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Printing presses are among the most expensive investments any business can make for their print companies. Presses are also the single-most important piece of equipment when it comes to the long-term success and profitability of professional print operations. The presses that maintain like-new performance over a longer period of time deliver more consistent, high-quality outputs with less waste and fewer reprints than presses that struggle with performance issues. When properly set up and maintained, presses can provide many years of excellent operation while also avoiding expensive repair costs like replacing or resurfacing an anilox roller or extensive downtime from out-of-house deep cleanings.
In these ways, presses are similar to new cars in that both are significant investments for the professionals or families who drive them. Another similarity is the fact that both of these expensive pieces of machinery require additional consumable components to keep performing at optimum levels. The balance between maximizing performance while minimizing out-of-pocket expense is always tricky – spending more doesn’t always guarantee better performance, just as spending less can end up costing more in the long run. With that in mind, true “value” lies in spending the just-right amount to ensure performance over the longest-reasonable period of time, effectively minimizing total out-of-pocket costs to enjoy maximum output. Perfecting this formula requires careful attention to three key areas: Proper Set Up, Proper Procedures, and Proper Preventive Maintenance.
PROPER SET UP
Consider the printing press vs. automobile similarities with a situation to which many of us can easily relate… tires. There are many options for tires out there, from very expensive high-performance models to low-cost ones that have fewer features or benefits. How you drive and what you expect from your car strongly influence your ultimate decision on which models you choose to buy. But that’s only part of the process. Consider how people (this author included) worry about getting new tires installed. It is never a short process and time is valuable, but rushing the technician might mean an important part of the installation process accidentally skipped or improperly completed, like balancing or torquing the lug nuts. Now, because of an avoidable rush, there will be issues down the road – not just for the tires, but perhaps for the entire vehicle. Taking the extra time to maintain proper air pressure and ensure correct alignment on a car not only maximizes the life of the tires, but also provides a better, more trouble-free ride.
This is a good way to look at building a doctor blade chamber. The better the chamber is prepped, the fewer issues you are likely to encounter on a job. Building the press chamber is where operators have the most control over print quality, and yet, it is often one of the most overlooked pieces of equipment, usually due to being in a rush. When rushed, press components are typically not cleaned thoroughly, and inconsistencies usually result in waves or uneven surface pressure in the doctor blade. Since blades should mount perfectly flat, press operators apply additional pressure to compensate for the waves — even though the preferable action is to remount the blade in a clean, precise chamber. Adjustments to pressure alone can lead to uneven metering, uneven wear on the blade, and most negatively — uneven wear on the anilox. This is the exact type of scenario that is most often the culprit when it comes to anilox and doctor blade failure.
“Wavy” blade due to inconsistent tightening or ink residue remaining in holder.
Just like tires on a car, doctor blades have a significant impact on how well printing presses run. Everyone wants that do-it-all doctor blade, but just like certain tires are meant for certain roads or driving conditions, doctor blades perform best when correctly matched to the application for which they were meant. You wouldn’t run snow tires on a NASCAR track or NASCAR tires on a dirt road. The same holds true for doctor blades.
Take, for instance, white ink and all its harsh ingredients, such as Ti0 to help with opacity, plus the need to run a lower-line engraving anilox roll to deliver more ink for better opacity values.
Success under these conditions requires a more-robust doctor blade to help manage these challenges. Moreover, since white ink jobs rarely require small fine type or reverses, a radius edge is recommended for best results.
Conversely, for a high-line anilox engraving for use on combination and process printing, a finer-tip doctor blade is better suited for optimum output. Having higher anilox engravings means your cell walls are thinner (more fragile) and this is why finer tip blades are recommended.
You do not want a weak or thin-bodied doctor blade that will over-flex, because when doctor blades do so, they create more surface contact with anilox roll engraving (drag), which in turn causes more wear and friction on the blade and anilox, plus unnecessary over-use of ink. A thicker-bodied doctor blade with a Lamella or bevel metering tip is the best option here as you want to control the ink film thickness to control color variations.
Think of it like tire pressure and how that air pressure impacts tread wear – again, very similar to a doctor blade. The aim is for the doctor blade to exert only the absolute minimum amount of chamber pressure to the anilox roll. With a fine tip doctor blade, you do not need excessive blade pressure for good metering. Just like a kiss impression of plate to substrate, you want the same kiss impression between doctor blades and anilox rolls.
PROPER PROCEDURES
If there’s one word every pressroom hates, it is “downtime.” Changing a doctor blade means you will need to flush down that print station, use solvent doing it, and create “downtime.” On average it takes a pressman/assistant 20-30 minutes to properly change out a doctor blade when needed on press.
There is a dollar amount per hour on a press and everyone related to this press should be made aware of it so they can take ownership. Being down for changing worn or bad doctor blades is not only an unfortunate waste of time and money, it is also completely avoidable.
Just like installing new tires on your car, a doctor blade chamber needs to be properly built every time. Doctor blades need to be properly mounted on blade holders and properly aligned.
This is where many pressrooms really struggle in the name of saving time. By rushing through the process of changing a doctor blade and getting the press going again as soon as possible, print quality and equipment condition both suffer. In an effort to save time upfront, pressrooms end up losing way more time and encounter more issues in the long run.
The ideal scenario that will consistently yield the best results is to invest in a professional-grade parts and equipment washing system specially made for applications like printing, coatings, or adhesives. These systems are optimized for thorough, yet gentle cleaning of components with solvents, pressurized sprayers, specialized brushes, or a combination of these methods. Rather than send equipment to a third-party service (which would cause more down time), your operation can utilize the same caliber of cleaning equipment in house for bringing equipment and parts up to like-new condition between each and every change over, if desired.
It’s like having a full-service mechanic and an auto detailer right in your own garage to flush the fuel injectors and change the oil, filter, and fluids every time you drive. If you want your car, or in this case, your press, to perform like new longer, then an in-house professional cleaning system is a worthwhile investment.
However, if your operation isn’t quite ready to bring professional-grade cleaning and maintenance in house, you can improve your results by adopting a few policies and behaviors:
When the above steps are followed, doctor blade changes can be planned instead of being the result of blowouts and doctor blade failures. Once chamber and doctor blade set-up is optimized, you should be able to run more consistently and have longer uptime rather than “downtime.”
Allow the extra five/ten minutes to properly build chambers with the right doctor blades, end seals, and settings. Taking the extra minutes to do it right can save hours of downtime cleaning out blowouts from poorly built chambers. Housekeeping does play a huge role in properly troubleshooting and maintaining a good running press.
Ensure no items are left around print station areas after building chambers in press; dirty rags, tools, solvent cans, and even excess ink on print stations or drip pans.
PROPER PREVENTIVE MAINTENANCE
Another important factor is maintenance on the print station itself through PM (preventative maintenance). Just like performing an alignment on your car tires, having proper alignment of chamber to anilox roll is very important. PM needs to be performed on all moving parts on a press and specifically on print stations. It will not matter how well you properly build any doctor blade chamber if it is not properly aligned to anilox roll. Most newer presses do come with their own jigs
Rapid changeovers only really save time when done correctly. Rushing for improper set up actually causes more problems than it solves.
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to align chambers to the anilox roll. Setting up a quarterly or semiannual PM action plan to create or check alignment is very important. No matter how many print stations your pressroom has, properly maintained print stations that can operate as expected is one of the most important areas for ensuring clean print, register, and consistency.
Downtime can be properly managed by following the above guidelines primarily by being proactive instead of reactive. Scheduled downtime to perform preventative maintenance on a press can save hours of unexpected time stops, waste, and headaches. Investing in quality components, quality procedures, and quality maintenance all help deliver quality results in terms of print output… and it helps prevent damage to expensive equipment over time.
Nobody wants to be stuck on the side of the road waiting for a tow truck because of failing to do a couple of checkups. Making a commitment to quality keeps you — and your press — running at peak conditions.
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