Reasonable Expectations For Labeler Speed

There are a lot of misunderstandings and misrepresentations about labeler speed—more accurately termed as throughput—and a corresponding number of disappointments after purchase and installation. Many factors influence your ultimate labeler speed, but these are not often considered when specifying or selecting a labeler. Preparing yourself with a complete understanding of all these issues may prevent any false expectations and disappointments with your new investment.

If you are new to labeling and considering a semi-automatic labeler, you can get a pretty good idea of what your actual throughput will be by simulating the process. Gather up a quantity of product in the same form that the operator will see them: a case of 24 bottles, a tote of widgets, a loose pile of bags, or whatever. Carry them to the place where you will set up your labeler, pick up one product, pretend to label it using the actual hand motions required to operate the machine (this part will probably take 1/2 to 3 seconds with a semi-automatic machine—ask your supplier), place it into a "completed" case, tote, or pile, and repeat this process until you have completed at least ten products. How long did this take? Divide the number of products you labeled by the number of minutes it took (or the number of seconds divided by 60), and you will have the number of products you can label in one minute. Multiply by 50, and you'll have the number of products labeled per hour (allowing 10 minutes for micro-breaks like stretching, sneezing, etc.) You may feel silly doing this, but in my opinion, this will give you the most accurate throughput prediction possible. If you choose not to do this and then are disappointed by your actual throughput after buying a labeler, don't go crying to your supplier telling him his machine is too slow.

This exercise should point out several important points:

1. Your ultimate throughput may include as much product handling time as actual labeling time.
2. A one-person machine may require two people to operate at full speed--one to label, and one to haul product back and forth, tape up cases, etc. (If so, they can alternate jobs periodically.)
3. You cannot simply take the labeler speed that your supplier tells you, multiply that by the number of minutes in the day, and get a realistic throughput.
4. The people who did not point at you and snicker while you did this are your real friends.

With all that said, on a semi-automatic machine a person can usually label approximately 15 round bottles per minute, 10 front-back bottles per minute (if the labels alternate on the liner), or 20 flat single-label products per minute while they are actually labeling—not hauling product around.

Fully automatic labelers have the same issues if you are manually loading or unloading them. A labeler may be capable of 120 products per minute, but if you can only load it at 40 ppm, that's the throughput you'll get.

Automatic labelers in line are a different story because you have automatic conveyor feeding via a conveyor. If your labeler is rated for 120 parts per minute and your conveyor is providing parts that fast, then that’s the throughput you’ll get. Until it’s time to change labels. Make sure you allow for 2-5 minutes down time for replenishing the label supply roll.

When looking at labeler throughput, just as important as the motor speed on the labeler is the stability of your products. If you are labeling empty bottles, it may not take much to knock one over and start a domino effect. Even full bottles can have this problem—water bottles are notorious for this. Bottles can easily be knocked over at transfers onto and off of the labeling conveyor, metering wheels, wrap belts, and turns in the conveyor. Make sure you understand how fast you can reliably transport your products before you plan on increasing any speeds.

Print-apply shipping or product ID labels on boxes present a different source of misunderstanding. A print engine may be rated for 12 inches per second (ips) and if your label is 6 inches long, you can print 2 labels per second, or 120 labels per minute…right?

Wrong. First, printing at 12 ips does not give you the same print quality you get at 8 ips. If you are printing bar codes or fine print, you may not be satisfied with the print quality at the fastest setting on your printer; test this. Second, you have to allow time for the tamp pad to cycle out and back between labels. If your applicator can cycle in ¼ second—which is quicker than typical—and you are printing at 8 ips, your 2 labels per second is now down to 1 label per second, or 60 labels per minute.

But wait, there’s more. For you to hit this theoretical throughput, you need to have your previous box out of the way and the next box in place every second. I won’t go into the many sources of variability to this, but trust me, the timing will vary. You need to plan on the maximum barcode scan/data transmit/print-apply cycle time and the minimum distance from the leading edge of one box to the leading edge of the next. You’ll be doing well to label 30 boxes per minute.

There are too many different cases to get more specific than this in this post, but for anyone who wants an independent opinion on your throughput capacity or anyone who needs help optimizing your labeling setup to increase your throughput, feel free to call me at 800-331-7140 or email me at jdawson@su-solutions.com.