LED Exposure Units
Davis International is Proud to Offer the Latest LED Exposure Units for the Screen Printing Market.
LED Exposure Units Offer Many Advantages Over Other Light Sources:
– No warm up time required. LED units are at full power instantly.
– Expose very fine details and halftones. Direct and uniform light results in less undercutting than with many other exposure units.
– Ultra fast exposures with all types of emulsions. Exposure times 10-15 times faster than fluorescent bulbs & 25%- 50% faster than metal halide systems.
– Long lasting, consistent bulb output. LED lights don’t fade or weaken over time like traditional bulbs. Bulb life expectancy is 50,000-100,000 hours.
– Lower power consumption. Less expensive to operate on a daily basis than most other exposure units. Operates at 20% of the power required by metal halide units.
– Safety. No excessive heat or high voltage power supplies and shutters needed. This eliminates the need for multiple cooling blowers, keeping you cooler while saving you money!
-No Maintenance. LED UV lamps can last more than 50 years. Imagine what you can do with all the savings!
Efficiency Through Quality Light.
The only portion of the light that matters to exposing a screen is the light that aff ects the sensitizer and initiates the cross linking (the bright bluish purple ultraviolet light- not the white and yellow light). With LED UV exposure technology, there is no wasted white light.
LED’s…a More Green Solution.
With the energy savings on electricity use, and eliminating the need for deadly and toxic, metal halide and other gases… the LED UV Exposure Unit is more earth friendly exposure unit!
Other Light Sources…Whats the Difference?
Fluorescent Tubes Exposure units are an option for the screen printer that manufactures t-shirts, whose art work does not contain very fine lines or half tones. They are usually less expensive and reliable, but a common issue is inconsistent bulb output due to poor connections or worn out bulbs, resulting in underexposed screens. Yearly bulb replacement can be common. It can often be tricky making higher quality high screens with this type of light source, as undercutting of fine lines and halftones is common.
Halogen/Quartz bulbs are the next step up from the fluorescent tubes. They are single-point light sources, so they do a nice job exposing fine line detail, or half tones, but average bulb life is only around 3,000 hours, and they produce excessive amounts of heat which can be a safety hazard.
Mercury Vapor units are usually around 1000 watts and work very well. They are rich in ultra violet light, and can be classified as a single point light source. As long as the light is close to the screen, it will work admirably. Usually, the screens should be placed no further than two feet away from the unit. Any farther away and you will end up with excessively long exposures. Mercury vapor lights have a start-up time and a cool down time, so there is no instant on/off like you get with a fluorescent unit. These are generally moderately priced units.
Metal halide units are used by screen printing companies that primarily do very high end work or graphic printers that expose very large format screens. They can consume 1000-8000 watts, and exposure units range from roughly $3,000 to $12,000. The bulbs should be replaced every one to two years. It takes about 20-30 seconds for all of the gases in a metal halide lamp to reach full temperature and full spectral output before you can expose properly, so most units stay on, and use mechanical shutters to control exposures. “Instant on” systems are available that do not require warm up time, but the more times a metal halide lamp is turned on and off the faster it wears out. Some “instant on” type systems will only get 500 hours of use per bulb. These bulbs can be very expensive, and costs can really add up.
Carbon Arc Lamps are old school pin point UV light sources that were quite common in the past. They produce excellent UV light by creating a gap between two copper covered carbon rods and fl owing low voltage high current electricity across the gap creating an ‘arc’ of light. Unfortunately the intensity can vary depending on the gap and the machine’s ability to adjust this gap through automatic controls. They also are very un-healthy and can produce a thick acrid smoke that most states recognize as being harmful to the worker.
Pulsed Xenon lamps has instant on/off capabilities, but unfortunately they do not expose diazo and bichromate emulsions well, and they emit a
lot of infrared heat which causes the glass in the exposure systems to heat up. They are primarily used to create plates for litho and have limited use in a screen print shop looking to succeed.