PCB

[mstechca]

Now I have learned that the best way a PCB can be done is to do it the hard way, and that is what happened to me.

First I tried directly applying a few squirts (yes, a few squirts) of developer on the etch resistant PCB, after the exposure step, and unfortunately, all the green disappeared, and I ended up with a copper board, and a teaspoon of useless black liquid

Secondly, I went back to using the developer diluted with water in a dish. Everything is ok in the etching/developing process, but what shocked me was that a 1mm track width was too large, because the adjacent tracks were touching each other

So now, I am forced to use a 1/2mm track width.

So far, my experimentation has put me about $3 in the hole.

If anyone else has a tight budget like me and buys electronic stuff, tell me how you do it. Maybe I will copy you.

 

[Joel Rainville]

So far, my experimentation has put me about $3 in the hole.

If anyone else has a tight budget like me and buys electronic stuff, tell me how you do it. Maybe I will copy you.

I don't do PCBs for the very fact that it costs quite a lot more than using stripboard or copper clad breadboards. I am very happy with my Lochmaster-designed stripboards so far...

It has its limits obviously. All my TQFP, QFN and other tiny SMT components are impossible to use without a proper PCB layout. Not everything comes in DIP packages, unfortunately.

Budgetwise, my $3 CAD 4"x10" stripboards are hard to beat. But when and if I have no choice to cook up my own PCB, I will probably try the toner transfer method, which seems to be cheaper than photo-resist?...

 

[Jay.slovak]

...I will probably try the toner transfer method, which seems to be cheaper than photo-resist?...

You should! I love it (I mean Press-n-Peel), it's cheap, easy and fast to do . I have very good results with 3$/A4 PnP Blue foil, no broken tracks, no shorted tracks.
Of course it is not good for mass production, but it is ideal for prototyping/developement.

 

[Joel Rainville]

...I will probably try the toner transfer method, which seems to be cheaper than photo-resist?...

You should! I love it (I mean Press-n-Peel), it's cheap, easy and fast to do . I have very good results with 3$/A4 PnP Blue foil, no broken tracks, no shorted tracks.
Of course it is not good for mass production, but it is ideal for prototyping/developement.

You mean $3 per sheet? :shock:

I've **broken link removed** quite a few times that some **broken link removed** (and other brands) will do the work nicely (in a laser printer of course). At $15 CAD for 30 sheets, that makes it $0,50 a sheet! 8)

Quote from the first linked website :

THE BEST TONER-TRANSFER PAPER IS...

The very BEST paper I've found (basically PERFECT!) is sold as Staples "Picture Paper". It's available at Staples "office supply" stores, in the USA. (And also from their website, at http://www.staples.com .) [I almost can't believe that I didn't try that paper, before. It's one of the very FEW that I didn't try...!]

Below are the details, for buying the correct paper (at www.staples.com or at a Staples retail store). At the Staples website, search for the "SKU" (item number). At a Staples store, ask an employee to help you find the Staples Picture paper with the correct SKU. [Many thanks to Woody Eadie, for providing all of these details via email!]

Staples "Picture Paper" Details:
30-sheet package:
Staples' SKU (Item Number) for the "Picture Paper" (30-sheet package): 471861
UPC barcode is: 7 18103 02238 5
Cost: $9.99 (30 sheets) at www.staples.com, as of 06/23/04.

 

[Jay.slovak]

Yes 3$ is not as cheap, but it's the cheapest price I get them for (If I buy a single sheet only, multipak is cheaper).
And remember PnP is not the same as PhotoPaper! Anybody can do perfect PCBs with PnP, photo paper method is not as easy (and it takes longer). So you get what you pay for...

 

[Joel Rainville]

And remember PnP is not the same as PhotoPaper! Anybody can do perfect PCBs with PnP, photo paper method is not as easy (and it takes longer). So you get what you pay for...

I don't know, the guy suggesting the Staples paper inspires confidence... I'll have to try and see.

 

[zachtheterrible]

I tried the staples picture paper with OK results. The tracks were jagged and teh whole process is MESSY! I personally don't like staples picture paper, but maybe I was just doing it wrong.

I recently converted to phototransfer and I LOVE it!! I use a halogen light as a developer source and then make sure everything is nice and dark accept for my 1W red LED that I mounted on the ceiling of my bench so that I can see what I'm doing when I'm developing it and stuff.

mstecha, what is the spacing between the tracks? 1mm tracks are pretty dang small, and if you're using tracks that small, I wonder what your spacing is?

 

[Joel Rainville]

I recently converted to phototransfer and I LOVE it!! I use a halogen light as a developer source and then make sure everything is nice and dark accept for my 1W red LED that I mounted on the ceiling of my bench so that I can see what I'm doing when I'm developing it and stuff.

Yeah, there's no question that photo-resist is somewhat easier and gives excellent results. I'm trying to find a link to a page where a guy cooked up his own developer and etchant for the photo-resist technique, and the resulting PCBs looked amazingly flawless and professional.

But photo sensitive boards are more expensive than ordinary copper boards, and add to that the price of the developer solution. It isn't exactly the student-on-a-budget-friendly solution...

 

[Overclocked]

can the pnp/staples photopaper be done on an ink jet?

 

[mstechca]

What is the spacing between the tracks? 1mm tracks are pretty dang small, and if you're using tracks that small, I wonder what your spacing is?

Everything depends on the circuit.

Normally, I try to keep at least 1/2mm spacing between tracks.

I also found out that printing in the same spot twice prevents tracks from cracking up :lol:

 

[zachtheterrible]

I also found out that printing in the same spot twice prevents tracks from cracking up Laughing

I tried that but couldn't get it to always print in the same place twice. Foudn two solutions for this:
Print on two transparencies and then hold them together with water so you have two layers.

OR

Just scratching the surface that you're printing on with a scotchbrite pad makes the toner stick MUCH better.

 

[Nigel Goodwin]

can the pnp/staples photopaper be done on an ink jet?

I don't do PCB's, but no you can't use an inkjet - a laser printer uses toner which is heat fused onto the paper, you use a hot iron to transfer the toner from the paper across to the copper. An inkjet uses conventional ink, which is sprayed on the paper and then drys - just like using a fountain pen really. So you can't heat transfer it, and the ink would run when you tried to dissolve the paper off (it's water soluble).

 

[mstechca]

Just scratching the surface that you're printing on with a scotchbrite pad makes the toner stick MUCH better.

to the transparency, ok. But the design (the toner/ink) does NOT transfer to the board from the transparency.

 

[Joel Rainville]

Just scratching the surface that you're printing on with a scotchbrite pad makes the toner stick MUCH better.

to the transparency, ok. But the design (the toner/ink) does NOT transfer to the board from the transparency.

zach was probably talking about scratching the copper board for the toner-transfer method, not the photo-resist one...

 

[zachtheterrible]

I dont understand what you're saying mstecha. I was saying that you put little scratches in the sheet of transparency before printing on it. This gives the toner a better surface to stick to. The transparency by itself is too slippery.

 

[mstechca]

I was saying that you put little scratches in the sheet of transparency before printing on it. This gives the toner a better surface to stick to. The transparency by itself is too slippery.

It is a little difficult to scratch a transparency, just by touching it. I found there are two sides to it. a slippery (and possibly shiny) side, and a rougher side (sorry, I don't know the exact ingredients used). I always print on the rougher side to prevent the design from smudging all over.

I buy transparencies specifically for inkjet printers.

 

[zachtheterrible]

Oh you use inkjet :lol:
For some reason I just assumed you use a laserprinter . . . stupid me :x

The reason I was saying that is that the toner doesn't stick very well to transparency unless you scratch it with a not very abrasive pad.