What is a bag heat sealer?

A bag heat sealer is a packaging machine used to help form a bag, using heat to melt the sides together. Sealing things in their packaging is not only vital to protecting them and keeping them safe in transit, but also makes packaging. Particularly, clear poly bags. And to make that happen, you can use a simple bag heat sealer to close up the open end of a bag – you can even trim the ‘spare’ off to make for an even more professional job.

In this post we shall take a look at how a bag heat sealer works, the different kinds of heat sealers available and what kinds of bags they work on. As well as looking at heat sealing machines that can automate the process for you.

What is a bag heat sealer?

A plastic bag heat sealer is a simple heater that, when pressed and applied to a thermoplastic bag, seals the bag together using a combination of pressure and melting. The two plastic parts are brought together and pressed against one another and heated. This melts the plastic, which co-mingles and, as it cools, sets into a single plastic seam.

It is akin to welding, but with plastic. Once cooled the join is essentially one piece of solid, even plastic, contiguous to the rest of the two pieces joined together. In short, it is a water-tight sealed weld between the two.

It can be used to join together two pieces of the same or two similar thermoplastics, such as Polythene of different grades. It Is most commonly found in packaging where it can form a water and dust-tight seal on a bag of pretty much any size.

They typically use a heated element or bar, often covered by a protective Teflon guard, so that the melting plastic doesn’t stick to the element which is pressed onto the plastic at the point where the joint is needed. It takes only a few seconds to seal, but it is a precise process. Too little time and the joint won’t form, too much and the plastic will burn. So most heat sealers feature a light that comes on when the seal is done, or, on more sophisticated heat sealing machines – as we shall see – they lift off when ready.

There are different heat sealing bag devices available . Small, portable/desktop devices for smaller items at low volume; automated devices for sealing many individual items; and continuous heat sealers that seal continually as the item/items run through them.

Some also come with cutters, so that once sealed any excess plastic can be simply trimmed off, or, in the case of continuous sealers, a continuous row of items can be cut individually once sealed.

That’s how they work, but what can they seal?

Can you use a heat sealer on polythene bags?

You can use a heat sealer on a polythene bag. Most polythene bag heat sealers are used to seal poly bags. The polythene for heat-sealed packaging comes in several forms: it can be supplied as bags, which need just one end sealed; or it can come as a layflat tube, which is like an open ended bag that covers the items and needs then to be heat-sealed shut at both ends.

Low density polyethylene, from which most bags and layflat tubing are made, is ideal for heat sealing as it melts at around 160C. This is hot enough to melt together the two sides and cool enough for it to cool and seal quickly when the heat and pressure is removed.

An added benefit is that, as it cools, the polythene contracts and pulls the seal even tighter. This is one of the key advantages of heat sealers for poly bags.

Layflat tubing is available on rolls so that you can continuously package up goods at an industrial scale if needed. It allows the user to create the size of package they need, with the goods simply put inside, the tubing cut to length, then heat sealed. This is ideal if you have a variety of sized objects in your warehouse that need packaging.

It also comes in black, as well as clear and recycled polythene options, with black packaging being ideal for keeping goods not only protected from light when in storage or transit, but also keeping them confidential when sent through the post.

Are there machines for heat sealing plastic bags?

Machines are available for heat sealing plastic bags. One of the easiest ways to package and seal goods using layflat tubing or plastic bags is with a bag heat sealer machine. A heat sealer machine for sealing plastic bags allows you to handle medium to high volumes of goods, making for better and more efficient sealing.

A plastic bag heat sealer machine, such as the Opti-seal industrial heat sealers, offers a simple yet versatile operation with adjustable sealing and cooling times. The compact design of such machines means they can be conveniently placed within reach of workstations, or they can be mounted on an optional stand that also includes a film holder, and afoot pedal for hands free operation.

Opti-seal industrial heat sealers are impulse sealers, which means the heat is applied via the element wire for only a few seconds to seal the material together. The Opti-seal has a wide range of applications. It can seal a range of films including polythene, polypropylene and PVC with a durable 5mm seal, making this bag sealer the perfect choice for producing and sealing bags, sacks and pouches. Features a safety trimming cutter.

Other heat sealer machines, such as the RAJA Impulse Sealer, offer reliable performance and are ideal for low volume bag sealing. Suitable for layflat tubing or bag widths up to 400 mm wide, these are also impulse sealers that apply heat via the element wire for only a second before the mechanism begins to cool the seal.

Most heat sealers have an adjustable timer and a cutter on the sealing arm for leaving a neat finish to your bagged product. There are three sizes of heat sealer available: 200, 300 and 400mm sealing widths which produce a 2mm wide seal. Recommended for two layers of polythene film (PE film), each up to 150 micron (600 gauge) thick.

There are also a broad range of spare Teflon coated heating elements and cutters to make sure that your heat sealing machine stays in tip-top working condition.

Want to know more about our wide range of heat sealers, heat sealer machines, heat sealing bags and layflat tubing?

For additional advice on heat sealers, heat sealer machines, heat sealing bags and layflat tubing, our Packaging Experts are here to help you find the right solutions and arrange next day delivery. Simply contact 0800 542 44 28 or visit www.rajapack.co.uk.