Huge chatter with CNMG-FS insert, why??
 

Hello,

I have a problem with a MCLN boring bar insert.

It works ok with a "normal" CNMG insert, but I just can't
get it to work with the Mitsubishi -FS finishing chipbreaker.
Material is just mild steel, finishing diameter about
60mm. I get totally crazy chatter - huge surface "waves"
to the turned surface (which looks really smooth except
for the large waves) - it REALLY sings. =:(

I've tried depth of cut 0.1 - 0.25mm, feed 0.08 - 0.22 mm/r,
and many surface speeds - less speed makes less chatter,
but not that much effect (180 - 700 RPM tried). These same
speeds/feeds/DoCs work with a normal CNMG insert, the problem
is only with the -FS insert.

What's going on? I've never experienced chatter like
this before. The boring bar is 32mm diameter!!!!!
Should have no problem with a really small chipload like this.
The tool is at center height, and I've tried lowering
and increasing height a bit, but that hasn't mattered.
The lathe weights about 2000kg and is very rigid.

Any ideas? I've not used the -FS geometry before, so there
could be some trick but it sure ain't clear to me what
it could be..

Kristian Ukkonen

"Kristian Ukkonen" wrote in message
...

Hello,

I have a problem with a MCLN boring bar insert.

It works ok with a "normal" CNMG insert, but I just can't
get it to work with the Mitsubishi -FS finishing chipbreaker.
Material is just mild steel, finishing diameter about
60mm. I get totally crazy chatter - huge surface "waves"
to the turned surface (which looks really smooth except
for the large waves) - it REALLY sings. =:(

I've tried depth of cut 0.1 - 0.25mm, feed 0.08 - 0.22 mm/r,
and many surface speeds - less speed makes less chatter,
but not that much effect (180 - 700 RPM tried). These same
speeds/feeds/DoCs work with a normal CNMG insert, the problem
is only with the -FS insert.

What's going on? I've never experienced chatter like
this before. The boring bar is 32mm diameter!!!!!
Should have no problem with a really small chipload like this.
The tool is at center height, and I've tried lowering
and increasing height a bit, but that hasn't mattered.
The lathe weights about 2000kg and is very rigid.

Any ideas? I've not used the -FS geometry before, so there
could be some trick but it sure ain't clear to me what
it could be..

Kristian Ukkonen


I'm guessing something is rubbing - no cutting relief angle. I took the
liberty of cross posting this over to alt.machines.cnc because there's some
really sharp guys over there. Maybe they will have a better answer.

Just for grins, have you tried this insert on an O.D. cut; facing or
turning?

Karl

"Karl Townsend" remove .NOT to reply
wrote in k.net:


"Kristian Ukkonen" wrote in message
...

Hello,

I have a problem with a MCLN boring bar insert.

It works ok with a "normal" CNMG insert, but I just can't
get it to work with the Mitsubishi -FS finishing chipbreaker.
Material is just mild steel, finishing diameter about
60mm. I get totally crazy chatter - huge surface "waves"
to the turned surface (which looks really smooth except
for the large waves) - it REALLY sings. =:(

I've tried depth of cut 0.1 - 0.25mm, feed 0.08 - 0.22 mm/r,
and many surface speeds - less speed makes less chatter,
but not that much effect (180 - 700 RPM tried). These same
speeds/feeds/DoCs work with a normal CNMG insert, the problem
is only with the -FS insert.

What's going on? I've never experienced chatter like
this before. The boring bar is 32mm diameter!!!!!
Should have no problem with a really small chipload like this.
The tool is at center height, and I've tried lowering
and increasing height a bit, but that hasn't mattered.
The lathe weights about 2000kg and is very rigid.

Any ideas? I've not used the -FS geometry before, so there
could be some trick but it sure ain't clear to me what
it could be..

Kristian Ukkonen


I'm guessing something is rubbing - no cutting relief angle. I took
the liberty of cross posting this over to alt.machines.cnc because
there's some really sharp guys over there. Maybe they will have a
better answer.

Just for grins, have you tried this insert on an O.D. cut; facing or
turning?


First off a boring bar should be slightly above center to prevent
chatter. Second the FS geometry is intended for Stainless Steel. For mild
steel you should be using an FH geometry.

Good Luck.


--

Dan

"D Murphy" wrote in message
...
"Karl Townsend" remove .NOT to reply
wrote in k.net:


"Kristian Ukkonen" wrote in message
...

Hello,

I have a problem with a MCLN boring bar insert.

It works ok with a "normal" CNMG insert, but I just can't
get it to work with the Mitsubishi -FS finishing chipbreaker.
Material is just mild steel, finishing diameter about
60mm. I get totally crazy chatter - huge surface "waves"
to the turned surface (which looks really smooth except
for the large waves) - it REALLY sings. =:(

I've tried depth of cut 0.1 - 0.25mm, feed 0.08 - 0.22 mm/r,
and many surface speeds - less speed makes less chatter,
but not that much effect (180 - 700 RPM tried). These same
speeds/feeds/DoCs work with a normal CNMG insert, the problem
is only with the -FS insert.

What's going on? I've never experienced chatter like
this before. The boring bar is 32mm diameter!!!!!
Should have no problem with a really small chipload like this.
The tool is at center height, and I've tried lowering
and increasing height a bit, but that hasn't mattered.
The lathe weights about 2000kg and is very rigid.

Any ideas? I've not used the -FS geometry before, so there
could be some trick but it sure ain't clear to me what
it could be..

Kristian Ukkonen


I'm guessing something is rubbing - no cutting relief angle. I took
the liberty of cross posting this over to alt.machines.cnc because
there's some really sharp guys over there. Maybe they will have a
better answer.

Just for grins, have you tried this insert on an O.D. cut; facing or
turning?


First off a boring bar should be slightly above center to prevent
chatter. Second the FS geometry is intended for Stainless Steel. For mild
steel you should be using an FH geometry.

Good Luck.


I'm totally unfamiliar with the inserts of which you speak, but I'm somewhat
familiar with carbide grades. If the inserts you are using are, indeed,
intended for use on stainless, as Dan suggested, they're the wrong grade for
steel and would likely present premature tip failure, even if only on a
small scale. Surely enough to create poor cutting conditions. A change to
the right grade alone would be quite helpful. Considering you're taking a
light cut and feed, a C6 would probably serve you well. You're most likely
using a C2.

Harold

Harold and Susan Vordos wrote:

"D Murphy" wrote in message
...
"Karl Townsend" remove .NOT to reply
wrote in k.net:


"Kristian Ukkonen" wrote in message
...

Hello,

I have a problem with a MCLN boring bar insert.

It works ok with a "normal" CNMG insert, but I just can't
get it to work with the Mitsubishi -FS finishing chipbreaker.
Material is just mild steel, finishing diameter about
60mm. I get totally crazy chatter - huge surface "waves"
to the turned surface (which looks really smooth except
for the large waves) - it REALLY sings. =:(

I've tried depth of cut 0.1 - 0.25mm, feed 0.08 - 0.22 mm/r,
and many surface speeds - less speed makes less chatter,
but not that much effect (180 - 700 RPM tried). These same
speeds/feeds/DoCs work with a normal CNMG insert, the problem
is only with the -FS insert.

What's going on? I've never experienced chatter like
this before. The boring bar is 32mm diameter!!!!!
Should have no problem with a really small chipload like this.
The tool is at center height, and I've tried lowering
and increasing height a bit, but that hasn't mattered.
The lathe weights about 2000kg and is very rigid.

Any ideas? I've not used the -FS geometry before, so there
could be some trick but it sure ain't clear to me what
it could be..

Kristian Ukkonen


I'm guessing something is rubbing - no cutting relief angle. I took
the liberty of cross posting this over to alt.machines.cnc because
there's some really sharp guys over there. Maybe they will have a
better answer.

Just for grins, have you tried this insert on an O.D. cut; facing or
turning?


First off a boring bar should be slightly above center to prevent
chatter. Second the FS geometry is intended for Stainless Steel. For mild
steel you should be using an FH geometry.

Good Luck.

I'm totally unfamiliar with the inserts of which you speak, but I'm somewhat
familiar with carbide grades. If the inserts you are using are, indeed,
intended for use on stainless, as Dan suggested, they're the wrong grade for
steel and would likely present premature tip failure, even if only on a
small scale. Surely enough to create poor cutting conditions. A change to
the right grade alone would be quite helpful. Considering you're taking a
light cut and feed, a C6 would probably serve you well. You're most likely
using a C2.

Harold

Speaking of carbide insert styles and grades, has anyone found a good
reference with insert pics, specs and applications for the zillion
varieties of inserts?

Pete C.

On 1 Aug 2005 01:06:04 GMT, D Murphy wrote:

Second the FS geometry is intended for Stainless Steel.


http://www.tooling.net/MT/machines/d...89297026212303
"Model: CNMG-FS"
"Description: turning insert - 80-degree diamond, negative rake
insert for finishing mild steel."

They may be wrong?
--
Cliff

On Sun, 31 Jul 2005 22:15:14 GMT, "Karl Townsend"
remove .NOT to reply wrote:

The boring bar is 32mm diameter!!!!!

ID Turning.
I'd guess rubbing as well.
Or too little DOC .....
--
Cliff

"Pete C." wrote in message
...
Speaking of carbide insert styles and grades, has anyone found a good
reference with insert pics, specs and applications for the zillion
varieties of inserts?

Pete C.

Sounds like a job for....Pete! Sign me up for a copy!

Tom Gardner wrote:

"Pete C." wrote in message
...
Speaking of carbide insert styles and grades, has anyone found a good
reference with insert pics, specs and applications for the zillion
varieties of inserts?

Pete C.

Sounds like a job for....Pete! Sign me up for a copy!

It might be if I actually dealt with them as an occupation. I'm just a
HSM and use some insert type tooling, particularly that which I can
scrounge. I've probably got a dozen different styles in just the tooling
I've got, and that's just size and shape. Carbide grades, grind style
etc. add still more variations.

Pete C.

The problem with listing chipbreakers is that they are mostly different
with every manufacturer. Plus where the match, they may not look
anything alike.
http://www.mitsubishicarbide.com/mmu...akersystem.htm

Pete C. wrote:
Tom Gardner wrote:

"Pete C." wrote in message
...

Speaking of carbide insert styles and grades, has anyone found a good
reference with insert pics, specs and applications for the zillion
varieties of inserts?

Pete C.

Sounds like a job for....Pete! Sign me up for a copy!


It might be if I actually dealt with them as an occupation. I'm just a
HSM and use some insert type tooling, particularly that which I can
scrounge. I've probably got a dozen different styles in just the tooling
I've got, and that's just size and shape. Carbide grades, grind style
etc. add still more variations.

Pete C.

Cliff wrote in
:

On 1 Aug 2005 01:06:04 GMT, D Murphy wrote:

Second the FS geometry is intended for Stainless Steel.


http://www.tooling.net/MT/machines/d...10678929702621
2303
"Model: CNMG-FS"
"Description: turning insert - 80-degree diamond, negative rake
insert for finishing mild steel."

They may be wrong?

Yes.

http://www.mitsubishicarbide.com/mmu...akukougu/sensa
ku_ichiran.htm


--

Dan

Cliff wrote in news:e9ise119brmkonmda6hfl340kelj17h6hm@
4ax.com:

On Sun, 31 Jul 2005 22:15:14 GMT, "Karl Townsend"
remove .NOT to reply wrote:

The boring bar is 32mm diameter!!!!!

ID Turning.
I'd guess rubbing as well.
Or too little DOC .....

That makes no sense. According to the OP the CNMG works OK. The problem
only occurs with a CNMG-FS. Why would that insert rub? Rub what? It has the
same I.C, thickness, and side clearances just a different geometry on the
top of the insert.

As far as too little DOC, why would a finisher (CNMG-FS) need to take a
heavier cut than a rougher? (CNMG) Wrong Geometry/Grade for the mat'l is
likely the problem. The chipbreaker is probably crowding the chip or
somesuch, causing the bar to resonate. The insert tip could also be
chipping right away resulting in chatter.


--

Dan

On 2 Aug 2005 05:11:02 GMT, D Murphy wrote:

Cliff wrote in news:e9ise119brmkonmda6hfl340kelj17h6hm@
4ax.com:

On Sun, 31 Jul 2005 22:15:14 GMT, "Karl Townsend"
remove .NOT to reply wrote:

The boring bar is 32mm diameter!!!!!

ID Turning.
I'd guess rubbing as well.
Or too little DOC .....

That makes no sense. According to the OP the CNMG works OK. The problem
only occurs with a CNMG-FS. Why would that insert rub? Rub what? It has the
same I.C, thickness, and side clearances

Does it?

just a different geometry on the
top of the insert.

As far as too little DOC, why would a finisher (CNMG-FS) need to take a
heavier cut than a rougher? (CNMG) Wrong Geometry/Grade for the mat'l is
likely the problem. The chipbreaker is probably crowding the chip or
somesuch, causing the bar to resonate. The insert tip could also be
chipping right away resulting in chatter.

That might have been noticed.
--
Cliff

On 2 Aug 2005 05:11:02 GMT, D Murphy wrote:

As far as too little DOC, why would a finisher (CNMG-FS)

Well, THAT Site was bad G.
--
Cliff

Cliff wrote in
:

That makes no sense. According to the OP the CNMG works OK. The
problem only occurs with a CNMG-FS. Why would that insert rub? Rub
what? It has the same I.C, thickness, and side clearances

Does it?

Yes it does. All those funny little letters C-N-M-G all mean something.

--

Dan

Cliff wrote in news:r8oue1h4v3cu3b803snqi17641oofuuh2k@
4ax.com:

On 2 Aug 2005 05:11:02 GMT, D Murphy wrote:

As far as too little DOC, why would a finisher (CNMG-FS)

Well, THAT Site was bad G.

It happens.

--

Dan

Tom Gardner wrote:

"Pete C." wrote in message
...
Speaking of carbide insert styles and grades, has anyone found a good
reference with insert pics, specs and applications for the zillion
varieties of inserts?

Pete C.

Sounds like a job for....Pete! Sign me up for a copy!

I ran across a fairly decent insert chart:
http://www.use-enco.com/CGI/INPDFF?PMPAGE=60

Pete C.

On 2 Aug 2005 14:39:05 GMT, D Murphy wrote:

Cliff wrote in
:

That makes no sense. According to the OP the CNMG works OK. The
problem only occurs with a CNMG-FS. Why would that insert rub? Rub
what? It has the same I.C, thickness, and side clearances

Does it?

Yes it does. All those funny little letters C-N-M-G all mean something.

In quite a few different insert thicknesses it seems G.
As this seems to be a double-sided insert, how far from
centerline should it be to bore the ID?
--
Cliff

Cliff wrote in news:bu81f1980l8uljb9r35c83q14ja707jn3t@
4ax.com:

Yes it does. All those funny little letters C-N-M-G all mean something.

In quite a few different insert thicknesses it seems G.

In a CNMG? I've never seen that before. Unless it's a different IC. But I'm
kinda hoping that would have been noticed. Now CCMT, CNMG and CCGT's are
different.


--

Dan

"D Murphy" wrote in message
...
Cliff wrote in
news:bu81f1980l8uljb9r35c83q14ja707jn3t@
4ax.com:

Yes it does. All those funny little letters C-N-M-G all mean something.

In quite a few different insert thicknesses it seems G.

In a CNMG? I've never seen that before. Unless it's a different IC. But
I'm
kinda hoping that would have been noticed. Now CCMT, CNMG and CCGT's are
different.


Hmmm.....

Off the top of my head, I'm recalling the first number is IC, the second is
thickness and with the third number being nose radius......gonna hafta
google I guess......

Yup :

http://www.4carbide.com/tech.htm

--

SVL

snip
Yes it does. All those funny little letters C-N-M-G all mean something.
snip
from page 60 in the 2005 Enco mater catalog
C = Diamond [Rhombic] 80 degrees
N = 0 degree relief angle
M = 0.002-0.004 tolerance +/- from nominal
G = hole - yes
c'sink - no
chip groove - yes

On 4 Aug 2005 04:18:25 GMT, D Murphy wrote:

Cliff wrote in news:bu81f1980l8uljb9r35c83q14ja707jn3t@
4ax.com:

Yes it does. All those funny little letters C-N-M-G all mean something.

In quite a few different insert thicknesses it seems G.

In a CNMG? I've never seen that before.

Looked like it from your Web page link IIRC G.
Not at all unusual .... IIRC ...
--
Cliff

On Wed, 3 Aug 2005 21:33:48 -0700, "PrecisionMachinisT"
wrote:


"D Murphy" wrote in message
.. .
Cliff wrote in
news:bu81f1980l8uljb9r35c83q14ja707jn3t@
4ax.com:

Yes it does. All those funny little letters C-N-M-G all mean something.

In quite a few different insert thicknesses it seems G.

In a CNMG? I've never seen that before. Unless it's a different IC. But
I'm
kinda hoping that would have been noticed. Now CCMT, CNMG and CCGT's are
different.


Hmmm.....

Off the top of my head, I'm recalling the first number is IC, the second is
thickness and with the third number being nose radius......gonna hafta
google I guess......

Yup :

http://www.4carbide.com/tech.htm

I see three different thickness listed in that example G.

BTW, IF the thickness went with the IC you would
not need a designator for both.

"CNMG-FS" does not seem to tell us the thickness.

Insert shims .... and different toolholders ....
--
Cliff

Harold and Susan Vordos wrote:
I'm totally unfamiliar with the inserts of which you speak, but I'm somewhat
familiar with carbide grades. If the inserts you are using are, indeed,
intended for use on stainless, as Dan suggested, they're the wrong grade for
steel and would likely present premature tip failure, even if only on a
small scale. Surely enough to create poor cutting conditions. A change to
the right grade alone would be quite helpful. Considering you're taking a
light cut and feed, a C6 would probably serve you well. You're most likely
using a C2.

It is Cermet NX2525 - the only grade that the company I
bought them from had in stock with a finishing chip breaker.
They had no carbide inserts with finishing chip breaker.

Besides, Mitsubishi carbide lists FS as suitable for almost
any material so I don't see that as a problem:
http://www.mitsubishicarbide.com/mmu...on_turning.htm

I can't see the relevance of the grade - whether some carbide,
coated carbide, cermet.. As long as it's continuous cut,
there shouldn't be much of a difference, except in
lifetime of the insert. For me, it is pretty much the grade
that the company I buy them from has in stock - UTI20T,
US735, UC6010, NX2525 are some of the turning inserts I
have - and I have used them for all work with aluminium,
steel, stainless steel, Hastelloy etc.. Yeah, not optimal, but
works - my volumes are low enough that I can't get 10 pcs of
inserts of various optimal grade/chipbreaker for all different
materials. Just use one for all. The different materials
listed above are for different geometries of inserts,
WNMG, SNMG etc. - whatever they had to sell from stock.

I get absolutely no technical advice - I just pick from
catalog a code for insert, and the sales person tells
me on the phone the price and availability. Oh well, it
is like that in almost all companies - they only know the
price, but not technical stuff - so I just live with it.
At least, they have a reasonable catalog.

The CNMG-FS insert shows no physical damage after cutting a short
while with the huge chatter. The chips produced are very short
and shiny, not discoloured by heat.

I did try the height around, so it is not a simple mistake
of having the height totally wrong. The CNMG inserts have
same outside dimensions as the CNMG-FS.

Oh well, lesson learned - stay away from FS chipbreaker.
Still, really strange effect.

Kristian Ukkonen

Cliff wrote in
:

On 4 Aug 2005 04:18:25 GMT, D Murphy wrote:

Cliff wrote in
news:bu81f1980l8uljb9r35c83q14ja707jn3t@ 4ax.com:

Yes it does. All those funny little letters C-N-M-G all mean
something.

In quite a few different insert thicknesses it seems G.

In a CNMG? I've never seen that before.

Looked like it from your Web page link IIRC G.
Not at all unusual .... IIRC ...

Well thanks for solving the problem.

I guess he found some ultra rare CNMG-411-FS inserts. I wonder if they are
the unobtanium grade.

Do you have a list of sizes and thicknesses for Mitsubihi CNMG-FS inserts?


--

Dan

D Murphy wrote:
I guess he found some ultra rare CNMG-411-FS inserts. I wonder if they are
the unobtanium grade.

The exact type under green plastic package is:
"CNMG120408-FS NX2525
CNMG432FS"

On top of package there are listed cutting speeds
for stainless (70-150 m/min) and steel (210-300 m/min).
So these are obviously meant for steel also.

Kristian Ukkonen.

"Kristian Ukkonen" wrote in message
...

D Murphy wrote:
I guess he found some ultra rare CNMG-411-FS inserts. I wonder if they
are
the unobtanium grade.

The exact type under green plastic package is:
"CNMG120408-FS NX2525
CNMG432FS"

On top of package there are listed cutting speeds
for stainless (70-150 m/min) and steel (210-300 m/min).



So these are obviously meant for steel also.

Kristian Ukkonen.

No, they are not. Not necessarily. Certainly not with older carbide
grades-----can't speak for the current generation. I've been out of the
shop too long to have experienced any of them. The grade for machining
stainless is not the same grade for machining steel. Yeah, I know, makes
no sense, but that's the harsh reality. You'll come to understand that if
you A-B proper inserts and see how fast the improper grade fails, and how.
It shows its ugly head particularly fast when you use a C5 or C6 grade on
cast iron, where C2 should be applied. As I suggested in a previous
post, the proper grade for stainless is a C2-----which would equate to
Carboloy 883. I still suggest your problem is the wrong grade of
carbide-----the symptoms you discuss are hand in hand with what I'd expect.
You're experiencing tip failure, or you simply don't have the proper relief.

Harold

On Sat, 6 Aug 2005 10:54:07 -0700, "Harold and Susan Vordos"
wrote:

I still suggest your problem is the wrong grade of
carbide-----the symptoms you discuss are hand in hand with what I'd expect.
You're experiencing tip failure,

One would expect such problems to get worse with time,
not start at once.

or you simply don't have the proper relief.

It's an ID cut ..... how far above center must he be
with that insert?
We don't know the diameter of the ID yet ...

Personally, I'd probably use an insert/toolholder
that would clear on center at that DOC & diameter.....
--
Cliff

Cliff wrote:

It's an ID cut ..... how far above center must he be
with that insert?
We don't know the diameter of the ID yet ...

Cliff:

The diameter was stated in the first post. 60 mm or 2.362". The
boring bar is 32 mm or 1.259".


--
BottleBob
http://home.earthlink.net/~bottlbob

Kristian

The FS chipbreaker from mitsubishi is probably just to aggressive for the
stability of your setup. they work great to make a very small chip but do
have more tool pressure. If the material you are cutting doesn't chip
easily try gradually going up on the aggressiveness of the chipbreaker
mitsubishi has them listed in there book.

To those who feel an FS is only for stainless.
I use them daily on 9310 and 8620 for phenomenal chip control and unbeatable
tool life, oh but not in the grade that Kristian is using I use AP25N.

good luck

clayton

"Kristian Ukkonen" wrote in message
...

D Murphy wrote:
I guess he found some ultra rare CNMG-411-FS inserts. I wonder if they
are
the unobtanium grade.

The exact type under green plastic package is:
"CNMG120408-FS NX2525
CNMG432FS"

On top of package there are listed cutting speeds
for stainless (70-150 m/min) and steel (210-300 m/min).
So these are obviously meant for steel also.

Kristian Ukkonen.




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"Steen Family" wrote in message
...
snip----

To those who feel an FS is only for stainless.
I use them daily on 9310 and 8620 for phenomenal chip control and
unbeatable
tool life, oh but not in the grade that Kristian is using I use AP25N.

good luck

clayton

I have no problem with the chip breaker, only the grade, as you suggest.

It's a shame all manufacturers don't use a common grading system so their
designations would make more sense to the consumer.

Harold

Harold

On Sat, 06 Aug 2005 21:57:20 GMT, BottleBob
wrote:

Cliff wrote:

It's an ID cut ..... how far above center must he be
with that insert?
We don't know the diameter of the ID yet ...

Cliff:

The diameter was stated in the first post. 60 mm

I missed that. Perhaps I should save posts a bit longer g.

or 2.362". The
boring bar is 32 mm or 1.259".

So, how far above center must he be with that insert?
--
Cliff

Steen Family wrote:
The FS chipbreaker from mitsubishi is probably just to aggressive for the
stability of your setup. they work great to make a very small chip but do
have more tool pressure.

Ok.

It is just counter-intuitive that a finishing chipbreaker
with small chipload causes more cutting force (and thus chatter)
than a roughing bit with much more chipload. But, empirical
evidence speak for themselves, as there doesn't seem to be
any error in my setup.

If the material you are cutting doesn't chip
easily try gradually going up on the aggressiveness of the chipbreaker
mitsubishi has them listed in there book.

It is plain steel, Imatra 550:
Reh min 380MPa
Rm 490-630 Mpa

So, the material is not the problem. I could easily turn
the outsides, rough the inside with CNMG, I just couldn't
do the ID with CNMG-FS.

To those who feel an FS is only for stainless.
I use them daily on 9310 and 8620 for phenomenal chip control and unbeatable
tool life, oh but not in the grade that Kristian is using I use AP25N.

http://www.mitsubishicarbide.com/mmu...ade/cermet.htm
I'd understand AP25N is just coated NX2525, or very close to that.
Anyway, it is cermet, not carbide.

http://www.mitsubishicarbide.com/mmu...on_turning.htm
They do list the FS chipbreaker for pretty much all materials.

Kristian Ukkonen.

Harold and Susan Vordos wrote:
"Kristian Ukkonen" wrote in message
D Murphy wrote:
I guess he found some ultra rare CNMG-411-FS inserts. I wonder if they
are
the unobtanium grade.
The exact type under green plastic package is:
"CNMG120408-FS NX2525
CNMG432FS"
On top of package there are listed cutting speeds
for stainless (70-150 m/min) and steel (210-300 m/min).
So these are obviously meant for steel also.

No, they are not. Not necessarily. Certainly not with older carbide
grades-----can't speak for the current generation. I've been out of the
shop too long to have experienced any of them. The grade for machining
stainless is not the same grade for machining steel. Yeah, I know, makes
no sense, but that's the harsh reality. You'll come to understand that if
you A-B proper inserts and see how fast the improper grade fails, and how.
It shows its ugly head particularly fast when you use a C5 or C6 grade on
cast iron, where C2 should be applied. As I suggested in a previous
post, the proper grade for stainless is a C2-----which would equate to
Carboloy 883. I still suggest your problem is the wrong grade of
carbide-----the symptoms you discuss are hand in hand with what I'd expect.

Sure, TOOL LIFE can be affected by non-optimal grade.
That is NOT my problem.

Are you really saying that CNMG-FS insert performance
varies by grade - some would cut ok, some would cause
huge chatter, with same material to cut, same cutting
parameters, same toolholder? I'm not saying this can't
be - I just thought it is not like that, but only a
matter of tool life expectancy.

You're experiencing tip failure, or you simply don't have the proper relief.

I'M NOT EXPERIENCING TIP FAILURE.

There is proper relief.
The tool is high enough. As I wrote, I tried different heights.

I could turn just fine with CNMG, but not with CNMG-FS which had
huge chatter but NOT FAILURE OF BIT. CNMG and CNMG-FS have SAME
OUTSIDE DIMENSIONS, just different cutting geometry on top.

Kristian Ukkonen.

Kristian Ukkonen wrote in
:


D Murphy wrote:
I guess he found some ultra rare CNMG-411-FS inserts. I wonder if
they are the unobtanium grade.

The exact type under green plastic package is:
"CNMG120408-FS NX2525
CNMG432FS"

On top of package there are listed cutting speeds
for stainless (70-150 m/min) and steel (210-300 m/min).
So these are obviously meant for steel also.


Your depth of cut is way too small for such a large nose radius. You should
leave a minimum of .054mm (2/3)DOC for that radius. Better yet would be to
use a CNMG 431 or 430 insert for finishing.


--

Dan

Harold and Susan Vordos wrote:
Carboloy 883. I still suggest your problem is the wrong grade of
carbide-----the symptoms you discuss are hand in hand with what I'd expect.
You're experiencing tip failure, or you simply don't have the proper relief.

The following:
http://www.mitsubishicarbide.com/EU/...dimple_bar.pdf
suggests NX2525 as FIRST CHOISE for mild steel, WITH FS BREAKER.

So, it is not wrong grade, and FS is also for steel.

Kristian Ukkonen.

D Murphy wrote:
Kristian Ukkonen wrote in
D Murphy wrote:
I guess he found some ultra rare CNMG-411-FS inserts. I wonder if
they are the unobtanium grade.
The exact type under green plastic package is:
"CNMG120408-FS NX2525
CNMG432FS"

On top of package there are listed cutting speeds
for stainless (70-150 m/min) and steel (210-300 m/min).
So these are obviously meant for steel also.
Your depth of cut is way too small for such a large nose radius. You should
leave a minimum of .054mm (2/3)DOC for that radius. Better yet would be to
use a CNMG 431 or 430 insert for finishing.

What is "a minimum of .054mm (2/3)DOC" ???
Where does that come from?

The specs of FS breaker state minimum DoC of 0.2mm..
That is in catalog of Mitsubishi Carbide for this insert,
and in webpages documents of MC as well.. Like:
http://www.mitsubishicarbide.com/EU/...dimple_bar.pdf
That small DoC was why I selected the -FS in the first place..

My normal (working fine) CNMG inserts have a nose radius
of 0.8mm as well.. They "work" with 0.1mm DoC except the
surface finish is not so good - but no chatter..

Kristian Ukkonen.

"F. George McDuffee" wrote in message ...
snip
Yes it does. All those funny little letters C-N-M-G all mean something.
snip
from page 60 in the 2005 Enco mater catalog
C = Diamond [Rhombic] 80 degrees
N = 0 degree relief angle
M = 0.002-0.004 tolerance +/- from nominal
G = hole - yes
c'sink - no
chip groove - yes

http://tinyurl.com/a25bm

http://www.kennametal.com/images/pdf...OCFEVMCQFB0IV0

http://www.mmsonline.com/dp/zones/in...HSM07&zone=HSM

Kristian Ukkonen wrote in
:


D Murphy wrote:
Kristian Ukkonen wrote in
D Murphy wrote:
I guess he found some ultra rare CNMG-411-FS inserts. I wonder if
they are the unobtanium grade.
The exact type under green plastic package is:
"CNMG120408-FS NX2525
CNMG432FS"

On top of package there are listed cutting speeds
for stainless (70-150 m/min) and steel (210-300 m/min).
So these are obviously meant for steel also.
Your depth of cut is way too small for such a large nose radius. You
should leave a minimum of .054mm (2/3)DOC for that radius. Better yet
would be to use a CNMG 431 or 430 insert for finishing.

What is "a minimum of .054mm (2/3)DOC" ???
Where does that come from?

Actually, that is the rule of thumb for turning. For boring your DOC
should be as large or larger than your nose radius. In your case the bar
is not deflecting downward, it is deflecting away from the cut. You
either need to increase the DOC or decrease the radius. Decreasing the
radius would result in lower cutting forces and would be less likely to
chatter.


The specs of FS breaker state minimum DoC of 0.2mm..
That is in catalog of Mitsubishi Carbide for this insert,
and in webpages documents of MC as well.. Like:
http://www.mitsubishicarbide.com/EU/...01/pdf/lj395e_
dimple_bar.pdf That small DoC was why I selected the -FS in the first
place..

My normal (working fine) CNMG inserts have a nose radius
of 0.8mm as well.. They "work" with 0.1mm DoC except the
surface finish is not so good - but no chatter..

Read this:

http://www.manufacturingcenter.com/o...ok/chap_10.pdf


--

Dan