Bag Sealing Machine

Flat pillow bags

The simplest case. A flat bag lies naturally, the mouth presents square, and any format in the range will close it. Here the only decisions are the seal length - longer than your widest bag measured flat - and the volume.

This is where most courier, garment and small-parts packing sits, and where a hand or table top machine is usually all that is needed.

Gusseted and stand-up bags

A side gusset or a base gusset means extra layers of film at the edges of the seal. The jaws have to fuse four layers at the gusset and two in the middle, which is why a setting that works on a flat bag can leave a gusseted one open at the corners.

It is a solvable problem and it is worth raising before you buy rather than after. Send a photograph of the empty bag standing up, and say whether the gusset falls inside the seal line.

Filled bags that will not stay square

A bag full of loose goods, powder or heavy items has a mind of its own. The operator needs both hands to hold the mouth flat, which means a hand-pressed bar is the wrong format however good the machine is.

This is the single most common reason a hand sealer sits unused on a bench, and the fix is a foot-operated machine - the pedal closes the jaws while both hands stay on the bag.

Large bags and liners

Once a bag is wide, two things change together. The seal bar has to be long enough, and the film is usually thicker as well - so you are asking for more length and more heat at the same time.

It is also worth asking whether a heat seal is really what a large liner needs. Many carton and drum liners are closed with a tie or a strap and never see a sealer at all. If you are sealing them because that is what you have always done, say so - there may be a cheaper answer.

What to send

A photograph of the bag empty and, if it is not flat, standing up. The width across the mouth measured flat. What the bag is made of. How many you close in a day. Those four give an honest recommendation; anything less gives a guess.

Where on the bag the seal should go

Almost nobody thinks about seal position before buying, and it decides how much film you waste and how the pack looks.

Sealing close to the top of the bag leaves the most usable space inside and the least spare film above the seal. It also leaves the least margin for error: if the mouth is not laid perfectly flat, the seal runs off the edge.

Sealing lower down is more forgiving and gives a firmer grip for the operator, but it wastes the film above the seal on every single bag. Across a year of despatch that is a real number.

The middle answer most benches settle on is a seal a short distance below the mouth, with the excess trimmed - which is what a machine with a cutting wire does in the same press, and one reason to consider one.

If your bag is printed right up to the top, or if a customer will judge the pack's appearance, send a photograph of a bag you consider correctly sealed. It is easier to match than to describe.