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Drawing the PCB — Parallax Forums

Drawing the PCB

John A. ZoidbergJohn A. Zoidberg Posts: 514
edited 2011-07-03 11:45 in General Discussion
In early days my father (he learnt electronics and basic radio/tv repair in an institute for his hobby) used a Sharpie to draw the circuit lines on the copper clad board before it is dunked in the Ferric Chloride. He drew up an FM/AM radio circuit board, and he still kept it in the storeroom. It looks a bit messy but it did the job perfectly.

Anyone else actually drawn circuit lines without using computer? Or they had been doing that all along during the 70s/80s? :)

Comments

  • LeonLeon Posts: 7,620
    edited 2011-07-02 08:59
    I used to do that in the 1970s. I designed the PCB on 1/10" grid graph paper, using a pencil and eraser. I then punched through the holes with a centre punch, painted the pads with cellulose paint and joined up the dots with paint. I then left it in a warm oven for a few minutes to dry, and etched the board. I even made double-sided boards the same way.
  • TorTor Posts: 2,010
    edited 2011-07-02 09:26
    John A. Zoidberg wrote: »
    In early days my father (he learnt electronics and basic radio/tv repair in an institute for his hobby) used a Sharpie to draw the circuit lines on the copper clad board before it is dunked in the Ferric Chloride. He drew up an FM/AM radio circuit board, and he still kept it in the storeroom. It looks a bit messy but it did the job perfectly.

    Anyone else actually drawn circuit lines without using computer? Or they had been doing that all along during the 70s/80s? :)
    That was the method available to individuals in the seventies. I made many boards that way as a teenager. In fact I've never got around to use a computer for that.. I stopped when it wasn't feasible to make your own boards as single-layer, hand-drawn Ferric Chloride-etched boards. I think I still have a bottle of that stuff stored away somewhere btw.. a few drops of it can convert a piece of your car to a rust heap very quickly.
  • LeonLeon Posts: 7,620
    edited 2011-07-02 09:39
    I gave up on that technique when I got my first PC, an Amstrad PC1512, and a PCB package called Easy-PC became available. Easy-PC is still around, but it's been enhanced over the years.
  • xanatosxanatos Posts: 1,120
    edited 2011-07-02 12:57
    I used sharpies way back until Radio Shack started selling the rub-on dry transfer patterns. Used those untilI found the pre-photosensitized clad boards at Mouser, and I've been using the photo process ever since. But I used to make some pretty cool stuff with markers!
  • TtailspinTtailspin Posts: 1,326
    edited 2011-07-02 18:52
    Sharpies are great for small easy to draw PCB's.
    You can do a lot with a french curve and some time...
    circuit.JPG


    Now days, it is much easier with the computers, No more trying to rub the bubbles out of a corner,
    Just print out a picture and let the light and chemicals mix.

    -Tommy
    circuit.JPG
    800 x 600 - 423K
  • ihmechihmech Posts: 179
    edited 2011-07-02 22:15
    I've done both the Sharpie method and the rub on transfer patterns when I was a teen. I never had any luck with laying down the lines and corners, so I just used the pads and connected them with the Sharpie. Anymore I have just used perf board with and without the copper pads but would like to get back into etching my own boards.

    Has anyone turned out good results with the photo type boards?

    I saw a video of a board done on Jameco's website. Looks pretty simple, but I don't have a laser printer to print the transparencies.
  • LeonLeon Posts: 7,620
    edited 2011-07-02 22:35
    I get excellent results with the photo-etch process - 8/8 mil if necessary. I print the transparencies on a cheap HP inkjet printer.
  • xanatosxanatos Posts: 1,120
    edited 2011-07-03 05:12
    I don't get black enough transparencies with inkjet, so I print the image on glossy photo paper, then go to a local staples to use a copier to get the actual transparency. I also use two transparencies, stacked and in register, to do the actual exposure. Time consuming... But results that can't be gotten with a sharpie!
  • LeonLeon Posts: 7,620
    edited 2011-07-03 05:16
    My printer is an HP Deskjet 5940, used with Mega Electronics JetStar Premium film. The transparencies are nice and dense.
  • John A. ZoidbergJohn A. Zoidberg Posts: 514
    edited 2011-07-03 09:13
    Hmm. One layer is easy to draw, in EagleCAD. I would try two layers, but the problem lies on the transferring the artworks to two sides of the paper and both sides must 'tally' each other.

    I read in an instructables article once about feeding the two-layer system to the laminator. That is a pretty brave idea. Or it is a common, casual thing to be done already?
  • kwinnkwinn Posts: 8,697
    edited 2011-07-03 09:26
    John A. Zoidberg wrote: »
    Hmm. One layer is easy to draw, in EagleCAD. I would try two layers, but the problem lies on the transferring the artworks to two sides of the paper and both sides must 'tally' each other.

    I read in an instructables article once about feeding the two-layer system to the laminator. That is a pretty brave idea. Or it is a common, casual thing to be done already?

    Not sure what you mean John. Are you laminating 2 sheets together for a denser image to expose photo resist, or using a laminator to transfer toner from 2 sheets to a 2 sided PCB?
  • kwinnkwinn Posts: 8,697
    edited 2011-07-03 09:32
    Way back I saw an old HP xy plotter and desktop computer that was used to draw the pcb resist directly onto the copper. It was accurate enough to do 2 sided boards.
  • John A. ZoidbergJohn A. Zoidberg Posts: 514
    edited 2011-07-03 09:39
    kwinn wrote: »
    Not sure what you mean John. Are you laminating 2 sheets together for a denser image to expose photo resist, or using a laminator to transfer toner from 2 sheets to a 2 sided PCB?

    Toner transfering the artwork to both sides of the PCB. Here's the link: http://myweb.cableone.net/wheedal/pcb.htm :D
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2011-07-03 09:54
    ...a cheap HP inkjet printer.
    I didn't know that cheap intersected with HP or inkjet, let alone both.
    (I just found about "Baconnaise" last week.)

    Been drawing traces (draw it, dry it, draw over it, dry it) on copper-clad with a Sharpie for years and years.
    Nothing too fancy, it's easier than point-to-pointing power supply front-ends.
  • LeonLeon Posts: 7,620
    edited 2011-07-03 10:09
    That printer of mine cost about £60, and does 1200 dpi. The printers are cheap, it's the cartridges that are expensive, and where manufacturers make most of their money. The transparency material I use is expensive, I cut it to size and stick it to a piece of A4 with masking tape, to avoid waste. I can make a PCB in under 30 minutes, not including drilling, which is the most tedious part of the process. Surface-mount avoids the need for a lot of drilling, of course. I keep meaning to build myself a CNC drill.
  • kwinnkwinn Posts: 8,697
    edited 2011-07-03 11:42
    John A. Zoidberg wrote: »
    Toner transfering the artwork to both sides of the PCB. Here's the link: http://myweb.cableone.net/wheedal/pcb.htm :D

    That is a nice description and a fairly straight forward procedure for producing 2 sided boards. Aligning the sheets will take a bit of practice. The nice thing with smt is alignment is only critical for the vias and you can use slightly larger thru hole pads for that. Same for thru hole components. They tend to use larger pads as well. The tricky part will be getting enough toner transferred to the copper.

    BTW - MG Chemicals has a new product. It is a dry photosensitive film that adheres to the copper. Uses negative for exposure and developing. Around $20.00 for a 12" x 60" roll.
  • LeonLeon Posts: 7,620
    edited 2011-07-03 11:45
    I've made a couple of double-sided boards using the photo-etch process. I used the trick of sticking the transparencies for the two sides together to make a sort of envelope - it works quite well, but I'd rather make single-sided boards with dense tracks and a few wire links.
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