nos_slived said:
Hey exo, any chance that you could post instructions for your method? That sounds reasonably affordable and fairly easy. When you make your boards this way, does it create a solder mask?
No, my boards don't have a solder mask or a silkscreen. And if i see the prices pcb companies ask for those extra's i'm happy without them.
I do use a spraycan of colorless varnish when it's all done to protect the copper from getting filthy
I draw my boards with eagle (wich i bought to allow bigger boards & all features). A free limited version is available at
www.cadsoft.de.
I also draw them by hand 'cause the autorouter isn't that good at routing.
This requires a lot of patience an retries, but i always seem to get it done (the board above took me 11 hours to route :lol: )...
Also remember your limitations, for example i can't do plated holes. So for parts wich u cant solder on the top side of the board (ic sockets, connectors,...) try to route as much signals at the bottom and if you do require them at the top, start at the bottom towards a open space , then a via to the topside and so on...
Dont forget to draw a frame around your design with the exact size as the board it needs to get transferred to (10x16cm for example) this is used to get the top and bottom side aligned.
Then i print it using a laserprinter, its 1200*1200 dpi wich allows me to use traces 0.08" thick with 0.10" spacing. (thinner gets printed well but doesnt work, i guess the uv light creeps under it ruiing the trace)
Then tranfer it to a photosensitive pcb with a UV light. 2.5 minutes of exposure is what i always use.
Use the frame you drew to align the upside and downside. U may need to try a couple of times, but once u get the hang of it it works great. The board in my previous post succeeded first try.
Then etch the board - First u need a chemical that needs to remove the protective film, i forgot the name and don't have any of it lying around atm, i will post it later when i get some.
Then the copper is etched off with 'perchlorure de fer'. (->google for a pic)
pictures of the board i posted above when etched, sorry i can't show a finished board with parts on it cause it's already been sold, this is a second spare board i made. Of course u can do single sided pcb's to, in wich case it's even a lot easyer (3rd pic).