sfpm for finish cast iron

got new facemill for finish cast iron. it uses modified triangle inserts not trigon
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programmer says salesman says run 920 sfpm not sure where they got that, does anybody actually read catalogs anymore? . old cutter ran 550 sfpm (throws some sparks at 590 sfpm) so i figure try new one at 800 sfpm based on experience.
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well new facemill finishes at 800 sfpm but throwing sparks actually a fair amount of sparks. maybe inserts dull at 75 minutes
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of course manufacturers catalog say 330 to 820 sfpm so maybe 700 or even 600 sfpm better which is closer to what old cutter used. finish not bad actually shiny maybe inserts have better wipers at corners. i will indicate monday and see if flat within .0003" spec.
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so do others run their finishing facemills throwing sparks finishing cast iron?? or do you slow till it stops throwing sparks ?? these are just carbide inserts

Sounds like it is too fast, to me. If you really want to go to town, why wouldn't you be using a silicon nitride ceramic insert? Ceramics work fine producing continuous red hot chips.

HuFlungDung said:

Sounds like it is too fast, to me. If you really want to go to town, why wouldn't you be using a silicon nitride ceramic insert? Ceramics work fine producing continuous red hot chips.

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i am not in charge of picking tooling or insert types. they tell me what i can use. when salesman numbers for facemill work out to 920 sfpm it might be just a math error or max sfpm number and not middle of range. when programmers says try feeds and speeds i have to try.
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if it fails to work ok then i can adjust things. not sure if throwing sparks is failing to cut. it actually is leaving a shiny decent finish. i will find out monday if surface flat to .0003" spec. if not that is failing to work ok and i can adjust things.
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i am guessing 550-600 sfpm would be better for finishing cast iron which is also middle of recommended range for inserts by cutter manufacturer. but maybe new carbide better or insert coating better or chip breaker better on new facemill. does leave a shiny finish