Lay-Flat Tubing: How to Cut and Seal Bags for Variable-Length Products
If you pack the same type of product in several lengths, a stock of fixed-size bags can quickly become awkward. Short items sit in excess film; long items need another bag size. Lay-flat tubing offers a different workflow: draw material from a continuous reel, cut the length you need and seal the open ends.
That flexibility is useful at a packing bench, but a reliable result depends on more than choosing a width. The product, sealer, reel and packing method all need to suit one another. Here is how we would approach the specification.
Start with the product, not the reel width
Measure the widest point the tubing must pass over, including corners, handles or protrusions. The lay-flat width is the width of the tube when flattened, rather than its open diameter. If the tube is too tight, operators have to force the product in and may damage the film or the item. If it is far too wide, the finished bag has excess material that may interfere with a neat seal or handling.
For a simple rectangular item, the perimeter around its cross-section offers a useful starting point: half that perimeter is an approximate minimum lay-flat width. Add working clearance, then check an actual sample over the product. Stretchband Packaging's tubing specification suggests 10–20 mm clearance as a starting point and more where edges are sharp. This is a sizing aid, not a guarantee for every shape.
Allow length for both the product and the seals
The cut length has to include the product, the space taken by each seal and enough free film for the operator to position it cleanly. A sleeve cut to the exact product length may be impossible to close properly. Conversely, leaving a large tail on every pack adds film and slows handling.
Trial the shortest and longest items in the intended range. Record the cut lengths that let operators load, seal and inspect packs without stretching the film around the product. If items have highly variable shapes as well as lengths, more than one tubing width may still be sensible.
Match the tubing to the heat sealer
Stretchband Packaging's lay-flat tubing can be specified for impulse and constant-heat sealers. Before choosing a film, tell us the sealer type and jaw width, along with the required bag width and gauge. A seal needs to span the full tube and remain consistent at normal packing speed.
During a trial, check whether the seal is straight and complete across its width, and whether filled packs withstand their normal lifting and handling. A poor seal can reflect film, temperature or dwell settings, jaw condition, contamination, or the way the operator presents the tube. Record what was changed before deciding the film itself is at fault. Use the sealer maker's operating instructions for settings and safe use.
Choose gauge for the real handling route
The lightest film that survives the job is usually more useful than a gauge chosen by habit. Consider the product's weight, sharp points, friction during loading, stacking and any movement in transit. A smooth lightweight kit may need a different specification from a metal component with an exposed edge.
Test the filled bag through the normal route: off the bench, into a carton or tote, and through any expected handling. If punctures occur, consider the product edge and packing method as well as gauge. More thickness alone may not fix a sharp contact point.
Think about presentation and identification
Clear tubing lets packers see contents and labels. Coloured or opaque film can be useful where visibility is undesirable, while simple print can carry handling or identification information. Stretchband Packaging also offers specialist options such as anti-static and VCI blends for applications that require them; these need to be specified against the actual product rather than assumed suitable for every item.
If you want recycled content, discuss the intended use and test sealing, appearance and strength with the proposed blend. The material choice should be signed off against the same packing and handling checks as the current film.
A practical bench trial
Run several representative products through the proposed process and record:
• Product width, length range, weight and any sharp contact points.
• Tubing lay-flat width, gauge, reel size and material grade.
• Cut length for the shortest and longest products.
• Sealer model, jaw width and settings used for each sample.
• Time to load and seal, rejected packs, and film used per accepted pack.
• Seal appearance, punctures and performance after normal handling.
This gives the purchasing team a usable specification and the packing team a repeatable method. It also helps distinguish a material issue from a sealer or handling issue before a larger order is placed.
Talk through your application
If you are packing products that vary in length, send us the item dimensions, packing volume, sealer details and a description of the handling route. We can discuss a suitable lay-flat tubing specification and samples for your own bench trial. Contact Stretchband Packaging when it is useful.
