PCB Fabrication

Discussion in 'General Electronics Chat' started by Skeebopstop, May 18, 2009.

  1. Skeebopstop

    Thread Starter Active Member

    Jan 9, 2009
    358
    3
    Hi All,

    I recently had our production manager come back to me and ask that I alter a 4 layer PCB design to the 'cheap way' in the attachment, versus the 'expensive way' I used.

    Can anyone comment on this? Are there any repercussions of me allowing him to alter the process?

    Regards
     
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  2. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,535
    How high frequencies is this board? The only pitfall I see is dielectric constants of the board, and that would only affect really high frequencies. I have to say I'm no expert in this though, just my 2¢.

    Oh, then there is voltage breakdown, which is less common as an issue.
     
  3. Skeebopstop

    Thread Starter Active Member

    Jan 9, 2009
    358
    3
    I did find an e-book which discussed this briefly. Although prepreg is the same material, I guess the tracks are more prone to 'sink in' a bit during fabrication and as such the thickness can be slightly less than intended.

    This would impact the dielectric and clearances slightly, but as far as I can tell this cannot be predicted to such a degree and must be assumed to be the same as the core.

    I don't see any reason why this assumption is not valid, considering the material is the same, only the process of application differes.
     
  4. StayatHomeElectronics

    Well-Known Member

    Sep 25, 2008
    864
    40
    I have always used the standard method of board production. We made processor boards with clocks of 30 and 40 MHz. Our analog sectioins routinely went up to about 1 MHz.

    Even the other division of the company, working on RF circuits, used the standard method of board production.

    Unless you have a specific reason, that is somewhat measurable and reproducible, I would always start with the standard method. The standard method is pretty flexible with layer thicknesses and such.

    There's 2 more cents.
     
  5. Skeebopstop

    Thread Starter Active Member

    Jan 9, 2009
    358
    3
    Sounds good to me. Thanks.
     
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