Pad-printing the intelligent way Pad-printing on 3-D objects of various shapes and sizes like the keys on a keyboard, is one of the most successful printing methods developed for the printing industry. Since its invention however, there has been little development and there are some limitations to this method that make it expensive, labour intensive and unsuitable for modern production lines. New developments in both its automation processes and its inks now make it more competitive, cheaper and capable of dealing with large loads in a fully automated process. Industrial Technologies © Photodisc To successfully graft an image onto a 3-D object whose surfaces may not be smooth or symmetrical, when using pad-printers (either in open or closed systems) the viscosity of the ink is of paramount importance in order for the printing plates to adhere to the ink-pad so that the image can be pressed onto the recipient surface. In order for this to happen in a cost-effective manner, ink quality as well as the nature of printed surfaces is essential. Because of its peculiar method, certain surfaces and inks cannot be used. For example, silicon based or glass products cannot be successfully printed on and UV-curable inks are not suitable for the process. The new development however has made it possible to use UV-curable inks that require no solvents or additives. The market currently uses inks that can have retardants, solvents, matting agents, adhesion modifiers, thinners and catalysts added to them depending on the surface material being printed on. In all cases, inks are resin based to ensure maximum viscosity of the ink, so the blending or mixing of suitable inks is a complex and expensive process. This intelligent pad-printing system developed by a Dutch company offers some considerable advantages. Not only can it use UV-curable inks, which are generally of better quality and offer greater durability, but their system is automated to a high degree, making the entire process very quick and reliable. The high-speed process comes with sensor technology that can analyse image quality in-process as well as being programmed with the algorithmic capacity to analyse print failures. In being fully automated and using better quality inks, the pad-printing process has now become a single-cycle one in which re-printing surfaces is not required. It is therefore labour saving and cuts down on expenses and requires no specialized operator knowledge to maintain. The technical development also includes new laser etching of materials, concepts for building pad-printing equipment from modules and analysis of pad-deformation, making this product an implement that will increase European competitiveness in the pad-printing market.
