Why is my seal inconsistent across the width of the film?

If the seal is strong in the center but weak at the edges, or shows random weak spots that do not match a pattern on your sealing equipment, the cause is usually gauge variation in the film itself rather than the seal bar settings. A given temperature and dwell time is tuned to a target gauge. A band that runs thinner than spec will seal differently than the surrounding film at the exact same settings, often scorching slightly or sealing too fast, while a thicker band may not get enough heat penetration to bond properly.

The first diagnostic step is to measure gauge across the full roll width, not just at the center, and compare it to where the weak seals are showing up. If the weak spots line up with thinner or thicker bands, that confirms a gauge profile issue on the film side, which we can investigate and correct on the next run.

If gauge measures consistent across the width and the inconsistency is still happening, look at your seal bar pressure distribution next, an uneven bar can produce the same symptom even with perfectly uniform film.