Digital printers are enjoying explosive growth throughout on print markets and around the world but do have an Achilles heel that if not dealt with correctly can lead to a multitude of issues.
I am referring to the need for priming and over coating of many materials which is being accomplished in most cases with a convention Flexo coating unit complete with a laser engraved anilox.
These coatings help to improve print speeds, adhesion, color density and give added bleed resistance. Other coatings can improve scuff resistance, create a matt or gloss finish, and even a tactile feel to the finished product.
The problem is that many companies that have got into digital have little or no Flexo experience and fail to understand the critical nature of the anilox which once used if not cleaned on a regular basis will lose its volume carrying capacity.This can and will affect all of the above features including coat weights themselves.
For those that are new to this feature the anilox cylinder or sleeve has a ceramic coated surface which has been engraved into using a laser device and by means of varying the power output of the laser beam cells are created with varying cell openings,depth and walls that dictate the carrying capacity of each engraving.
More commonly the engraving is know as the screen or line count per linear inch (LPI) or (LP/CM) in metric . Generally the higher the line count the smaller the cell openings and the more uniform and hence thinner coating can be applied to the substrate.
The theoretic volume carrying capacity of the cells is referred to as BCM short for billion cubic microns.
While ceramic is extremely abrasion resistant it is very brittle and cannot withstand impact damage and will fracture and even lift from the the anilox core. It can also be very porous and is therefore prone to becoming contaminated with each use which eventually spills into the cells and in turn reduces the carrying capacity of the cell.
Other factors that can lead to banding , scoring and staining include:
- direct contact with the chamber unit
- entrapped material between the blade and anilox
- dried material being allowed to build up on the blades and not removing before running
- running the unit without sufficient coating pumped up into the chamber
- failure to pump sufficient material into the chamber during a print run.
So how do you overcome or at least reduce these issues. The first step is to obvious avoid any of the above but in a real production environment the above issues are almost unavoidable particularly if your operators and managers are unaware of the importance of the anilox and how to care and protect it.
Cleaning your anilox after every use by hand is a good start although labor intensive if you use our eliminator, glu-b- gon, rejuvenator or presscleen wipes along with our stainless steel scrubbing brushes and erazor sponges anilox can be restored to an acceptable condition. That said not every operator has the time or the energy to clean every anilox as well as is needed so we recommend purchasing one of our ultrasonic cleaning systems for maximum deep cleaning and minimum labor cost.
Our machines can be built and designed to suit your anilox and can clean single or multiple anilox at the same time.
There are also differences in the quality, durability ,porosity and hardness of anilox coatings which is why we recommend Sandon Global due to their advanced coatings, lasers,and software .
For more information please call or email us.