CASE STUDIES: Materials being machined by the MA Ford XT end mills

Since the introduction of the XT Series 4 flute, 5 flute and the new 279 series 4 flute ball nose end mills they have proven to be a huge success in the machining of Titanium and stainless steels.   These tools have already made their impact in the machining of many other areas such as all steels and super alloys.
 
MA Ford's spotlight focus is on some other materials that are widely used in the market.  17-4 PH stainless many feel is somewhat difficult to machine and performance may vary depending on the material hardness.  That is not the case with the new XT series end mills.  These tools do not seem to care what hardness is presented to them!  28-42 RC is primary range for this series of stainless steel.  

Example: A customer had a very difficult 17-4 PH medical component with lots of contouring both roughing and finishing.  A 1/2" 279 Series was used for roughing the profile at 600 SFM with a depth of .015 and .025 step over at 80 IPM.  The customer had to double the speeds and feeds as well as increase the step over to get the desired finish required!

The 277 Series 4 flute can full slot up to 1X dia. depth at speeds as high as 260 to 340 SFM. The chip loads will be lighter than profile milling dependent on the tool diameter and fixture set up. The slotting depth can be increased even beyond 1X depth (which generally requires a reduction in speeds and feeds).
 
The 278 Series 5 flute can slot up to 1X depth effectively but slotting is more suited for the  4 flute 277 Series if a lot of slotting is to be done.  The speeds and feeds are the same as the 277, but calculations must be made for the additional cutting edge.  It is not recommended to slot over 1X the tool diameter with this 5 flute tools as it is best suited for profile milling both conventional and high speed machining.
 
The new 279 Series 4 flute ball nose end mill is an excellent choice for both conventional and high speed machining of stainless steels.  With the added radial relief and a thicker cross section in the center of the tools it can withstand extreme speeds and feeds both roughing and contouring.