UV Cuirng system details

I spent many years in the printing industry and worked with a lot of UV curing systems on web presses, so I will venture some advice.

You do not state the "watts per inch (or cm)" that your current lamp(s) produces, and you did not state the speed of the paper media that passes underneath. You also do not say whether the lamp housing is air-cooled or water-cooled.

I recall a standard distance from the exterior of the bulb to the paper of about 1.25" (3,2cm) as an average. The UV bulbs are sold with different watts-per-inch (or cm) ratings, and most systems have variable power output so the lamp intensity can be matched to the speed of the passing media. I remember industry standard UV bulbs of 300 watts/inch, 400 watts/inch, and 600 watts/inch. Essentially, with more power output capacity you can cure at higher line speeds.

I can answer a lot of questions about UV systems if you can provide me with enough data about your application. As far as the amount of electrical energy required, the proper level is the one where you achieve full cure at maximum line speed with minimal energy. The choice of UV bulb size and style will make a difference, as will the media speed. The mounting height is critical, and I will explain below.

Just behind every UV curing bulb is a parabolic reflector that captures and reflects the UV rays from the bulb to a critical focal point. This is why the mounting height is critical, as the surface of the media must be in the centre of this focal point. I recall that light from the lamp alone provides only about 40% of the curing power, and a clean and properly-curved reflector provides the remaining 60% or so. Clean reflectors are a must for efficient UV operation.

The very sophisticated systems use a variable voltage power supply and this is governed by a light intensity sensor that is built into the lamp. As UV bulbs age they lose their curing output power, and this type of circuit helps to minimine energy usage and promotes longer bulb life.

Feel free to e-mail me if you have more information, and I will try to help you.

Best Regards,

Ing. Robert Forbus

Dear Friend,

I hope you are referring to UV lamps and not UV tube, which works on high voltages (app. 10000Volts). The most importaant is UV frequecy spectrum and no. of flashes it generate for curing. Normaly specimen is kept close to focusing plane of parabolic reflector. It helps curing of object uniformly in shortest period.

Regards

PS

Just wanted to add one or two comments. Not all systems use parabolic reflectors. Some use elliptical which will give you less intense peak energy. This is often done for 3D objects or for heat sensitive substrates. Some lamps also include IR filters to help reduce the heat sent to the substrate. Your lamp supplier should have specs on their system. Radtech is the trade association that focus on UV curing. Their web site is Radtech.org. They may be helpful.