Monday, October 13, 2008

Setting Your Label Stop Position

I commonly get calls from people who are having trouble getting their labels to stop where they want them to on their labeler. Here is the correct procedure to set your label stop position.

The first step is to verify that your label sensor is properly calibrated. This is the “eye” that detects the gap between labels to tell the machine when to stop. As labels go by the sensor, check that the indicator light comes on exactly one time per label. This is usually a quick flash at the gap, but if the light is on the entire time the label goes through the sensor and flashes off at the gap, that’s okay, too. If no light flashes, if the light is always on, or if the light flashes more than one time for every label, you need to recalibrate your label sensor, which I will cover in another post. Fix that problem, then return to these instructions.

There are two ways to set the label stop position, depending on your brand and model of machine. One is to physically move the label sensor; the other is to adjust the delay setting electronically. Many labelers will let you do both. First, I will assume that the label sensor is fixed in position and you have to adjust the label stop electronically.

You need to start at a known position, so set your label feed length to zero. This setting may also be called label stop, feed delay, off delay, label flag, or something else like that. Jog a label by either pressing the jog button or triggering the product sensor. The label web should advance until the next gap reaches the sensor, then stop. You will have one label extending partly past the peel edge. If anything else happens, you probably need to recalibrate your label sensor.

Generally, when you dispense one label, you want the next label to stop just barely short of the peel edge. Some technicians recommend the next label stick out past the peel edge a little, but I don’t. Either way, your next step is to make the label web advance until one whole label peels off the liner, then stops. Change your label stop position from zero to some arbitrarily small number, like 10. Jog another label and see where it stops. If it stops in the same place as before, then the machine may not have accepted your new setting. On some labelers, you need to jog a second label before you see the new result; on some others, you need to press an enter button.

Your label web should have advanced farther this time. Keep increasing or decreasing the label stop setting until exactly one label peels off the liner and the next label stops just barely short of the peel edge. What fools some people is the fact that you are looking at how far the label peels off the edge, but you are controlling this by how far the gap travels past the sensor. Always watch the gap and the sensor to understand what the labeler is doing.

If the setting that you need turns out to be zero because the distance from the label sensor to the peel edge is exactly the length of one (or two or three) labels, then you have a unique and perhaps unfortunate situation. When this occurs, many labelers will sporadically dispense a second label because the sensor is seeing some gap and some label, and its average light input reading is very close to its decision point. Try setting the label stop to a small number. This will advance the gap a little past the sensor and dispense a small amount of label over the peel edge. If this works in your application, go with that setting. If your labeler has a vacuum pad, then you don’t have this option; you will probably need to move your sensor upstream or downstream. You may have to get creative with this or enlist the aid of a machinist or a good handyman. There are also some tricks that are beyond the level of these instructions, so you can always call me if you’re still stuck.

If your labeler lets you move the label sensor, then you can slide it toward the peel edge to advance the label farther, or away from the peel edge to shorten the label advance. If you also have an electronic label stop adjustment, you probably want it at a number that is not zero to avoid the problem described in the last paragraph. Either follow the instructions above or move the sensor to where it makes the label stop where you want it. If you run out of travel, which is very common, then put the sensor in the middle of its slot or rail, and follow the above instructions to set the stop position electronically. You can always fine-tune it by moving the sensor a little if you want.

This should cover 99% of the applications out there, but if you think you may be in the 1% or you’re still having trouble in general, then call me at 800-331-7140 or email me at jdawson@su-solutions.com, and I will try to get your labeler setup working.

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