ABG International Sabre Extreme laser cutting unit
While most wide web flexo is simply slit and rewound for subsequent processing at a packer/filler, that is not the case for label manufacture where converting is key. There are many types of finishing with additional print/coating, lamination, foiling, die-cutting and matrix removal, slitting and rewinding in general use for self-adhesive stocks. By Sean Smyth.
Finishing is dominated by mechanical systems and as runs shorten the trend is firmly toward more flexibility. Servo motor control and magnetic tools reduce die and set up costs and suppliers have done a lot of work to shorten set up times with quick release and fast changeover systems.
The UK has several innovative and successful suppliers. AB Graphic International is probably the market leader in converting after digital presses with over 500 of its Digicon systems now in operation. It provides modular systems offering a full range of options including semi-rotary die-cutting with accurate re-registration, spot colour or coating with flexo or screen, flatbed screen printing, lamination, hot and cold foiling and hologram application, embossing, matrix waste removal, slitting and rewinding. There are camera verification systems for security and users can add modules as the job range grows.
Nottingham-based Focus Label Machinery offers its Reflex range with full rotary servo drive technology and auto re-register system, allowing printed webs to be overprinted and finished to roll or sheet. Rotary die-cutting enables higher converting speeds than semi-rotary convertors and top speed is over 100 m/m.
Daco Solutions is based in Yorkshire and it sells the D250R as an off-line system for smaller digital label printing presses, either rolls or sheeted. It incorporates servo drive technology with maximum speeds up to 100 m/min. There can be either one or two rotary die stations, slitting and independent tension control for unwind and rewind. It incorporates web guides and an ultrasonic sensor for guiding of opaque and clear materials. The touch screen control has an accurate count facility and optional equipment includes closed loop tension control, lamination, slitting and dual rewind.
Also from Yorkshire is Bar Graphic Machinery, which offers the Elite FDTR (flexo die-cut and register) system for digital producers and reports six installations since its launch last year. It is also offering inkjet print modules to make a complete print and finishing line.
It is not just the UK. Italian company Prati has the VEGAplus series, a modular design with single or twin die-cutting stations with full servo drive and electronic control of speed, position and torque. The die-cutting stations are reversible for front or back cutting with automatic registration with continuous correction to reduce waste.
Minneapolis-based Delta Industrial provides a full range of finishing options on the Spectrum series, with semi-rotary die-cutting and laser cutting among the expandable modules. Systems are touch screen controlled with much work on developing its HMI (Human Machine Interface) software and they include thermal printing and barcoding options.
Laser cutting
There are also digital finishing systems coming to the market with laser cutting and this is steadily growing.
Laser cutting systems use high powered lasers to vaporise material in the beam path. Extraction systems remove the vaporised components at point of cutting with through and kiss cutting, and perforating possible. The cutting path is fully adjustable, throughput speed depends on the total beam path length and many systems employ multiple lasers.
The benefit of using lasers lies in the time saving achieved in the set up and removal of tools and dies. There is no delay in obtaining the die and faster set up of finishing, even against the latest quick change analogue finishing. They are used for both prototyping where there is no delay or expense for tooling, and increasingly full production as performance improves and cost falls. There are other functions with patterned cutting and etching available that can be useful for security applications. As more systems are installed there will be new capabilities.
Novel applications are being opened with laser cutting. German converter Hagmaier Etiketten & Druck uses a CSat (Heidelberg) inkjet press with a Cartes 350 laser finishing system to produce labels. It uses laser cutting to broaden the functionality, one innovative product is a ‘drop indicator’ to show if a pack has experienced a severe shock, for example being dropped in transit. Hagmaier’s system involves a precise cutting pattern to cut some 99% of the path, leaving the rest to keep the parts attached. If dropped, the shock breaks the joined strands, indicating potential damage for the recipient. It is virtually impossible to provide this accuracy from a mechanical system whereas laser cutting can guarantee easily reproducible results.
There are two fundamental types of laser cutters, gantry and galvo (galvanometer) systems.
Gantry systems are mounted over the material path with the laser path like an X-Y plotter. These are straightforward in design, are quite slow for complex cuts but are low cost with a single laser source. Clean cuts result when the laser cuts in the perpendicular, wider paths can give noticeable undercut but this is not an issue in narrow web. Galvo systems use mirrors to direct the cutting beam(s) that give more consistent angles of cut, with greater throughput. They adjust the mirror angle to reposition the laser beam in different directions, as the artwork dictates.
Laser technology is developing with power increases at lower cost with 400 mW models being used, often with multiple sources. The lasers are powered on and off at high speed, delivering a series of power bursts that follow the pattern with great precision, while not allowing the substrate to overheat or burn. There is better software control and integration; improved software reduces time for all operations yielding speed increases alongside cutting sequence optimisation for faster throughput.
Digital finishing set up is comparable to that for a digital press. The systems will show the throughput speed and set up specifications can be saved. Calibrating substrates is necessary and a simple routine that works out the required power delivery and cutting will be phased with any other finishing operation.
Several digital press suppliers offer integrated inkjet and finishing units such as the INX Systec NW140 or EFI’s Jetrion 4900, while standalone systems are available from many sources. High-end laser cutting can run to over £150k but the prices are falling and there is a growing installed base.
It is not just for labels. In carton production a new technology launch shown at drupa was the Highcon Euclid, a digital cutting and creasing for sheetfed which splits cutting and creasing. Creasing uses a rule extruded onto a foil mounted on a cylinder, while the cutting is a laser system. The benefit will be reducing the finishing set up time, saving the cost and time for a die and setting up the cutting and creasing.
Highcon is an Israeli start-up, trying to transform cutting and creasing from an analogue to a more streamlined digital process. The first beta machine has been installed at Israeli carton producer, Graphica Bezalel, which is happy with the initial results. Quality is indistinguishable from traditional mechanical cutting and creasing. The rationale for the installation was to handle more designs, taking short and medium runs off analogue cutting and creasing machines. The Euclid can cut many shapes and allows greater flexibility over conventional dies – new products include kids games and puzzles. It takes some 15 minutes for a job change and the machine lets Bezalel combine multiple designs on one sheet saving costs, providing the next run to be a different composition with no standing dies. It offers new features such as enhanced security with individual marking, engraving and embossing capability.
Laser show
At Labelexpo Americas in Chicago, there will be a workshop for laser finishing, comparing machines from Sei Spa (which provides the cutter in the Jetrion 4900), Spartanics, AB Graphic International and Delta Industrial. At the show each will run several jobs, digitally and flexo printed for food, personal care, industrial and pharma labels on several stocks. There will be cutting and the systems will also be used to etch numbers to let visitors see their full potential.
Each session will include an explanation of the origination and pre-press, how the labels have been pre-printed, the different requirements for re-registration and job changes during the run, the incorporation of sequential coding and workflow implications and outputs. As with previous Labelexpo technology workshops, the sessions will conclude with questions and answers, and the availability of sample packs of all the different laser cutter outputs so there will be first-hand opportunities to examine the quality of the cutting and compare with analogue methods. Other suppliers not in the workshop include Cartes, LasX, ALS and Prati.
I expect to see more digital finishing systems. They are easy to operate (Spartanics claims that the level of operator skill is similar to ‘operating a cable TV menu’), when combined with printing make single pass conversion fairly straightforward. This will encourage new entrants into the market, with commercial printers seeing the technology as way of broadening their product range. They offer more control and flexibility for many short run products. Prices will continue to fall and as systems are installed new added-value features will develop from innovative converters.
