Reasonable Expectations For Labeler Alignment, Part 1

We buy automatic labelers for two reasons, speed and alignment, right? So how good of alignment can we expect? To a large extent, we can answer that by looking at your products and labels. Since bottles show this the best, I will use those as examples.

Let’s start with a round glass bottle, like a wine bottle. Hold a straightedge vertically against the side of a bottle and you will probably see a gap at the center of the bottle. Most glass bottles are hourglassed to some extent, and when you apply a label to that, one of two things typically happen: either the label forms a wrinkle horizontally across the center, or the label spirals slightly up or down because it adheres more to the slightly tapered area below or above the “waist.”

With most plastic bottles, you will see the same gap under a straightedge; however, the soft sides of the plastic bottle will conform to the straight labeling mechanism so wrinkles are avoided. You still have the same problem, though, of there being a greater circumference and therefore more bottle surface to spread the label over at the top and bottom of the bottle than at the center.

The bottom line of all this is that if you don’t have perfect straight-sided bottles, your label positioning will vary from bottle to bottle and lot to lot. Misalignment of the two ends of a label where they wrap around a round bottle and meet at the back can vary as much as 1/8” even with the perfect labeler setup. You can tweak your labeler and might improve the situation, but when you get into a different lot of bottles, you’ll probably have to tweak it again.

Oval and F-style bottles have the same problem, but to a much lesser extent. For the most part, your setup tweaks will maintain a fairly consistent label position.

If you were to machine a perfect sample bottle out of a solid piece of material and run it through your labeler, you would probably see perfect labeling. I have seen this done twice, and both times, hours of tweaking a setup without success were reduced to a few minutes with essentially perfect repeatability.

So this long-winded post is all my way to tell you how to answer your own question: lay a straightedge along your product surface. If you see daylight under it, then you should expect label placement variation. If not, then any decent labeler should provide repeatable positioning within ±1/32”.

I'll have a more technical and detailed post for this later.