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UV Curing

(November 2000) posted on Tue Nov 14, 2000

Bron Wolff discusses how you can assess and improve your UV-dryer performance by learning from his company's experience.

By Bron Wolff

However, if a company is like Joliet Pattern, which is located in a large industrial complex with other manufacturing operations, it's likely to see periods of peak usage when the incoming power level drops. Such power variances will directly influence a UV dryer's ability to deliver a successful cure.

When you turn on a UV system and set the wattage level at which the lamps will operate (e.g., 125, 200, 300 watts), the system will draw a particular amperage until it is turned off. Think of voltage as a reservoir of electricity and amperage as a pipe through which the electricity flows from the reservoir. The higher the amperage, the wider the pipe.

You can monitor and record the power going into the curing unit, and as our experiences prove, you should do so regularly because it will change weekly, monthly, and seasonally. The power available from the transformer directly affects the voltage available at the UV ballast. Most ballasts for UV lamps are designed to operate at particular voltage levels, such as 208, 240, or 460 volts. The main thing to verify is that the correct amount of voltage is available to operate the curing system.

Using a voltmeter is the easiest way to find out what voltage is coming in. Begin by checking the voltage at the terminal that will power the curing unit. First, check the voltage with no load (all UV lamps off). The voltage should be within ±5 % of the expected rating. Next, power up the curing system and check the voltage again. The amps you are now drawing through the lamp should cause a big voltage drop. It is not uncommon to lose 20-40 volts on a 480-volt line (or 10-20 volts on a 240-volt line).

Note that this is just the loss experienced on one electrical line supplying one machine with one curing head. If you're running an inline printing system with multiple curing modules, you'll need to power them all up and check the voltage at each curing head. With multiple lamps drawing power simultaneously, you'll see an even greater voltage drop. The amount of the voltage drop can even vary from one lamp assembly to the next.


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