You know most RSC box styles when glue and strapped are not totally flat, due to the extra thickness of the glue flap. This adds some instability to the finished pallets and may prevent stacking.
To solve it we´ve tried to crush the glue flap, but if we do this, the scoring between the flap and the first panel, kind of disappears and it causes the box to fold in a weird way.
We´ve also tried alternating the directions of the bundles, and it helps in some styles, but some others, have the flap right in the middle and it’s difficult to avoid.
Do you have an idea how can we solve the problem without affecting the score?
Yeah, that’s a tough one and one that most plants encounter at one time or another. Unfortunately, there is no one-size-fits-all answer. Crushing the glue tab helps, but, as you mentioned, you sometimes get a soft crease at the glue tab fold. That typically may not be a big deal for manually set up boxes but can be a huge issue for case erectors. It helps with the center thickness issue, but it would never completely alleviate the problem. You still have the thickness buildup of the liners and the medium. The two folded scores on the on flat RSC also contribute to this issue. When it’s folded flat there is tension caused by the two panels at the score pressing against each other. This makes the folded box want to spring open. So, you are not only fighting thickness, but you are also fighting tension.
Try to keep the bundle or batch count as small as possible. The fewer in the bundle or batch the less deviation you’ll get, or at least the more opportunity you will have to compensate for it.
When you have a center glue flap, whether running bundles or batches, interlock the bundles or batches of RSCs as much as possible. If you can overlap three lengths across your pallet you can build a pretty stable load. You just need to make sure your top layer is the center bundle that locks the two outer bundles in place as shown below.
A chimney stack configuration (similar to the illustration below) may help as well. Again, keeping your bundles or batches as small as possible and interlocking the layers.
Of course, shrink wrapping or cross-strapping will help keep them together during shipping. Most of the time the end user wants to rip all the shrink wrap off first thing. If they can cut the wrap and open on only one side, the rest of the wrap may hold the stack in place until it gets used down. That will probably require changing the customers procedures or habits. Sometimes it’s not practical… and sometime not possible.