hy, a while ago i prepared a long series setup, for a few months, in 41Cr4, 42-47hrc, cutting at 170M/min, using a mapped feed between 0.1 and 0.5mm/o, diametral doc 2.25
i could have gone above 170M/min, but i did not wanna go beyond 2000rpms on the 250mm chuck ... i consider it to put to much stress on the spindle above that value, and also there was a long bar inside a spindle liner custom built
changing inserts once/shift, etc
using kyocera and walter, W and later D geometry, rad0.8 - 1.2 ... if you wish, i will look for more informations about those inserts
toolholders had been modified, coolant holes had been increased, and also there were 2 coolant nozzle / cutting edge, one from above and another from below
normally, few people look into such things, and in most cases having coolant on the top of the insert seems nice, but in reality it hits the chip, not the cutting edge ... this does not matter in most applications, because toollife seems to be ok, but when turning hard materials, such details can make a huge difference
oh, yes, i almost forgot : coolant concentration was >10%, or, if you wish, coolant was much more concentrated then on a regular day, and it was making bubbles
onestly, there is not so much difference between those 2 valuesWe currently machine at 134m/min with one type of insert and 112m/min with another type on the same material
during long setups i use to push specs really hard, and i noticed that a tool with less overhang will be more stable ... otherwise, the lathe will start to vibrate, just like when you move a heavy fridge or something, is a very unpleasant noisemax tool stick out
to achieve repetability and avoid re-checking the colisions, i use to write down offsets value, and also check them inside the program
i would say that you have to design the toolpath&cutting-specs in such a way, that minimizes chips tangling on the part / material / or tool ... i used to cut in reverse some toolpaths, modify them a bit here/there, etcor something that also needs to be considered?
you can't push a setup with chips tangling arround / kindly