I would agree with your formula, however, when I met Mark Simmons at IPC
EXPO 1997 he pointed out that tip wear was indeed a measurable factor.
Basically, I would do(and did) the following:

1) Find out the 'worst case' tip wear, i.e.: how short the flat or rounded
cutter of the blade is from a perfect point before re-sharpening [in my
application .005"]
2) Determine your manufacturing tolerance of artwork (registration,
dimensional stability etc..) [in my application .006"]
3) Now the math parts, use the .021 and add the .005 to it, then apply this
to your formula.
A) In addition, in my case I would account for the web not being centered by
adding and additional .001-.002.
4) The answer to this particular instance, for me, would have been .022".

JOE SENDZ......

(Joe Duclos - TYCO Printed Circuit Group, Stafford Division)


If you would like to contact me on or off line for more info
[log in to unmask]


-----Original Message-----
From:   TechNet [mailto:[log in to unmask]] On Behalf Of [log in to unmask]
Sent:   Thursday, July 30, 1998 12:42 PM
To:     [log in to unmask]
Subject:        [TN] Scoring

     I am looking for input as to what others use as a rule for cutting
     back copper on artworks

        <<<SNIP>>>

                                 Thanks

                                 Ernie Smith    [log in to unmask]

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