When offset is worthwhile

PACKAGING Reduction of costs of print forms, flexibility in the processing of the substrates and a better environmental balance: the advantages of variable format web offset printing on Muller Martini’s VSOP printing presses.

The remarkable affordability of print forms certainly helps, and in no small measure, the growing popularity of variable format web offset printing with UV or EB curing. One of the biggest European printers of packaging, a Müller Martini customer, did its sums and verified, in relation to this kind of costs, the ratio between the VSOP web offset and gravure is about 1:10. And this is not the only advantage. The VSOP press also features good waste management and considerably reduced commissioning times.

The small lot variable
The smaller the print runs the greater the saving, print runs that have notoriously become ever shorter due to the progressive extension of the range of consumer products (food in particular) and frequent promotional operations and campaigns. Here too the figures speak for themselves: in the last ten years, the volume of packaging converter orders has halved, reaching about 10,000 linear metres as the average between job orders of 500 to 40,000 metres.
The economic advantage for the printer is passed on to the customer, who benefits from a reduced price per square meter: «Being able to cut the initial costs is an obvious plus» Matthias Roth strategic purchasing head of the Swiss manufacturer of beverages Rivella SA testifies on this count. And the savings are also in terms of time. The extreme rapidity and ease with which VSOP enables the creation of the print forms generates reaction times unthinkable in flexography and rotogravure; the simplicity of the format change speeds up the set-up; web offset printing requires no plate mounting or dismounting (as in flexo), neither is a handling system of storage of heavy cylinders required (as in gravure printing). Lastly, the exposure process makes the offset plates immediately available and, more in general, the short response times ensure great flexibility in production to order and hence high productivity.
 
Ever new substrates
Another factor that is decisive in terms of quality and competitiveness of a system is the greater variety of printable substrates. Only up to a few years ago some materials - for example polyethylene - were not used in that they required a complex print job and very specialized knowledge, while today they can be printed in a stable and safe way with web offset presses.
The cooperation between Müller Martini and materials suppliers has contributed decisively to multiplying the substrates, from PE to thermoplastic material, from PLA to stretch sleeves, increasingly more popular due to the new VSOP machine web tension adjustment system. As was the case with LDPE printed by another of Müller Martini’s European customers, leading to a softer surface more consistent to the touch and with a lower density: ideal for the packaging frozen foods.
 
More respect for the environment
The third decisive advantage of web offset printing concerns the environment. The use of UV inks or electron beam (EB) curing avoids having to comply with environmental directives concerning the treatment of exhaust air and the explosion protection; in particular, explosion proof color and solvent storage facilities are not required, and aboveall there is no danger of material residue. component, cylinder and inking roller washing procedures are also no longer necessary and overall the insurance costs of the plant are reduced substantially.
The process
The purchase of a variable format web offset machine for the production of flexible packaging requires the adoption of a relatively new process.
In most cases, in fact, offset printing is supplemented by varnishing operations for the application of matt white varnish, other varnishes and ornamental colors. Hence hybrid configurations can be fielded, which make the application more complex but also more versatile because different printing processes can be combined on the same job order. The packaging converter can thus choose between numerous alternative solutions with which to enrich their range of products. And for this reason, supporters of the process sustain, variable format offset printing is set to further increase its flexible packaging market share.