Two methods of making PCBs using an inkjet

[gez]

Are you all sitting comfortably?  Then I’ll begin…

The last few weeks I’ve been trying out everything and anything to get an inkjet to work at producing decent PCBs.  I’ve found two methods that both work well.  Both use photo board, but before some of you switch off you can use a fluorescent strip light to develop board by tapping it, plus your transparency, to the light’s surface so that it’s in contact with it.  The down side is the board can be no wider than the strip light, unless you develop in stages (a real pain!).  I’ve always mounted my boards vertically so I’m used to keeping them slim and this isn’t a problem for me.  Having said that, it’s not that hard to build your own exposure box - I’m sure many here have and might chip in.

The first method is of my own devising (though I’d be surprised if someone else hadn’t thought of it) but inspired by various posts I’ve read in the archives of this place: (They’re a pretty hard-core and innovative bunch - and I thought WE were nerds!)

http://groups.yahoo.com/group/Homebrew_PCBs/messages

Although you can buy ‘Jetstar’ transparencies for Epson inkjet printers, they only seem to work with Epson printers!  I also had a problem with the thin film crinkling under the heat of the light.  So I came up with the following.  Basically you print your artwork, reverse image, onto a bog-standard ‘glossy’ transparency intended for inkjet use.  I use Ryman’s (a UK stationers) own brand.  Then lay it on your board (ink side down), place a sheet of tracing paper over it (well, in my case Sainsbury’s ‘greaseproof paper’), secure it with masking tape and then develop.  Without the tracing paper it doesn’t work, the ink isn’t opaque enough, but with it the results are superb!

The second method uses ‘transparent’ spray made by ‘Kontakt Chemie’ in Belgium (so, not just chocolates then!).  You print off your artwork onto paper, spray this stuff on and it makes the white bits ‘transparent’ to UV - just tape it to the board (it sticks to it while still wet which helps) and develop.  It too works really well though the type of paper seems to determine the quality of the image.  It worked fine with the normal stuff I use, but not with a photo copy from my local printer (despite it being of better quality!).

ESR in the UK sell it, but I’ve also seen it elsewhere (don’t ask me where, I can’t remember).

www.esr.co.uk

I’ve always done my artwork by hand so I don’t yet have any PCB software, but here’s a couple of samples I did using lettering.  The one on the left is the spray.  Although it doesn’t show in the photo, the first method gives the best detail.  Dirt on the transparency caused the F to go wonky, but seeing as these were samples I didn’t bother cleaning it up (the shame!).




Anyway, thought I’d let you know…

[Marcos - Munky]

Cool!!!

[Craig V]

Sounds awesome!


Folks around here seem to have very complex and intricate ways of doing them.  All I do is print the design up, copy it onto clear transparency with a copy machine, iron and etch.  Seems too simple.

[Aharon]

Thanks for the tip gez.
Hey,when you work with the light sensitive board,do you need a dark room?.
Thanks again
Aharon

[gez]

Hey,when you work with the light sensitive board,do you need a dark room?

No, you don’t need a dark room or anything.  The photo resist would take at least 15 hours exposure to normal light to develop, so there’s no problem with doing this in day light - it’s the amount of time it’s exposed to a strong UV source that counts (3mins with the board I use).  Once it’s been exposed you dip it in developer for about 30 secs.  I use one that’s ‘safe’ made by Seno.  Then you just wash it and etch in Ferric.

Incidentally, It’s rumoured that WD40 does the same job as that ‘transparent’ spray, though I haven’t tried it.

[Aharon]

I see,thanks fopr that one too.
Sorry that questions come up as I envision the process in my mind.
So I need a fluorescent UV tube like the ones we used at parties in the 60' or regular fluorescent whites?.
Thanks
Aharon

[gez]

Aharon, most people use UV bulbs/tubes, the sort of things that get used in tanning salons.  

However, I just use a bog-standard fluorescent strip light, the one providing all the light in my kitchen when I'm peeling veg and stuff!

Takes up less room than a ruddy box! :lol:

[gez]

PS.  Although you get great results, the board has to be in direct contact with the light (unlike the UV type tubes).

[Aharon]

Great gez,thanks again for the help.I'll get a UV light since I have to buy supplies anyways to make this,I'll also make a box.
So,great,I know now,I used to make screens for printing this way,sorta.....
It's good to have more than one method.
Aharon

[gez]

I didn't have the time to sort out the wheat from the chaff (sorry!), but there's plenty of links here:

http://www.google.co.uk/search?q=How+to+make+a+PCB&ie=UTF-8&oe=UTF-8&hl=en&meta=

That forum I linked to will help out anyone who wants to make their own UV box.

If you do some trial runs first you'll get the hang of this in no time.  I haven't had a single duff board since I've been doing this.

[Gringo]

Sounds awesome!


Folks around here seem to have very complex and intricate ways of doing them.  All I do is print the design up, copy it onto clear transparency with a copy machine, iron and etch.  Seems too simple.

I switched to that method too! I love it

[Jason Stout]

Just a thought, for developing you could make a 555 timer led driver to drive and pulse width modulate ~40 UV leds for max brightness, ummm....maybe not so good, would need some kind of diffuser for even distribution of 'light'...oh it's late, and i think uv leds are expensive.

Good night all.

[nooneknows]

with positive photoresist you can use a normal 60W daylight blue bulb, it's cheap and the exposure time is 25/30 minutes, depending on the brand of photoresist you use. Always use two copy of the inkjet glossy paper circuit trace, one over the other, the black parts get darker.

[idlefaction]

lol, i just got an etching tank which was a really good investment...  i normally use sharpie and ferric chloride, which takes about 45 minutes to etch, with a tank and an aquarium aerator it took about 7.  thats a number i'm much happier with  

[gez]

Always use two copy of the inkjet glossy paper circuit trace, one over the other, the black parts get darker.

I tried this and the problem is lining it up to get sharp results.  It's a lot easier (and cheaper) to just use one transparency then cover it with greaseproof/tracing paper.

[Gringo]

lol, i just got an etching tank which was a really good investment...  i normally use sharpie and ferric chloride, which takes about 45 minutes to etch, with a tank and an aquarium aerator it took about 7.  thats a number i'm much happier with  

I use a pan with boiling water to heat a glass bowl (where the etching actually takes place). When the chloride is hot, the process speeds up a lot! 5 minutes max to etch a small board (2" x 1,5"). Rocking the bowl is optional (but gives you something to do in those 5 min :lol: )

Just a free alternative to an etching tank

[GuitarLord5000]

Now that's an idea Gringo!  I've been running a sinkful of hot water and placing the etchant bowl in it to keep it hot.  Wow!  I never even thought of putting it on the burner like that.  That should bring my etching time down greatly!

[troubledtom]

don't you get it gent's.
    use a really cheap coffee maker to keep the acid warm and the coffee pot has a handle to agitate the the pot. you can do a board in 3-7 minutes.
  i buy ones for 10 bucks.....    i can make proto types asap.
           - tom

[Aharon]

Right on trubledtom,that's even better than my crockpot.(doubleboiler ot hotpot/plate for you guys).
The problem is that ferric chloride(sp) looks like coffee.!!!!!!!!!!
Aharon

[GuitarLord5000]

Sweet!  That's what I love about this site...all the different (and cost effective!) ways of doing things.  I'll be looking for an old coffee pot at the next flea market/garage sale I see.