Hello all,

Well, the results on my solicitation of information relating to acceptable
Warp and Twist (WT) seem to be somewhat polarized between the board
fabricators and the users.

Although the total number of respondents is less than a dozen, it really
seems that the fabricators really don't want to agree to anything less than
the IPC specification of .075" total. A couple of specifics related from
users did indicate that the finer the pitch used, the less WT acceptable,
but unfortunately I did not get enough data to correlate. One respondent did
indicate that his specifications call out for a max .003"/inch.

One fabricator commented that they are being asked to hold to within .062"
regardless of board size however this is tough to do without extra cost.
They also acknowledged that more and more customers are asking for tighter
tolerances based on automated equipment requirements.

I did 'canvas' several equipment manufacturers via their respective web
sites to see what is commonly being called out from their perspective and
got only one response. This along with our manufacturers quoted
specifications gives me two very opposite factors. So, not much to gain
there.

Bottom line personal conclusion, technology is moving forward....with or
without us!! (Sound familiar???)

Stay tuned for another 'exciting' report from the world of peelable mask.

Thank you to all who did respond and share information.

Richard Hamilton
Clemar Mfg. / Rain Bird
[log in to unmask]

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