Marry,
    I am studying for the IPC design cert. and I was just reading SM-840. I
came away with the understanding that solder mask serves two purposes one
being that the soldermask is to help protect the board on it's way to the
assembly house, and protect it during the cleaning of the board after
assembly. Two is to keep unwanted solder off cretin areas of the board.
    I know that solder mask contains some dielectric properties and on a
high speed board missing solder mask would cause a problem. So unless this
is a high speed board it is more of a cosmetic problem then a functional
problem, per IPC SM-840
    The real question is why is the solder mask missing?

Ted Tontis

-----Original Message-----
From: Mary Jane Chism [mailto:[log in to unmask]]
Sent: Friday, June 01, 2001 11:32 AM
To: [log in to unmask]
Subject: [TN] Exposed copper



I have a question concerning the subject matter of "exposed copper" on
conductors and/or ground planes due to missing solder mask. I have reviewed
the IPC-A-600 and SM-840 and have came to a conclusion on this. I want to
hear from the experts, which includes all of you, the interpretation of this
condition. I want to know if this is a defective condition or not, what
makes it defective, or if it is acceptable; anything you all want to tell
me. Thanks much.

Mary Jane Chism

Technical Trainer/ Learning Center

Kimball Electronics Group

Phone: (812) 634-4462

Fax: (812) 634-4501

email: [log in to unmask]