In at the finish
Sophie Matthews-Paul looks at some of the finishing techniques which improve workflow and guarantee perfect end results.
The greater the variation in materials being used for applications, the higher the chances are that some sort of straight-edge or contour cutting will come into play. Although investment into flatbed cnc tables is never a low-cost consideration, the time saved and the accuracy enjoyed both make these automated additions good value for money. Shaped signs and complex geometries have always held an important place within the display sector, transforming basic square and rectangular offerings into myriad variations, now made far simpler with computer-controlled devices which can take vector data and cut to precise tolerances on a wide range of rigid and flexible material.
Cutting goes one step further, with prototyping for packaging now able to be cut and creased prior to long-run manufacture or for short-runs where the entire job is to be produced digitally. In this sector, even pharmaceutical and other small applications can be produced, with printers like the Roland DG LEC-330 able to print layers of varnish to produce a tactile finish such as Braille as well as the ability to kiss- and through-cut card stocks, boards, plastics and polycarbonates up to 1.3 mm thick. Not surprisingly, this machine uses many of the same principles as found in the company's print-and-cut technologies, thus making it suitable for smaller displays, decals and labels plus industrial work such as membrane switch panels.
However, the majority of cutting machines aren't like the Roland, which is a roll-fed unit. The preference is for a flatbed solution which is solid and stable, often based on heavy-duty routing systems where heavy-duty production was key. Thus, it is not surprising to find manufacturers formerly in the industrial routing arena moving across to digital wide-format; their cnc knowledge and expertise made it a logical step into finding new markets. Obvious examples are companies like Tekcel, whose Australian technology and build has found its way successfully into British markets, and Axyz whose Canadian origins back in 1990 formed stronger UK roots when it acquired Nottingham-based Pacer Systems in 2006.
Mimaki, too, is another name well-known amongst the sign-making and digital printing cognoscenti whose cutting technology extends to solid, flatbed tables. It is easy to forget, at times, that manufacturers with an intensive engineering back-ground lend themselves to the design and production of industrial strength equipment, such as routers, as well as printers.
The pedigrees of all these companies now dovetail with those whose products have been synonymous with cutting tables, such as Z?nd, which pulled out of the printer manufacturing market to concentrate on its core technology, and Kongsberg, now part of EskoArtwork. The construction of this machinery cannot be skimped or compromised because, in essence, it is the strength and ruggedness that enables it to perform in a stable manner. These are heavyweight beasts but, with the speed and accuracy expected from the heads, a solid build is an essential counterpoint for efficient operation.
In quintessential terms, a cnc cutting adopts the same principle as a vinyl cutter or, even, a printer in that the work is generated on a computer and the resulting data is sent to the machine for processing. The difference lies in the third dimension which requires the co-ordinates of X, Y and Z to be controlled, with the latter being the depth of cut required. This needs to vary according to thickness of material and whether it is being through-cut or merely creased for future folding. Within these parameters there are other available variants, such as Kongsberg's V notching tool where thick media, typically corrugateds used in point-of-sale and packaging applications, are cut at an angle of 45 degrees to enable a subsequent right-angle fold to be made.
With digital print in particular, the magic element remains as to how the cutter knows where to start and which route it is to follow. Origination of the job is where this starts, with the graphic element then having a contour line added as a non-printing vector. Most Rips will detect this automatically to be generated as a cutting path and each has its own, straightforward method of ensuring that the print-and-cut workflow is honoured whether it's to be carried out in a combination machine or via separate units.
Taking a sheet out of the printer and putting it on the cutting table could be deemed to create additional nightmares - a contour cut even a fraction of a millimetre out could render the end job useless. So how does the cutter know where the material lies, and what happens if it's not absolutely square on the bed? During the generation of the job, registration marks are placed on the print and, once the cutting device detects where these are, precise results are guaranteed.
Investing in a quality cutting table might seem like a hefty price to pay but the benefits far outweigh the disadvantages in many ways. Such is the efficiency of today's cutters that double-sided jobs can be produced with precision, and there are software options which enable nesting and step-and-repeat to be used when working with all types and sizes of display material, thus optimising the use of the sheet area.
Zund cuts a dash at imageData
The recent addition of a Z?nd G3 L-3200 cutting table at imageData Group's digital production facility at Howden, East Yorkshire, has brought the company fully automated cutting and trimming functions. This machine now enables fast prototyping as well as the production of low volumes for graphics used for displays and three-dimensional applications.
Designed to remove the bottlenecks which can be caused when using high-speed digital printing machines, the Z?nd G3 series enhances productivity and is able to work with materials in thicknesses up to 50 mm. The design of cutter allows access from all sides yet is based on heavy-duty construction and the highest safety parameters.
David Danforth, managing director of imageData Group, is confident that the table will add to the company's competitive edge in the point-of-sale and display graphics arenas. "We are actively pursuing these specialist markets and make no bones about wanting a bigger slice of the cake," he states. "We already offer a great service for display material, including screen-, litho, small- and large-format digital printing, but the Z?nd now gives us an even better service."
The Z?nd G3 L-3200 has a working area of 1.8 x 3.2m. Its maximum speed of 1 m/second makes it a productive unit when finishing rolls of printed material and it also automates the cutting of media as varied as Perspex and acrylic sheets, foam boards and other rigid substrates as well as vinyl films. Simplicity in job set-up and user-friendly interface were the deciding factors for imageData when it was sourcing a solution, and the company bought the unit from Z?nd UK.
"Clients have always demanded fast turn-rounds of their print projects," Danforth continues. "But, in today's breakneck, competitive climate, their requests are even more demanding. With the Z?nd G3 we are confident that we can more than keep the pace."
This installation follows the recent purchase of an Agfa MPress Tiger. As a group, imageData currently employs more than 250 people at its sites across the UK, with all of its manufacturing premises being ISO 9001:2000 and ISO 14001 accredited.
The good companion
Mimaki's manufacturing heritage lies with cutting technologies, an area in which it gained expertise long before the days of wide-format digital printers. Duncan Jefferies of UK distributor, Hybrid Services, is now seeing a sales surge of flatbed cutters and routers, saying: "This is due primarily to customers investing in companion products to work alongside their flatbed printers, with seamless workflow."
The Mimaki CF3 series, for example, has a zoned vacuum system with a blower function for easier positioning of heavy substrates. This machine comes with the necessary software for plug-and-play operation, with Mimaki's Plotter Assistant controlling the cutter from the PC and monitoring its status, whilst FineCut7 optimises the performance including direction, speed, order and depth of cut.
"The flatbed cutters utilise Mimaki's optical eye technology for highly accurate print and cut registration," Jefferies concludes. "Combined with their flexible LED UV-curable inks, cutting through a bleed on uncoated board gives a spectacular result."
Life left in laminating
With all the talk of ink durability, laminating still plays an important role in the production of wide-format print and this is true across all ink technologies. With aqueous-based print it became the norm to use an additional protective layer to give jobs longevity and this ethos followed across to solvent-based production. Many applications today, such as vehicle wrapping which we feature in this month's issue, rely on additional coverage to enable them to the perform as intended.
The quality of laminates employed not only act as a protective layer against outside influences. They are designed to be resistant to scuffs and scratches, chemicals and other forces all of which reduce the quality of a finished job and shorten its life cycle. Another advantage to lamination lies in the way the process can actually enhance an application, giving it an improved, smoother finish and bringing through the vibrance of colours.
UV-curable print, too, is increasingly being laminated and, again, the results show that the overall appearance of a job can be enhanced visually as well as being more resistant to the wear and tear of everyday life. Despite the improved durability of inks and materials when working together for all types of application, lamination is set to continue as an important element of the finishing process for many end uses. Dull prints can be enlivened with a glossy surface and matt laminates can aid visual appearance where reflection from external light can cause a problem.