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Feeds and speeds 303 stainless milling

Fastguy

Plastic
Joined
Mar 18, 2021
All the carbide companies lump 303 into the general category of Austenitic stainless just like 304/316
I know that 303 has way better machinability. But,from actual experience how much higher can one push the SFM with the 303?
 
185 - 195 sfpm is a good starting point for process reliability. But that can be way different depending on a whole bunch of variables. Rigidity of the part, rigidity of the setup, rigidity and power of the machine, DOC, LOC, .... the list goes on
 
When I tried the book approach rather than the see/feel approach I found that my speeds and feeds were too high.

Made up a table of numbers from looking at the Machinery Handbook. Appears that my BP has feeds and speeds almost on the mark.
They didn't pick the numbers our of thin air. I would look in the book and see if 303 has different numbers than 304.
 
Depending on the part size, machine, tool, size and application- together it will determine how aggressive you can go. Rough fast and finish slow is my style.
I just did a couple of similar parts out of 304 last month and roughed with a 1/2 4 flute end mill at 4k and 50ipm with a 20% step over. I drilled at 35 SF since I was using regular cobalt split point drills.
The lead guy likes to use 85 sf and a 304L plate job he programmed melted a drill on the second hole of first part, so to each his own lol. (turns out about 35sf for a Gurhing firex coated drill with a G81 worked much better)
 
Treat it like 4340 and it should be great, unless an unscrupulous supplier has sent you 304, instead (cheaper, but a BITCH to work, by comparison).
 








 
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