Anilox Roll Cleaning

Blast That Roller

In Flexo Factor Blog by Steven

Blast that roller – Considering how relatively fragile the ceramic coating is on any anilox roll, the word ” blast” is not the type of noun that I would recommend associating with cleaning of any anilox. That said this is a word that many printers associate with cleaning of their anilox with the use of baking soda, plastic media or even water blasting the surface of their anilox to assist with the removal of dried ink.

While this process does indeed remove the dried ink and coatings from the surface and to some extent from within the engraved cell none of these methods is able to fully remove the contamination from the very bottom of the cell and certainly not from the porosity of the ceramic coating.

As each of these methods is dependent on positioning a nozzle a precise distance from the surface of the anilox and is also dependent on a consistent roll rotation speed and nozzle traverse speed, any interference with the recommended manufacturers guidelines can and often results in damage to the engraved surface, banding or barber pole effects that permanently mark the surface of the anilox. More insidious is the fact that the very thin cell walls often suffer micro fracturing which is invisible to the naked eye and will ultimately lead to cell wall breakdown and the inability of the engraved cells in that area to be able to carry a consistent volume of ink or coating.

In the case of the media type blast cleaning systems they always leave a residual of the material both in the cell and on the roll surface which itself can lead to plugging of the cells, contamination of the ink or coating being used, premature damage to the doctor blade, printing plate and even the bearings on the journals of all rolls in the inking chain.

While liquid blasting systems don’t suffer from quite the same issue, because water droplets are relatively large they struggle to clean higher line count engravings above 600lpi. They also generally depend on very alkaline solutions to assist the cleaning process that in some cases are so strong that they can undermine the ceramic coating, and need to be neutralized before being removed by a specialist waste company.

Environmentally none of these processes are very green in that they generate a lot of waste and can be toxic to the operator if inadequate safety clothing and equipment is not used.

Is there an alternative? Yes of course!! The topic is called “ultrasonics” and we will be discussing this in our next article.