Editing Anilox (section)

==Roll manufacture and specification==
[[File:Anilox cells.png|thumb|Optical micrograph of anilox cells. Each cell is about 100 μm across.]]
Anilox rolls were originally made using a process of mechanical engraving, utilizing hardened steel tools of various cell counts and cell shapes [[diamond]] [[pecking machine]], but modern rolls are [[laser engraving|laser engraved]].
The characteristics of an anilox roll determine the amount of ink that will be transferred to the plate: angle of the cells, cell [[volume]], and line screen. A 60 degree angle ensures maximum [[density]] in a given space. Lower volume makes for less ink. Low line numbers will allow for a heavy layer of ink to be printed, whereas high line numbers will permit finer detail in printing. Both cell volume and line screen are closely correlated.   

The rolls are often specified by their line screen,<ref>{{cite web|title=What is a line screen?|url=http://facweb.cs.depaul.edu/sgrais/color_line_screen.htm|website=depaul.edu|publisher=depaul.edu|accessdate=23 October 2017}}</ref> which is the number of cells per linear inch. These often range from around 250 to upwards of 2000, though the precise numbers vary by manufacturer. Most rolls sold are within 800 LPI, although a spike in demand for those with 800–1200 lines has been seen. 
Anilox rolls are almost always designed to be removed from the press for cleaning and for [[interchangeable parts|swapping out]] with different line screen rolls.

Anilox rolls are properly specified by cell volume for the required print application. Lower volumes = thinner ink films for the highest quality process printing. Higher volumes address combination, screens, line work, solid coverage and coating applications. In virtually all printing applications with various print requirements, one volume will not print all to the highest quality. Limited print stations generally call for a compromise between the highest quality graphics and color.

There are many variables to consider when specifying an anilox roll beyond the print requirements, such as substrate, ink system, plate material, plate mounting tape, press speed, and drying capacity. The best course of action is to consult suppliers of all these components for proper engraving specifications from their experience.

=== Anilox roll specifications ===
There are two ways to specify anilox roll settings: on transfer volume or on line count. Each specification has both a European standard and an American standard.

==== Transfer volume ====
Transfer volume is the volume of ink that will be transferred per unit surface area of paper. The European standard for transfer volume is cm<sup>3</sup>/m<sup>2</sup> or cubic centimetre per square meter, which means 1 cm<sup>3</sup> of ink will be transferred onto 1 m<sup>2</sup> of paper.

Sometimes ink suppliers will give a recommended transfer weight per square meter, expressed in g/m<sup>2</sup>. This can be converted to cm<sup>3</sup>/m<sup>2</sup> by dividing by the density of the ink in g/cm<sup>3</sup>. 

The American standard for transfer volume is a billion cubic microns per square inch, typically written as BCM / in<sup>2</sup>, BCM/sq in, or BCM. A cubic micron (μm<sup>3</sup>) is a unit of volume and one billion cubic microns (1 000 000 000 μm<sup>3</sup>) is equal to 0.001 cm<sup>3</sup>. Since one square meter is equal to 1550 square inches, it follows that <u>1 BCM/in<sup>2</sup> = 1.55 cm<sup>3</sup>/m<sup>2</sup></u>.

==== Line count ====
Line count<ref>{{cite web|title=What is a line screen?|url=http://facweb.cs.depaul.edu/sgrais/color_line_screen.htm}}</ref> measures the fineness of the pattern on the anilox roll. It measures how many cells are engraved per centimetre or inch.

In Europe the standard is LPCM or lines per centimeter.

In America, the standard is LPI or lines per inch.

The conversion from transfer volume to line count is not straightforward. This is because depending on the pattern used for the cell and depth of gravure of the anilox roll, the cell might contain higher or lower volumes of ink. The only way to convert cm<sup>3</sup>/m<sup>2</sup> (transfer volume) to LPCM (cell finesse) or BCM to LPI is to look at the conversion chart provided by the anilox roll supplier.

Also, any given anilox roll will age after some time and its actual transfer volume will be less and less.