, when properly constructed, has the ability to fuse together two sheets of fairly heavy thermoplastic materials.


 

 


Impulse heat sealers may feature one or two replacement heating elements made of a specialist material - typically a Nichrome alloy - situated in the top and/or bottom of the sealing bars. These heating elements can be round or flat and can be found in the impulse heat sealers. The element of Nichrome is protected by a Teflon fabric that is wrapped around it, a heat-resistant and elastic rubber cushion, and another Teflon fabric. After the materials that need to be sealed have been positioned within the sealer jaws, the jaws will close, and either pneumatic or mechanical pressure will be used to keep them in place. The Nichrome element is then briefly heated by an electric current for a predefined amount of time in order to reach the required temperature for sealing.


 

 

 

 

After the heat cycle is through, the jaws continue to hold the work piece in position (again, for a specified amount of time), which allows the material that was welded to fully cool and fuse together before the jaws are released. The temperature, amount of pressure, and amount of time that must pass between each step of the heat sealing process are often dictated to a large extent by the material that is being utilized.

What is an impulse sealer used for


The fact that impulse sealing has an inherent level of safety is one of its many benefits. Only when the sealing jaws are closed under pressure and the sealing element is powered will there be a significant amount of heat produced. Because of this, it is quite unlikely that one may suffer burns if they come into contact with the jaws used for sealing. After hours of continuous usage, the jaws may store a little amount of heat due to residual friction, but the temperature is never allowed to reach a level that could be harmful. Impulse sealing is capable of accomplishing all that continuous heat is capable of accomplishing since the temperature of the seal wire may be controlled.

 

 

 

 

The fact that the user is able to manage the cooling cycle while the material is still contained between the sealing jaws and under pressure is one of the primary advantages of the impulse sealing method. One additional benefit of using impulse sealing is that it results in lower running expenses. There is a potential decrease in power usage due to the fact that the sealing elements are only activated for a very brief amount of time during each sealing cycle. Last but not least, in contrast to constant heat sealers, impulse sealers allow for the regulation of cool times and do not need a "warm-up" period before they may reach their operating temperature.

What is an impulse sealer used for

 

 


Constant heat sealing

In contrast to impulse sealing, which involves a rapid increase and decrease in temperature at the seal bar, constant heat sealing involves the maintenance of a higher and more consistent temperature at the sealing jaws. As a result, this method is better suited to the sealing of certain thermoplastic or poly-coated materials. Two sheets of thermoplastic material can be joined together using a constant heat sealer, provided that the material does not overheat, which would cause it to become fragile and thin. In the same way that impulse sealers do, constant heat sealers have one or two heated sealing bars. However, in contrast to the impulse method, the constant heat sealers maintain the specified sealing temperature for the whole time the bars are in use. Constant heat sealers are able to maintain an accurate degree of temperature control in the sealing bars once they have achieved their operating temperature. Even though the seal bars on current constant heat sealing machines stay hot, most of these machines incorporate protective barriers that are intended to decrease or even eliminate the risk of burn damage. Sealers that use constant heat do have some advantages over sealers that use impulse heat. If an impulse sealer does not include a temperature controller, the repeated heating and cooling cycles can cause the sealing element to become stressed and deformed. This can be prevented by using a temperature controller, which also slows the wire's deterioration. Sealing using constant heat can help limit the amount of expansion and contraction that occurs repeatedly. When working with particular materials, such as the numerous multi-layer Mil Spec bags, for example, consistent heat sealing is the method that is recommended since heat is readily available when the temperature is elevated.


 

What is an impulse sealer used for

Sealing with ultrasonic heat waves

In the 1960s, a method known as ultrasonic sealing was invented. This method involves applying pressure and high-frequency vibrations to two pieces of material (often stiff plastic) in order to create a seal or weld between the materials. Although it is not used in the flexible packaging industry, ultrasonic sealing is frequently used for joining plastics components in the automotive, aerospace, and consumer products industries as well as in many other industrial applications where rigid plastic is required. This method is not used, however, in the flexible packaging industry. The capacity to join different materials with ultrasonic sealing is one of the benefits of using this technique. This includes the ability to bond plastic to metal and plastic to carbon fiber materials. In order for ultrasonic sealers to successfully attach the materials, it is necessary for all three of the primary components to resonate and interact at the same specific ultrasonic frequency. The transducer (also known as a converter), which converts an electrical signal into a physical vibration; the booster, which controls or modulates the vibration; and the sonotrode, which actually transmits the vibration to the work pieces, are the three essential components. The transducer transforms an electrical signal into a physical vibration. Because ultrasonic sealing has a low thermal impact on the work piece, it is possible to join a wider variety of materials than traditional joining methods, which typically involve the use of adhesives or solvents. Ultrasonic sealing also has the advantages of being cleaner and faster than traditional joining methods.


What is an impulse sealer used for


Integrity of the seal and strength of the joint

Seal integrity and join strength testing can be done in a number of different ways, and the level of rigor of the test might vary depending on the unique requirement. This is an important factor in the industry that manufactures medical devices. It is essential to point out that there is room for misunderstanding regarding the difference between what constitutes seal strength and what constitutes seal integrity. The integrity of a seal is not necessarily correlated to how strong the seal is. This is owing to the fact that a seal that passes a specified strength test may not establish the microbiological barrier (due to the presence of channels and spaces in the seal), which is necessary for the packaging of sterile barrier devices. Bags and pouches that have been heat sealed can be put through tests to determine their pull strength, ability to maintain a vacuum, burst strength, permeability of the seal, and capacity to keep a seal while being subjected to sterilization treatments, amongst a variety of other criteria. ASTM F88/F88M-09 (seal strength test), ASTM F2054M-13 (burst testing), and ASTM F1140/1140M-13 are the documents that explain the techniques that are currently considered to be the industry standard for sterile barrier testing (whole-package, internal pressurization). While it is possible to seal any bag with an impulse sealer, steady heat can only be used on materials that do not melt when they are heated.



Heat seals are produced on a daily basis at a rate of millions of times all over the world. Your grasp of the precise techniques, methods, and materials required to achieve a good quality seal for your individual application is essential to the success of your sealing processes. This information is required in order to achieve a successful seal.