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Inkjet printing on PCB for layout?

Discussion in 'General Electronics' started by Ethan, Aug 24, 2004.

  1. Ethan

    Ethan Guest

    Hello,

    Some geeks and myself are talking about making some moderately
    advanced circuit boards. I was thinking back to the plotter idea,
    where you use a XY plotter to plot directly onto the PCB surface. This
    seems nice, and should yield a quicker turnaround versus the iron one
    blue toner transfer stuff.

    But I have a different idea. What about modifying an inkjet printer
    to print directly on the board. Will the ink resist the etchant like a
    sharpie marker will?

    People have modified inkjet printers to print on CD-ROM disks, so
    I'm assuming it can't be that hard to mod one of these printers, but
    the value would be the question.

    If a marker could be had for a X-Y table pen plotter that could do
    1mm tracks (surface mount devices are the goal here) then that would
    be acceptable.

    Help and tips appreciated!
     
  2. WDino

    WDino Guest

    What about modifying an inkjet printer
    Yes, has been done before. But you must use waterproof ink.
    Epson, Lexmark and HP have this type of ink for some of their printers.
    Ensure that the inkjet head returns to the sealed head cover area after
    printing.

    I used an Epson (can't remember the model) but gave up after the second
    head burnt out. I now use an XY plotter with HP "permanent" ink pens.
     
  3. No one bothers to use plotters or other such systems any more, don't
    bother, it's not worth the hassle.

    I use a laser printer directly on transparency film and then expose a
    positive pre-coated photoresist PCB. I can do 6thou/6thou double sided
    surface mount boards if I'm careful, and 8thou/8thou (0.2mm) with no
    trouble at all.
    Quality will depend on the transparency you use though.

    Dave :)
     
  4. Eric Snyder

    Eric Snyder Guest

    Here is how I do it. Using a CAD program to make the PCB circuit
    layout, I make a mirror image of the circuit. I then print the
    circuit on injet transparency film using a standard ink jet printer.
    I place the film, ink side down on a presensitized photo resist copper
    clad board. I lay a pane of glass on the transperancy and expose it
    to UV light. Etch as normal, and I get a great looking board. I've
    been using this technique for years, prototyping and producing Ham
    Radio circuits. Because the transparency film affects exposure time,
    you probably will have to increase exposure time approximately 10-15%.

    Eric Snyder N7DLV
     
  5. Ethan

    Ethan Guest

    No one bothers to use plotters or other such systems any more, don't
    Interesting... I should look into this, my main beef with the iron on
    toner transfers was that it was alot of work to remove the toner
    transfer stuff from the PCBs, and the time to iron was hard to
    predict, so it would be cool to have the capability to do more
    accurate stuff, to allow surface mount work.

    I like the idea of a pen plotter, but the photo methood sounds pretty
    easy.

    I've heard of people stacking two transparencies....

    I'm definitly going to look into the photo method!
     
  6. Eric Snyder

    Eric Snyder Guest

    Hello Ethan;

    Here is a follow up on my original post. I make a mirror image of the
    circuit so I can lay the transparency ink side down. This eliminates
    the thickness of the transperancy becoming a factor in the PCB trace
    quality. I can produce traces as thin as .33mm using this technique.
    I like the laser printer method as described earlier and that is
    probably best. As you know, ink jet printer ink runs if it gets wet,
    ruining the template. Unfortunately, I dont have a laser printer,
    just a cheap Lexmark. Be sure to set your printer to the maximum DPI
    available. If not enough ink is used for the traces, some UV light
    could bleed through. I don't know if laser printers will have this
    problem.

    Eric N7DLV
     
  7. Yes, I do this if one isn't dark enough, although it does limit your
    ability to do really fine spacing under say 10thou. You can buy proper
    transparency film designed for this exact purpose, although I have not
    tried it as it's quite expensive. I just try all the different brands
    of standard office film we have until I find one that works :->

    Dave :)
     
  8. WDino

    WDino Guest

    XY plotter is a far superior method for home users, with low volume use.
    It is much much cheaper - uses standard uncoated boards and no photo costs.
    The quality is superb with NO pinholes or marks.
     
  9. KevinR

    KevinR Guest

    Having some light leak through the print can be a problem with laser
    printers, It's not a problem on normal or smaller tracks, but large
    areas of copper can end up quite porus by the time the board has been
    etched.
    I bought a brand new toner cartridge for my HP LJ2200 and even that
    is not completely opaque on large areas of black.
    I keep the new toner cartridge just for PCB work, swapping out the
    older one which I use for normal stuff.
    I had particularly good results with some special transparrencies
    which we got from CPC, but they were a little pricey. They were
    translucent rather than transparent and one side had a slightly mat
    finish which picked up the toner better.
    Arrange the printing such that the toner is directly against the
    board, not on the other side of the transparrency from the board,
    othewise you can end up with slightly thin edges on the tracks from
    where the light is dispersing within the transparrency.

    I use pre-sensitised boards and "fine etch crystals" (sodium per
    sulphate) from farnelll, which is so much less messy than ferric
    chloride.

    It is good to use some form of agitation while etching, if you just
    allow the board to sit in the etchant, then the edges of the board
    could be done in an hour, while the middle of the board could take two
    or three hours, in which time the parts near the edges of the board
    become seriously undercut. I made a cam, stuck it on a geared down
    motor connected to a variable power supply and used that to rock a
    flat surface on which I place the tray of etchant, works like a charm.

    Kevin R
     
  10. I shortly had access to a HP Lsaerjet 5000. It gave good cover both for
    tranparancies and peel method. Unfortunately I have only a HP laserjet 4000
    Si now which covers badly (with respact to the 5000 of course.) So I guess
    I'll have to use two transparancies for the photomethod. Press and peel is
    totaly out of question.

    Still have a plotter, but never could make good transparancies with it.
    Maybe I never got the right pens. What makes things worse is the speed
    difference during operation. Horizontal and vertical lines are drawn very
    quick, others much slower. Can hardly imagine to get good cover that way.

    Anyone has experience with it? Please let us know.

    petrus bitbyter
     
  11. Warren Weber

    Warren Weber Guest

    Eric.. To keep ink from running (from moisture or damp fingers) I give a
    light spray of Krylon clear lacquer. W W
     
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