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farnell photoresist experience

Discussion in 'Electronic Design' started by [email protected], Jul 18, 2006.

  1. Guest

    hi,
    im planing to buy a positive photo-resist from farnell. (order code -
    130-552). i have no pror experience on making PCB in this way. if any
    one got any experiance with this product pls let me know. would
    appreciate any other suggessions on this too.

    thanks you.
    CMOS
     
  2. Spray photoresist is a waste of time for all but the lowest-resolution PCBs unless you have a
    cleanroom and a lot of time to practice.
    It's next to impossible to get an even coating, free of dust. Use the pre-coated stuff - the extra
    cost is well worth it.
    For lots of info on making good quality PCBs, see www.electricstuff.co.uk/pcbs.html
     
  3. Eeyore

    Eeyore Guest

    I have in the past used Kodak's photoresist chemicals.

    It's very messy indeed. It requires alot of trouble to get even half decent
    results.

    Graham
     
  4. Guest

    Making your own PCBs is giant waste of time, it's messy, innacurate,
    and you'll never get plated through holes.
    Just send your artwork (you are using a PC here right?) to any number
    of online proto PCB shops like APC, Olimex, Futurlec, etc...
    If you like playing with copper and chemicals, may I suggest taking up
    a stained-glass course instead?
     

  5. If you have the space to have the equipment set up permanently, it is quick & easy to do all but the
    most complex prototype PCBs in under an hour. You wouldn't want to do it for production but it can
    save huge amounts of time during development.
     
  6. Robert Baer

    Robert Baer Guest

    I used KPR also and had zero problems after replacing their
    "developer" with (now banned) TCE.
    I found a repeatable and reliable way to get a thin and uniform
    coating by adding CP benzine.
    I even made my own vapor degreaser using a 1-gallon can, copper
    tubing, a 100 watt heater and fiberglass insulation. With that, i could
    make a quart of TCE last a long time.

    Most of the boards i made were 2-sided, but not plated thru; i
    arranged the traces and vias to minimize those that had no part leads.
    20 mil traces with 20 mil spacing was easy and that was 20 or more
    years ago.
     
  7. Ross Herbert

    Ross Herbert Guest

    Yes, I recently used a can of PRP200 and I found several deficiences
    compared to using Kinsten pre-coated board.

    Firstly, it is damned expensive around AU$30 per can.

    It is difficult to get an even coating and dust particles can be a
    real problem. And drying the board after spraying takes considerable
    time using a hot air gun in the semi-dark.

    Exposure time is extremely long compared to Kinsten pre-coated.
    Kinsten takes me 85 seconds exposure but PRP200 takes 5 min in the
    same light box. Anything less and the developer just takes all the
    resist off.

    The propellant in the can ran out before all the resist had been used.

    The results for PRP can be excellent but Kinsten pre-coated is far
    more reliable and the results are repeatably excellent.
     
  8. Barry Lennox

    Barry Lennox Guest

    I don't have their catalogue handy, but if it's made by Electrolube,
    your results might be variable. Some years ago, it was good, but it
    was a green colour. About 5-6 years ago I bought another can, and it
    was distinctly blue-green, and it was crap. Results were very variable
    but generally poor, even with careful process control.

    I have gone back to my small remaining stock of KPR, it has to be at
    least 30 years old, but still works good. I have also had good results
    from the blue "Press'n'peel" transfer paper, although I only had one
    small free sample sheet.

    Barry Lennox
     
  9. The postive pre-coated boards from Farnell are excellent. Well, the FR4
    ones are excellent, the CEM1 phenolic base ones are crap, as all
    phenolic base is.

    I use a laser printer transparency, getting the right type of
    tranparency to avoid pinholes is the key. You can print out to copies
    and stack them to get it extra dark. Make sure you put it toner face to
    the board to avoid undercut.

    I expose mine for 15min on a home made light box, or 5 min in the
    Australian summer sun.

    Excellent resolution, I can easy get 8thou/8thou, and 6/6 is achievable
    too.

    Dave :)
     
  10. Inaccurate? I can get 6/6 resolution double sided no problem.
    No plate through, but perfectly adequate for a prototype.
    Can you get the board made and in your hands within an hour?
    That's a HUGE benefit of making your own.

    Dave :)
     
  11. Leon

    Leon Guest

    I can confirm that. The old stuff worked quite well, but the current
    stuff is useless. I asked Electrolube about this at a trade show a
    couple of years ago and they confirmed that they had changed the
    formulation, and it no longer worked very well. Probably something to
    do with RoHS.

    I use resist-coated CEM1 material from Farnell and other suppliers:

    <http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=710143&N=0>

    and can do 10/10 and 8/8 mil PCBs at home with very few problems.

    Leon
     
  12. Leon

    Leon Guest

    CEM1 isn't phenolic, it's a fibreglass/paper composite. I find it works
    just as well as FR4 for most purposes, is cheaper, and *much* easier to
    cut and drill. The resist is the same as the FR4, AFAIK, which is the
    main thing.

    Leon
     
  13. Use tracing paper - works much better than transparencies - get the thick stuff - 90gsm or more to
    avoid crinkling.
     
  14. Incidentally, these rivets are really good for through-plating - you don't need the punch tool - you
    can use the rivets on their own with tweezers.
    http://www.megauk.com/through_hole_rivets.php
     
  15. Leon

    Leon Guest

    The thin stuff is OK, I cut a piece to size and stick it to an ordinary
    sheet of A4 paper with a piece of masking tape. I get better results
    with Mega Electronics JetStar film in an inkjet printer. It's expensive
    stuff, though.

    Leon
     
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