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.
The Super Air Knife has been featured as the cover photo of every EXAIR Compressed Air Products catalog since I got here in 2011…except for Catalog #26 in 2013, which featured the Super Ion Air Knife. BIG difference, right there.
The highlighted application photos may change from catalog to catalog, but one that always remains is the iconic (I think, anyway) image of the Super Air Knives blowing off the orange soda bottles:
This is a darn-near ‘textbook’ application for the Super Air Knives…the even, laminar flow wraps around the bottles, stripping moisture away. Among other reason why this is important, it improves the next step in the process – the labels stick better.
In my younger, intemperate days, I’d join my friends at a popular watering hole to celebrate special occasions like…well, Tuesday, for example. Sometimes, there’d be a ballgame on the TV, or lively conversation, to entertain us. Other times, we’d make a game out of trying to separate the labels from the beer bottles, in one piece.
Some years later, I tried to teach my young sons this game…except with root beer bottles. It didn’t work near as well, because these labels adhered much tighter to the root beer bottles in my dining room than the ones on the beer bottles at the bar.
Some years after that (those boys are teenagers now,) I became an Application Engineer at EXAIR, and found out that this drying-the-bottles-to-make-the-labels-stick-better thing was for real, because I got to talk to folks in the bottling business who told me that the Super Air Knives had made all the difference in the world for their operation.
Just the other day, I had the pleasure of helping a caller who operates a micro-brewery, and had just installed a set of 110009 9″ Aluminum Super Air Knives for the express purpose of (you guessed it, I hope…) making their labels stick better. The only thing that could make it better, according to them, was if they could use less compressed air, and they were interested in what the EFC Electronic Flow Control could do for them.
As a micro-brewery, their production lines don’t run near as fast…nor do they want them to…as some of the Big Names in the business. As such, there’s some space between the bottles on the filling lines, and they thought that turning the air off, if even for a fraction of a second, so they weren’t blowing air into those empty spaces, would make a difference. And they’re right…it’s a simple matter of math:
Two 9″ Super Air Knives, supplied at 80psig, will consume 26.1 SCFM each (52.2 SCFM total). This microbrew was running two 8 hour shifts, 5 days per week. That equates to:
52.2 SCFM X 60 minutes/hour X 16 hours/day X 5 days/week X 52 weeks/yr = 13,029,120 standard cubic feet of compressed air, annually. Using a Department of Energy thumbrule which estimates compressed air cost at $0.25 per 1,000 SCF, that’s an annual cost of $3257.00*
Let’s say, though, that the micro-brewery finds that it takes one second to blow off the bottle, and there’s 1/2 second between the bottles. The EFC is actually adjustable to 1/10th of a second, so it can be quite precisely set. But, using these relatively round numbers of 1 second on/0.5 seconds off, that’s going to save 1/3 of the air usage…and the cost…which brings the annual cost down to $2171.00*
*As a friendly reminder that the deadline to file our USA income tax returns is closing fast, I’ve rounded down to the nearest dollar. You’re welcome.
That means that the Model 9055 EFC Electronic Flow Control (1/4 NPT Solenoid Valve; 40 SCFM) with a current 2017 List Price of $1,078.00 (that’s exact, so you know) will have paid for itself just short of one year. After that, it’s all savings in their pocket.
I recently worked on an application with a manufacturer who was having issues with their labeling process. The sticker label is applied to the side of their container by a print roller and then passes by a 6” homemade manifold system with 3 nozzles to help permanently affix it n(see below). They were experiencing irregularities/air bubbles in the label and realized they were getting an uneven airflow which was stronger at each end nozzle but the middle nozzle had very little flow. They were operating at around 80 PSIG and previously tried to lower the pressure but the label would start peeling off. If they increased the pressure they were experiencing tearing and ripping in certain areas of the label. Another issue was the loud noise level. They were having to stop the line and turn off the air so an operator could manually replace the label. They emailed me a picture of the manifold and asked if EXAIR could improve their process.
After reviewing the picture and further discussing their application, I recommended using one of our 6” Aluminum Super Air Knives. The Super Air Knife , with a 40:1 amplification rate (surrounding ambient air to compressed air), provides a high velocity laminar sheet of airflow the entire length of the knife. By continuing to operate at 80 PSIG, the Super Air Knife will produce a velocity of 11,800 feet per minute (6” away from target object) and consume only 17.4 SCFM (2.9 SCFM per inch of knife) with a low noise level of only 69 dBA.
By replacing the manifold, the customer was able to improve their process, decrease their air consumption and increase their personnel’s safety.
If you are experiencing a similar issue or need help with a different compressed air application, please give us a call.
I worked with a customer recently who was experiencing a static issue when trying to apply a bar coded label to their cardboard box. The boxes travel down a conveyor then passes by a labeler that uses a mechanical arm with air vacuum to hold the label in place. As the box passes by a sensor, the arm applies the label to the corner (front and side) and then the box passes by an applicator brush that ensures the label is firmly applied.
They were starting to see wrinkles in the label as it passed by the brush and were thinking the label was holding a static charge which was making it be rejected by the box during the process. They were experiencing this about every other box. When it would occur, they would need to stop the line and manually check to make sure the label was seated properly. As a result, this was negatively affecting their production time and increasing wasted labels.
Since they thought it was the label holding the static charge, they wanted to use one of our Ionizing Bars to remove the static from the label as it was attached to the arm. The Ionizing Bar produces a high concentration of positive and negative ions able to dissipate 5 kV in 0.30 seconds, 2” from the object’s surface. It is also UL listed for safety and RoHS compliant.
The customer is local, so they asked if someone from EXAIR could visit their location and take a look at their process. I was able to make the appointment for the next morning and brought a few of our Static Eliminating products and a Static Meter to take some measurements. By measuring within 1” of the surface of the product, the Static Meter measures the voltage and polarity up to +/- 20 kV.
Upon arrival, I was directed to the labeler and took a measurement – I was only getting a reading of about 0.2 kV. I then decided to take a reading on the box itself as it traveled down the conveyor. Now I was getting a reading of 3 – 5 kV, which meant that it was the box and not the label that was holding the static charge.
Since the customer could get within 2” of the surface of the box, they were able to mount a 6” Ionizing Bar vertically to remove the static prior to the labeling process. This helped to greatly reduce the downtime of the line.