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Cheapest way to produce a one off PCB

Discussion in 'Electronic Basics' started by Bob, Apr 6, 2004.

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  1. Bob

    Bob Guest

    I have designed a PCB and printed it off on my inkjet.

    I have no pcb equipment (etch tank/light box etc) so what would be the
    cheapest way to get this from paper to board?

    Are there any simple kits or methods that would work?
     
  2. CFoley1064

    CFoley1064 Guest

    Subject: Cheapest way to produce a one off PCB
    If this is a "one-off", by far the cheapest way to do this would be to go with
    Express PCB or one of the other board shops that specialize in limited quantity
    single/double-sided boards. You'll get a professional job the first time, and
    will be able to get finer detail than you would get with a
    do-it-yourself-poorly etching setup, especially one which has been optimized
    for cost. There's a significant learning curve with this process, and there
    are also hidden costs in disposal of etchant (the solution with etched copper
    shouldn't be chucked down the drain -- you obviously _can_ dump it, but you're
    just making cleanup somebody else's problem, so don't).

    If you insist on doing it yourself (if nothing else, to get it out of your
    system), look at Don Lancaster's tinaja.com site for a Blatant Opportunist
    article on the direct toner method of transferring artwork to PC boards.

    http://tinaja.com/glib/dirtoner.pdf

    All the information in the article is valid, even if several of the companies
    mentioned are no longer in business. There are also several outfits that sell
    iron-on transfer kits. If you go with one of these, make sure you apply heat
    as evenly as possible to optimize transfer. Read and follow manufacturer
    instructions.

    As for etching, you might as well go with ferric chloride etchant. There are
    several inexpensive setups available from GC Electronics which can get you
    started. Remember that, if you want to heat the etchant, use good ventialtion.
    I once used the GC Cat. No. 22-0394-0000 "Professional PC Board Power Etching
    System". It's a little over $100 USD. Not professional at all, but it still
    is capable of doing a fairly good job on boards up to 7" X 9". It has a
    litttle aquarium heater for the ferric chloride, an aerating holder to hold the
    board in the solution while it's etching, and a small bubbler pump to agitate
    and aerate the ferric chloride solution. Remember to keep the aquarium heater
    from touching the plastic side of the tank (it'll melt), and prevent ferric
    chloride solution from seeping back up the bubbler tube into the aquarium pump
    -- it'll destroy it right quick. Bitter experience on both counts there.
    Leave a border around your board -- no etching occurs where the board fits into
    the slot of the holder. Also, turn off the heater when you're not using it for
    obvious reasons. You might want to put the whole assembly in a big plastic pan
    to prevent spills. Remember all etchants are toxic -- keep 'em away from kids
    and pets.

    http://www.gcwaldom.com/catalog.html

    Be responsible, be safe
    Chris
     
  3. Tim Auton

    Tim Auton Guest

    If possible, redesigning the circuit to fit onto stripboard would be
    the cheapest of all. The only cost is that of the stripboard (plus a
    bit of solder and electricity for your iron).

    Etch resist pen + ferric chloride + board (and something to hold the
    ferric chloride while you etch - a used plastic takeaway carton will
    work) is the cheapest way to make a PCB, perhaps 15-20 euros/dollars
    for everything you'd need for a few boards. But you have to draw the
    board yourself, which makes using SMT parts a bit tricky. You might
    want to redesign the board to minimise tracks between pins of ICs
    (which are possible, but tricky with a pen).

    It's a tiresome way to do it though, and the results are rarely great
    - you can almost guarantee your first board will be headed straight
    for the bin, but that's OK, you'll have enough ferric chloride and ink
    left for more.

    If you have access to a laser printer you can use a toner transfer
    method, which is much better than drawing it by hand. You can also get
    transfers and use them for holes, tracks etc. instead of drawing them
    by hand.

    It wouldn't cost a whole lot more to have a one-off board
    professionally produced, depending on the size.

    Search the net for more info on all of the above.


    Tim
     
  4. Garrett Mace

    Garrett Mace Guest


    Olimex. Since you're starting with no existing equipment or materials, you'd
    be spending some time and money accumulating everything to etch it yourself.
    Then you'll have to learn how to do it, and probably waste time, boards, and
    materials. Don't forget that you will need to find some PCB drills and set
    up a small drill press with a Dremel or something.

    If you buy your board from Olimex, you'll get a very professional-looking
    4"x6" board with drilled and plated-through holes, double solder mask, and
    silkscreen for $26 plus $8 shipping. You can have them put multiple boards,
    even entirely different designs, on a single panel and they will cut it
    apart free. If all you need is a single-sided board, that's even cheaper.

    I rarely etch my own boards anymore. Sometimes an adapter here or there when
    I want to prototype a surface-mount component right away. I just take the
    extra time that I gain from having Olimex do the board, and use some of it
    to check the PCB design very carefully and make sure it matches the
    schematic exactly. That's why you make the schematic in Eagle first, then
    build the PCB and auto-check your layout.
     
  5. AtPCLogic

    AtPCLogic Guest

    I have designed a PCB and printed it off on my inkjet.
    Olimex and other board houses will do an excellent job.... but the original
    poster was looking for a very cheap way to do the board. However, he also
    wanted to be sure it worked ;) so, perhaps the original poster could tell us
    how many components, what type of densitey is used, and how wide the traces
    are? For some really simple boards, toner transfer is the cheapest reliable
    way to get a board done. If the board is at all complex then he will probably
    need a different type of fabrication. But, I'd sure like to know more about
    his board before I made a recommendation.
    Brad
    PC Logic

    Schematic entry and PCB design software
    http://www.pclogic.biz
    http://members.aol.com/atpclogic/index.html
     
  6. Garrett Mace

    Garrett Mace Guest


    He doesn't have any tools, materials, or chemicals. It is not possible to
    assemble everything needed to etch a single PCB, for less than the cost of
    ordering a board from Olimex. You can't forget time either. The cost
    tradeoff only appears after you have accumulated everything you need, have
    enough experience to get reliable results in minimal time, and build a good
    number of boards. Even then, the value of the un-tinned, un-plated-through,
    un-soldermasked, un-silkscreened end product may still be low enough to make
    a professional board the cheaper option...the final product has a value too.
    You also need to consider panelization: many projects are pretty small. I
    once had a panel with ten board of two different types in a single $26
    panel, making the board cost only $2.60 per. And that was all cut apart,
    too...I'd hate to breathe all the fiberglass dust generated if I cut it
    myself.

    This really is the future of hobbyist circuits...so many components now are
    surface mount, you pretty much have to make a board every other project. We
    should support and encourage board houses until the processes get so
    streamlined that you'd never think of making your own board. Imagine how
    great it would be to get custom multilayer boards at these prices. How about
    combining that with partial assembly...have them solder on those BGA devices
    for you. Imagine if full assembly services became cheap enough for
    hobbyists. The hard fact is that electronics is getting tougher to do
    without specialized equipment. Instead of complaining and wishing for
    wire-wrap, just evolve the hobby itself and move up one level. Design the
    subassemblies, have them made, then put them together. It's just as
    hands-on, but you have more time to do more complex things. Don't fight
    progress, grow with it.

    Of course for the really simple circuits, I always keep a bunch of solder
    boards and through-hole components around.
     
  7. Tim Auton

    Tim Auton Guest

    Yes it is. Assuming you have some normal household tools (a hacksaw, a
    drill and a plastic container), the bare minimum is a pen, some
    etchant, a board and perhaps a new drill bit. That lot can be had for
    less than $34. Heated bubble tanks, drill presses, guillotines, laser
    printers, light boxes, tinning chemicals and the rest all make the
    process easier and make for a (far) better result but they are not
    absolutely necessary to make something that works.

    A professionally produced PCB is of course much nicer and is certainly
    worth the money, but you can do several small boards at home with the
    minimum of equipment and supplies for less. Is it the best way? No. Is
    it the answer to the question "what's the cheapest way to produce a
    PCB"? Yes.


    Tim
     
  8. Bob Masta

    Bob Masta Guest

    I have a tutorial with lots of practical tips on
    how to make hand-drawn boards using a
    Sharpie felt-tip marker and ferric chloride
    etchant. This method has been honed over
    a couple of decades by myself and the guys
    I used to work with. Check it out at
    www.daqarta.com/lptxh.htm

    Hope this helps!


    Bob Masta
    dqatechATdaqartaDOTcom

    D A Q A R T A
    Data AcQuisition And Real-Time Analysis
    www.daqarta.com
     
  9. If I read your web page right, you recommend drilling before drawing.
    I tried this, and find the holes hard to write over with the Sharpie
    pen. And if you don't get the ink in the holes, the holes etch larger
    than the board holes and soldering is difficult. If you get the
    inside of the holes resist covered, it is hard to get them clean, and
    soldering is difficult.

    I found it easier to clean the board, center punch (A spring loaded
    automatic punch does a very consistent job), draw, etch and then
    drill. This makes sure the copper hole is the same diameter as the
    board hole, and it is completely clear of resist inside the hole, and
    cleaning up the burrs is just part of the resist removal.
     
  10. JeffM

    JeffM Guest

    [if] you have some normal household tools
    Add a pin vise and a pyrex disk and I agree.

    Do you have a link to homebrew soldermask techniques?

    Otherwise, it might be worth mentioning that
    soldering to pads with closely-spaced pads/traces will be more difficult
    (as compared to any previous work you've done on boards built by pros).
    This alone might make sending it to a pro an attractive alternative.
    If not, at the least, inspect your soldering work carefully.


    Folks keep saying "ferric chloride".
    If you like looking thru mud to see what you're doing--OK.
    Otherwise, Ammonium Persulfate or Sodium Persulphate if you can get them.
    http://froogle.google.com/froogle?q=Ammonium-Persulfate+etchant
     
  11. Would it be easier to centerpunch, then use the stick on holes to get
    a consistent pattern/diameter? Then drill after etching.

    I used to use carbon paper and a dull pencil, then cut the pattern
    out with an xacto knive, spray paint the traces, and go etching.
    Obviously the outcome was iffy at best, but worked for what I needed.


    Use the usual techniques to reply via email.

    Molon Labe!
     
  12. Bob Masta

    Bob Masta Guest

    If you drill from the top side (on a single-sided board)
    then the burrs are fairly easy to remove with wet-or-dry
    sandpaper and water, as part of the surface prep before
    drawing. When I've tried center-punching the metal side,
    it typically makes a little crater: the indent is fine, but there
    is a smooth ridge of raised copper surrounding it. This is
    much harder to remove by sanding. If you don't remove it,
    it makes it hard to draw a neat pad... the ridge deflects the
    felt-tip. We made boards that way for a while (using the
    spring-loaded punch) and just cursed a lot, until somebody
    hit upon the idea of drilling from the top. We never went back.

    But you do have to do a good sanding job, not only to avoid
    the etch problems you mention, but to avoid having a burr
    catch the felt tip. So it's a little more work than just prepping
    a smooth board, but seems easier overall. YMMV ;-)






    Bob Masta
    dqatechATdaqartaDOTcom

    D A Q A R T A
    Data AcQuisition And Real-Time Analysis
    www.daqarta.com
     
  13. My guess is that you used the center punch set to a much higher impact
    than I do. Is yours adjustable? Mine makes a just barely visible
    mark, so that my pads are accurately located. Those small drills need
    very little dimple to center accurately.
     
  14. Bill Jenkins

    Bill Jenkins Guest

    For $0.50/sq" s/s or $0.75/sq" for d/s with plated thru holes and a
    small film charge I can produce pcb's for you.
    Boards are FR4 with bright tin/lead finish and are sheared. If you can
    email gerber photoplot files, I can start right away.

    Bill Jenkins
     
  15. Bob Masta

    Bob Masta Guest


    John, you are probably right about the high impact force.
    That was over 15 years ago, and I don't know what the
    guys in that shop are using now. I never liked that punch;
    maybe that was why. I prefer to use a sharp tool (scratch
    awl) and tap gently with a carefully selected stick. (I have
    a favorite that's perfectly balanced. ;-) The awl has a long
    slender tip that makes it easier to see the work, whereas
    the auto-punch had a fat squatty barrel. I may give
    your method a try again on my next board; but after so many
    years it may be tough to retrain myself!

    The other advantage of the top-drill method is that you
    can work from a single top-view layout and punch through
    it onto the top of the board. I often make simple little
    boards by drawing the layout on graph paper, and this
    way I don't need any fancy see-through mylar film.
    (Of course, I do need to get a back-side view when I'm
    inking, and I use a light box for that.)

    One more note: You mention small drills. I haven't used
    a small drill on a circuit board in nearly 30 years. A ball-tip
    carbide dental bur will *never* break from a side load, whereas
    the standard carbide drills will snap if you look at them funny.
    I use dental burs in a Dremel, and you can use the same
    tip to carve slots and cut traces. In all those years, the
    only ones that have needed replacement were those where
    the shank bent when the Dremel fell off the bench and landed
    on the business end. I now have a metal cap I slip over the
    tool when I set it on the bench. End of problem. And these
    burs were pretty cheap, too, from the local dental supply house.
    Since I haven't needed to visit them in 20 years, I don't know
    any current prices, but the originals were about the same as
    single carbide drill bits, a couple of bucks back then.

    And, true, they don't need much of a dimple to center. You can
    zip along at about 1-2 seconds per hole. The only drawback is
    that the taper leading up to the ball tip means you can't do stacks
    of boards for production.

    </evangelizing>







    Bob Masta
    dqatechATdaqartaDOTcom

    D A Q A R T A
    Data AcQuisition And Real-Time Analysis
    www.daqarta.com
     
  16. One comment -

    Sharpies permanent ink will dissolve in isopropyl alcohol - which might
    be an easier way of cleaning up than using a scrubbing pad.

    Also, the Staedtler brand of Lumocolor pens (high quality marking pens,
    designed for overhead transparencies) include an erasing pen, that can
    be used to apply the alcohol in a controlled manner, and may be useful
    for correcting drawing errors.

    --
    It is almost always incorrect to begin the decomposition of a system
    into modules on the basis of a flowchart. We propose instead that one
    begins with a list of difficult design decisions or design decisions
    which are likely to change. Each module is then designed to hide such
    a decision from the others.
    -- David Parnas
     
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