This is currently a rough guide to the equipment we have for DIY PCB etching and how to use it.
Print your design mirrored on to tracing paper. The printer in the main room works well, select 600dpi, disable any toner saving options and use the manual feed.
Place the printed design toner side up in the UV exposure box, peel off the protective cover from the PCB laminate and place it copper side down over your design.
Close the box and expose for ~10 minutes. After exposure the design should be visible on the PCB but can be very hard to see.
This step removes any photoresist that has been exposed to UV light in the previous step.
Place your PCB in the 'Dev' tray and use the SN110 applicator to apply the developer. Press firmly to open the internal valve and release some of the developer, then scrub the board gently for somewhere around 30 seconds. Be very careful of damaging the applicator sponge on the edges of the PCB.
Once developed, your design should be clearly visible on the PCB with a slight green tinge.
Plug in and turn on the etch tank, give it some time to warm up.
Put your PCB in it, it takes somewhere around 5 minutes to etch. It's finished when all the unwanted copper is gone. If left too long then you'll start getting rough edges and/or breaks in small tracks.
Once etched, remove the board and rinse with lots of water before touching the board.
This step removes the rest of the photoresist from the board. Apply a few drops of methylated spirit to the board and allow it to coat it, wait a few seconds, rinse (or rub gently).