Well the dog days of summer have come to an end, and the cold dry air of winter is on the horizon! There’s one other thing that comes along with the cold dry air of winter, and that’s SANTA! (Sorry that was the child in me).
Actually, it’s STATIC! During the warmer months the moisture in the air does a good job at eliminating a good amount of excess static charge. But as that cold dry air comes into play you need another way to rid your production of static or things will start to go wrong.
Static holding foam bead material to a surface.
In many painting or finishing applications dust and debris from the ambient environment can settle on the part prior to painting or coating. Just blowing them off with a standard air gun won’t remove all of the particles if they’re statically charged. The static must be neutralized in order to remove it or it’ll cause imperfections in the paint or coating. This often results in a high amount of rejected parts that must be scrapped out.
Other processes that benefit from static removal include printing, slitting, molding, sheeting/trimming, shrink wrapping and packaging.
Static Eliminators
Break out your fall / winter gear and enjoy the cooler weather and activities that accompany the coming of Fall, but don’t let static wreak havoc in your processes. EXAIR has a wide range of solutions available that are designed to solve these problems. Give an Application Engineer a call and we’ll be happy to help recommend the best solution.
Static electricity is the enemy of the printing industry. Downtime and inefficiency caused by static means longer lead times and angry customers! EXAIR can remove static electricity in the many printing applications across wide and narrow webs. With our rugged line of EXAIR Super Ion Air Knives and Ionizing Bars, EXAIR can improve your efficiency and printing quality.
Digital printing dries out the printed substrate, creating high static charge that can cause printing defects, ink overspray, and even print head clogging and print head shorting issues. If a press is printing on non-porous substrates like plastic, metallics and highly coated glossy papers, a device called a corona treater is used to increase the surface energy of the substrate to ensure the ink droplets adhere and do not spread too much on the substrate. A byproduct of the corona treatment is static charge, which must be removed. This can be achieved by installing an EXAIR Ion Bar after the corona treatment device across the web.
Static is also created anywhere in the printing or finishing operations where sheets are moved over each other. Sheet-fed presses, for example, create friction in the stacking of individual sheets on top of each other. This friction induced static creates misfeeds, print registration issues, multiple sheet pickups and equipment jams.
Folding operations cause static issues too. Like a sheet-fed press, static is created by folded pieces being dragged across each other.
In both cases, installing an EXAIR Super Ion Air Knife or Ion Air Cannon that can direct a stream of ions between the stack and the top sheet can eliminate the static that causes misfeeds and jams.
The typical easy fix printers employ is what’s called a tinsel bar. Also called garland, it looks just like what you drape on a Christmas tree, except that it’s made of highly conductive copper that needs to be grounded to the printing press.The problem with tinsel bars is that although they are cheap initially, they don’t last long. They’re not a set-it-and-forget-it solution. The sharp strands work on induction and interact with the static field on the substrate creating a neutralizing cloud that surrounds the area, reducing both positive and negative ions. Printing operations are usually dusty environments and when the tinsel becomes dusty, oxidized, or matted and crumpled, they don’t work as effectively.
Static is also created in unwinding and rewinding operations, when rolls are slit to needed widths of various presses. The removal of the web from the roll creates static charge that attracts dust to the substrate surface and can cause major problems in downstream printing operations. Installing an EXAIR Ion Bar on top of the web can eliminate this static.
EXAIR Super Ion Air Knives don’t need to be placed close to the surface like a tinsel bar. Static dissipation of 5 KV can occur in less than a half second up to 20 feet away and can be adjusted from a blast to a breeze, depending on static level.
If you are a printer, finisher or labeler, EXAIR has a static elimination product that can improve your operations. For more help you can contact one of our EXAIR application engineers to talk you through a solution.
Dann Woellert Application Engineer dannwoellert@EXAIR.com @EXAIR_dw
A company that made credit cards was having issues in their print quality, and static was the culprit. They used PVC sheets as a base material to print on, and like with any non-conductive materials, static can be generated easily and create problems. For this company, static was attracting dirt to the surface of the material, causing blemishes in the print. They contacted EXAIR to find a solution.
When non-conductive materials slide, hit, peel, and rub; electrons from the surface can move from one atom to another; thus, creating static. The type of material and the amount of movement governs the amount of static forces. These strong static forces can attack debris and fibers, as well as generate shocks, misalignment, and machine jamming. Another feature of static is that it can regenerate if the materials continue to slide, hit, peel, and rub.
For the company above, they were printing on 30 cm by 48 cm (12” X 19”) PVC sheets. They used three different processes to print a complete credit card; silkscreen, digital, and offset. After each printing process, they would lose sections of the sheet due to poor image quality. At the end, they were losing between 20 to 30% in visual rejections.
For this application, we had to do two operations; remove the static and clean the surface from debris. The Gen4 Super Ion Air Knife can do both of these operations at the same time. With the laminar air stream that comes from the Super Air Knife, it can carry both positive and negative ions from the attached Gen4 Ionizing Bar. Together, they can remove any type of static charge as well as becoming a very effective tool as a non-contact wiper to remove debris. With this ability, the print quality would not be affected during cleaning. Since static is a surface phenomenon, I recommended to also remove the static from the other side of the sheets. We did not want to have any dirt or debris that could be remaining on the bottom surface to transfer from one surface to the next during stacking. This could scrape the finish during loading and unloading of the sheets.
I recommended two pieces of a model 112012 Gen4 Super Ion Air Knives that are manufactured to 12” (30 cm) in length. This customer can easily mount one above the sheet and one below the sheet prior to printing. To operate the attached Gen4 Ionizing Bar, EXAIR offers two types of power supplies, a two-output unit, model 7960, and a four-output unit, model 7961. They can save you money when needing multiple Static Eliminators to operate in your system. With a model 7960 Gen4 Power Supply, they now had a system to remove static and clean the sheets. Once they installed the Gen4 Super Ion Air Knives onto their system, the rejection rate dropped to near zero.
All EXAIR Gen4 Static Eliminators use one of two Power Supplies – your choice of the 2-port Model 7960, or the 4-port Model 7961.
Rejected parts are costly, wasteful, and reduce production rates. If you have rejection from static problems in your system, EXAIR has a large line of Static Eliminators to help you. You can contact an Application Engineer to review your application. For the customer above, the Gen4 Super Ion Air Knives made it possible to generate more credit cards per sheet.
During a recent trip to South America while visiting our Distributor in Lima, Peru I had the opportunity to look at a few applications at an abrasives manufacturing plant. The company manufactures a wide range of abrasive products as well as adhesive tape.
Before we dive in to the application, let’s discuss static generation. There’s three ways that static can be generated. The simplest method of static generation occurs when two non-conductive objects come into contact with one another and separate. Electrons are transferred from one object to another according to the Tribolectric Series. The second method of static generation occurs as a result of friction. When two materials rub together, especially if increasing force presses the objects together, electrons can also transfer from one material to another increasing the static charge. The final method, and the one occurring in this particular application, is detachment static buildup. Due to the large contact surface area, significantly greater static charges can be generated.
Triboelectric series showing the propensity of a material to gain/lose an electron
They had several converting applications that were causing static issues in the plant. The primary concern was the operators that were constantly getting shocked whenever they had to change out the rolls. A side concern was that there was occasionally a buildup of static that resulted in the product jamming, causing production to be stopped while they fix the jam and re-feed the material.
The application that I’d like to highlight was on a slitting and rewinding machine. A roll of plastic film was fed through rollers where it is slit into three different sizes and then re-rolled. As the film separates from the roll, a high static charge is generated. After each operation, an operator had to go in and remove all (3) rolls from the machine. Each time he was zapped as he touched the roll. This not only affects productivity as they’re hesitant to remove them quickly, but was also a major concern for their safety department.
The proposed solution was to install (2) Model 112006Super Ion Air Knives, one above and one below the plastic film just after it was slit. All EXAIRStatic Eliminators produce an equal quantity of both positive and negative electrons. So, regardless of if the charge is positive or negative there’s sufficient ions to neutralize it. After installation, the static charge was immediately removed. The operator, although hesitant at first, was able to remove the finished rolls from the machine without getting a nice jolt! As an added bonus, they also no longer had an issue with the material periodically jamming in the machine.
Don’t let static problems cause problems in your process or potential harm to your operators. With a wide range of different Static Eliminators available from stock, EXAIR has a solution available that will quickly take care of it for you. Reach out to an Application Engineer today, you’ll be shocked (no pun intended) at how quickly you’ll notice an improvement.
