…or how to select a good label supplier.
“Help! I need a service engineer quick, the labelling machine keeps snapping the labels.”
Snapping of the web (backing paper/liner) at the dispense edge, is more often than not caused by die strike, the term given to the cutting die, used in label manufacturing, pressing too far through the face material and striking into the backing. The affect of this is that of weakening the backing material, which when placed under tension through the labeller, causes it to break. It is usually quite obvious and can be seen by peeling off some labels, you will see an outline. If it is less obvious then take a felt tip marker and rub it over the backing – the ink will show up the outline.
There should be no excuse for die struck labels. All cutting dies wear down eventually and either need re-sharpening or replacing by the manufacturer but this costs money. Some label converters will try to prolong retooling by pressing down the cutting die harder than it should, so the labels are still cut but the backing gets crushed.
A high-speed automatic label applicator requires there to be a certain amount of constant tension in the web, to allow the label to dispense correctly, so if your application demands high-speed or uses a particularly thin or clear material, then your label converter needs to know this.
However, snapping is one issue but a labeller which mis-feeds labels can often be down to the labels as well. When labels are made, dust is created – more so with paper labels. The gap sensor in your labeller detects the edges where one label ends and the next begins. If the dust is not removed at the converting stage, then it lies on the surface of the labels and builds up covering the gap sensor, stopping the machine. The only solution is to clean the sensor more often than usual, which means more down-time for the line. We always ensure dust is extracted during manufacturing and you should insist that your supplier also implements such a procedure.
And another thing – when I previously said that too much pressure on the cutting die is bad, so is too little as it can result in some of the waste material in the gaps between labels, not being removed properly. If a gap is not present then the labeller will continue to feed until it does see a gap, giving the appearance that the machine has fed two labels from one product signal. This one can be hard to prove because the material left in the gap will also get dispensed along with the two labels and being so small (typical label gaps are 2-3mm) it can easily fall away and be hard to locate again.
Hopefully you can start to appreciate that there is more to making good quality labels for automatic application, than meets the eye. Now, here’s the pitch – ALS make good quality labels at competitive prices but we don’t cut corners. Label pricing is fiercely competitive and there are some great deals to be had at the moment but beware, cheap labels can often be very costly in terms of production line down-time, reject labelled products and more frequent machine servicing. We know – our own service engineers still get called out to many instances where the perceived machine “fault” was actually due to the labels and although we charge for the call-out, I think a little knowledge about labels helps you to help yourself and make the right choice of label supplier.
If you think its about time you changed your label supplier, why not give us a call on 01844 2131777 or email [email protected]