Flexography machines or flexo printing machines are usually called modern letterpresses. The name is accurate, since flexo machines are capable of leaving a print on almost any type of surface. Most commonly, flexography machines are used to print on paper, cellophane, plastic or even metal sheets. Flexo printing (flexography) is one of the methods of high printing, where elastic flexo forms are used instead of rigid printed plates. When using low-viscosity paints, it allows printing on a wide variety of materials – paper, cardboard, foil, polymer films, etc. Flexographic printing technology allows you to choose form cylinders with different diameters, which is an undoubted advantage in comparison with other types of printing machines.
Flexo printing process
Flexography uses several types of paints – water based, paints using volatile solvents (alcohol) and UV-based inks. Water-based paints are absorbed into the material, it is quite easy to work with them, but, unfortunately, they can not give a very high print quality. Some time ago, paints appeared that cured on the materials with the help of ultraviolet drying. These paints are now the most popular in the flexo printing industry, since they provide excellent image quality on virtually any material. They are, of course, somewhat more expensive than paints on water or alcohol bases, but the brightness and clarity of the picture on labels and tickets justify a slight increase in the cost of production.
Flexo printing uses printing machines with several colorful sections. In each section an anilox cylinder and a cylinder with a printing form for a certain ink are installed – anilox transfers the required amount of ink to the printing form. Very simply, the process of printing in flexography can be described as follows: a web of material from a roll is fed into a printing machine, then the printing plates that create the image are successively “rolled”, and a die that cuts out products of a given shape. After that, excess material is removed from the web, and finishing operations are started.
Advantages of flexography
The advantages of flexographic printing are clearly manifested in the manufacture of labels, tickets, labels, tags; at the press on a cardboard and other packing materials as the similar production is rather various in the sizes. In addition, flexographic printing differs from other printing methods by the ink supply system on the printing plate.
A printing house that uses flexo printing technology always orders the production of flexible printing plates from a special polymer, and large companies in printing industry have their own flexoform manufacturing department. Modern equipment allows to achieve very high quality of flexographic printing of labels, tickets and packaging, while the cost of finished products is mostly very low and competitive with other types of printing.
Flexo machine types
Printing machines in flexography are of three types – tiered (the color sections are arranged vertically), sectional (with horizontal arrangement of the paint transfer sections) and planetary ones, in which the printing units are grouped into one central cylinder. For our purposes – flexoprinting on films, on a thermo-cardboard, self-adhesive materials – the section type of a flexo-machine is the most suitable. The flex printing process allows one side to seal both sides of the material side in several colors. This feature of the technology significantly reduces the cost of finished products. Moreover, it is possible to install some types of post-printing sections on the printing machine and get the finished product right at the output from the printing path – it will only be necessary to pack the products in boxes and accurately label them.