Re: Tool Wear

From: Jim Paravantes (
Date: Fri Jan 16 1998 - 04:26:26 EET


Tool wear (end mill) can be identified visually or by the touch as you
mentioned. If the dull end mill is used in cutting, multiple things happen.
Excessive tool defection , increased horsepower at the spindle, slower feed
rate, not able to hold size (pockets and slots),noise and then catastrophic
failure. Visual inspection (look at the lands on the flutes) and by touch
 do they feel sharp) are the best methods. Re-ground end mills can cause
problems. If the cutter grinder is out of adjustment, the end mill will most
likely be tapered. On critical jobs a new end mill is usually called for
(time saver overall ). Measuring tool wear on the fly (under CNC operation)
controls to measure tool wear (mostly for CNC Lathes) can do just that, but
not predict. Under load, a sound change is usually a good indicator that
the cutter is beginning to fail.

Jim Paravantes
Trident Systems Group, Inc.
Voice: 313-844-9033
Fax: 313-844-2652
-----Original Message-----
To: <>
Date: Thursday, January 15, 1998 5:26 PM
Subject: Tool Wear

>-- [ From: Al Hastbacka * EMC.Ver #2.5.3 ] --
>I was wondering if anyone on this list has a good way of measuring tool
>wear. I would like to have a definitive way to define a tool (e.g. and
>end mill) as being sharp or dull. Visual inspections are relatively
>subjective depending upon the skill of the operator. I would like to
>have a means to measure the tool quality that is relatively independent
>of the skill of the operator. Any and all ideas would be appreciated.
>Al Hastbacka

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