I have a large order for milled parts made from Nitronic 50. I have made a similar part in the past from the same material, but I would like to try and cut down on tooling and time spent changing tools, inserts. The part is rectangular and flairs out a 40ish deg angle on the side down the length of the part. I have to start with round bar due to the lack of availability of plate or flat bar. My main question is what SFM you are running. I have found sharp tools work well. The tools giving me the most trouble are my facemill inserts and my roughing endmill. I am currently running a 2.5 inch Iscar Helido SOF with the ONHU 050505-TN inserts grade IC808. I run it at 180sfm, 275 rpm, and .005 per tooth with a .050 doc. I feel like I am constantly changing these inserts. The rouging endmill is an Iscar ECPI-E4L ½ inch Grade IC900. I am running it at 157 sfm, 1200 rpm, and .0025IPT .125 step over and .500 DOC. The biggest problem is the serrated tips seem to dull and chip off. I am thinking of changing from the rougher to an Iscar ECI-EL variable helix 5/8 diameter. Any suggestions on tools speeds or feeds would be great.
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