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Speeds and Feeds for Small End Mill

Waldner

Plastic
Joined
May 6, 2021
Hi,
I'm doing some slot milling with a .125 endmill 1.5" deep taking off .015/pass and I've been breaking off a concerning amount of bits. I'm setting my spindle speed at 6000 rpm (max) and feedrate I,ve gone from 3-6 ipm but usually end up with the same results. Maybe the fact that I'm cheaping out on endmills might have something to do with it.
Looking for some recommendations. Anything is helpful.
Thanks
 
Need more info.

What matl?
What is the whole slotting process? Are you ramping down the middle and finishing in .015 depths or...?
 
Need more info.

What matl?
What is the whole slotting process? Are you ramping down the middle and finishing in .015 depths or...?

My apologies. Still new to this. :)
The materiel is Tool Steel. I tried to find more information on it but no such luck.
I'm basically moving straight cross the slot at .015 depth, no ramping. The slot is also not going all the way through the part. Would it be possible that maybe the chips are piling up and causing an issue?
Thanks
 
My apologies. Still new to this. :)
The materiel is Tool Steel. I tried to find more information on it but no such luck.
I'm basically moving straight cross the slot at .015 depth, no ramping. The slot is also not going all the way through the part. Would it be possible that maybe the chips are piling up and causing an issue?
Thanks

Sorry, but Tool Steel isn't defined enough...huge difference between milling S7 tool steel and M2 tool steel
 
What I found is that its 1730 tool steel, which is C45U a non-alloy cold-work tool steel.
Would this help?
Thanks
 
Hi,
I'm doing some slot milling with a .125 endmill 1.5" deep taking off .015/pass and I've been breaking off a concerning amount of bits. I'm setting my spindle speed at 6000 rpm (max) and feedrate I,ve gone from 3-6 ipm but usually end up with the same results. Maybe the fact that I'm cheaping out on endmills might have something to do with it.
Looking for some recommendations. Anything is helpful.
Thanks

Harvey has a pretty good [rimer on this

Speeds and Feeds 101 - In The Loupe

dee
;-D
 

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Let me see if I got this right ...

1/8" endmill
1-1/2" deep slot (so a 12x L/D ratio :scratchchin: )
some sort of tool steel

No wonder you are breaking endmills.

Does the slot go all the way through the thickness of the material? Can they be WEDM'ed?

Regards.

Mike
 
What “mill” are you using, if you spindle/rigidity is at all suspect then that small endmill could vibrate and catch/snap.

Just to put that in perspective: that is 12 diameters, would you slot 6" deep with a 1/2" EM? Brave soul :-)
Plunge milling to rough and then clean it up might work. Some things are just not easy.
 
Let me see if I got this right ...

1/8" endmill
1-1/2" deep slot (so a 12x L/D ratio :scratchchin: )
some sort of tool steel

No wonder you are breaking endmills.

Does the slot go all the way through the thickness of the material? Can they be WEDM'ed?

Regards.

Mike

No wire EDM is not an option.
 
How are your end mills breaking? Does it appear to be melting or snapping? Also how much is the tool sticking out and final depth of the slot?

I think they are snapping off because the blade part still looks good on most of them.
 
I have the tool sticking out 1.5" final depth of 1.38"

Definatley slow down the rpm to around 2500-3000, with it not being coated the heat will get to it even if you slow the feed IPM down. Also I would go really slow like 1 inch per minute because of the tool being so long and sticking out so far. It will take a while but if thats what you have to use on it and are going in a straight G1 move theres not much you can do. Whats your slot width? Also do you have access to M-Cam or a cam system?
 








 
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