CI flexo in practice
Automatic and semi-automatic systems make plate mounting fast and accurate. Sleeve technology combined with simple unlocking, removal and locking systems on the machine print stations make plate unloading and loading a simple task that can be completed within 15 minutes for an eight-colour job.
In-the-round plate making eliminates the joining line and can be used in smaller sized jobs where such a line may not be acceptable. The joining line is by-and-large not an issue in bags 1kg and above or in pre-formed bags where the line is rimmed out as part of the bag making process.
The CI drum supports a large number of substrates from light- to medium-gauge aluminium foil; PET films from 10 to 50 microns, BOPP films from 12 to 50 microns, BON films from 12 to 30 microns, paper from 30 to 100 gsm, PVC Films from 30 to 50 microns as well as their metallised versions. Modern CI flexo can run all these substrates non-stop at speeds from 300m/min going up to 600m/min with splicing at input and output at full speed.
Electron beam curing at the output (post application of a suitable curing lacquer at the last station) enables high gloss scuff resistant surface printed jobs. This is a boon for surface paper jobs for ORS, condom, cough lozenges and pan masala.
Current CI flexo applications
Heat seal and cold seal lacquers can be applied in line in register with the help of a reversing station. Thus, two-ply chocolate wrappers can be reduced to single ply wrappers. Nestle Brazil is using a surface printed 35 micron metallised BOPP wrapper (for one of their major brands) with registered cold seal printed in CI flexo with e-beam curing.
The benefits are quick converting, lower cost, easy tearability and recyclability. CI flexo easily handles stretchable substrates such as poly films and CPP films, which can be printed in gravure only at lower speeds and with high wastage. With e-beam curing, scuff resistance is not an issue even with rough handling and bumpy transit in sacks. E-beam cured lacquers also add to barrier properties.
Opening new markets
A large number of products currently packed in Pet/poly bags such as detergents and flour can easily be switched to surface printed e-beam cured CI flexo printed poly bags. These bags are more compact, free from crumpling and have no failure in drop tests. Pinholing to take out entrapped air is not required. The pack feel is soft. COF of the e-beam lacquer can be adjusted to ensure stackability. These bags are easily recyclable.
The market for diapers for babies and incapacitated senior citizens is growing rapidly in the country. Female hygiene products are in great demand not only in urban area but also in rural areas. They are giving new freedom and dignity to our womenfolk. All the diapers and female hygiene products are being packed in poly bags which are highly amenable to printing in CI flexo.
Modern HD flexo prepress with new generation thermal plate technology makes possible gravure quality reproduction. A complex new job can be printed in CI flexo within 48 to 72 hours. Short runs are not an issue given the ease of changeover, time for changeover of only 30 minutes and low changeover wastage (50-100m).
Modern CI flexo facilitates solvent recovery by using less solvent. The inks are free of toluene and ketone and are primarily alcohol based. Solvent recovery is much simpler and can be a practical option even in India.