At 16.34 15/1/98 -0500, you wrote:
>-- [ 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.
>
>Regards,
>Al Hastbacka
>
>
Dear Al,
I've got some experience measuring tool wear, specially in high speed
milling proceses and I think my experience could help you.
First of all it's very important to consider what cutting process you want
to test exactly and what is it's enviroment and surroundings. I mean the
cutting process at all it's diferent if you are turning, milling, grinding
.., what kind of machine you are using and what you are trying to machine
(geometry and material).
In milling processes you should have a look at the International Standard
Recommendations named ISO 8688-1 ( face milling ) and ISO 8688-2 ( end
milling ). There you will find a lot of explanations about the diferents
ways to test and "destroy" a "poor" tool and other elements related with
the milling processes as the cooling fluid, chips, workpiece ..
Other cutting processes: you have to look for other papers or
recommendation although I think it isnt's so far ( may be 8688-3 ?? .. I
don't know).
Well, about the tool wear measuring I'm very glad with the results
obtained with my optical system. I used a standard Sony video camera (not a
'Handycam' of couse! but a cheap commercial cam like the used in
supermakets, for example) with a 50X amplifier zoom all enclosed in a
special protection case made of aluminium which was inside the machine.
After working, the program located the tool in front of the camera an I
could see on the screen a big image of the tool and using a grid fixed on
the screen it was possible to measure the tool wear with a resolution up to
0.025 mm (0.001 inches).
Of course, you always have to spin the tool by hand, before making whatever
measure, in order to guide it always in the same position to be sure the
wear point is always the same. The method described here it's acurated
enought to a compute a good statistical model.
If you need some additional explanations or information about milling or
HSC, please, don't doubt to contact with me again!
Best regards!
John C. Marin
ASCAMM Tec. Dep.
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Juan Carlos Marín
Dep. Enginyeria
Fundació ASCAMM Centre Tecnològic
Tel:+34 3 5800426
FAX:+34 3 5801102
Email:materials@ascamm.es
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