DIY PCB Silkscreen?

Discussion in 'General Electronics Chat' started by spinnaker, Feb 9, 2010.

  1. spinnaker

    Thread Starter AAC Fanatic!

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    Is it possible (realistically) to DIY silkscreen on a PCB? If so, can anyone point me to a link on how to do it?
     
  2. jpanhalt

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    Conventional silk-screen is not too difficult, once you are set up for it. I don't have any links for it, though.

    As an alternative, some people use a modification of the toner transfer method, but instead of etching, they apply a white foil transfer to the toner. It is sold by and described on the Pulsar site: http://www.pulsarprofx.com/index.html

    John
     
  3. BMorse

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    I have been thinking of doing my own silkscreening, I am getting tired of "hand writing" legends on my PCB's >>[​IMG]

    I think my boards would look a lot better with a silkscreen legend and possibly a DIY solder mask too>>[​IMG]

    [​IMG]

    I think a good silkscreen print could be easily done, usefull too if making more than one of the boards
    .... I had found this stuff once, have not ordered any to try but I might soon.>>>.http://photoezsilkscreen.com/about.htm
     
  4. SgtWookie

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    I just started doing a pseudo-silkscreen using Cadsoft Eagle.

    I turn off the display of the trace layers, leaving all the documentation, vias, etc turned on, and then laserprint on magazine-type paper using mirror image.

    Sand the top of the board to roughen it up a bit, clean with acetone, line up the newsprint with the holes, and iron it on with iron @ 300°F.

    Soak in hot water and scrub off with worn toothbrush. The "pseudo silkscreen" is black instead of white, but I don't really care - black works for me, and it's neat, too.
     
  5. SgtWookie

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    Can't figure out an easy way to mirror the output from ExpressPCB; there's not an option for that. Exporting to a file and then flipping it using MS Paint works, but then you have the scaling problem when you go to print.

    Some trial-and-error could get you there reasonably quickly, I think.
     
  6. SgtWookie

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    OK, found a work-around... but might not work unless you have Microsoft Office installed.

    1) In ExpressPCB, view your board, and select File -> Print...
    2) In the print dialog box;
    Printer: "Microsoft Office Document Image Writer"
    Check box next to "Silkscreen, pads and text on top layer"
    Orientation as desired.
    Number of copies: 1
    Un-check: print page footer, print in color, enlarge to fit page
    3) Click OK.
    4) In the next dialog, give the output file a different filename if you want.
    5) Click Save.
    6) The file will open in Windows Picture and Fax Viewer. Press Ctrl+E to edit it in MS Paint.
    7) Click Image -> Flip/Rotate -> Flip Horizontal (OK)
    8) Save the image if you'd like.
    9) Click File -> Page Setup
    10) U-check the centering boxes. Set all margins to 0 (they'll change to something else, but that's OK). Scale to 100%, then click OK
    11) File -> Print.
     
  7. retched

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    Silk screening is a very easy process. You do not need to use standard "inks" or standard silks.

    Build a screen:
    Take 2x2x18 lumber and make a square. Be sure to use 45 degree cuts to put the four pieces together. Get some decent porous fabric. Even panty hose, doubled over, will work. The thing you cant skimp on is the emulsion. Buy a $20 tub of silk screening emultion, (it will last MONTHS) You smear the emulsion on both sides of the screen in a room with a yellow safe light. (bug lights are fine) Let it dry to manufactures specs.

    Prep and exposing screen:
    Print the layout exactly as you want it on to transparancy film using BLACK ink only (toner is better). Use some corner or registration marks to assist in lining up.
    Press the transparancy to the screen with the up side of the print to the bottom of the screen. (I use 2 sheets of glass. One on top of screen, one on the bottom sanwiching the film against the screen)

    If you have a UV light source, use that to expose the screen to spec on emulsion manufactures sheet.
    If no lamp, use the sun. Let is sit for a half hour in the sun.

    When your time is up, remove the glass and tranparency. Run water over the screen to get both sides nice and wet. Let sit for 2 min. Then either spray out where the image is, or rub with a dish sponge until the emulsion is removed completely from your image.

    Let dry for a half hour. (or longer depending on emulsion manuf. spec)

    You can use thinned latex paint for an ink. But, if you have a craft store near by, you can get a bottle of silk screening ink.

    The trick is to rub the ink into the image before pressing to the PCB and squeegeing.
     
  8. SgtWookie

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    Just so you get an idea of what black silkscreen looks like, this is a quickie project I threw together in a couple hours last week:

    [​IMG]
     
  9. t06afre

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    Some use a ink writer to make the etching mask. Could the same method be used for the silk screen?
     
  10. spinnaker

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    Have I read right that some people use this method of the actual traces?
     
  11. BMorse

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    Sep 26, 2009
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    Yes, it is referred to as the "toner" transfer method.....
     
  12. retched

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    There is a yellow inkjet ink that has a high acid resistance, used for the etching mask. As for silkscreening, You can use a mask method, but removing the mask without removing the print is very difficult. The mask should be removed while the ink is wet, and that isnt easy without a physically removable mask.

    ---END--
    --NOW BACK TO PRINTING TO PCBs---

    Instead of emulsion, you can print, directly to the screen, (using 220 mesh or higher) allowing you to skip the emulsion. However the price for inkjet ink is exponentially higher than photoresist emulsion and water.

    If you decide to try direct to silk printing, you must not use water based inks to screen print with, you will just smear inkjet ink. Plastisol inks can be used with good results.


    If you have an inkjet printer than can do straight-through printing of something as thick as a pcb, you can have a much easier time. If you do a bit of pcb making, you can convert your ink supply to DTG ink (Direct to Garment) This allows your inkjet to "silkscreen" directly to the pcb. After a few sec in a toasteroven to set the ink, and done.
     
    Last edited: Feb 11, 2010
  13. jpanhalt

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    Are DTG and Plastisol inks available for common, consumer-level inkjets? Do you have any links that describe using them that way?

    John
     
  14. retched

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    You will have to do some searching to find links. There is plenty of info out there. If you want a good place to start the research, check out
    http://www.t-shirtforums.com/

    If you need any help, I screenprint regularly.
    If you want to give it a try, get a used inkjet printer and get some refillable(empty) heads/cartridge or preferably a CIS (continuous inking system). If you are doing masking, you will only need to purchase one color of DTG ink. To help save money.

    In the early days, before I made my own films, I would use a screen to make another screen in reverse. I screened to the screen. After curing the inks on the screen, I masked the outline with tape, then printed from that.

    It makes no sense, if you have a DTG printer to print a screen because you dont need one.

    You can check the craft forums for "inkjet stenciling" a few people use the ink to fabric in negative to make a stencil.

    If you want to give it a try, I can give you any info you may have trouble finding.
    If you need to get plastisol into a CIS, I'll help. If you use water based on the silks, for the stencil, You may melt your screen while trying to cure it. Not being able to get it to temperature, you will want to use plastisol for the stencil. You can use a heat gun to flash the ink, then let it sit for an hour. Water wont have an effect on it.
     
  15. retched

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    Youtube DIY DTG and you can see plenty of people using consumer printers for DTG.
     
  16. jpanhalt

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    Thanks. Apparently, you do not have any links or concrete evidence to support your claims.

    So far as I know from the DIY inkjet PCB forums and my own experiments a couple of years ago, the inks you mention* are not compatible with Epson, HP, and similar consumer-level inkjet engines.

    John

    *Other than baked-on, yellow Epson ink, which gives variable results.
     
  17. retched

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    I am not speaking of baked on for resist. And I am not speaking of using inks that came with your printer. Using DTG inks in your printer, which will require some work, will allow you to print onto your pcb. NOT for ETCHING. For PRINTING legends. If you need a further tutorial on the BASICS of screen printing, start a new thread.

    If there was some confusion. sorry.
     
  18. retched

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