Evolution of Slitting-Rewinding in Narrow web label converting.
An Indian
perspective!
Slitting, rewinding and more, are pre-printing and post printing processes in the narrow web label printing industry. Prior to printing, larger width labelstock rolls or jumbo rolls as they are referred to, must be slit to the size as per the printing format of the label job in hand.
The operation basically involves unwinding, slitting with circular knives or razor blades and rewinding. Paper stocks are slit with circular knives while filmic substrates are slit with razor blades. Additionally, the equipment would have web aligners and tension controls.
Narrow web label printing in roll form made its entry in India in the early 1970s when very narrow flatbed label presses imported from Japan, started being used to print labels. In the earliest times 4 or 5-inch-wide label presses were in use on which single label across was printed. So, post printing slitting was not required. These presses would print at 5 to 10 meters per minute.
By the
1990s, rotary narrow web CI label presses like the Mark Andy 830 were launched and started going wider
to 7inches and on to 10 inches enabling printing of multiple labels across the
web with need to slit them after printing and die cutting. Narrow web slitting
and rewinding started being done online with an extra die cutting station and
dual rewinders on the presses. These presses would run at anything between 30
to 50 meters per minute. It was an innovation at that time, to do unwinding,
printing, die cutting and slitting online in a single pass.
Instead of investing in another label press, it would be better to invest in a slitter rewinder. At this time, an offline narrow web slitting rewinding machine complementing the width of their label presses became a necessity.
The transformed slitter rewinders in the narrow web label
industry to complement digital label printing became further evolved to be
finishing equipment with a lot of automation, higher speeds and capabilities to
have one or two flexo stations to do hot or cold foiling or multiple types of
varnishes, print barcodes with monochrome digital barcode printers, inspection
system, intermittent or full rotary die cutting, waste matrix removal, slitting
and rewinding finished label rolls. All this is offered with automatic slitting
width blade setting systems. As the industry evolves to take in its fold
products like in-mold labels, shrink sleeves and pouches, sheeting and
conveyers are added with counting and stacking options for increased
productivity.
The upgraded slitter rewinder, renamed as finishing machine has now become a necessity for any progressive label converting facility. A friend from leading label company that has multiple units in the Middle East, said to me, “the scenario has evolved such that for every press that we acquire, it has to be complemented with a finishing machine or an evolved slitting rewinding machine.” He further asserted, “this is to achieve more, with less!”
Written by Harveer Sahni, Chairman Weldon Celloplast Limited
New Delhi India May 2024
The above article is written for publication in Magazine published in UK
Reproduction without author's consent is prohibited.