Taking ultrasonics to the next level

As a supplier of ultrasonic cleaning systems, Alphasonics has spent the previous two decades honing its technology and processes used in the care and maintenance of critical components of various printing processes.

Established in the early 1990s, the UK-based company has a product portfolio covering anilox roll and gravure cylinder cleaners, blanket wash module cleaners, flexo plate cleaners, parts washers, flocculation systems and industrial water recycling systems. More than 2,200 systems are installed worldwide, with partners and clients spanning a variety of applications, from the label and narrow web, packaging and corrugated markets, to electronics and engineering industries.

In the label and package printing segment, Alphasonics has worked itself into a strong position, supported by its core technologies – Alphasound, Betasound and Active Cavitation – and high-profile partnerships, with Amcor and Coveris naming it as a preferred supplier. Nilpeter, Mark Andy, AB Graphic, Omet, Xeikon, Edale and Troika Systems also work closely with its ultrasonic cleaning systems. Troika Systems designs and develops quality control 3D analysis management systems for the print industry, such as the AniCam and SurfaceCam 3D scanning microscope and management systems. It and Alphasonics have worked closely in recent years to highlight the role anilox management plays in the flexographic printing process, and that maintaining regular cleaning is integral to this process, something the two companies have termed ‘Anilox Control’. This notion holds the connotation that control of the anilox means control of the process of flexo. There is, they suggest, a fine line between this element of control and profit accumulation and protection through waste reduction and print quality, and the ability to clean a roll to 100 percent, they say, means the control printers require is realized easily. Alphasonics and Troika Systems describe this as ‘the new anilox paradigm’ and note that this message is taking hold in print houses across the world, with Europe leading the way.

The relationship between Alphasonics and Troika Systems has been further cemented through continuous anilox roll cleaning trials that Alphasonics has run, the latest at Labelexpo Americas 2016, to highlight the capabilities and safe use of its ultrasonic cleaning technology. Troika Systems has provided pre- and post-test inspection of aniloxes used in the trials to show the degree to which they are cleaned using Alphasonics’ ultrasonics technology.

Ultrasonics

Ultrasonic systems combine high frequency vibrations and a cleaning agent. Transducers generate vibrations directly related to the high frequencies that disturb the liquid at an extremely fast rate. This creates bubbles in the form of voids and vacuum chambers that collapse with enormous, heat, pressure and energy but over a nanosecond and on a scale so small that they only remove surface dirt and contaminants. The size and strength of these bubbles is controlled by the frequency employed. The higher the frequency, the smaller the bubble and therefore, the gentler the cleaning action. The bubbles implode on the medium being cleaned, drawing contamination away, while the implosions in the fluid also create a chemical reaction, meaning cleaning in this regard is two-fold.

Alphasonics ultrasonic systems operate two such frequencies, with transducers fitted to the bottom of cleaning tanks, forcing the base to flex up and down at a pre-determined rate. This core technology, Alphasound, was developed to allow aniloxes to be cleaned as often or little as required depending on the operator’s requirements. This flexibility ensures the system can in fact grow with the printer’s business as they increase their screen counts and their capabilities.

Chris Jones, marketing manager at Alphasonics, as well as being the company’s UK and Ireland sales manager, notes that when placing sound into a liquid, it is necessary to employ additional techniques to level out the ultrasonics and minimize fluctuations in activity from areas with an abundance to those where there is little to none – referred to as nodes and antinodes.

This includes the introduction of a frequency sweep to regulate the ultrasonics and minimize the creation of nodes and antinodes.

Alphasound employs this principle, although takes it a step beyond comparable systems. ‘Our nearest competitor is sweeping around 2 or 3kHz either side of a lower frequency of 40kHz, which creates an environment not conducive to consistent or safe cleaning,’ states Jones. ‘We used to employ a sweep range, +/- 5kHz, at a higher frequency, which meant our equipment creates a gentler, more precisely controlled cleaning environment. This stood us in good stead for many years, but we had to take it further. Our constant state of R&D meant we could.

‘We’re now using the transducers on the bottom of the tank to work for us to further widen the sweep rate. For this, we’re using the optimum harmonic peaks at which the transducer function. Sweeping down to this harmonic peak and back up means we’re sweeping wider than ever, 10-12kHz, and not sweeping into “dead space”, rather we’re sweeping to the perfect pitch for the transducers, meaning they are not having to work as hard, making them last longer and meaning we can offer ultrasonic cleaning that is even more consistent than before. We’ve worked with a number of sonolysis experts who note they have not seen sweeping of this nature anywhere in the world.’

Betasound takes the concept yet further by using two different frequencies at the same time along with a frequency sweep. High and low frequency pairings are designed for parts that are even more delicate than usual, such as ultra-high screen anilox rolls. Active Cavitation is an additional proprietary technology that creates disturbances in the tank that increases and enhances the formation and collapse of the vacuum bubbles that give the cleaning effect. This not only enhances the cleaning on the surface of the part being cleaned, but also causes a chemical reaction which speeds up the cleaning process. The company is also making the move to digital controls, which they believe mean that in the not too distant future the potential to service and repair systems remotely can be realized.

Concerns

Despite these innovations, Alphasonics finds itself having to defend its technology as being safe to handle anilox rolls and other soiled components of the printing process that require cleaning, owing to overall concerns about ultrasonic cleaning. Damage to components sensitive to cavitational attack appears as very small comet-like spots on the surface, while vibrational resonance may result in fracturing during the cleaning process.

Jones acknowledges that the concept of ultrasonics could cause damage in its raw state. However, he makes clear that Alphasonics’ 20-plus years of in-house engineering expertise and an unblemished history in the field means its technology cannot be fairly compared to other ultrasonic cleaning systems.

‘It’s like comparing a hard scrubbing brush and a feather duster. The other system’s scrubbing brush approach is aggressive and inconsistent but with half the bristles. Here, problems do exist, but not with Alphasonics as we’ve engineered the problems out that caused roll damage in the early days, before we were even in the industry. Unfortunately, we’ve been tarred with the same brush as other manufacturers that caused the issues.

‘The frequencies our systems operate at, the wide sweep range and the know-how that goes into building our machines [each unit is custom built to the customer’s specifications] means we can categorically state that our ultrasonic cleaning systems do not and cannot damage anilox rolls. We can also categorically state that a roll is cleaned to 100 percent of its volume capability through the use of our equipment. We actively look to be put to the test on this; we put our money where our mouth is.’

Alphasonics has such confidence in this claim that it is now providing a written guarantee to ensure, says managing director David Jones, ‘our customers feel confident in our equipment, in our technology, and most importantly our honesty and sincerity.’

Medical

This belief and the quantifiable capabilities of its technology has further enabled Alphasonics to look beyond its core markets into new areas, and to identify where its highly developed systems could be utilized. One such area is the medical market.

‘The NHS [the UK’s National Health Service] is reporting the same issues as we see in flexo when not equalizing the ultrasonics, although here the issue is reversed as over activity means there are hot spots being cleaned to the point of sterilization and cold spots where there is no cleaning, leaving residual proteins, bacteria and germs,’ says Chris Jones. ‘With a few adjustments, our technology that has served us so well the printing industry allows us to serve this critically important market. We’ve cleaned down to zero micrograms of protein, and are testing down to zero nanograms. We’re streets ahead of what’s currently available, and will start on-site trials shortly with a view to making this available to the market.

‘This will mean big things for us and the healthcare sector. I don’t feel I’m overstating things here when I say this could save lives through greatly reducing the risk of theatre-born infections. This can also provide massive cost savings to the NHS, with insurance premiums potentially reduced. We’re able to measure the results and prove them, which we already demonstrate in print houses and can now show to the medical sector.’

Future developments

As well as technical developments, corporate advances are being undertaken to ensure Alphasonics can serve the medical sector. It is going though ISO 13485 accreditation, a quality management system for the design and manufacture of medical devices, and which Jones describes as ‘ISO 90001 ++’.

This has brought about a reorganizing of Alphasonics’ operations and supply chain to meet the requirements of ISO 13485, with a focus on round-the-clock support and service capabilities. Providing the pathway into the NHS goes as planned for Alphasonics, Jones anticipates expansion of its manufacturing footprint will be ‘a must’, while the company could even split into separate divisions to serve its different markets.

Alphasonics is also soon to establish a direct presence in the US, where Jones identifies ‘huge opportunities’. ‘We ship worldwide and have many customers already in the US; now we’re looking to appoint a “Mr Alphasonics” to build trust, deepen our relationships and be the face of the company in the US.’