Wide format finishing, as with offset and digital, is what turns a piece of print into a sellable product; it’s a vital part of the process. There are several finishing options, depending on what you want to produce and the effects you want to create. In the latest Print21 magazine, Nessan Cleary of Digital Dots presents an overview of technology options.
Wide format finishing, as with offset and digital, is what turns a piece of print into a sellable product; it’s a vital part of the process. There are several finishing options, depending on what you want to produce and the effects you want to create. In the latest
Many wide format users tend to concentrate investment efforts on the printing process, which means that finishing can be something of an after-thought. Yet it’s the finishing that turns the printed sheets into sellable products, so it pays to know what options are available. This can best be summed up as laminating, cutting and welding or other forms of ‘joining.’
Laminating covers both surface protection and bonding printed sheets/rolls to rigid boards. UV-curable flatbed printers capable of printing directly onto 50mm or thicker boards have reduced the need for bonding but it is still popular using roll applicators, particularly for lenticular traffic and safety signs.
Protection of printed jobs is the widest use of lamination in wide format; either to give fade-resistance for aqueous dye inkjet prints, or to increase the outdoor durability of solvent or latex prints. There’s also a wide range of laminate films available with added effects ranging from anti-glare, anti-slip for floor graphics and anti-graffiti, to textures and finishes such as lustre, pearl and gloss.
Hot or cold
There has traditionally been a choice between thermal lamination, which relies on heat as well as pressure to activate the adhesives in the material; and cold lamination, where pressure only is used to force special adhesive to bond the layers together. Top of the range machines still have two heated rollers for encapsulation as well as laminating, but lately there’s been considerable emphasis on ease of use. These days most people opt for a laminator with a single heated top roller and use pressure-sensitive laminates with some heat to help activate the adhesives for a better bond, which is an easier set-up to work with.
An interesting variation is the flatbed laminator, which is useful for adding laminate effects to rigid materials. The media stays still while a pressure roller moves over it. There are also liquid laminators which are suitable for applying UV- protective coatings for outdoor durability and for enhancing the finish of the print. Protection, bond and evenness using UV liquid lamination is first class and at a lower cost per square meter, but the machine itself costs considerably more than a roll film laminator. Liquid UV also has the advantage of coating and rewinding an entire roll of wide format graphics, with cutting taking place afterwards, thereby increasing productivity.
Cutting tables
Flatbed cutting tables, some adapted from other industries such as routing, gasket and leather-cutting, started appearing after the first flatbed printers came onto the market and they can cost almost as much. However, cutting tables are integral to getting the most out of flatbed printers and they are often sold together as a complete package. Manual cutting is a slow process and any mistakes mean the job will have to be reprinted. An automated table can be left to cut multiple identical shapes out of a complete sheet and can also add creasing or V-cuts to create folds for packaging or 3D items such as Point of Purchase (POP) display boxes. Optional camera systems mean that an automated table can pick up registration and cut marks and recognise sheets placed on the bed for cutting.
There are two distinct classes of cutting tables. On one hand, there are several large, highly automated models capable of handling the largest sheet sizes up to five metres wide. Some of these use conveyor systems to help move the boards on and off the table quickly and can also handle roll-fed materials. At the other extreme, there’s a move towards simpler, smaller and more affordable cutting tables. Tandem modes, whereby the bed can be split, so that a board can be cut on one half while another board is loaded onto the other, can help improve productivity.
An alternative to a cutting table is to use a CNC router (the CNC stands for Computer Numerical Control). It’s becoming harder to define the differences between routers and cutting tables, because the tables have gained increasingly powerful routing tools. They can now cut more difficult materials including thin aluminium. But equally, most routers now offer a good range of standard cutting tools and can handle materials such as cardboard and foamcore that might otherwise require a cutting table. Routers are still a better choice if you’re routinely cutting through heavier materials such as aluminium and steel. Such is the range of materials that can be cut with this technology that many companies have found that cutting tables and routers have taken them into other more industrial applications, such as cutting out switch panels.
Another variation on the cutting theme is the cutting plotter, which is particularly handy for making labels and decals. Most are capable of different types of cutting, including through-cuts, perforations and kiss cutting, used to cut through the top layer of pressure-sensitive material, while keeping the carrier backing sheet intact. These are not particularly fast but most can be left running overnight.
Print and cut machines, as the name implies, combine printing and cutting heads, saving the cost of having to buy a separate cutting plotter, but it does mean that the printer is tied up if you need it for cutting and vice-versa.
Welding, sewing and grommets
Another common requirement for wide format print is to add pockets or seams to printed graphics such as banners, so that they can be suspended using cable or cord. Banner production may also require eyelets for lacing onto a framework. There’s a choice of bench-mounted and hand held machines for this type of work and most will work with popular flexible materials from vinyl to synthetics as well as stiffer display materials such as Foamex.
For textiles that have to be stretched and inserted into a frame, for instance backlit graphics; it’s increasingly common to use a sewing machine. A number of sewing machines are designed specifically to be easy to use for display work but one of the most popular adaptations is to use sail-making sewers as they can handle the large areas. Welders are available for use with banner materials such as PVC, PE plastic and synthetics as well as some for use with textiles. They use heat and are available in both automatic and semi-automatic variations and can weld three to six metres in one stroke.
Finally, for textile production there’s a choice between flatbed and calendar heat presses to transfer dye sub prints to fabric under pressure. Flatbed heat presses tend to be cheaper but are slower to use. Calendar presses are better suited to faster production environments such as sporting and club apparel and a good calendar press is a wise investment as it can keep up with the output from several textile printers.
There is no ‘one size fits all’ in wide format finishing so it is vitally important to determine what finished products are required before shopping for solutions.