Sizes close to each other are common in the glass trade. Put 490x251 next to 491x286 and they cannot be told apart by eye; two pieces get mixed up and the mix up is only discovered at installation. That is why a label is not decoration but the identity of the piece.
What a glass labelling system has to carry is plain: which order, which position, which size, which customer. With those four the person at the bench does not hesitate. Hesitation produces mistakes, and once the glass is cut the cost of the mistake cannot be taken back.
Designing the label is part of the work too. Fields are dragged into place, arranged on a page grid and printed in batches. Millimetre placement is needed because the label prints onto a sticky sheet of a given size and anything overflowing is cut off. Flexibility is usually what is meant by a labelling system for glass workshops: every workshop has different label stock and a different printer.
Having a barcode on the label opens a separate door. The piece is scanned as it passes a station and the current stage enters the record; scanning takes a couple of seconds. A barcode system becomes the engine of the tracking screen here, but not on its own: with no label there is nothing to scan.
The same label does its work on the dispatch side. When packed pieces are scanned it becomes clear by itself which order is complete; a missing piece becomes visible the moment it happens rather than on dispatch day. A dispatch system working correctly depends on this.
When the label is printed matters too. Printed together with the cut, the piece gets its identity before it even leaves the bench; printed later, deciding which piece gets which label becomes a task on its own. That decision can go wrong every time, and the mistake is seen at installation.
The language of the label can follow the recipient as well. On a job going abroad, the information on the pack comes out in a language the other side can read. That small detail keeps the wrong pack from being opened at installation and lowers the number of returns for exporting workshops.
Usable offcuts can be labelled as well. A piece put on the rack, labelled with its dimensions, becomes searchable on the next job. An unlabelled offcut counts as absent from inventory even while it sits on the rack; nobody looks for it and it is usually thrown out to make space.