Clients often ask which sealing system we recommend they use with for a particular application. Whether if a the type of sealer is more suitable for one application or the other depends on a variety of factors such as the type of bag, the product being packaged, production levels, industry and product specific packaging standards, and the customer’s preferences, among others.
 
This guide offers basic information on the subject of bag sealers for sealing bags made of thermosealable materials. The topic of bag materials is further discussed in our guide “Packaging Materials: Bag Types and Their Applications”

Impulse Sealers

Impulse Sealers are inexpensive, easy to use, and can seal bags of most varieties (PE, HDPE, LDPE, PP, BOPP, MOPP, OPP, PVC, Most Laminations, Cellophane). They come in two configurations: Manual Sealers (sometimes known as Hand Sealers), and Pedal Sealers (also called Foot Sealers). These machines run a timed impulse of electricity through a heat element which fuses and seals the bag. The heating process can take anywhere from a fraction of a second a few seconds, depending on the thickness and seal qualities of the material being sealed. Manual and Pedal sealer operation require involved handling from an operator, and generally only one bag can be sealed at a time. Thus, they are used in applications where speed is not at a premium.
Some Pedal Sealers come equipped with a printing coder that will print numbers and/or letter onto the bag simultaneous to the sealing process. Other Pedal Sealers use powerful electromagnets and timers to automate the rhythm of the packaging process. Pedal Sealers may also come equipped with dual seal elements (one seal element on the top and bottom jaw) when the product to be sealed is especially thick, or when the material needs very high temperatures to seal.
The seal of impulse sealers tends to be fairly thin, offering anything from hairline seals produced by using round heat elements (preferred in shrink packaging processes) to 2 ~ 5 millimeter wide seals produced by using flat heat elements.

 A note on sealing Shrink Films with Manual Sealers

Some vendors often market hand sealers equipped with flat sealing elements as shrink film sealers. This claim is incorrect, as sealers configured in this manner are not designed to cut shrink film. Shrink film sealers are equipped with round heat elements to seal and cut the shrink film. Customers who buy machines with flat elements are told to increase the sealing time and pull the material to separate the bag from the rest of the plastic. This results in an unsightly seal that often breaks, consumes more power, and produces a high rate of wear on the sealer and its components. Thus, when buying a shrink sealer for low production levels make sure it is equipped with round sealing elements.

Constant Heat Sealers

 These machines are widely used as they are inexpensive an easy to use. They offer a great-looking, extra wide seal that is perfect for food products and other applications that require extra secure sealing. Constant heat sealers sandwich the bag between two pre-heated metal bars. The temperature of these bars can be adjusted depending and the seal characteristics of the material being sealed. These sealers should not be used to seal Polyethylene (PE, HDPE, LDPE) as they lack Teflon coatings. The seal process can take a fraction of a second or more. One important difference between Impulse sealers and Constant Heat Sealers is that in the latter the operator ends the seal process, as the seal time is not controlled by the machine. Although available in hand-held versions, Constant Heat Sealers are typically used in a Pedal Sealer configuration, similar to the Pedal Impulse Sealers. These sealers require the involvement of the operator thought the seal process, thus are not capable of handling high speeds.

Band Sealers

Band Sealers come in a variety of sizes and configurations, and are used by commerce and industry to seal large bag quantities quickly and uniformly. These versatile machines can seal bags of all types. They are called band sealers as the top or mouth of the bag is held between two bands. These bands typically made of fiberglass infused in Teflon, but can be found with metal and rubber bands. Band sealers come in Vertical and Horizontal orientation. Vertical orientation is preferred if the bagged product flows out of the bag if tipped (ie. Powders, grains). Horizontal Sealers are used when the product can be laid on its side.  Many come equipped with a conveyor to hold the weight of the product. Clients often choose to purchase Band Sealers that are equipped with printing coders, which print characters (ie. Expiration Dates, Lot Numbers) onto the bag.