milling speed

Gahagan

Gahagan

Well-Known Member
What speed do you all run your milling machine at for your end mills? I have been running mine at 250 and have been burning up a lot of bits. Is this to fast or am I doing something wrong?
 
Your speed all depends on your material and the diameter of your cutting tool, In this case it's your end mill. What are you cutting, and what is you end mill size?
 
http://www.vm68.com/stuff/sfpm.html

A link to recommended surface feet per minute. The formula for cutting speed in RPM is 3.82xSFM/tool diameter.

The chart in the link says 90 is a good SFM for 1095. Now plug 90 into the formula, and I'll assume you have a .500" end mill. So the Formula would look like this

3.82 x 90 / .500 = 687 RPM

Now if you have 1/4" end mill

3.82 x 90 / .250 = 1375 RPM

I hope this helps. Find the SFM of your material and plug it into the formula with your end mill size.
 
I don't know what you're milling or the feed rate your using, however, milling at 250 may be a bit slow for what you are doing. If you try to feed the material into a mill turning to slow you are trying to take to much material off with every rotation of the mill. That would definitely eat up an end mill. That would be like running a regular drill at a slow rpm and hanging off the handle to put downward pressure on the drill bit to cut. I'm new to machining myself. Some of my ideas may be a little off, who knows.
 
I am usually using a 1/4 end mill and either 1095, Damascus or different types of stainless
 
I'm new to machining myself and I've been using the trial version of the GWizard calc from the CNC Cookbook website. It has been very helpful.
 
Gahagan said:
I am usually using a 1/4 end mill and either 1095, Damascus or different types of stainless
Click to expand...

Sounds like you were running way to slow. Speed it up and listen to it as you cut. Make sure you don't get chatter, vibration, squealling, etc. Don't take a pass at more than half of your cutter's diameter, .125" in your case. I would start with .010" and move up from there. Let us know how it turns out.
 
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