Re: End Milling Strategies
- From: BottleBob <bottlbob@xxxxxxxxxxxxx>
- Date: Sun, 19 Feb 2006 12:55:59 GMT
There is an interesting article in Modern Machine Shop titled "Steering
Clear Of Corner Concerns".
The new minimal "TEA" toolpaths from Surfcam seem like they'd be quite
It's unfortunate that the article seems to have had a couple of
boo-boos in the RPM of cutting 4140 (12,000 RPM), and the feedrate
Here's another article titled "CAD/CAM Considerations For Micromilling"
in what I believe to be the same issue of MMS that also seems to have a
couple of numerical mistakes.
For example, to maintain a cutting feed of 100 meters per minute with a
10-mm cutter, the spindle should rotate at approximately 3,200 rpm. For
a 0.1-mm cutter, the spindle would have to rotate at 320,000 rpm. Such a
high spindle speed currently isn't available. The maximum cutting feed
possible with a 0.1 mm cutter is approximately 15 meters per minute?far
from being considered HSM.
I don't think fluently in metric, so let me roughly translate the
numbers to their English/Imperial equivalents:
100 meters per minute = ~ 3,900 inches per minute.
10 mm dia. = ~ .394" dia.
..1 mm dia. = ~ .004" dia.
15 meters per minute = ~ 585" inches per minute
So what they seem to be saying is that a .394 dia. cutter is being spun
at 3,200 RPM and fed at 3,900 IPM. Assuming a 4 flute cutter I figure
that would be like a chipload of about .305 per tooth. Quite the
healthy chip load there, wouldn't you say? LOL
Also for a .004 dia. cutter and roughly assuming a 30,000 RPM speeder
head, feeding @ 585 IPM would work out to a chipload of something like
..0049" which is larger than the cutter dia! Even a 60,000 RPM speeder
head would give a chipload of something like .0024 which is over half
the cutter dia. A chipload of 15% (which is on the large side), of
cutter dia. for a 4 flute .004" end mill would probably be something in
the (.0006) range.
I like Modern Machine Shop, I don't subscribe, I just come across them
from time to time, and I know they must be under some extreme pressure
and time constraints to get their articles published. However, I think
it might be in their best interests to have a machinist proof read their
articles before they are sent out for printing.
- End Milling Strategies
- From: BottleBob
- End Milling Strategies
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