Is the question how many resharps could a resharp resharp if a resharp could resharp resharps?All humor aside,when we were fabricating our own PWB's we monitored the number of hits per drill on the .016 and .0135 holes.We had different numbers based on the materials.The last holes drilled were always in the coupon.Evaluation of the microsection validated those controls.DOE's should be conducted to determine the number of hits and resharps each different construction can tolerate.Adequate PCP's should be in place then to keep you from throwing away good drills or drilling bad holes.
Dewey
 
 

Ed Cosper wrote:

Just curious,

How many board shops are still using color coding to control the number of
re-sharps?  Currently, we primarily use flute length to control our
re-sharps. However, we think we are finding a significant difference of how
many re-sharps different re-sharp houses can get when a shop only specifies
flute length. We have learned that depending on the re-sharp house and
specific operators, the amount of flute removed when re-sharpening can vary
from as low as .0015 mils up to .007 mils. This would suggest that the
number of hits a drill sees before it is discarded for flute length can vary
by as much as 3-5,000.

The reason for this posting is due to a recently seen increase in drill
debris. Especially on .0135 holes. We are thinking that there may be a
significant difference in the evacuation properties of a bit that has been
re-sharpened 4 times ( or 6,000 hits ) verses a bit that has been
re-sharpened 6 times ( or 9'000 hits ).

Any thoughts on this matter?

Ed Cosper
ABC

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-- 
Dewey Whittaker
Honeywell -- Air Transport Systems Division
US Mail: P.O. Box 21111 MS: M16A2 Phoenix AZ 85036
Phone: +1 602 436 436-2766
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