Regis,
Thanks for the response. We have done extensive wear analysis, which was the
original base of deciding to move away from color coding. However, our wear
analysis only focused on the point and cutting edge. I am now wondering what
effect extended hits has on the flute itself with respect to how it channels
debris up the length of the flute and expels it out of the top of the hole.
I can visualize how the more hits on a drill could possible effect the flute
channel due to effects of normal run out and deflection variations. I
Ed Cosper
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Regis Froats
Sent: Thursday, March 23, 2000 10:43 AM
To: [log in to unmask]
Subject: Re: [TN] Drill bit control
When repointing via overall length, you need to do a wear analysis on the
tool after use to determine the minimum amount of stock removal needed to
repoint the tool to insure a good point. Depending on your product mix and
drill parameters (feed/speed, hit count, stack height, etc.), your minimum
removal could be as little as .002 or as much as .007. Margin wear is the
critical factor for hole wall quality. Work with your supplier to help you
determine your minimum stock removal, which will vary upon diameter ranges.
At 10:04 03/23/2000 -0500, you 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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--
Regis Froats <[log in to unmask]>
Process Engineer - Herco Technology Corp.
13330 Evening Creek Drive North
San Diego, Ca. 92128
Pho:858.679.2800 - Fax:858.679.7565
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