The challenge for packaging printing manufacturers has always been to produce various packaging products in a wide range of print lengths—and to do so at a reasonable cost. And, for years, the print processes that met these criteria were either sheet-fed presses or web-based flexo or gravure machines. A new era of sheet-fed/flexo/gravure substitution is emerging however, as web offset becomes an increasingly viable alternative in packaging printing.
What’s made web offset a player? New and innovative technologies that provide printers with both the format and flexibility needed to compete. In year’s past, web offset’s major hurdle was its inability to allow quick and efficient format changes—critical steps in packaging printing due to the myriad of formats and precise print lengths.
Conversely, with flexo or gravure, plate cylinder changes were both routine and inexpensive. For example, one simply needed to change an inexpensive plate cylinder on the flexo press and a new repeat length ensues.
Enter exchangeable sleeve or cylinder technology, within infinitely variable size web offset presses. Now, print formats on a web offset press can be changed easily without having to exchange the entire printing inserts. The resultant process is not just quick and simple, it is also exceptionally cost effective for print lengths that change frequently.
One example of this technology is Muller Martini’s variable sleeve offset printing (VSOP) technology that contains two light weight sleeves as the only parts that need to be exchanged in order to change the print length. VSOP printing units give printers a flexible printing press suitable for an almost endless order spectrum of labels, flexible packaging and folding carton printing, as a complete job changeover is possible within a matter of minutes.
Web offset packaging printing is particularly inviting for smaller and medium-sized runs, where response times play a key role. Because manufacturing printing plates for an offset press is a very efficient and inexpensive process, frequent versioning or job change-overs are much more cost effective, versus flexo or gravure workflows.
Gravure or flexo plates are more complex, more expensive and if a plate gets damaged, it takes a lot more time and money to replace it.
And there are other bottom-line benefits when considering web offset:
- Additional cost savings. The high cost associated with printing a wide range of sizes has become a thing of the past with web offset printing. Infinitely variable plate and blanket sleeves or cylinders are very competitive to similar format size change parts for flexo equipment.
- Increased flexibility in format variability. Web offset requires just one plate cylinder for each repeat, on which different printing plates can be installed for all different types of jobs. With gravure, each and every cylinder has to be specific to that particular job, both with the additional production costs associated with manufacturing the cylinder and then storing it for future use.
- Added efficiencies. Whereas labels were historically manufactured primarily with sheet-fed press technology, today many printers are utilizing the efficiencies of printing in a roll-to-roll configuration on a web offset press. In bottling plants, in particular, it’s much more efficient to ship, handle and unroll these types of labels.
In addition, the substrate range handled by web offset presses exceeds that of comparable sheet-fed machines, with the ability to handle an extraordinarily thin 12 micron film for in-mold label production, up to a thick 300 microns for folding carton applications.
- Enhanced print quality. The keys to a successful package design are linked to both clarity and differentiation among other brands. And print quality can certainly play a key role in this regard. In some cases there is dramatic improvement with offset: it’s quite difficult to produce a good halftone with flexo, but you can make a spectacular one with offset.
And with web offset’s ability to configure a press with both in-line UV and/or EB curing technology, the task of complying with the extensive environmental requirements of the packaging industry is much less of a concern over some of the previous technologies.
- Competitive advantage. Traditional packaging printers who utilize web offset technology can expand their product range—and thus their profit potential. Hybrid web offset press configurations are available that can include in-line processes like flexo, gravure and screen printing, laminating and various finishing capabilities such as die cutting and matrix removal.