etching pcb with uv light

[ndrew2505]

wasnt sure where to put this but....

i was wondering if any1 knows of a good tutorial or can explain the pcb etching process with uv light.

 

[pocketfluff]

Buy a blank PCB with pre applied photoresist

Print the design onto a transparency. Make sure the print is nice and black.

Put a piece of glass over the transparency which is on the board. Make sure its not upside down

If you are making small numbers of boards, use UV led's. (I use about 40) exposure time of 90-120 secs. Or you can use a UV or regular fluorescent lamp.

Develop the board with a sodium hydroxide (drain cleaner) solution of one teaspoon per litre. No real set time, just shake it around until the pattern emerges.

Etch

Expose again

Remove the photoresist covering the copper with the same sodium hydroxide solution.

 

[rkcstr]

Here's a tutorial for photoresist boards I had:
http://www.electricstuff.co.uk/pcbs.html

I typically use toner transfer as the boards are cheaper (regular copper-clad vs presensitized boards) and don't really require any tools or chemicals that aren't found at local shops. I suppose photoresist could be done with stuff from local places, but it may require more time to get working right. For toner transfer, you just need access to a decent laser printer or copier (most schools or businesses should have one), though you may have to find one whose toner transfers well (some just doesn't stick well).

Another option that I contemplated was similar to photoresist, except you use regular copper clad board and basically sensitize it yourself:

http://www.pcbhobbyist.com/

 

[Bionic-Badger]

Here's another. I've wondered if those UV LEDs would work to expose these PCBs properly, since these tutorials use those big UV lamp thing.

 

[ndrew2505]

thanks guys. i wonder if blu ray would work for etching? ;D :

 

[BluRay]

probably would burn everything off the fibreglass board ;D

 

[pocketfluff]

thanks guys. i wonder if blu ray would work for etching? ;D :

I'm going to give it a go now

EDIT: Just tried. It worked. But I don't think it would work well for larger boards.

 

[BluRay]

i've ruined 3 large piece of photo sens board. they arent cheap too. after it didnt work, i cleaned it, then left to dry and it start turning brown smokey marks. couldnt use it for normal etching. I guess you have to use UV light. The guys i bought them from say just use strong light like a spot light and it should work. Guess WHAT??? Nothing.

 

[pocketfluff]

i've ruined 3 large piece of photo sens board. they arent cheap too. after it didnt work, i cleaned it, then left to dry and it start turning brown smokey marks. couldnt use it for normal etching. I guess you have to use UV light. The guys i bought them from say just use strong light like a spot light and it should work. Guess WHAT??? Nothing.

Whats your exposure time? What are you developing it with?

If the board is really ruined, you can easily clean the photoresist off with acetone.

 

[BluRay]

I exposed it to 2 spot lamps leaving them exposed for 5mins just to be safe.

Im developing it with AE Developer. Already made in a bottle. just need to immerse it in there.



Tommy

 

[ndrew2505]

insted of the ferric chloride would this work for etching? i already use acid/peroxide solution for etching normally but i wasnt sure if it would work for the photoresist.
http://www.instructables.com/id/Stop-using-Ferric-Chloride-etchant!--A-better-etc/

 

[toked323]

insted of the ferric chloride would this work for etching? i already use acid/peroxide solution for etching normally but i wasnt sure if it would work for the photoresist.
http://www.instructables.com/id/Stop-using-Ferric-Chloride-etchant!--A-better-etc/

Etchants are standard they all work on those boards, I use that etchant and it works great and is reusable.

 

[ndrew2505]

so i still need a developer..any DIY solutions or should i stick to the stuff off the shelf?

the guy at radio shack just told me they dont carry developer anymore b/c the feds said it could be used to make bombs or something...lmao so can most home chemicals anyway...i guess ill have to get some from the net. freakin extra money for shipping costs

 

[toked323]

so i still need a developer..any DIY solutions or should i stick to the stuff off the shelf?

the guy at radio shack just told me they dont carry developer anymore b/c the feds said it could be used to make bombs or something...lmao so can most home chemicals anyway...i guess ill have to get some from the net. freakin extra money for shipping costs

I think for developer you can use sodium hydroxide (soda wash).

 

[BluRay]

All in all, i just find using a normal copper clad board and printing the design and ironing on is much less confusing and gives just the same result. But at a cheaper price, cause those photo sensitive boards are really exspensive to test around if you havent used them before.




Tommy

 

[pullbangdead]

^But photoresist is so much cooler and more fun to show off and stuff. Really now, where are you priorities?