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Cutting 304SS a lot of it

SiggiS

Plastic
Joined
Apr 17, 2019
I'm looking for some suggestion on ends mills that can hog out 304SS our work piece is 1.5 x 3 x 12. cutting 3/4 of the material away. 30+ parts. I don't want to use a insert cutter because my pass experience is that a insert breaks and the cutter body is toast....I plan on calling my Iscar Rep but would like other choices...
 
I did a job that was about 100 hours of cut time, Milling 304. I tried a lot of different things. Eventually, I was using a 3/4" indexable Endmill to Rough pockets out, and 5 flute Endmills to Finish.

If insert Mills are failing on you, that's not the fault of the cutter, something else is wrong. Usually Speed, but holder, condition of material, Machinery, cut parameters, entry, coating, coolant, etc etc are the real problem.

R
 
We have had good luck with Titan VI-Pro for heavy cutting in various steels including PH stainless. I don't think we've done much 304 though. They don't seem to do well with light cuts but are great for hogging. Curtiss (exkenna) sells them.
 
Niagara STR440 2.0 is the best value for money we've found. We've out performing indexables 3-1 in cost savings alone on consumables and with higher MRR and surface finish compared to Sandvik R390 and R245. Just follow the speeds and feeds right out of their book it's no BS.
 
I'm looking for some suggestion on ends mills that can hog out 304SS our work piece is 1.5 x 3 x 12. cutting 3/4 of the material away. 30+ parts. I don't want to use a insert cutter because my pass experience is that a insert breaks and the cutter body is toast....I plan on calling my Iscar Rep but would like other choices...


How recent is your experience with indexables?

Because I couldn't agree more with you for old skewl days and cheap cutters, but I have had some apps come up in recent years where I had a lot of steel to hog away, and I ended up trying a Kenna shoulder mill and have to say that I have been quite impressed and no broken inserts to date that I can think of.

Guessing that they are using tougher grades that don't want to shatter so easilly?

Cannot say that I have tried it on 304 tho.


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Think Snow Eh!
Ox
 
I'm looking for some suggestion on ends mills that can hog out 304SS our work piece is 1.5 x 3 x 12. cutting 3/4 of the material away. 30+ parts. I don't want to use a insert cutter because my pass experience is that a insert breaks and the cutter body is toast....I plan on calling my Iscar Rep but would like other choices...
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304 SS varies widely. work hardened or cold rolled, cold worked 304 can easily be 200% more difficult to machine and if its full of larger hard spots or slag it can reduce tool life easily 10x. that is tooling cost can go up 1000% machining cheap 304 SS
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usually if you buy the cheapest 304SS if harder to machine it and it warps 10x more. tool life can often drop to below 30 minutes
 
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304 SS varies widely. work hardened or cold rolled, cold worked 304 can easily be 200% more difficult to machine and if its full of larger hard spots or slag it can reduce tool life easily 10x. that is tooling cost can go up 1000% machining cheap 304 SS
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usually if you buy the cheapest 304SS if harder to machine it and it warps 10x more. tool life can often drop to below 30 minutes

Finally you write something I agree with. Sorry, I couldn't resist.


I hate 304, dealing with a lot of it at the moment, but am lucky it isn't in big quantities. Customer supplied material, cuts like concrete with HSS.

Kidding, of course, but it is definitely cheap material and it shows. Ran this 5 years ago and didn't have this much trouble with the material they gave me then, which was, at the time, from Brazil. This I suspect is Chinese.


To your question, don't expect to set any records in speed, variable helix endmills with high speed adaptive toolpaths can be your friend. But stay on the low side of recommendations you find, even lower than that, and you might be OK.

Traditional type toolpaths, insert tools might be ok, but as Ox said, don't use cheapo ones. I do not have any specific recommendations, sorry.


But I can tell you, if you deal with Iscar, who make pretty good tools, do NOT use their H490 type facemills. I love them, I really do, but they are only good in carbon/alloy steels. I've broken several inserts trying to use it for stainless. So I can only tell you to learn from my experience, don't waste your time with them.

If, tomorrow you have a batch of 4140 with a ton of facemilling, they are good tools...
 
Garr VRX have been cost effective for my use, around 350SFM in 316 and they go all day. They do real good in duplex too, which is a little worse and gummier than 304...
I don't have very any options in my area and some other fancier brands are a lot more $.
 
Niagara STR440 2.0 is the best value for money we've found. We've out performing indexables 3-1 in cost savings alone on consumables and with higher MRR and surface finish compared to Sandvik R390 and R245. Just follow the speeds and feeds right out of their book it's no BS.

How do you feel about your Niagara cutters since Seco bought them?
We have used ALOT of Niagara Stabilizers. Since Seco bought them they have chasnged the grind and we noticed a significant decline in performance. We are currently testing what we believe will be our replacement for them.
 
How do you feel about your Niagara cutters since Seco bought them?
We have used ALOT of Niagara Stabilizers. Since Seco bought them they have chasnged the grind and we noticed a significant decline in performance. We are currently testing what we believe will be our replacement for them.

That would have been around the time they released the Stabilizer 2.0 eh? We’ve had tremendous success with them but they need to be pushed for proper tool life. Perhaps there is something better but for the prices we’re paying for a 1/2” and the quantities we do it’s not worth our time to gamble on anything else.
 
I just order some myself and will let y'all know the outcome. Also ordered T CARB from SGS will be running next week if the schedule doesn't go to hell in a hand basket.
Siggi
 
there are expensive free machining grades of 303 SS that machine so much easier they actually can be machined faster than regular 1018 carbon steel
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really for some jobs its a dramatic difference like machine 300% to 600% faster just by using a different grade of stainless. just having 304 SS annealed can also make machining go easily over 200% faster with less than 1/2 the tooling costs besides far less part warpage.
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many places all metal goes to heat treat to be annealed or stress relieved. just having reduced warpage can easily make it easily worth the expense
 
there are expensive free machining grades of 303 SS that machine so much easier they actually can be machined faster than regular 1018 carbon steel
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really for some jobs its a dramatic difference like machine 300% to 600% faster just by using a different grade of stainless. just having 304 SS annealed can also make machining go easily over 200% faster with less than 1/2 the tooling costs besides far less part warpage.

That's great. In fact just don't even tell the customer you switched from 304 to 303, they won't notice. They won't notice, because 304 and 303 have a virtually identical alloying component---they are both called Stainless.

Recommending that someone use 303 instead of 304 is like telling them to use motor oil instead of butter for breakfast.

R
 
That's great. In fact just don't even tell the customer you switched from 304 to 303, they won't notice. They won't notice, because 304 and 303 have a virtually identical alloying component---they are both called Stainless.

Recommending that someone use 303 instead of 304 is like telling them to use motor oil instead of butter for breakfast.

R

i mention 303 and 304 and also annealing 304 before machining. most times both need to be discussed with the customer. work harden 304 has roughly 200% higher tensile strength. obviously if you anneal it costumer needs to approve of it
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many times customer doesn't care if 303 or 304. i have had thousands of jobs where it was allowed for the machinist to use either. all i had to do was talk to the engineer about it and get the ok.
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many places you can be talking about metal types for a hour because many engineers really are into picking metal alloys. other dont care as long as it dont rust as fast as carbon steel thats all they care about. many its more a price per pound thing. but mentioning cost of dealing with part warpage and machining difficulties it often is cheaper to not pick the cheapest metal
 
literally many jobs you can save $20. on getting the cheapest 304SS and spend easily over $200. or more on tooling and labor dealing with the "cheap" 304
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i learned long time ago cheapest metal is often not the cheapest to make a part with when you count total cost to manufacture a part
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lathe guys know this more. a metal that makes short chips is far easier to deal with than long stringy chips wrapping around a part like every couple of minutes. sure chip breaker grooves help but having the right metal alloy often is the biggest factor in cost of manufacturing
 








 
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