If you want to print on plastic, it’s challenging – most plastics are chemically inert and non-porous. That means you can apply all the ink you want; it’s not going to stick. In the 1950’s, a Danish engineer named Verner Eisby experimented with various techniques to overcome these challenges. He found that exposing the surface to be printed on to gas flame or sparks modified the surface to improve adhesion with the ink. It did so, though, in a crude & uneven manner, leaving imperfections & inconsistencies in the printed product. He then tried applying a high frequency corona discharge in a linear array. The plasma (gas in an ionized state) generated left a homogeneously treated surface on which to print, smoothly & evenly.
This has become the “industry standard” for many of the labels we see on commercial products, from shampoo & wine bottles on the grocery store shelf, to pennants & banners at public events. It also leaves the surface even more prone to picking up a static charge from rolling or unrolling, stacking, sliding, etc.
One of our customers makes a great many labels for all kinds of these commercial products, and uses an EXAIR Gen4 Ionizing Bar immediately prior to the printing operation:
Using EXAIRSUniversal Air Knife Mounting System greatly ease’s the installation of all Air Knives (Except PVDF). It will save you the time and expense of designing and fabricating your own mounting system which will maximize your uptime and keep your staff focused on key plant tasks!
When a customer has a problem with a labeling process within their operation, many times they call EXAIR to provide a solution. The company in this example manufactures honey and dispenses it into jars and squeeze bottles. Due to an increase in demand, they were looking to increase their output. To do this, they simply increased the speed of their conveyor to accommodate approximately 70 jars per minute instead of their typical 50 jars per minute. This began to present a problem and they reached out to EXAIR for a solution.
After dispensing the honey, the jars and bottles travel through a washing station. The containers pass through a heated chamber that dries the excess water from the jar. At the higher speed, they were experiencing some residual water left on the containers. This began to pose an issue when they reached the labeling process. With water remaining on the jars, the labels adhesive would not adhere properly. This led to an increased amount of rejections and additional rework time to remove the rest of the label and re-run the defective containers.
They had a point in the conveyor just prior to labeling that the sides of the jar would be exposed. My recommendation was to install (2) 110009 9” Super Air Knives on each side of the conveyor to remove the water that was left after exiting the drying chamber. This worked like a charm and the customer was able to maintain an increased level of output without experiencing any further complications. Their previous rate of production without the Super Air Knives was approximately 50 jars per minute. By installing the Super Air Knives, they were able fully realize their 70 jars per minute goal and increase their production by 40%!
The laminar flow that exits the Super Air Knife wraps itself around the outside of the jar, stripping away any leftover moisture. Supplied at 80 PSIG, each knife will consume only 26.1 SCFM of compressed air at a sound level of just 69 dBA. The flow and force from the knife are infinitely adjustable by dialing in the operating pressure with a pressure regulator or swapping out the shims with a Super Air Knife Shim Set. If you’re experiencing an issue with residual water or liquid on your product that is causing a problem during production, give us a call. An Application Engineer will be happy to take a look and recommend the most suitable blowoff solution!
Last week, I used this space to brag on our Super Air Knives, and how they solve a common problem in bottling applications: label adhesion. This week, I have another opportunity to brag on the Super Air Knife. AND it’s another solution to a labeling problem.
Self-adhesive labels are commonly applied to goods are they travel on high speed conveyors. If they’re going onto a flat, smooth surface (like a box,) it’s pretty easy…they come right off a timed roller with a wheel that presses them in place. This can even work with round containers (like drums, jars, or bottles) by putting an idler on the wheel to take up the slack as it rolls over the rounded surface.
Sometimes, the label needs to go around the corner of a box. This requires the roller to turn that corner. Or two rollers to pull the old “one-two” on the label. Either way, that’s going to slow down the speed at which the conveyor can be run. And time is money.
Enter the Super Air Knife…mount it so it’s blowing at the corner. The laminar, high velocity air flow will then press the label in place on each adjacent surface.
Another benefit: when supplied with clean, dry air, the Super Air Knife will run darn near indefinitely, maintenance-free. Those rollers get dirty, and the bearings will fail eventually. Same with the idlers, and they’ll need adjusted from time to time.