http://www.youtube.com/watch?v=mRuSYQ5Npek&hd=1


Regards,

Boris Mohar

Got Knock? - see:
Viatrack Printed Circuit Designs (among other things) http://www.viatrack.ca

void _-void-_ in the obvious place

On Mon, 11 Jun 2012 09:02:46 -0400, Boris Mohar
wrote:

http://www.youtube.com/watch?v=mRuSYQ5Npek&hd=1

Fascinating!

--
Doctors prescribe medicine of which they know little,
to cure diseases of which they know less,
in human beings of which they know nothing.
--Francois-Marie Arouet Voltaire, about 250 years ago

"Boris Mohar" wrote in message
...


http://www.youtube.com/watch?v=mRuSYQ5Npek&hd=1
Regards,
Boris Mohar


Very educational. What type of distance of travel were we looking at there?
It seemed like in all cuts it would build up a wedge of garbage on the
cutting edge and then eventually roll it under or deflect the cutter
creating a larger imperfection in the surface. For finer finishes would
that mean atleast in cnc you could use a form of peck turning? Its hard to
gage in that video, but the distance between the more substantial
imperfections seems quite short.

Regardless, very entertaining.

Thank you.
Bob La Londe

On Mon, 11 Jun 2012 14:20:39 -0700, "Bob La Londe"
wrote:



"Boris Mohar" wrote in message
.. .


http://www.youtube.com/watch?v=mRuSYQ5Npek&hd=1
Regards,
Boris Mohar


Very educational. What type of distance of travel were we looking at there?
It seemed like in all cuts it would build up a wedge of garbage on the
cutting edge and then eventually roll it under or deflect the cutter
creating a larger imperfection in the surface. For finer finishes would
that mean atleast in cnc you could use a form of peck turning? Its hard to
gage in that video, but the distance between the more substantial
imperfections seems quite short.

Regardless, very entertaining.

Thank you.
Bob La Londe

That pattern was first observed at Carnegie-Mellon Univ. in the 1950s,
and by Dr. Eugene Merchant at Cincinnati Milicron. This video is much
better than the films they made, showing close-up at high resolution
how the compression-failure/shear-failure mechanism works.

In very fine cuts, it's mostly shear. At deeper cuts, it's often
compression failure, then shear. In some materials it's mostly shear
even with deep cuts.

Some of the interesting work they did was taking spark photos of
ultra-high-speed machining (over 10,000 sfm). For that, they shot a
..30 cal. bullet across the edge of a cutting tool. The failure
mechanism for that is extrusion/shear, and cutting forces per cubic
inch of metal removal actually go down. The chips are much longer than
the path of the cutter in the material, with the chip extruding far
ahead of the cut.

--
Ed Huntress

"Bob La Londe" fired this volley in news:IitBr.5700
:

it would build up a wedge of garbage on the

That's called "a false edge", Bob. It happens to all tools; more without
proper coolant/lubricant.

Dija notice that the T.I.N. HSS bit cut _very_ cleanly for a little while,
then the metal started to adhere to the rake, and started stuffing-up?

That happens, too, for the same reasons as above.

LLoyd

Importance of a chip breaker on the insert.

The difference in coatings was impressive also.


Martin

On 6/11/2012 4:20 PM, Bob La Londe wrote:


"Boris Mohar" wrote in message
...


http://www.youtube.com/watch?v=mRuSYQ5Npek&hd=1
Regards,
Boris Mohar


Very educational. What type of distance of travel were we looking at
there? It seemed like in all cuts it would build up a wedge of garbage
on the cutting edge and then eventually roll it under or deflect the
cutter creating a larger imperfection in the surface. For finer finishes
would that mean atleast in cnc you could use a form of peck turning? Its
hard to gage in that video, but the distance between the more
substantial imperfections seems quite short.

Regardless, very entertaining.

Thank you.
Bob La Londe

I was thinking of a dull table knife pushing thru chocolate.. or a road
grader pushing up packed dirt.
A lot of cutting is more of a scraping process, and that leads me to believe
that cutting lubricants are definitely a major benefit, in many ways.

I have a difficult time recognizing that a negative rake cutting edge is an
effective method of removing metal, but it's a commonly used process/method.

The popular TiN coatings don't actually make cutting edges sharper, instead,
the coatings are intended to aid in chip evacuation, as black oxide can also
make a surface slicker.

--
WB
..........


"BQ340" wrote in message
. com...
On 6/11/2012 9:02 AM, Boris Mohar wrote:
http://www.youtube.com/watch?v=mRuSYQ5Npek&hd=1


Regards,

Boris Mohar


Neat!

Makes me wonder -what is the point of sharpening the tool? The cutting
edge appears not to be doing much actual cutting.


MikeB

--
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