Types of sealers and how to choose them

Sealers are used in a variety of situations, such as packaging confectionery and separating industrial parts into smaller packages. Sealing plastic films by heat welding is very useful in the food industry because of its high hermeticity. Since each product has different features, such as usage and functions, make sure to select the one that best suits your application.

What is a sealer?

A sealer is a specialized machine for sealing the opening of plastic film packaging. The term ‘sealing’ refers to sealing the opening of polyethylene or polypropylene bags by welding the opening with heat, such as by using a heater, etc.

Since sealers allow anyone to seal easily, they are used in various fields, including the food industry. Major applications include individual packaging of confectionery, preservation of dry goods, packaging of clothing, subdivision of parts and precision machinery, and degassing packaging. It is widely used as an alternative to rubber bands, staplers, and cellophane tape. There are several types of sealers depending on their shapes and functions. There is also a feature in how to use it, so make sure to select it according to the use and purpose. The selection points are introduced below.

Select by shape

The shape and size of the sealer will determine how it is used and how easy it is to use. Select a sealer that is appropriate for the shape and size of the object to be packaged, the environment in which it will be used, and the intended purpose.

Clip type


This type is compact, lightweight, and easy to use. Grip the handle like a clip and sandwich the bag to weld it. It can seal from any angle, so it is recommended for sealing small bags and complicated shapes. A cordless type is also available.

Pen type


This type is also called ‘roller type’ because it has a roller for welding at the tip. The pen type can easily weld the part to be sealed by simply tracing the area to be sealed like a pen. Therefore, it is suitable for sealing irregularly shaped or three-dimensional objects.

Desktop type


This is the most versatile and common type. This is an ‘instantaneous energizing type (impulse type)’ in which a large current is instantaneously sent to the heater to generate heat for welding. Anyone can easily seal products by lowering the crimping lever on the top with one hand and clamping the bag.

With table


Place the bag on the small table attached to the machine and push down the table to crimp the bag. Since the bag can be sealed while being held with both hands, more delicate work is possible, such as adjusting the contents evenly and fine-tuning the sealing position. It is suitable for individual packaging in stores and packaging work in factories.

Ultrasonic type


This type uses ultrasonic vibration to generate strong frictional energy on the film for instantaneous adhesion. There is no risk of burns because the adhesive is made using internal heat generation. Since it is suitable for pinpoint bonding and can bond most plastics, it is also used instead of staplers for food packs and the like.

Select by function

There are types of sealers that simply seal and types that also cut at specific positions. Understand the difference between ‘welding’ and ‘fusing’, and choose the type with the function you need.



This type specializes in welding, which is a common function. Melt the film along the heating wire and adhere firmly. The advantage is that the width of the sealing portion is as wide as 2.4 to 10 mm, which ensures a reliable seal. However, the excess portion must be cut by hand or other means.

Welding + Cutting


This type of sealer is a welding type sealer with a cutter function. After welding, slide the built-in cutter to cut off the excess portion. You are recommended to choose this type when you want to seal tightly and cut roughly. This type is used for sterilized roll packs, etc.



This type welds the film along the heating wire and cuts the film along the line at the same time. When the bag is cut with a cutter, the cut end is welded. The advantages of this method are that it can make bags of different sizes according to the packaging and that the cut edges are clean.


Determine the best type in terms of both shape and function, and select the sealer best suited for your application. The thickness and bag width of the overlapping plastic film to be sealed are also important selection points.