Tool/Process Suggestions

[cwatson1982]

I am a custom knife maker and just picked myself up a 1999 Mighty MV-40 bed mill with an a2100 control, box ways, 400IPM max travels. Prior to this I had been running a small CNC hobby mill.

 

I am cutting annealed CPM s30v (stainless but manufacturer claims machinability similar to d2) and trying to rough out the blade bevels with high speed area clearance prior to heat treating.

 

Using a .375 4 flute tialn coated carbide end mill I am getting less than 20 minutes of tool life. Wear seems to be on the face + corners of the tools.

 

Cut parameters are 20% XY stepover, .035 step down, add cuts turned on with (default) min step down of 0.003125, max stepover of .1875 and minimize burial turned on.

 

Running at 6000 rpm and 90 IPM

 

I am thinking maybe the axial depth of cut is too small and I am just rubbing the edges off? I get 2 bevels roughed out before the next set starts raising a burr, after that trying any kind of helix entry for the next part of the process results in a glowing tool tip!

 

I am new to running a machine with more than 3k rpm and 100ipm travels so any ideas or suggestions are appreciated!

 

I am thinking of maybe running a smaller tool to increase chip load with similar step downs or maybe running a .240 3 flute feed mill from lakeshore carbide for this part of the process.

[Chipmakr]

Can you put up a file or send a file over in an email?

 

Sounds like your DOC is too small as you suspect, but if I can look at what shape you trying to cut I could give you better advice.

 

How deep are you going?

[cwatson1982]

Max depth of material to be removed is .078 or .063 depending on whether I am running 3/16ths or 5/32 stock at the time.

[Mr. M]

Use a bull nosed endmill to start with. Also for .07" just take in in one DOC towards the spine of the blade. A raster or flow line toolpath should work well. Let's see a picture of your work!

[cwatson1982]

Here are a few

 

 

[Mr. M]

Some wild designs! I like it!

[Matthew Hajicek - Singularity]

Sounds like the toolpath you're using would work best with a high-feed style cutter. I use these: http://www.fraisausa...p?caract_54=705

 

and these:

http://www.ingersoll...r-Feed_Plus.pdf

 

on H-13 at 47RC and they work well.

[cwatson1982]

Thanks Matthew. Ordered some of the Fraisa ones and a couple similar from YG. Also discovered my drive belt was causing a significant amount of vibration which probably wasn't helping a whole lot.