The latest
development in printing is the adaption of Dry Ice Blasting technology known as
DIB for cleaning the printing machines using CO2. The cleaning process by DIB enhances
the life span of the machines besides remaining an easy cleaning technique compared to conventional mode of manually cleaning the machines using solvents, chemicals, scrubber and other accessories. However the
DIB is non toxic as no chemicals are used, non abrasive as no manual cleaning
or scrapping is involved as the process is by blasting and not conductive
technology. Cleaning by DIB won't damage sensitive parts or production
equipment but on the other hand extend the useful life of equipment and prevent
the chances of parts getting worn out early. This process is also environment
friendly as no waste is generated even after cleaning.
The DIB technique is deployed for cleaning the surfaces of the machines as well
including the inking rollers through a combination of kinetic energy (Kinetic
energy is the energy of motion- whether it is vertical or horizontal motion),
extreme temperature change and converting the solid Dry Ice into to gas all
combined and blasted with force through a small machine/ apparatus supplied by
the DIB suppliers. The blasting process i.e cleaning is done by a gun like
apparatus that has nozzle that sprays the ice pellets which are converted into
gas while operating. The machines and equipments used in the DIB process which
is latest in the adaption for cleaning the printing machines are lighter in
weight, portable and easy to manoeuvre and use.
One more
advantage of this cleaning process is that it can be deployed even when the
machines are hot due to continuous operation and reduce labour energy thus
saving considerable amount of cost in cleaning once the initial investment is
recovered within short span of time. Further advantage of DIB is that one can
clean the equipment or machines online without disassembling the parts thus
saving considerable time and cost in reassembling the dismantled parts as the
downtime of the machine and labour costs involved in the said process are
reduced.
What exactly is the DIB technology?
Dry Ice or CO 2 blasting is called DIB and is a relatively new cleaning process
using solid CO2 pellets (known as dry ice). Dry Ice Pellets used in this
process is sublimated i.e converted directly into gas, once they have hit the
surface being cleaned, finally leaving a clean, dry surface with no residue
after cleaning. For effective DIB process proper Dry Ice blasting equipment or
machines must be used along with the Dry Ice pellets also supplied by the
reliable manufacturers. The Dry Ice
pellets are made through the process of expanding the Liquid Carbon Dioxide
(CO2) to produce a snow like substance that is further compressed to make hard
Dry Ice Pellets. In the Dry ice-blasting process, the Dry Ice pellets which is
the solid form of carbon dioxide gas and which is very cold, say something in
the range of minimum 110 degrees F. is accelerated to supersonic speeds in a
pressurized air stream and directed at a surface in order to clean the
contaminants.
What happens at that point of time? The Ice pellets turning into
gas, strike the surface and lift off the strongly adhered dirt and dust and
other contaminants by mechanical abrasion and thermal shock without affecting
the surface of the part themselves on which the strongly adhered dirt and dust
and other contaminants are found. Once the strongly adhered dirt and dust and
other contaminants are cracked into minute particles, the ice pellets in the
form of gas absorb them quickly before they fall down and evaporates into the air.
Therefore it is important to use only high quality Dry Ice pellets to achieve
the best results for DIB process. Ideally high density Dry Ice pellets and cut
block Dry Ice are the two best forms of Dry Ice used for Dry Ice blasting and
the Dry Ice pellets are also supplied by the same manufacturers who supply the
DIB machines and equipments. Therefore no drying time or cleaning by solvents
arises.
DIB process
involves blowing the pellets at extremely high speeds on to the surface at
which they are targeted. The actual dry-ice pellets are quite soft, and much
less dense than sand or other plastic material. Upon impact of the blast, the
pellet sublimates (turning into gas like form) almost instantly, transferring
minimal kinetic energy on to the surface with minimal abrasion. During the
sublimation process large volume of heat is absorbed from the top layer of the
surface targeted. This accelerates the cleaning process as the top layer of
dirt or contaminant is expected to transfer more heat than the underlying
substrate which flakes off more easily. The efficiency and effectiveness of
this process depends on the thermal conductivity of the substrate and the
extent of impurities, dirt gathered on the surface. The rapid change in the
state from solid to gas also causes microscopic shock waves, which also assist
in removing the contaminant.
Wikipedia, the
free encyclopaedia gives the following information on CO2:
Quote:
Carbon dioxide
was first liquefied (at elevated pressures) in 1823 by Humphry Davy and Michael
Faraday. The earliest description of solid carbon dioxide was given by
Adrien-Jean-Pierre Thilorier, who in 1835 opened a pressurized container of
liquid carbon dioxide, only to find that the cooling produced by the rapid
evaporation of the liquid yielded a "snow" of solid CO2.
-Unquote
How far the DIB
cleaning process will be helpful compared to conventional cleaning process?
Build-up of ink and other dirt mixed with grease on printing machine can cause
several technical problems during printing and further clogging of ventilation
slots on the machine in general and dirt and dust and impurities of extraneous
material build-up on machine components inside the machines can result in
reduced print speed. Therefore the machines are thoroughly cleaned up on
maintenance days.
Generally during manual cleaning process, the built up of highly dried ink and
others are first removed by scrubbing or scrapping by and then cleaned with
some cleaning agents in the form of chemicals. Compared to this orthodox
process of cleaning, alternate cleaning process with DIB can remove ink,
grease, paper lint, and other built-up coatings in more effective manner.
Further the cold jetting process or DIB allows safe and effective online
cleaning in a fraction of the time, eliminates the use of dangerous solvents,
save cost on scrapers, wire brushes and emery clothes and eliminates the need
to dismantle the press thus reducing many direct and indirect costs such as
downtime, poor printing quality, scrap, wear of machined parts, hazardous waste
and solvents.
The machines and
equipments used in the DIB process which is latest in the innovation for
cleaning though are specialized equipments are lighter in weight, portable and
easy to manoeuvre and use. The equipments or machines for DIB have minimal
moving parts, virtually need no maintenance and has a low psi requirement.
In short few advantages seen in the use of DIB are:
-
Better Cleaning than conventional manual process in maintenance
-
No waste disposal as the gas picks up the minutely broken contaminants and
evaporates into air without leaving waste
-
Minimal Down Time as online operation possible
-
No water, solvents or Chemicals are used
-
Clean Your Equipment On-Site
-
No abrasion or damage to the parts of the machine cleaned