Having trouble facing 305 stainless

I have to face 1" off a 304 stainless plate. I'm using a seco 3" 5 tooth facemill with me15 inserts. My machine is a millport rhino IV and I'm just destroying inserts. I've played with a lot of speeds feeds etc and after using math I'm getting 160 rpm with 1.2 feed. That's so slow at a doc of .015, I was using 800rpm at 15 ipm but it's just killing me. I always machine basic steel and aluminum and have basically no experience with 304 and my machine is having trouble handling it. Can anyone offer an option on if this is even feasible or what a good starting point is. I'm lost

have you got the horsepower to pull that? i would be using a 50mm high feed tool at 1mm depth of cut 150m/min 1mm/tooth for roughing then a face mill to finish, 0.25mm depth of cut 150m/min 0.05mm/tooth.

I have extremely limited tooling, I have a 1" carbide insert endmill and a 3" insert facemill. We aren't a machine shop but I learned this machine and they want me to do it

ME15 is the chipbreaker, it doesn't tell us anything about the grade.

Typical starting point for 304 is 275-300 sfm, so 350 rpm and 5" of feed is pretty conservative. DOC, I'd start at .100 (with my finger on the feed hold) and see if the HP is there. You;ll know pretty quick. Leave the speed and feed alone and adjust DOC to something the machine handles, then bump the speeds and feeds up a little at a time.

That's a light machine, it may not be happy .100 DOC.

304 eats inserts no matter what you do, but too much vibration in the cut will kill them quick.

It's not happy with that at all, cutting it by a third seems to be ok considering my machine is basically a cnc Bridgeport. The table just cant handle that doc.

Jeet401 said:

It's not happy with that at all, cutting it by a third seems to be ok considering my machine is basically a cnc Bridgeport. The table just cant handle that doc.

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The machine is what it is. You can't change that.

Reduce the DOC, step over so you aren't slotting the full 3" diameter, or use a smaller dia cutter.

Do you really need to start with that thick a plate or are you "saving" money by using material on hand...?

From a Haas, light duty CNC machine guy I'd skip facing that material off and go with HSM toolpath if you can.

Ballpark for 1/2 4fl endmill / DOC .99 / Feed 20IPM taking .06-.07 cuts. Flood with coolant to keep chips clear of tool. Its alot of moving around but keeps endmill in a happy spot, load meter stays fairly low. I went from changing inserts 1/4 way through the part to running 5 pcs with the same roughing endmill. Could have pushed further...but better to let it sing happy then leave heavy burs for finishers...or have tool pop. Parts started as 60lb blocks and finished at 10lbs...so lots of material coming off.
Floor still needs a face cut after.
Light cuts and 304SS is tough on tools...face mills of any size are tough with low hp...going easy brings you back to light cuts being tough on tools. Coated inserts...careful with coolant...I have a few that won;t make a part if I use coolant...dry can run all day(AKA- lots of parts)

Jeet401 said:

I have to face 1" off a 304 stainless plate. I'm using a seco 3" 5 tooth facemill with me15 inserts. My machine is a millport rhino IV and I'm just destroying inserts. I've played with a lot of speeds feeds etc and after using math I'm getting 160 rpm with 1.2 feed. That's so slow at a doc of .015, I was using 800rpm at 15 ipm but it's just killing me. I always machine basic steel and aluminum and have basically no experience with 304 and my machine is having trouble handling it. Can anyone offer an option on if this is even feasible or what a good starting point is. I'm lost

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Are you using coolant? If you are....turn it off.

I'll try with no coolant but even with coolant it starts to glow, idk if that's ok but my first instinct was wow that's hot I gotta use coolant but I get carbide cant handle fluctuation