How often do you think about cleaning? When visiting with customers, it’s usually the least popular subject to discuss, because adding parts washing equipment is thought of as an expense with no value-added benefits.
Is it really? It may surprise you to learn that during our press assessments and lean events, the root cause of print production issues typically points back to poor housekeeping and cleaning practices.
All images courtesy of Daetwyler USA
We often spend millions on gleaming new presses and forget they will eventually be filled with ink and need to be cleaned. Problems associated with cleaning are also overlooked. They include extended downtime, increased waste and employee safety. Cleaning issues start small but can lead to a host of additional problems that ultimately cost time and money. Let’s evaluate the problems associated with cleaning and potential solutions to those issues.
Doctor Blades
Daetwyler USA is known for doctor blades, so let’s start there—specifically, the challenges associated with dirty doctor blade holders.
Let’s see if this scenario sounds familiar to you: A doctor blade must be mounted to a flat surface. Waves created by ink buildup left in the holder cause uneven wiping by the doctor blade. This can lead to uneven ink metering, requiring a higher blade pressure and ultimately leading to premature anilox wear and scoring.
Another issue related to dirty doctor blade holders concerns end seals. As you know, the end seal must sit firmly and squarely within its cavity. Not doing so results in ink leakage leading to more parts to be cleaned and wasted ink. Improperly seated end seals can also lead to changed contact points of the doctor blade at the ends of the chamber. Once again, you’re looking at more ink leakage, and excessive doctor blade and anilox roller wear due to the additional pressure required.
Mounting brackets must also be cleaned. A doctor blade holder must sit parallel with the anilox roller. Dirty mounting brackets can prevent this, causing uneven ink film. Your customers certainly won’t appreciate the resulting color variation, dot gain and dirty print. Just think of the extra press downtime while chasing these defects. Moreover, just like the other cleaning issues mentioned, press crews overcompensate for dirty holders by using excess pressure. This can lead to warped or damaged holders and brackets.
Next, let’s turn our attention to dirty ink sumps and pails. Maybe this scene is familiar to you. (photo) Leaving ink to dry can cause ink chips to blend in. This can lead to streaks in your print. It can also cause damage to your doctor blades. The result is additional downtime to change out blades and ink.
Chemistry & Characteristics
The solution to this is obviously a parts washer. However, not all parts washers are created equal. First you need to select whether you require a solvent- or aqueous-based system. Typically, if you run solvent-based inks, then a solvent-based washer makes sense. The same goes for water-based. What if you run multiple ink systems in your facility? With the correct chemistry, a water-based mild caustic system makes the most sense.
You’ll want to consider what the most important characteristics are for a washer. Yes, of course size and price are important considerations, but they aren’t the only ones. Some, you may have never thought of before. Spray impingement is incredibly important. The closer the spray bars are to the parts, the more direct pressure they’ll receive and the faster they’ll clean. What about the up-front costs? Some parts washers require you dig a costly pit for installation. Depending on the number and size of your parts, that isn’t always the best answer. In fact, parts washers come in all shapes and sizes.
Fixturing is also extremely important to consider. Some solutions may look appealing because they have fixtures that allow you to fill your washer to the brim with parts. This practice can be detrimental to your process times and cleanliness levels due to the spray being blinded by an adjacent part. Fixturing is important, but not at the expense of functionality.
The intangibles of proper parts cleaning can’t be overlooked. Automating the cleaning process allows you to minimize your labor cost, but it also provides for faster turnaround parts, meaning you’re back up and running without a thought. A parts washer can also be safer for your operators than hand washing with solvents. Cleaning is also more repeatable. This leads to more predictable and less problematic results on press.
Dirty solvent can bog down even the most effective parts washers. Dirty solvent can leave residue on parts and increase the time it takes to clean parts. Many of our customers recognize this challenge and opt to send their solvent out for reclamation. The biggest issue with this is cost. Off-site companies often charge a premium to deal with your waste. Plus, the collection of solvent can be time consuming, labor intensive and create a storage issue where floor space is a premium.
An on-site solvent recovery system provides a closed-loop solution that is safe and efficient. You can even tie in your new press’ onboard wash-up to a distillation unit, reducing the handling and supervision required. The best news is that a distillation unit typically pays for itself within the first two years of ownership.
Lasers for Anilox
What about anilox? To function properly, a cell must be completely cleaned of dried ink. A typical water-based washer may clean away a portion of the surface ink. However, it typically leaves behind a layer of monomer. This hydrophobic substance is repelled by water and stays behind in the cell, robbing you of your full cell volume. The result is an inconsistent ink film which leads to color variation and excessive down time for color matching.
You may see the loss in cell volume and send the sleeve out for refurbishing prematurely. Ink densities are too low from plugged cells—not worn cells. Proper inspection of your rolls should be a high priority. Microscopes with automatic volume calculation are paramount for determining anilox cell condition.
Laser cleaning is the best way to clean your anilox inventory—full stop. Unlike a media-based cleaning system, laser cleaners ensure a thorough clean. The laser can penetrate every cell, no matter the size or volume. Additionally, there is no waste stream to deal with. That means no unsafe chemicals, no dirty rinse water and no guessing chemical concentration. Simply put, it is much better for the environment. They’re also safe for anilox and prevent unnecessary remakes of those with plugged cells.
Inspection of your rolls also ensures optimal cleaning results. Imagine washing your car, but not drying and inspecting it afterward. A scope—specifically one with the ability to record results—allows you to confirm and catalog cell volumes over time. As a result, it reduces downtime associated with color matching and takes the guess work out of cleaning anilox rollers.
I hope I’ve impressed upon you that clean components are critical to predictable and repeatable print results. The goal of running your business is to keep your presses running and your employees producing printed product. Good employees are hard to find. Keep them focused on tasks that generate revenue for the plant. By choosing to invest in proper housekeeping, you can improve your print results. Taking that extra step to select the right equipment means you can reduce the need for re-cleaning, reduce makeready times, and improve the environment in and around the plant.
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