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Bob La Londe

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Feb 12, 2010, 10:37:40 AM2/12/10
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What is the big key to the speed of this machine?

http://video.google.com/videoplay?docid=4550191913648686955#docid=-1684953814431369082

Looks like they are cutting about 1/4 plate at a really aggressive rate.
Obviously ramping and spray lubricant help, but that is not all it takes to
cut that aggressively or is this also a super high speed spindle?

My experience so far has been that if I try to take off more than about .003
by .250 per pass I can run about 20 IPM with aluminum with lubricant. This
looks like they are taking about .250 by .1875 in a single pass after
ramping in at something like 60 IPM.

Excuse my numbers if they are off since I can only judge this process by
what is shown on the video and guess at the dimensions.

Pete C.

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Feb 12, 2010, 11:14:35 AM2/12/10
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Definitely a high speed spindle with a fair amount of HP, high pressure
coolant to clear chips, and most importantly rigidity.

Bob La Londe

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Feb 12, 2010, 11:51:44 AM2/12/10
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"Pete C." <aux3....@snet.net> wrote in message
news:4b757cbb$0$25614$ec3e...@unlimited.usenetmonster.com...

I was thinking spindle speed had to be the key. Everything else you can
see. How fast do you think they are spinning to be able to do that?

RoyJ

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Feb 12, 2010, 12:46:46 PM2/12/10
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maybe 5" per second on the long runs would be 300ipm. 4 flute cutter,
.003" tooth loading, would be 50k rpm. Tone down the tooth loading a bit
would be a 30k rpm spindle. The chips are distinctly flat pieces so the
tooth loading has to be right up there. Probably running an end mill in
better shape than the ones I have laying in my tool box. :)

Jon Anderson

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Feb 12, 2010, 12:59:59 PM2/12/10
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Bob La Londe wrote:

> Looks like they are cutting about 1/4 plate at a really aggressive rate.
> Obviously ramping and spray lubricant help, but that is not all it takes
> to cut that aggressively or is this also a super high speed spindle?

Not sure what machine is in the video, but some of Datron's machines run
40k spindles.


Jon

Wild_Bill

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Feb 12, 2010, 1:02:22 PM2/12/10
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From the info I've read about them, these types of machines are referred to
as HSM, for high speed machining.

Spindle RPMs in the tens-of-thousands and the overall machines are built
specifically for this purpose, not just a standard machine with a powerful
high speed motor retrofitted.

The videos are very impressive, but I could enjoy spending a day just
watching various parts being machined.

They are so fast/efficient that they can machine a part from solid stock,
that would've previously been made by fabricating the part with several
pieces of sheet stock, such as airframe structural members.

--
WB
.........
metalworking projects
www.kwagmire.com/metal_proj.html


"Bob La Londe" <no...@none.no> wrote in message
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Pete C.

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Feb 12, 2010, 1:38:59 PM2/12/10
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Guessing based on sound at least 10k, perhaps 15k. Has to spin fast to
keep the chip load per tooth low at those feeds.

Richard J Kinch

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Feb 12, 2010, 1:54:26 PM2/12/10
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Bob La Londe writes:

> What is the big key to the speed of this machine?

Gotta be that salsa music. Chukka chukka tick tick tick ...

Bob La Londe

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Feb 12, 2010, 4:52:57 PM2/12/10
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"Pete C." <aux3....@snet.net> wrote in message
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I turn 10K with my machine and there is no way I could get a fraction of
that speed or chip removal.

Mark Rand

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Feb 12, 2010, 6:55:29 PM2/12/10
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On Fri, 12 Feb 2010 08:37:40 -0700, "Bob La Londe" <no...@none.no> wrote:


>Looks like they are cutting about 1/4 plate at a really aggressive rate.
>Obviously ramping and spray lubricant help, but that is not all it takes to
>cut that aggressively or is this also a super high speed spindle?
>

Given the typical use that the machines are sold for, it may well be 1/8"
plate for panel fronts, with the square holes being for 1/2" push button
switches.


Mark Rand
RTFM

Jon Elson

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Feb 17, 2010, 6:00:07 PM2/17/10
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Bob La Londe wrote:
> What is the big key to the speed of this machine?
>
> http://video.google.com/videoplay?docid=4550191913648686955#docid=-1684953814431369082
>
>
> Looks like they are cutting about 1/4 plate at a really aggressive rate.
I read a book on some early experiments at Boeing with high speed
machining in the late 60's I think. They were running a huge
Cincinnatti horizontal mill with a 1/2" end mill at 75,000 RPM and 80
Hp, 600 IPM feeds and 640 cu. inches of aluminum removal per minute.
These numbers made my head spin, 80 Hp into a 1/2" end mill!
YIKES! I put the book back and figured I'd never get into that class of
machining.

Part of the trick is to maintain totally INSANE feedrates to keep the
heat generation moving along as fast as possible. Much of the heat goes
off in the chip, but you want to prevent the aluminum, especially, from
warming up much. I think the tests I refer to may have been run dry, to
protect the carbide tools and also because at these metal removal rates
all you'd be doing is boiling a huge amount of water and not really
cooling the work or tool much.

Jon

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