hardened stavax machining

[riverracer]

i need to pocket out some hardened 48-50Hrc stavax mould inserts
using a HAAS tm2 cnc mill with mastercam
the pockets are about 25x16mm (1"x5/8") and about 20mm (3/4") deep
using a solid carbide HPMT cutter 8mm dia and helixing in .25p/rev

problem is i karnt find any decent data for machining the hardened steel
everything relates to <45Hrc
have gone thru a couple of cutters already

you guys have any thoughts on speeds and feeds i should be using?
or any decent online calculators?

thanks

[Delw]

one rougher one finisher.
rougher needs to run under 1000 rpms as well as finisher, feed as fast as you can with out breaking it. maybe around 2ipm? and lots of coolant. no coolant breaks tools on hard metal. I always go slow rpms on harden steel usually have of what is recomended. DOnt care how long it takes just want good parts with out tool breakage.

They do have diamond tools, I havent tried them yet, going to soon.


Delw

[marleecnc]

1200 rpm, 4.8 ipm feedrate maybe a .002" or .003" max chip to start... Get braver from there!
I would beg to differ on coolant though. you should use air on hardened steel. coolant wreaks havoc on carbide cutters.
Also, diamond tools arent really a good idea. They are great for graphite, much better wear resistance than standard carbide, however I have found that the diamond coating chips off of the cutting edge easily in hardened tool steel.