A DIY UV Exposure Unit

UV exposure unit is a vital component in printing and mass-manufacturing industries. I decided to build a UV exposure unit to assist my screen-printing and PCB prototyping needs. After examining the market, I decided to construct this unit using black fluorescent tubes. Those black fluorescent tubes are usually available to purchase in many electrical shops here in Sri Lanka.

To drive the exposure unit, I build an electronic controller using ATtiny2313A MCU. This controller is capable to handle the exposure unit for up to 999 seconds (approximately 16 minutes). This electronic controller got two high-power relay driver stages, an audible notification unit, a safety lock, and a programmable timer.

The fluorescent tubes are drive using four separate chokes and starter units. For this unit, I use four NEC 20W - 60cm (T10) black fluorescent tubes. 12V, 5A SMPS is used to drive the relays and electronic controller unit.

Enclosure construction is the most time-consuming part of this project. It took nearly two and half months to finish the enclosure with all the fittings. Primarily, I build the enclosure using aluminum bars and aluminum composite panels. The dimensions of the enclosure unit are 74cm × 40cm × 19cm (with lid) / 15cm (without lid).

I exposed several paints and adhesives using this unit with higher success, including screen-printing photo emulsion paints and inks, several PCB protective coatings, etc. Usually, I use this unit to produce screen-printing screens and to fabricate PCBs for my prototyping projects.

The controller schematic, PCB design, firmware source code, and compiled firmware binaries of this exposure unit are available at the GitHub repository.