Connect with us

Prototype TSOP MQFP Solder Mask?

Discussion in 'Electronic Design' started by John H P Southall, Apr 12, 2004.

Scroll to continue with content
  1. This will be a small company's first attempt at a board with TSOP and MQFP
    packages.
    We intend to purchase a one-off board from the "PCB-Pool" and we would like
    to save costs by dispensing with the solder mask.
    We intend to use a "Pace" TempWise with a mini-wave bit; oh and some fume
    extraction. Yes and we'll have to get a bit of skill from somewhere too.

    Q: Is a solder mask essential, usefull, or just nice on a protype board?.


    I have only seen this process done with lots of an unpleasant liquid rosin
    flux.
    Q: Can you recommend a suitable product?

    Q: Would a no-clean water based flux suffice?

    Thank you,

    John Southall
     
  2. Boris Mohar

    Boris Mohar Guest

    I solder these by dragging a fine soldering iron tip over the pins of the
    chip that has been tacked down. Stereo microscope is essential for me.
    I use a water soluble flux in a felt pen dispenser. It is applied to the
    board and again to that pins of the tacked down chip.

    If you think that rosin is unpleasant you will not like the water soluble
    flux. I use it because it is more aggressive and yo do not need any
    chemicals to clean it off.

    Regards,

    Boris Mohar

    Got Knock? - see:
    Viatrack Printed Circuit Designs http://www3.sympatico.ca/borism/

    void _-void-_ in the obvious place
     
  3. John Larkin

    John Larkin Guest


    Good. It's not really hard.
    You'll save, what, $5?
    Useful. Looks nice, too.
    RMA liquid rosin flux is not unplesant, aside from being sticky.
    Dilute a bit with alcohol, maybe.
    Water-soluble fluxes can leave conductive, hygroscopic ionic residue,
    especially under fine-pitch parts that are essentially flat on the
    board. That may not matter much if your circuits are all digital.

    John
     
  4. Leon Heller

    Leon Heller Guest

    I use Metcal equipment with a 'hoof bit' for drag soldering fine-pitch
    devices. I think Pace makes something similar. I also use a stereo
    microscope.
    I've managed without it on occasions. It does make things easier, and it's
    worth paying the extra.

    I use an Electrolube SMF12P flux pen. It's not too messy and any residue is
    easily removed with IPA.

    Leon
     
  5. This will be a small company's first attempt at a board with TSOP and MQFP
    ============== Cut ====================

    Thank you for the help,

    John Southall
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-