Hi.

Sorry Chris. If you spec .001" minimum plating (per the IPC spec), you
best get .001" minimum plating, or else you have rejectable boards. If
you're fab house can't give you .001" min plating, regardless of CU
thickness, you best find one that can. Make sure you get some cross
sectioned boards, if you're not sure of plating thickness.

Mitch

---------Included Message----------
>      Date: Wed, 20 Jun 2001 12:26:08 -0500
>      From: "Chris Robertson" <[log in to unmask]>
>      Reply-To: <[log in to unmask]>
>      To: <[log in to unmask]>
>      Subject: Re: [DC] Plating Thickness
>
>      Paul,
>      It doesn't quite work that way.
>      Hole copper plating is driven by external plating.
>      If you have a 1oz (.0014) external, it will most likely be
>      .5oz(.0007) copper and .5oz(.0007) plating. The hole will
>      actually plate only .00057 or .0005
>      2oz finished is 1oz start and 1oz plating (.0014") or
>      .0012" in the hole wall. I'm sorry I don't have the exact
>      number.
>
>      This is a very, very common misconception.
>      What ever the plating thickness, is also your minimum
>      annular ring, no matter what the IPC table says.
>      The number stated in the spec is a minimum necessary.
>      So if your plating 1 oz don't count on a .001" minimum
>      annular ring.
>
>      Chris Robertson
>      [log in to unmask]
>
>      Senior Designer
>      Lockheed-Martin Services Inc.
>      4912 Research Dr.
>      Huntsville, AL 35805
>      (256) 722-2626
>
>
>
>
>
>      >
>      > Hi All
>      > Just curious to know if most Designers include their own hole
>      > copper plating
>      > thickness at say 25 or 30 Microns or what ever they feel that
>      > they require
>      > on the manufacturing notes, or do most people prefer to just
>      > leave it at the
>      > IPC specifications usually 20 Microns. I am just interested
>      > perhaps people
>      > are designing boards that will have a lot or current flowing
>      > through them
>      > and feel that 20 Microns is not quite enough.
>      > Any comments on this?
>      >
>      > Regards
>      > Paul Noonan
>      >
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