UV drier with air-cooled chill drum from Honle

Temperature-sensitive substrates can now be cured without water-cooling. This procedure is provided by a combination of cold UV and an air-cooled chill drum.

The high requirement for printing onto unsupported films and shrink sleeves are well known. New is the combination of UV radiation with reduced infrared portion and a chill drum without any water-cooling. This technology is provided by Hnle’s UVAPRINT RL series with air-cooled chill drum and Advanced Cold Mirror Technology.

In the flexo printing field, i.e. for arc lengths up to 540 mm, it is possible without water-cooling and with a low-level energy expenditure. For creating cold UV radiation the Advanced Cold Mirror Technology (ACM) was developed. The ACM allows for a major portion of the disruptive infrared radiation to be filtered out. The ACM system consists of a dichroic mirror, whose geometry and coating notably reduces the percentage of IR radiation that is focused onto the substrate. If one compares a UV drier with an ACM system with a direct radiating UV system, then the IR radiation is reduced by up to 85 per cent with ACM system. Depending on the material in question, this means that the substrate temperature can be lowered by up to 65 per cent. The high UV intensity, which is equivalent to that of a direct radiating device, allows for the simultaneous achievement of high production speeds. Summarized, the new system provides high quality UV curing with less installation work.

The UV modules are operated with Hnle developed electronic power supplies (EPS). In addition with their use, the efficiency of the drying process can be increased by more than 10 per cent in comparison to conventional ballasts. That means that the EPS technology either reduces the energy expenditure for the operation of the UV drying system – or which is more important for most users – the drying speed is further increased. Hnle offers various power supplies for diverse applications. The EPS is available with a power output of up to 7.2 kW, two cascaded EPS’s with a power output of up to 12 kW, and the EPS 200 with a power output of up to 20 kW.

All Hnle dryers that are available for sheet-fed applications can be equipped with a compact inert chamber. Due to the inert atmosphere, cross-linking chemistry takes place with low oxygen inhibition. The result of this is that less photo-initiators are required for the curing process. Or, due to the nature of the process, considerable energy savings are achieved with low inert gas consumption at the same time. High-quality UV printing with cost-efficiency is the outcome. Compared with standard processes, the colors are better cured and the surface quality of the end product is enhanced.

At the heart of every UV curing unit is the lamp. Hnle manufactures its own high-performance UV lamps and apart from standard spectra lamps, customer-specific and process-specific lamps are produced. The lamps are available both for Hnle products and other system manufacturer.

Hnle supplies lamps with arc lengths between 10 mm and 2500 mm and outputs of 0.2 kW to 40 kW.