PCB making questions

Started by Karmasound, January 25, 2005, 11:40:43 PM

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Karmasound

Hi,
I did a search and just a have a few questions. I get the gist of the process but...

1) Is PNP blue the best method to use?

2) What about using the photo and UV method?

3) I don't have a laser printer. Could I go to Kinko's or something and do it there?

4) Do you just print from the PDF file? How do you center it in the printer and on the computer to not waste the PNP. ie. like making a small pcb in the center of the paper?

5) What is a low cost for a printer and what should I mainly be looking for in one?

6) I believe I could draw smaller simpler ones by hand. I just use a sharpie right?

Thanks

Heavner

Read over this photo essay.

http://www.tonepad.com/photoessay.asp?photoEssayID=10

Yes, kinkos has laser printers.

Yes, can freehand with a sharpie.  Just make sure to get your pad spacing close.  Printing from the PDF is a wiser choice though.
The older I get... the better I was.

Karmasound

Ahh, thanks a bunch that clears up alot.

NaBo

press n peel always seemed kinna expensive and not really worth the hassle...  not for the relatively simple world of stompboxes (is it worth it for a 2"x2" circuit with like 1/16" traces?)...  and as a university kid, i have more time than money.  i do mine by hand with a super thin tip sharpie, its actually really really easy.

i just print the reversed-reversed pcb layout, colour on the back with a pencil, tape it down on some copper-clad, and go over everything really hard with a pen.  it works pretty great.  another way i've done it, with varying results, is if you have a bubble/ink jet printer, you know, the kind that can just soak the page in ink and needs time to dry after printing...  just print on "best" quality, then quickly tape it down and rub it with something hard and smooth, like the wrong end of a pen.  my printer is kinda crap and doesnt always work well like that, but i can see other people getting perfect results.  

then its just a matter of tracing with a marker!  you CAN deviate in some places if you feel like you're getting cramped... you can make pads bigger, traces further apart, add stuff for mods easy, etc... thats not a problem, EXCEPT for ICs, and transistors if you socket (which you should).  even then, the socket legs can bend a bit if you weren't exact.  you always have a a fair bit of lee-way with Rs and Cs and Ds though.  just try one or two and you'll get a feel for it really fast, i know i sure did!

sir_modulus

I think I'll take a shot at some answers.
Quote from: Karmasound
1) Is PNP blue the best method to use?
It is is you are a bit experianced with it. It gives really nice and clean transfers etc... You could also use the photo paper method (do a search for it), which works equally well, but the transfers are hard to get on some types of paper/irons.
Quote from: Karmasound
2) What about using the photo and UV method?
Those are all viable options, but the startup cost is a bit on the high side (buying the bulb, and exposure kit etc...). You also need to buy presensitized boards. I know some people on the forum do this also, so I'm not the best person to ask for the pros of this method.
Quote from: Karmasound
3) I don't have a laser printer. Could I go to Kinko's or something and do it there?
Yes, Kinkos, Staples, Office Depot, or any office store that does photocopying will do it for you. but there is a hitch. You have to print out a full sheet of PNP or photo paper...they won't print on tiny little pieces.
Quote from: Karmasound
4) Do you just print from the PDF file? How do you center it in the printer and on the computer to not waste the PNP. ie. like making a small pcb in the center of the paper?
For this, all you do is print out the PDF onto normal paper. For printing set it to center, and no page scaling, or resizing. Now after it's printed, cut out a piece of PNP that will cover the PCB design, leaving about 1-2cm on each side...for printer inconsistiences. Now tape this by the edges over the design, and print on this sheet again. Now just take off the tape, and your set  :D  
Quote from: Karmasound
5) What is a low cost for a printer and what should I mainly be looking for in one?
I have a decent HP one, and it has NEVER let me down in any way...build quality is great, great divers, etc...
anything here will be good.
Quote from: Karmasound
6) I believe I could draw smaller simpler ones by hand. I just use a sharpie right?
Yes, that's always a good thing to do! In fact, even on PNP blue transfers/photo transfers, you always use a sharpie to touch up areas that didn't transfer all too well. Ammonium Persulfate doesn't agree with Sharpie markers too well though... (you can use acid etching, Ferric Chloride, or Sodium Persulfate).

Cheers, and hope that helps!

Nish

Karmasound

Thanks a bunch for the replies, this really helps mucho grande :)

mojotron

Quote from: Karmasound
1) Is PNP blue the best method to use?
I use the picture paper method - and I had tried every kind of paper I could find - and  I have found that if I follow the directions EXACTLY as shown in http://www.fullnet.com/u/tomg/gooteepc.htm, with the right paper (from staples - OH YA... pick up an "easy" button while your there - you'll need one of those too) and using HP Microfine fuser... everything works great... it's worth all the time and effort... 10% of the time I get a perfect transfer, but the ones that are flawed can be fixed with a sharpie - usually smaller traces... The important thing is to really rough up the board and get all of the oil.. off.
Quote from: Karmasound
3) I don't have a laser printer. Could I go to Kinko's or something and do it there?
I tried this, and after explaining things to people every time I did this... "You can't use that paper in this"... "What do you mean I wrecked it.. I just put my finger on part of the copy..." I just went and bought my own printer off of ebay.... YOU WILL WANT TO BUY A "NEW" PRINTER - don't get one off of ebay - unless you want to learn a lot about printers...
Quote from: Karmasound
4) Do you just print from the PDF file? How do you center it in the printer and on the computer to not waste the PNP. ie. like making a small pcb in the center of the paper?
I do a whole sheet at a time, which is about 6-12 pcbs - much easier. Even if I dont use them all, it's not a big waste if you use the picture paper method.

Usually working with PDFs is intended to keep people from cloning the layouts.... But, this is easy to work around - the images can be lifted from the read only PDFs by doing a screen capture of your computer desktop with the PDF fully maximized - then cut/paste/massage in window's paint or photo edit kind of program.. Of course GGG has layouts that are usually just .gif files. Then I use Word to layout the graphics to scale to print a whole sheet at a time... This works for me. NOW, keep in mind that if you use other's layouts for comercial puposes, you need to get permission..... it's all copyrighted and you will get found out... Some of my stuff is derived where I used layouts from the WWW where I made some major mods to the layout... eventually using Orcad or Egale to make a new layout (minimizing wire lengths, fat trace widths...) is what I use if I really like a design and want to get serious with it.
Quote from: Karmasound
5) What is a low cost for a printer and what should I mainly be looking for in one?
Any printer that uses HP's Microfine fuser... but buy a new printer. Any used printer is going to have issues..
Quote from: Karmasound
6) I believe I could draw smaller simpler ones by hand. I just use a sharpie right?
That would be the way to go if you just wanted to make a few here and there.

gez

If you can photocopy a reverse image on to 'coated paper' (the glossy stuff) then you can transfer the image using acetone.

Place image side down onto the board then dab with cotton wool soaked in acetone (nail polish remover works fine).  Leave to dry then soak in warm water for about 10mins or so.  Gently peel away the paper (lot easier than ironing).

If you use normal paper bits of 'wood chip' remain on the board once peeled off, so it must be 'coated'.

I've only ever done this once, but it works.

It's possible to use an inkjet with UV board etc (there are posts in the archives about it).
"They always say there's nothing new under the sun.  I think that that's a big copout..."  Wayne Shorter

Mark Hammer

Quote from: Karmasound
1) Is PNP blue the best method to use?
2) What about using the photo and UV method?

Different methods have different resolutions.  UV can be "better" than PnP which can in turn be "better" than glossy photo paper.  HOWEVER, if we're talking a simple 1 or 2-transistor PCB pattern that isn't too crowded, glossy photo paper is more than good enough.  My own rule of thumb is that if the PCB pattern has either traces that run between IC pines, or has more than two traces running between the legs of an IC, I would avoid photo paper and turn to PnP.  If it was an extremely high density layout with many thin traces running close together, UV is probably the only way to go.  Think of it like this: some types of graphical depictions are feasable and clear enough on a 1st-Gen Gameboy, while others would require more but still be acceptable on a 640x480 8-bit screen.  Other things you wouldn't dream of viewing on anything less than 1280x1024 in 32-bit colour.  In general, there is a surprising amount that is quite feasible with "mere" photo paper.

Quote3) I don't have a laser printer. Could I go to Kinko's or something and do it there?

People who work in photocopy shops are understandably wary of things they haven't seen before.  After all, that's an expensive machine they're in charge of and they don't want anything buggering it up.  It would seem from comments that the blue emulsion REALLY throws them for a loop and the odds are pretty good that if you came in with a couple of PnP blanks and asked for copies, they would hesitate.  You can persuade them by letting them know that this is the identical acetate sheet used for overhead transparencies, and that the blue emulsion is not dramatically different than the *clear* emulsion on overhead blanks.  It is simply opaque for the purposes it will be used for.  If their machine can handle overhead blanks, it will handle this stuff JUST FINE.  If they still balk, ask if they can copy it to glossy photo paper as a backup plan.

Worse comes to worse, you go to a public coin-operated facility, select "manual paper feed" and stick the sheets in yourself.  First make sure from the staff that the machine CAN do overhead transparencies.

If you don't hand them a master that has a dense enough image (i.e., VERY black where it is supposed to be black), get them to turn up the contrast a bit.  The more solidly/consistently black your original is, the better the transfer to the copper board since it is the toner which forms the "adhesive" for the pattern ultimately.

Quote4) Do you just print from the PDF file? How do you center it in the printer and on the computer to not waste the PNP. ie. like making a small pcb in the center of the paper?

When you print from PDF, there are options available in the little pop-up print window that let you specify whether you want Acrobat Reader to adjust the image, sizewise.  You will generally want it to simply print the image as is, without fitting the image to the page.  If not, the image may be expanded to fit the default margins, and the spacing corrupted (even if only a little).  Personally, I generally keep around a spare 16 pin chip to place over the pads on what I print out, just to verify spacing.

Quote5) What is a low cost for a printer and what should I mainly be looking for in one?

By the time you read this, I have no doubt printer prices will have changed...yet again.  For heat transferable materials, you'll want laser not inkjet.  the startup price is generally higher than comparable inkjets, but the nice thing is you can leave a laser alone for 8 months and it will still work when you come back to it.  Print heads on inkjets tend to dry up if you don't use them often.  Alternatively, do what I do sometimes.  Print out sheets of a variety of layouts, do some creative cut and paste so that you have a dozen or more layout patterns on one sheet of paper.  Photocopy until suitably dark, then bring to a photocopier/service with your glossy paper blanks or PnP.  

BTW, the laser glossy paper is generally cheaper than inkjet glossy, though it would appear that both work fine for transferring patterns.  Just make sure that you DON'T get double-sided glossy.  You want one side of the paper to be amenable to exposure to hot surfaces.  Although you can use inkjet *paper*, you will need a printer that applies a thermal process in printing (i.e., inkjet paper into a laser printer/copier).

Quote6) I believe I could draw smaller simpler ones by hand. I just use a sharpie right?

In my experience, Sharpie's are fine, but their rather abrasive tips tend to accumulate copper deposits quickly and you can easily lose the use of the tip of the marker.  They are also not particularly cheap or adapted to touching up or even drawing neat patterns.  Personally, I prefer fine-tipped Staedtler Lumocolor pens.  Many folks think you need black pens.  Not true.  It's actually the clear media that the pigments are mixed with that forms the resist, not the pigments themselves.  The color just shows you where the media has been deposited.  I've made PCBs with what appeared to be light red and green pens and they came out just fine.  What I like to do (or did, since most of what I do now involves photopaper) is use two colors of pen - a lighter color (e.g., red) for the first coat and a darker one (blue or black) for the 2nd.  Using two colors simply helps to let you know what parts you've done already, and what parts you haven't.