Service Bulletin: SB 076.1
Subject: Anilox: Roll — PMC Inline Printer
The care and maintenance of anilox rolls used on printing-units is very important. An anilox roll is a precision manufactured component of the press ink distribution system. It is also very sensitive to mishandling damage, operating accidents, and improper formulated inks.
To assist all customers we are attaching a general information sheet on the proper use and care of anilox rolls. We strongly recommend that this information be studied by all personnel responsible for the operational use of these rolls. While our experience over many years has been very good with our supplied anilox rolls, there are instances where premature failure has been reported. Usually the failure has been related to surface damage and/or corrosion.
Whenever a problem has been brought to our attention we have assisted customers in obtaining a satisfactory settlement from our supplier. Since anilox rolls are manufactured by firms who specialize in this type of roll, PMC has minimum direct control on the unique process used to etch and plate the ink cell surface. We can not apply our standard machine warranty to this part of our Printing Press line of machinery. In fact we can not obtain any supplier of this type roll who will guarantee the roll for anything more than visual or dimensional defects as determined at the time of shipment.
Since PMC is totally dependent on an independent supplier for anilox rolls we can only transfer the limits of the supplier’s warranty to our customers. We will of course, assist any customer in filing a claim in the unlikely circumstances that any problems occur.
We are recommending that all customers inventory a minimum of one anilox roll for every two or three in service. Also to review the Information attached and discuss with your ink supplier the critical relationship of ink formulation particularly water base inks to the surface of the anilox roll.
ANILOX INK ROLLS
The PMC inline printer is equipped with an Anilox metered ink distribution system which accurately controls the flow of ink allowing the operator time to oversee other phases of the operation.
The entire surface of the Anilox Roll is engraved with minute cells, which trap or lock a predetermined volume of ink below the surface. A rubber roll serves as both a furnishing and doctor roll. You will note that the adjustment between the rubber pickup roll and the Anilox Roll is not critical; as long as they are in firm contact with moderate pressure, the f low of ink is even and consistent, as that ink which is contained in the cells is virtually all that can pass between the doctor roll and engraved roll to reach the plate or print roll. There should be no heavy layer of ink on the surf ace of the Anilox roll. When the ink is of the proper consistency, the roll has a silky appearance, indicating that the ink being furnished to the plate is being contained or locked in the cells. If the surface of the roll is covered with ink and is opaque in appearance, there is too little pressure between the fountain roll and form roll, or the ink is in need of thinning in order to permit the system to meter properly.
YOU CAN INSURE CONTINUOUS SATISFACTORY PERFORMANCE
OF YOUR ANILOX ROLLS, AND ELIMINATE FREQUENT REPAIRS, BY FOLLOWING THESE FEW SIMPLE BUT VERY IMPORTANT RULES:
Always wash Anilox Rolls thoroughly whenever the ink distribution system is to be stopped for any length of time. Use a special roll brush, with appropriate solvent, to loosen and remove all ink from roll, blotting it dry with a clean, dry lint free cloth.
Separate rolls when ink distribution system is not running. (Rotating) Do not allow either the rubber roll or Anilox Roll (depending on your type of. press) to remain in contact with the ink or with any other surface for prolonged periods, when not in use. DO NOT allow rolls to rotate in contact with each other when dry. Ink in the system provides sufficient lubrication between roller surfaces to prevent excessive wear.
Treat an Anilox Roll with the care you would use if it had a mirror finish. Remember, the surface is engraved with extreme accuracy, each tiny cell being perfectly formed. Even though the surface of these rolls is hard chrome plated over the steel engraving and “clad” bonding, for maximum protection, any scratches, nicks, or abrasions resulting from abusive handling will damage the engraving and show up in critical printing.
Keep protective fountain covers on as much as possible. This avoids the possibility of damage to roll surface due to carelessness as well as helping to prevent loss of solvent, resultant change in ink viscosity and related operational problems.
Anilox Rolls are manufactured to the exact tolerances in order to contribute their full share to the maintenance of the highest standards of which your press, at its best, is capable. Be certain that any new plate cylinders, or rubber fountain rolls (and gears) which may become a part of your equipment at any future time, are manufactured to your press builders’ specifications, and the same accuracy. This will help to insure the continuation throughout its life of the same high standards of quality originally engineered and built into your press.
Use only inks specifically formulated for metered fountains. Even minute quantities of free acids in the presence of basic dyestuffs can cause the formation of Hydrochloric acid, which dissolves the chromium plating from the surface of the Anilox Rolls and leaves the steel surface exposed to physical and chemical damage. Rolls have been known to deteriorate in a matter of hours, due to improperly formulated inks.
Anilox Rolls are of steel contruction, further protected by a high density, corrosion resistant “clad” protection, and a hard chromium surface plating for maximum durability, but they will require re-engraving eventually. The frequency will be determined largely by the extent and kind of use and the care which they receive. On an average, it may be said that Anilox Rolls in normal use on a three shift basis in average Flexographic equipment, may be operated up to one year even in variable ratio systems, before re-engraving is necessary. On the other hand, abuse has been known to reduce the life expectancy of these rolls to a single month! The above tips are intended to help you keep Anilox Roll maintenance at a minimum and to insure quality work from your press.
Keep at least one spare Anilox roll on hand for each three in use, so that worn rolls can be replaced as soon as there is evidence that the plating is worn through and before corrosion necessitates excessively costly repairs or replacement. This will help to keep maintenance costs and press downtime at a minimum.
Anilox Rolls can usually be re-engraved several times without excessively altering their diameter, unless damage or corrosion is too deep. It is therefore advantageous to catch any minor damage or corrosion as soon as it appears, rather than allowing it to develop to a point where it becomes necessary to turn the roll to a smaller pitch diameter or make other extensive repairs