Berlin based Bally Wulff specialises in the design and manufacture of gaming machines. 2005 was a record year for the company, with a large percentage of the equipment being exported. Joachim Weber, manager of the company's screen printing and graphics department, says such success in international markets means very short production and delivery times, which have led to a dramatic growth in demand for screen printed glass panels and emblem supports. As a result, the company is continually confronted with numerous production challenges, such as the achievement of consistent high quality and near perfect registration.
"All of our designs and films are produced in-house as they are required to be sub-surface printed in reverse on the glass panels with UV inks," explains Mr Weber. "The close viewing distance of the gaming machines requires us to print fine halftones which can cause some problems. The demands for reproducibility are also very high. Depending on the need and also the success of a game, the numbers to be produced vary between 150 and 6,000 items and are often repeated.
"Typically ten, 12 or even 15 colours are printed on each panel so you have to be very careful. The high thread count of the fabric [150/cm] that is needed for printing UV inks can also cause some problems as we are printing onto glass. As a result, we use a considerable number of screens in a month, each of them over one square metre in size. Precision in mesh tension, stencil thickness and flatness, as well as print reproduction is all-important, because even the smallest deviation in the colour value will be shown up by the back illumination.
In Mr Weber's opinion, there is no other choice but capillary films if print jobs are to be uniformly repeated and the best quality obtained. He believes the most consistent films are those of the Autotype Capillex range from MacDermid Autotype. The company has been using Autotype Capillex CP across Europe for more than three years now and finds that this film best meets its needs.
Autotype Capillex CP photostencil has been specifically formulated for very fine halftone and line printing. The Controlled Profile technology used in Autotype Capillex CP gives it the low stencil profile and optimised Rz value, which minimise the ink skipping and stacking problems that can so often plague UV printing.