45 Degree Facemill Theory

Staying with Facemills and the Chip Thinning Factor takes me into 45
Degree Facemills. Compared to a facemill with inserts located at 90
degrees that are positioned to make square shoulders, if you are
simply slabbing off material to get to a certain dimension, the 45
degree lead will make a thinner chip, requiring less horsepower, so
you can increase the chipload and utilize the available horsepower.
If you viewed the video from Ingersoll showing what they deemed was a
300HP cut, you would be amazed by the metal removal rate and how you
could see the chips being formed right in front if you eyes. Here is
the link once again if you didn=92t see it.
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They show the cutting parameters of the tool going across the screen.
The parameters are enough to put you in shock but to see the cutter
working is really cool. But the one thing, probably one of the most
important things beside the spindle rigidity is how the lead angle of
the cutter they are using makes for a more efficient, less power
consuming cut than if they were using a 90 degree cutter. Either way
you look at this it is a monster tool working as it was designed to
work if not better. I always get a kick out of the brush or broom
catching on fire from the heat of the chips then seeing the heat
disipate from the pile of chips at the end of the video. I would say
the parts was cool to the touch, the cutter was warm but those chips
are the signature of transferring heat with the chips. Sometimes you
just have to shut the coolant off.
One such number they show is a MRR (Metal Removal Rate) of 300 Cubic
Inches. By calculating the Width of Cut 18=94 x Depth of Cut .750=94 x
Feedrate 22 IPM it calculates out to 297 Cubes per Minute, close
enough for me to call it 300 cubes. BUT, and it=92s a BIG BUTT, that
doesn=92t mean it=92s a 300 HP Cut, or does it?
Machinability Rating for the 2714 Forged Steel was 80% from the very
first site that I Googled. So let=92s take the 300 HP and multiply it
by .8 and we get 240HP that we could debate is really getting consumed
instead of 300HP. Again, it=92s an awesome cut, but let=92s do the math
But there is still one more factor to consider here. The Lead Angle of
the Cutter. Let=92s just say that the Ingersoll Shear Clear cutter is a
45 degree cutter. (which I don=92t know that it is but let=92s use 45
degrees anyway for this math exercise) This lead angle is 30% more
efficient than a 90 degree style cutter. So now let=92s take the 240HP
and multiply it by .7 (100%-30%) and we get 168 HP that is what I
would say is much closer to what is being consumed by that monster ass
Why did I do this? I=92m going to take this back into saving time. If
you could speed up your processes that did not require a square corner
and made it necessary to use a 90 degree cutter then you could use a
facemill like a 45 degree lead cutter and reduce cycletimes resulting
in more throughput, reduced labor, more jobs going across the
machines, less need for more machines, more profit in your bank
So with the High Feed Cutters, (using a ballnose factor) as with the
45 Degree Lead Cutters (more efficient) you can achieve what is
perceived as a heavy duty cut on a light duty machinery, making you
more profitable.
Let me know if you like this stuff. I love talking about it and
helping shops out in these tough times.
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I like circular inserts on a facemill even better.
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Pretty much common knowledge. Believe it or not the reason I don't see them used as often as square shouldered cutters is lazy programmers. I reprogrammed 45 deg facemills for a few jobs at my previous employer to reduce HP requirements (faster cutting). When cutting to a stepped down square shoulder you must increment the tool away from that shoulder. Then, run a single tool to clean the angled shoulder. Though faster in production, the programmers there were just plain lazy.
Btw, Seco, Iscar, and others are offering 75 & 86 deg configs which also reduce HP needs and still provide an almost square shoulder.
-- Bill
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Maybe you should start the Bill Triffet, I hated working for Haas blog. Seems like you have enough material.
Jon Banquer San Diego, CA
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I hate blogs even more.
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Sounds like you need to visit the e-Mastercam forum to remind yourself just how good my blog is. ;>)
Jon Banquer San Diego, CA
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