It’s a high-maintenance technology, but a methodical care regimen ensures excellent results, as Sergio Molino, FTA Europe, explains
Anilox is one of the most important considerations in flexography when assessing the cost vs quality balance. The user must also bear in mind maintenance – since anilox is a high-technology component, it requires significant care.
So, when choosing which anilox best suits our needs, we first must consider which substrate or medium are we printing on, and what quality level the customer requires. Naturally, the perception of quality is subjective and personal, so it is useful to establish a shared definition between printer and customer. For example, you might agree that “high quality” indicates the presence of coloured images, fine lines, coloured gradients, “medium quality” involves images with one color, strokes and screen bottoms, while “low quality” features tracts and full funds.
From this agreement, we have a basis for defining the technical characteristics necessary for the final product. This table illustrates the relationships between the main characteristics (the engraving specifications) of the anilox, considering a 60° hexagonal design of the anilox cell.
The main indication is the fineness of the screen that will be used to produce the plate, through which the anilox lineature and its volume will be determined.
What must be avoided is the minimum dot % cell catching more ink than requested, resulting in a build-up of ink on the shoulders and thus risking a stained print.
The higher the screen line, the closer the image is to the continuous tone we are used to looking at in reality.
The characterisation phase of the press allows us to establish the correct formulation of the ink to be used for four-colour printing, or with inks suitable for the enlarged gamut.
The previous reasoning leads us to say we are going to use an anilox with bands of constant lineature but with a variable volume between a minimum and a maximum possible for the lineature chosen for the optimisation phase.
Of course, an anilox with characteristics suitable for high-quality #will be much more sensitive, so we must take care to maintain its maximum efficiency by cleaning it correctly after use and storing it properly when not in use. Remember, it takes very little to change the quality result in print.
Packaging MEA Business Editor-Europe Elisa Conselvan caught up with some of the key Anilox manufacturers across the world to take their thoughts on the big question that determines Anilox’s importance, longevity and reliability:
Cheshire Anilox Technology
Sonia Arcos, Technical Director
Cleanliness is critical because dirty or clogged cells can degrade performance by reducing cell volume and causing uneven appearance or random patterns in the print or coating. Implementing a maintenance and cleaning schedule, sticking to it, and tracking it will save a converter a lot of money and downtime. This means not only ensuring rolls are thoroughly cleaned after each use but also tracking their essential data points. For example, before a job even starts, converters need to know if their anilox rolls meet the criteria they logged the last time that job was successfully produced.
Most of the damage and wear we see on anilox rolls is preventable. One of the most common problems we see is chipping at the edges of the rolls. This can lead to more serious problems like scoring. By taking proper precautionary measures and maintaining a strict cleaning regimen, converters are likely to see vast improvements in how long their anilox rolls remain viable.
We pioneered elongated cell engraving and channels to improve the ink transfer capabilities of anilox rollers and continued to expand the boundaries of print quality, performance, and consistency with our laser engraving geometry and digital measurement technology.
Cheshire anilox rolls are produced entirely in-house. This allows us to manufacture standard and custom rollers more efficiently and cost-effectively while maintaining the highest quality. This also gives us the flexibility of developing specialised manufacturing processes and meet tight delivery times.
Simec Group
Sara Besnati, Marketing Specialist
What really sets us apart is the high level of customisation we offer for specific press models, helping customers to get longer product life and guaranteeing repeatability.
Our business model is based on three pillars: data management, product customisation and performance analysis. By recording a customer’s data, its anilox is developed around his tools and his requirements, pre-settled, tested and coded. Risks and costs are reduced and preliminary tests are no longer needed. This also guarantees specs repeatability and fast deliveries by benefiting from a warehouse of pre-engraved products or ready for delivery with consequent reduction of capital.
The product customisation requires that rollers or sleeves produced by Simec Group respect specific production cycles established according to the printing machines they are intended for. It combines the cost advantages of standardisation with those typical of a tailor-made approach. Obviously, there is no chance of managing a production this way unless you control the entire manufacturing chain – and we do.
Performance analysis is based on more than five years of statistics, implemented continuously. All construction drawings are coded, each anilox manufactured by Simec has a digital ID card which works as its life tracking number; each anilox shipped to be refurbished undergoes an inspection, and data are automatically recorded. This system anticipates customer needs, predicting the end of a cylinder’s service life.
Sandon Global
Stephen Lloyd, Global, Marketing Manager
A well-looked-after anilox will wear gradually, so with regular checks printers will be able to track the reduction of wear and accurately schedule when a refurbishment is required. Experience tells me printers working to tight deadlines don’t always make time for completing detailed anilox audits, therefore we find the detailed reports with magnified cell images and best practice maintenance recommendations are invaluable to the modern-day print house.
The majority of our customers don’t have the appropriate equipment to inspect anilox cells accurately. Inspection kits can be cost-prohibitive, so for independent print houses, it is a limiting factor. However, as a responsible anilox manufacturer, we provide on-site audits for all our customers which delivers a number of key outputs including a full report on volume measurement, cell wall integrity, physical condition, and achievable ink density for their anilox inventory in a controlled way.
Praxair Surface Technologies
Geert Penne, Sales Manager, Printing Business Europe
Anilox rolls must be cleaned as soon as possible after a press run. A delay or interruption may cause an anilox roll to become ineffective due to build-up of dried deposits in the cells. The build-up reduces the roll’s ability to carry the proper amount of ink/coating.
Performing a timely audit on your anilox will help categorise the rolls by volume, screen count and pattern, giving a clear picture of the condition of rolls, thereby reducing downtime, product waste and unnecessary roller changes. Praxair developed a unique liquid volume measurement tool named URMI that helps keep track of the volume condition of your roller, maximising print quality.
The Praxair Novaline series produces better ink transfer from the cell and improved cleaning, increasing wear resistance, while the higher opening-to-depth helps increase maximum achievable volumes by 20% to 40%.
Praxair Surface Technologies performs every step in the production process including making our own coating powders and gases, developing our own coating technology and equipment, engraving, and finishing in-house.
Equipped with testing instrumentation and software, our technicians evaluate and certify every anilox roll or sleeve to the same high standard of quality everywhere in the world.
TLS Anilox
Rainer Schroers, Business Development Manager
As a basis for a constant ink film as well as high reproducibility, good and dense layers (adhesive base and ceramic layers), precise grinding machines for perfect concentricity and cylindricity values as well as the latest laser and finishing technology are required.
In addition to the TeroCoat layer, which has been successfully used for years, we have a new, innovative TeroLux layer in our portfolio, which guarantees the printer an excellent basis for great results in combination with extremely long service lives. We also offer our customers the corresponding laser engravings for all printing and coating applications.
Another very important aspect is that we have an excellent sales team which, thanks to its many years of experience, is able to offer perfect solutions for all printer applications. This latest generation of ceramic anilox rollers and/or sleeves is available at good, market-conforming prices and conditions.