Flexo’s Achilles heel

The most overriding, yet under-estimated factor in Flexo over the past 30 years is the negative effect not keeping the anilox clean enough has on the whole of the business. From top to bottom, side to side, who would think that such a very small amount of contamination on an innocuous little roll could cause so much upset and cost so much money and lost profit?

Businesses large and small spend all they possibly can on new presses, but in many cases, fail to understand or account for the negative impact not controlling the anilox will have on their investment. The big-ticket items often overshadow the little things that really matter in the process of Flexo.

The true process of Flexo is found in the pre-press arena. The press, whether big or small, expensive or cheap, is only a vehicle that takes wet ink and puts it onto paper…some do it at great speed and amazing accuracy, others don’t. But at the end of the day, they all basically do the same thing. A bit like a car that gets you from A to B, some do it in great comfort, speed and style, others don’t, but you get there in the end. The essence is to get the best out of what you have by controlling the process.

Within the pre-press area, there are 4 basic elements; ink, substrate, plates and the anilox. When all things are considered and the first 3 are correct, they tend to stay on track and it is only the anilox volume that will change from day to day, making this the most critical area of control in the whole process. Failing to properly address this will have a negative impact on any Flexo house, especially in a reduction in print quality and consistency, leading to lost profit and poor ROI.

So why has Flexo as an industry found it so difficult to get on top of this Achilles’ Heel?

There are two basic reasons for this. Firstly, Anilox Development. What has been noted over the past 20 years is how anilox producers have led the charge for higher screen counts on the back of laser development. Why? Because they can. Higher screen counts were introduced into the market as a means of achieving higher print quality, but nobody gave a thought as to how these rolls would be cleaned, or the effect inconsistent cleaning would have on the industry.

It was left to the producers of cleaning systems to play continual catch-up with the incessant increase of screen counts. It is also fair to say that the first casualty of this was early Ultrasonics, as the initial rise in screen counts back in the early 1990’s caught everybody off guard. The low specification, more aggressive Ultrasonic equipment that was happily cleaning 250lpi aniloxes with their nice thick cell walls in the early 90’s, was suddenly expected to clean 600lpi aniloxes by the mid 90’s, with their much thinner, more delicate cell walls. What must be understood is that all machinery has a field life and it was not the fault of the manufacturers that the item that the machine was originally designed for changed to an item that it was not. Yet this fact was either not recognized or simply overlooked and it was Ultrasonics that obtained the bad name.

The next methodologies to fall were the blasting methods, Polymer Bead and Bi-Carbonate of Soda, who picked up the mantle from early Ultrasonics. Their ‘reign’ lasted about 5 years from about 1995 to 2000, over which time screen counts had again risen from about 600lpi to 1000lpi, leading to blasting of any persuasion to fall from grace because of poor performance and or damage to the cell walls.

Throughout this decade, 2 systems stood the test of time; Alphasonics and Jetwash

As we all know, screen counts have continued to increase further over the past 20 years, with average counts now between 1200lpi and 1500lpi, even going up to 2000lpi. Where they will end up in the future is anyone’s guess

Anilox manufacturers for sure had the best interests of the industry at heart when launching higher screens. The same cannot be said however for the perpetrators of the second reason. ‘The Long Con’ as practiced by one particular Jetwash supplier, who set out to deliberately blacken the name of Ultrasonics as a method of cleaning anilox rolls, citing the damage caused by the early ultrasonics systems and using emotive language at every opportunity to plant the seed of doubt in the minds of prospective customers. This widespread, deliberate mis-leading of the industry as a whole has been highly effective for them, but a shameful practice nonetheless. A shrewd sales tactic one would think, But what damage have they really done to the industry?

The fundamental flaw in the tactic is that Jetwash as a method for delivering an acceptable cleaning level is a very poor one, with inconsistent results, excessive on costs and environmental issues. In essence, the aggressive tactics employed in the Long Con have caused great damage to the sector by engendering poor print quality, along with high chemical and disposal costs. It is fair to say that they have ‘kidded’ the industry into believing something that they knew was not true, therefore costing every customer that was taken in by their deception. However, all is not lost, as it is now becoming clear that the industry has realized what has been done both collectively and individually and is turning its back on this method of cleaning anilox rolls. Jetwash is clearly not (and never was) fit for purpose. However, the damage to the industry over the past 20 years should not be underestimated, forgotten or forgiven.

As Jetwash as an acceptable anilox cleaning method falls away, a new way of cleaning rolls has emerged, primarily due to the Long Con. Most Jetwash users will generally not buy a second system and with the negative press that ultrasonics has wrongly been given, when a new system is required, what are the alternatives? The customer doesn’t want another Jetwash and ‘everybody knows’ that ultrasonics will damage rolls, so what else is there? As it stands today, the only other choice is Laser Cleaning.

This method of cleaning an anilox has its issues (please see our ‘Good Reasons’ leaflet), but the major concern is that of the Nano-Particles that are released when the toxins in the ink are vaporized. (To find out more about this, go onto the internet and simply tap in ‘Nano particles and the effects on lungs’.) A whole raft of academic documentation can be found regarding this. There is nothing more that needs to be said about this method of cleaning, other than as it stands the smoke emitted during this process is known to be carcinogenic.

The risk is clearly real and as these particles can sit in lungs for may years before causing issues, it may well be that the manufacturers of these devices will be long-gone before the full effects are known, meaning that recourse may be impossible.

This just leaves Alphasonics and other ’commercial grade’ ultrasonic cleaning systems as the only viable method for anilox cleaning going forward. But comparing the devices is like comparing apples and pears. Here’s why.

When sound is applied into fluid, the dispersion is quite erratic, with both spikes and troughs of sound every few seconds. The spikes have the potential to erode cell walls and the troughs have the potential to engender impaired cleaning.  It was not until 2018, when a device was developed to measure this disparity, did the scientific evidence emerge as to why some ultrasonic cleaning systems have the potential to damage cell walls and others don’t. Alphasonics have applied this cavitation measuring device to every other ultrasonic cleaning system we know of and found that they all possess the same traits that make them capable of damaging cell walls through regular cleaning. I should stress that these devices have the ‘potential’ to cause issues, not that they will.

GRAPH 1 Shows the activity in a commercial grade system. The spikes of sound that can be seen are not particularly large at 6mV, but are incessant, happening every few seconds. It is these spikes of sound that give rise to potential cell wall damage.

The fundamental problem lies in the screen counts that are being used today. The cell walls are an issue for sure, but it is the actual volume of these cells, meaning that cleaning needs to carried out much more regularly to maintain control of the anilox and as such, the process. Any ultrasonic cleaning system that does not have the requisite safety features can damage the cell walls through undertaking the regular cleaning that is needed to take full benefit from the higher screens. In all honesty, we are entering an almost medical grade cleaning requirement in Flexo. These rolls, with their 2µ-3µ cell walls have to be cleaned to 100% full available volume at least daily, if not more and a standard, ‘commercial grade’ cleaning system, does not ‘cut the mustard’ at this level. The risk is there, it is real and can be proven.

GRAPH 2 By comparison shows the very even distribution of sound in an Alphasonics Advanced Ultrasonic device. Note that the spikes have been compressed to only 1.6mV and while we know that we can never completely eradicate the spikes and troughs, (nor would we want to as this is what gives us the chaos required to effect cleaning) we have been able to reduce their size so that we achieve a very even distribution, thus enabling cleaning safety, efficacy and consistency.

The advanced technology developed by Alphasonics, especially since 2013 is a unique, safe, highly effective methodology that offers peace of mind and is the only feasible cleaning system for anilox rolls and sleeves going forward. The equipment is now recommended by several large print groups, plus most press and anilox manufacturers. The technology can safely clean even the highest screens on a regular basis without causing damage and as such will deliver a speedy ROI. The effectiveness of this technology is highlighted further by it’s uses for precision cleaning of surgical equipment and instruments in the healthcare sector. This technology has a ‘No damage’ guarantee against aniloxes from any supplier and any screen count. Furthermore, gone are the days when anilox development will outstrip the ability of an Alphasonics system to safely render the roll 100% in complete safety no matter how often cleaning takes place.