Choosing Heat Sealers For Secure Packaging

What are Heat Sealers?

Heat sealing machines, also called bag sealers, direct heat sealers, and heat impulse sealers, are used to wrap and seal items such as food and any other materials that need to be protected from bacteria, air, and pollution. With a special heat sealer, the task of secure wrapping can be undertaken in no time. When choosing a heat sealer for your particular needs there are certain basic things to consider such as the size, type, packaging material, and speed of the machine.

Types of Plastic Bag Sealers

Heat sealing machines fall into two main types based on the particular function required.

Impulse Sealers

These work by applying an energy pulse to the sealing area for a specified period of time. They don’t need any warm-up time and cool down quickly. They come in various different subtypes that are suitable for a variety of different  material.

Direct Sealers

These use electric power and once warmed up maintain a constant heat in the jaws of the machine. They are more suitable for thicker materials because the heat penetration is much deeper than an Impulse Sealer.

In addition to these two main types of heat sealers, there are other specialised types like a clamshell sealer and a vacuum sealer.


The size of a heat sealer will depend on the size, namely the width, of the plastic bags that need to be sealed.   If the point at which the cutters typically trim is less than the width of the arm on the machine, then a few centimetres have to be added on when choosing the most suitable  heat sealer for your needs.


The speed of a heat sealer is measured by the number of bags it can seal in one minute. For home use, a small portable sealer is usually sufficient as they can seal between six and fifteen bags per minute. For high production jobs, faster sealers are required such as a continuous band sealer. These faster models are suitable for industrial settings.

Types of Materials

The type of materials to be packaged and sealed will determine the type of heat sealer to choose. For example, for materials that require a low sealing temperature such as thermoplastic materials like polyurethane, polypropylene, polyethylene, nylon, foil, and bubble cushioning wraps, an Impulse Sealer is most suitable. Thicker materials like cellophane, poly cello film, waxed paper, gusset bags, and coated aluminium foil is best handled by Direct Sealers.

How Are Plastic Bags Sealed?

A heat sealing machine uses heat and pressure to seal packaging materials such as uniform thermoplastic monolayers or several layers of materials. Two similar materials can be joined together or dissimilar materials can be joined, one of which has to be a thermoplastic layer. The process uses a direct contact method that utilizes a constantly heated sealing bar or dies to apply heat to a specific area to seal two materials together.

Direct Contact Sealers or Hot-Bar Sealers utilize tooling kept at a constant temperature using one or more heating bars to interface with the materials and form a bond. A release layer, or various slick interposer materials like teflon films, are used to prevent materials sticking to the hot tooling.

Impulse heat sealers have one or two heating elements of Nichrome situated between a resilient synthetic rubber and a release surface film. Heat is only generated when current flows and the heating elements are  heated for a specific time at a temperature required to seal the materials together. After the current is stopped, the materials are held in the jaws of the machine which allows the materials to fuse together. Sometimes cooling water is used.

A good seal is a combination of adequate time, pressure, and temperature applied to clean, appropriate material. Several test methods are applied to measure the strength of the seals and package testing is done to determine the ability of the seal to withstand pressure, retain its integrity and barrier sterility.

Poly Bag Heat Sealers from Pinpak-Grayson

With more than 28 years experience in the industry, Pinpak-Grayson is able to supply the best heat sealers and heat sealing spare parts such as elements and Teflon for all your heat sealing requirements. We carry a wide range of commercial grade, top quality poly bag heat sealers that are suitable for a number of different applications including:

–    Constant Heat Sealers

–    Pedestal Impulse Heat Sealers

–    Shrink-A-Pack Systems, among others.

 Contact us today to discuss your particular requirements and one of our friendly and knowledgeable service providers will be happy to assist you in choosing the right plastic bag heat sealer for your business. We specialise in the made-to-order printed and plain plastic bags and films including high clarity Polyprop, singlet style bags, and courier satchels. We are well-known in the industry for the fastest turnaround times and the best customer service when it comes to warehouse supplies and packaging requirements.

You can browse through our website or give us a call on 1300 855 571 if you are looking for something special. We look forward to being of service and helping you with any packaging related requirements