Lathe, how much material can these inserts take off at a time?

[4GSR]

I'm not sure what kind of info to provide. It's a 3 jaw chuck, that holds onto roughly 1/4" of material. The material is 6" diameter and maybe 1.25" thick. About a inch of material is to be bulked off, on the outer edge, as well as some bulk facing... Sorry about my terminology. Also trying not to tell too much about the part, don't want to get into any kind of trouble. I don't have the best memory of the part, so things are a bit vague. Believe it was mild steel. I'm not the programmer either, nor understand any of it.

They are chucking on about an 1/4" of the 6" OD disk that is 1-1/4" thick.

The jaws are probably sprung on the old 3-jaw chuck and more than likely were not bored out properly. And because of this, the part has probably poped out of the chuck a few times and causing all sorts of excitement. Because of this, they are just "babying" the making of the part. That's probably the reasoning of why they are taking such small cuts in machining of the parts. Also makes me wonder if they are cutting on some high strength material that is giving them HAVIC trying to cut it. Even though he said that it maybe mild steel.

 

[awaqa909]

I'm trying to learn this stuff, but its so vast it's like where do I start and what to learn that I can actually use. Plus when I'm at work I'm working more then learning and afterwards I'm burnt out. On the 80 CNMG, it generally wears out on the tip. I was thinking if we took a bigger bite, even if slowed down, it could make the tool last longer, but in the same time... Not quite sure how to say that. I've only ever seen the lathe throw a part on a partoff, because there's not much other option, as far as I know. Sometimes you can break it off, but sometimes even if setup to do that, it will partoff instead.

The part I originally started this topic for, is done. But still question if it could have gone faster. I'm sure they were old jaws, I'm not sure how often the lathes get new jaws. I think the lathe, a Mazak Nexus 250-II (something like that, I don't pay attention the the Mazak machine names) was set at 200psi for the jaws. Some some kind of steel, not stainless steel. I don't know anything about speeds and feeds. My lathe setupguy has been a machinist for 35 years or something (think he said he was 55) He used to give me setups all the time that I would complain about, in some way. Usually tolerances/specs.

Had to flip the toolholder pictures.
80 Deg rougher. CNMG432-TF IC907

35 Deg finish. VNMG 331-NF IC907

35 Deg finish. MVJNR 16-3C

80 Deg rougher. MCLNR 16 4D 16M

 

[Dan_S]

This page will be a good reference for you, as it tells you how to read the insert designations.

http://www.carbidedepot.com/formulas-insert-d.htm

CNMG432 & VNMG 331

TF and NF are the chip breakers and IC907 and IC907 are the carbide/coating grade.

The color coded letters tell you what material in general the insets are designed for.

P = steel
M = stainless steel
k = cast iron
N = non-ferrous material
S = heat resistant super alloys
H = hardened materials


underneath the 2d barcode, you can see it says "ISO M" on both packs and then feeds and speed, so these inserts are designed/rated for steel, but might be usable for other materials. The iscar product page will give you more details, more on that later.

under the "ISO M" are the general feeds and speed for steel

for the cnmg you have the following:
Vc - the surface feet per minute range - 660 to 990 surface feet per minute. This link shows you how to calculate it base on the part diameter and the rpm of the machine.
Fz - the recommended feed rate range - .0047"/rev to .0137"/rev
Ap - the recommended depth of cut, i.e. how much you are taking of the radius - .039" to .157"


if you are only taking .045" you are on the very low end of the range. if you don't know specific grade steel being turned, its better to shoot for the middle of the range and adjust from there imo.


If you know the specific material being turned you can go the iscar product page and get better recommendations for the surface footage.

CNMG 432-TF IC907
http://www.iscar.com/eCatalog/Grade.aspx?grade=IC907&item=5598518&fnum=60&mapp=IS&app=21


VNMG 331-NF IC907
http://www.iscar.com/eCatalog/Grade.aspx?grade=IC907&item=5566950&fnum=482&mapp=IS&app=24

 

[4GSR]

I'm trying to learn this stuff, but its so vast it's like where do I start and what to learn that I can actually use. Plus when I'm at work I'm working more then learning and afterwards I'm burnt out. On the 80 CNMG, it generally wears out on the tip. I was thinking if we took a bigger bite, even if slowed down, it could make the tool last longer, but in the same time... Not quite sure how to say that. I've only ever seen the lathe throw a part on a partoff, because there's not much other option, as far as I know. Sometimes you can break it off, but sometimes even if setup to do that, it will partoff instead.

The part I originally started this topic for, is done. But still question if it could have gone faster. I'm sure they were old jaws, I'm not sure how often the lathes get new jaws. I think the lathe, a Mazak Nexus 250-II (something like that, I don't pay attention the the Mazak machine names) was set at 200psi for the jaws. Some some kind of steel, not stainless steel. I don't know anything about speeds and feeds. My lathe setupguy has been a machinist for 35 years or something (think he said he was 55) He used to give me setups all the time that I would complain about, in some way. Usually tolerances/specs.

Had to flip the toolholder pictures.
80 Deg rougher. CNMG432-TF IC907
View attachment 246961
35 Deg finish. VNMG 331-NF IC907
View attachment 246962
35 Deg finish. MVJNR 16-3C
View attachment 246963
80 Deg rougher. MCLNR 16 4D 16M
View attachment 246964

There's a small chance I may know your setup guy. I'm only about 100 miles from you down here in Victoria.