Parting off 300 series stainless

p4th4ss · Aug 18, 2014

I am using a mazak quick turn trying to part off a 2.45 finish o.d 303 stainless part. Tool keeps breaking or inserts break. What kind of rpm, ipr and doc am I looking at? I am using a cp500 insert in a steel blade. It is on center. I'm going to take a wild guess and say 2-3 grande rpm is too much. Hasn't worked to well.

Krovvax · Aug 18, 2014

I usually part of 304 ss with the same insert i usually use 400 sfm 0.005 ipr full width. Work like a charm never break a insert or a parting blade but its a job shop and ours biggest production run is around 30 to 50 part.

Bobw · Aug 18, 2014

1300-1900sfm on a groove tool, in 303... Shouldn't be a problem... :rolleyes5:

Think surface speed, not RPM... I'd back that down to 600sfm on the high side, for the groove, down to 200sfm depending...
And then if its parting off completely, even lower for the break off, just so we aren't making projectiles....

Feed, I'm a little wussy on my part off feeds... I know .0016 a rev works, and works well... But I would go .003 and change trying to
make time and see how its going.. In 303, you could probably push harder, but I'm a wuss on part offs, seems when you lose the
insert, you lose the tool holder also.

Guest · Aug 18, 2014

Not going to look up your tool, how wide is the carbide insert and how wide is the blade? I would use around a .125 wide insert on a 2.5 diameter. Also I don't like using an insert close to the blade size, need clearance for coolant and the chips to escape. I prefer at least .030 + clearance. I have seen some blades that are .085 wide and have .093 inserts in them, don't like those.

WILLEO6709 · Aug 18, 2014

you do realize to get the tip on center when cutting it has to be intentionally high depending on blade width,etc. don't you? I set up a parting tool on center parting 4340 and blew it up, called the tech guy and its runs great once I "set it wrong". I 303 and oil I go about 250 sfpm with about a 0.002 per rev feedrate but in that machine on 303 I only run 1/2 round.

Kiwi 'smith Dean · Aug 18, 2014

I do a lot of 303 round bar in 1.250" or smaller sizes. Coolant at 15% concentration.
200 Sfm or less, and 0.003" feed per rev. That is with a 2.5mm wide insert though. Get reasonable life out of inserts, none broken yet...

D.

SDConcepts · Aug 18, 2014

we use widia inserts exclusively in stainless steel and get phenomenal tool life. that being said coolant concentration has to be about 12%. also we use 1/8 inch inserts, personally I prefer double ended ones as I think the chips have more room to flush out of the deep groove. also we only do 150-200 sfm and .002 ipr.

DMF_TomB · Aug 19, 2014

p4th4ss said:
I am using a mazak quick turn trying to part off a 2.45 finish o.d 303 stainless part. Tool keeps breaking or inserts break. What kind of rpm, ipr and doc am I looking at? I am using a cp500 insert in a steel blade. It is on center. I'm going to take a wild guess and say 2-3 grande rpm is too much. Hasn't worked to well.

.
2.45 dia and 2500 rpm ? thats what 1600 sfpm
.
500 sfpm x (12/3.14) = 1910 / dia (2.45) = 780 rpm
.
i suggest stop take 60 seconds with calculator before destroying inserts

Ox · Aug 19, 2014

I have found that the parting off the bigger diameter SS's that by the time you get to center, the material must be getting pretty hot down in there. Have had lots of trouble on one certain 2" job once. But on a smaller D material - not so much trouble.

I backed off on the finish cut. I started cutting off to maybe .100" and then twist it off with the sub-spindle.
Another option is to break it off by hand.
Another option is to even break it off with the turret somehow.

I have my Top Cut on the barfeed macro set to cut to .100 as well. Then the trigon just breaks it off when it makes the face cut.

My broken cut-off issues have gone bye-bye after these two changes.

I understand that if this is set just right, and the coolant is just right, and the nozzle doesn't get whacked out of the way, and if ... , and if .... , then you shouldn't have these troubles...

I found a way to not have the troubles in less than ideal conditions.

-----------------------

Think Snow Eh!
Ox

litlerob1 · Aug 19, 2014

Ox said:
I have found that the parting off the bigger diameter SS's that by the time you get to center, the material must be getting pretty hot down in there. Have had lots of trouble on one certain 2" job once. But on a smaller D material - not so much trouble.

I backed off on the finish cut. I started cutting off to maybe .100" and then twist it off with the sub-spindle.
Another option is to break it off by hand.
Another option is to even break it off with the turret somehow.

I have my Top Cut on the barfeed macro set to cut to .100 as well. Then the trigon just breaks it off when it makes the face cut.

My broken cut-off issues have gone bye-bye after these two changes.

I understand that if this is set just right, and the coolant is just right, and the nozzle doesn't get whacked out of the way, and if ... , and if .... , then you shouldn't have these troubles...

I found a way to not have the troubles in less than ideal conditions.

-----------------------

Think Snow Eh!
Ox

We the knowing gotta invent a word for the machinist for; "whatever can go wrong will go wrong". I use these same methods for part off ops. For the same reason--heat.

Robert

Search

Largest Manufacturing Technology Community on the Web

Search

Parting off 300 series stainless

p4th4ss

Aluminum

Krovvax

Hot Rolled

Bobw

Diamond

Guest

Guest

WILLEO6709

Diamond

Kiwi 'smith Dean

Cast Iron

SDConcepts

Stainless

DMF_TomB

Diamond

Ox

Diamond

litlerob1

Diamond

Similar threads