|Prof. Ober: LINGA has once again shown us new paths in the field of surface finishing technologies. The topics of energy and material savings during manufacture were everywhere. I was particularly impressed by the new systems in digital printing, inert hardening, UV-LED, and the “Ven Spray Vario” newly presented by Venjakob. Although in the past it has only been possible to coat difficult geometries using expensive narrow-area coating processes on a clocked line, the “Ven Spray Vario” offers the option of using a robot to coat these geometries in a continuous running mode. The major advantage of this technique is that some of the paint can be recovered and, in addition, it is possible to increase output.
Another impressive novelty is the UV-LED system for two-dimensional hardening in rolling lines offered by Bürkle. If we take a rolling line for “IKEA White No. 5” as the reference, conventional UV systems require an overall power of 512 kWh. With UV-LED, this power can be reduced to 99 kWh. Venjakob offers the UV-LED system for three-dimensional hardening for workpiece heights of up to 50 mm of the spraying machine. The new UV system permits a reduction in power from about 40 kWh to about 7 kWh.
Both novelties offer significant cost savings and resource reduction of about 80%. In addition, surface heating is significantly reduced and yellowing of the paint is avoided. Amortization times are 3 – 5 years, still relatively long due to the rather expensive UV-LED elements, although their service life is extended from the conventional 2,000 hours to about 15,000 hours.
The technology of inert hardening may not be new, but its refinement and the offerings from Bürkle and Cefla have made it possible to put it on the market. In this process, paint can be applied in relatively thick layers of about 40 – 60 m. The resulting rolled texture is smoothed using the applied foil and/or by the first roller. The foil also keeps the oxygen in the surrounding air away from the paint layer, preventing inhibition from ambient oxygen. This allows the quantity of photoinitiators and even the energy costs for UV hardening to be reduced.
The surface structure of the foil can give the paint surface a texture from high gloss to matte to other textures as well.