Can you explain what is considered a small label?
The definition depends to some extent on the converter’s experience, and the label sizes they are used to working with. In general, we can say that a small label is less than 25 by 25 millimeters. Labels can be filmic as well as paper, depending on the application and end user needs.
What are the most common applications for small labels?
Sometimes there is no need for a large label on a large package, but most often small labels are used for smaller products in smaller packaging. Most commonly, small labels can be found in the pharmaceutical industry, for example tamper-evident labels for medicine boxes or small bottles containing eye drops or cough medicine. You also find them in the food industry, for small chocolates or jars containing spices. They are even found in the automotive industry, where many labels with specific information or warnings need to be present in a car - in most cases those are small labels as well.
Often conversion of small labels is considered to be difficult, why?
Actually, die cutting a large label and a small label is exactly the same. The principles are the same. Nonetheless, some customers say that they believe a smaller label is harder to die cut than a larger label. This is because although the die-cutting process is no more difficult, handling matrix stripping is more challenging for a small label than it is for a larger label.
What is the difference between converting small and large labels?
If you want to achieve good matrix stripping of small labels then the matrix stripping roll or bar is a critical element. Most converters do not change this bar, which has a standard size. An operator will not change it when they change to die-cutting smaller labels. If I want to achieve good matrix stripping of small labels, with no labels lifting into the matrix, then installing a matrix stripping roll with a smaller diameter can help. This is something that not many operators are aware of. Usually, when the labels are lifting up into the matrix, leaving missing labels on the liner, the operator looks into the die-cutting process. Instead, they should look at matrix stripping.
What is the critical point in matrix stripping, and can it be improved?
Unfortunately, this is something we cannot influence. Many modern machines have quite a long distance between the die-cutting station and the matrix stripping. What would improve conversion is a very short distance between die cutting and matrix stripping, because the longer it takes to strip the matrix away, the more time the adhesive has to flow back into the cut. When the material is die cut it is split and that’s when the matrix should be stripped. Otherwise, labels can be missing on the converted roll because they were stripped together with the matrix.
What are the other steps that a converter can undertake to make conversion easier?
It is not easy to give a simple answer, but I would say first of all try to follow protocol. If a customer is planning to use an unfamiliar material, we advise sending a piece to his die cut supplier, asking for advice on what is the best flexible die needed to achieve proper die cutting. The die cut supplier will then assess the material, taking into account also the data sheet from the self-adhesive material supplier, the adhesive, the type of facestock (PP, PE, PET or paper) and the type of backing paper. This will result in advice on how to convert the material, and the specific angle needed with a specific height and specific abrasion or anti-abrasion properties. This will ensure that the operator achieves the best possible results during die cutting.
What does Avery Dennison advise to help meet the small label challenge?
We always go back to the basics. That means your die-cutting unit, your press, must be in good condition and checked regularly. It is important to ensure that the whole process around converting is well equipped and organised. The Avery Dennison technical sales team is always willing to support you and provide guidance.
So then you go to the customer and check the machine to make sure everything is set up correct?
At the first stage, I always try to give general advice based on my experience. When this is not working, and there is a specific issue, I prefer to visit the customer together with the die cut supplier, I call this the three angle approach. By combining our own expertise with that of the converter and the die cut supplier, we have a much more complete and effective team in place, and the most challenging conversion issues can be overcome.