Printing A Circuit Board Design

[Lancelot59]

Hey guys, I'm trying to make a circuit board for my school project and need to print the pattern. The thing that makes this slightly trickier is that some of the traces are 0.4mm apart. Now either way I need to print over twice, and that's not an issue, I can double layer it easily.

I'm just wondering, what gives more accuracy on a transparency? A laser printer, or an inkjet printer?

 

[berkeman]

Hey guys, I'm trying to make a circuit board for my school project and need to print the pattern. The thing that makes this slightly trickier is that some of the traces are 0.4mm apart. Now either way I need to print over twice, and that's not an issue, I can double layer it easily.

I'm just wondering, what gives more accuracy on a transparency? A laser printer, or an inkjet printer?

Do you mean you are just printing the layout layers on paper? Or are you trying to print on FR4 board?

To make a PCB, you need to chemically etch away the unwanted copper, leaving the desired copper pattern behind. Are you planning on etching the board? I don't think you will be able to etch the board on your own at that kind of resolution. That takes very tight process control, and isn't something you will be able to do in your chem lab without a lot of practice, IMO.

 

[misgfool]

To make a PCB, you need to chemically etch away the unwanted copper, leaving the desired copper pattern behind. Are you planning on etching the board? I don't think you will be able to etch the board on your own at that kind of resolution. That takes very tight process control, and isn't something you will be able to do in your chem lab without a lot of practice, IMO.

Also you can make a PCB by drilling and some schools do have drills.

 

[berkeman]

Also you can make a PCB by drilling and some schools do have drills.

Yeah, we used an LPKF milling machine here in our lab for several years -- pretty handy:

http://www.lpkfusa.com/protomat/index.htm

There are definitely some tricks to making milled boards too, though. You can do relatively fine pitch, but you have to tune up your pad shapes for soldering -- too easy to get solder bridge shorts otherwise.

 

[mheslep]

Hey guys, I'm trying to make a circuit board for my school project and need to print the pattern. The thing that makes this slightly trickier is that some of the traces are 0.4mm apart. Now either way I need to print over twice, and that's not an issue, I can double layer it easily.

I'm just wondering, what gives more accuracy on a transparency? A laser printer, or an inkjet printer?

Google is your friend. Yes the laser is more accurate and laser toner works better than ink. With the common UV exposure board stock 0.4 mm will be no problem.
http://www.fullnet.com/~tomg/gooteepc.htm
http://www.turbokeu.com/myprojects/pcb.htm

 

[berkeman]

Google is your friend. Yes the laser is more accurate and laser toner works better than ink. With the common UV exposure board stock 0.4 mm will be no problem.
http://www.fullnet.com/~tomg/gooteepc.htm
http://www.turbokeu.com/myprojects/pcb.htm

Hmm. That first link is pretty good (I didn't make it to the 2nd one). From that link:

[FAQ about using INKJET printers: I've been getting a lot of email, asking me if an INKJET printer can be used to print the patterns, for this PCB-making process. The answer is: NO! The toner in laser printers and most copiers is made mostly of PLASTIC, which resists the acid that eats away the copper that doesn't have any toner on it. Inkjet printers use INK, not toner. And their ink is typically NOT a good etch-resistor, at all.]

I must have been a pretty big klutz when I tried making my own PCBs, because I had a lot of trouble getting uniform etching across the PCB. Especially because I had some areas with just sparse traces, and other areas with ground pours.

Please be careful with the etchant chemicals! From that first website again:

(Caution: The concentrated acid's fumes would be very bad to breathe, or to have around metallic items. And the acid would be very bad to get onto anything that's not plastic.)

 

[Lancelot59]

With the common UV exposure board stock 0.4 mm will be no problem.

Today I printed the pattern using my schools laser printer (This is a high school, so no fancy PCB milling machine). The result turned out pretty decent. However between some of the tighter traces there was a bit of toner that almost seemed to overlap. Creating this sort of faint checkerboard between the traces.

My exposure setup at school is just a big tanning bulb, above the main tray, where the board goes under the pattern which all gets compressed down by a heavy piece of glass.

 

[mheslep]

Today I printed the pattern using my schools laser printer (This is a high school, so no fancy PCB milling machine). The result turned out pretty decent. However between some of the tighter traces there was a bit of toner that almost seemed to overlap. Creating this sort of faint checkerboard between the traces.

My exposure setup at school is just a big tanning bulb, above the main tray, where the board goes under the pattern which all gets compressed down by a heavy piece of glass.

Sounds like you might want to try tweaking the printer driver configuration. Make sure its on the highest possible resolution, no 'quick print' defaults.

 

[dlgoff]

Well, you could always print a positive pattern that is double sized then have it reduced 50% on film (negative) at a graphics shop. This should clean up the ragged edges.

 

[Averagesupernova]

I have done single sided PC boards with a laser engraver. Black spray paint resists the etchant quite well. Just burn the paint off in the areas you want to etch.