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Author Topic: What kind of bit/end mill should I be using?  (Read 1546 times)

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Re: What kind of bit/end mill should I be using?
« Reply #20 on: August 28, 2018, 12:31:51 PM »
I have been wondering if its worthwhile for me to try and figure out the coolant system on our setup, as I have no idea how to configure the airline relays. Is conventional milling something I would be OK using a 3/16" O-flute on 1/4" 6061 alum sheets?

Also, this is a separate concern, but I cannot tell if the spindle is sinning at the RPMs shown on screen or if it's full bore at all times. I have it set tp a 18+ dc unregulated pin, and it doesn't seem to sound different at different RPM - FROM 1000RPM - 21000 RPM the motor seems to be spinning the same. Should I be setting this up with step and dir outputs?
Re: What kind of bit/end mill should I be using?
« Reply #21 on: August 28, 2018, 02:47:23 PM »
Hi,

Quote
Is conventional milling something I would be OK using a 3/16" O-flute on 1/4" 6061 alum sheets?
If your machine is sufficiently rigid and without backlash the climb milling is preferred. There is extensive discussion on the net as to why
that is the case.

Quote
Should I be setting this up with step and dir outputs?
Does the spindle have a step/direction drive? From what you have described I don't think so. what make and model is the spindle motor?
What sort of spindle controller do you have? Can you post some pics?

Craig
My wife left with my best friend...
     and I miss him!
Re: What kind of bit/end mill should I be using?
« Reply #22 on: August 28, 2018, 03:23:01 PM »
The Spindle is a Perske - not sure about the model because the tag is covered by a block.

BoB is a Sound Logic PC-2--> (https://www.scribd.com/document/217900646/Pc-2-Route-for-Mach-Rev-1-9)
Re: What kind of bit/end mill should I be using?
« Reply #23 on: August 28, 2018, 06:51:26 PM »
Hi,
Perske is a very good brand, so is Yaskawa and they are both very expensive.

The VFD is for an asynchronous motor and step/direction is not possible, that requires a servo type motor.
The VFD and spindle are very good indeed, I suspect that if yo set to 20000 rpm it will do it whether you
believe it of not.

You could put an index sensor on the spindle and have Mach count it out to confirm what speed its doing.
I am inclined to think that your PWM to DC converter is not linear.

For the work you are doing and the size tools (bits are for woodworkers) you are using just set it to run at maximum
and leave it be.

Quite frankly I think trying to buggerize with that spindle is wasting your time, you could very much more profitably
work on a flood coolant or air cooling solution.

Craig
My wife left with my best friend...
     and I miss him!
Re: What kind of bit/end mill should I be using?
« Reply #24 on: August 29, 2018, 11:31:49 AM »
Thanks for the info - I am starting to cut 6061 1/4" alum. sheets now, what would you recommend as a starting point for IPM, RPM, and depth per pass. I configured my coolant mister so this should help.

Current tool (https://www.amanatool.com/51408-solid-carbide-cnc-spiral-o-flute-aluminum-cutting-3-16-dia-x-1-2-x-1-4-inch-shank-up-cut.html?ff=1&fp=11947)

The provided feed and speeds from the mfg. seem really high to me, I did a test run with the recommended rates and the tool deflected quite a bit.
Re: What kind of bit/end mill should I be using?
« Reply #25 on: August 29, 2018, 03:00:43 PM »
Hi,
why use single flute?

Download a demo copy of HSMAdvisor.

The surface speed for 6061 with uncoated carbide is in the region of 200-500 m/min. What you can actually achieve will depend to a large extent
on the rigidity of your machine and whether you can avoid recutting the chips. If you recut chips ALL BETS ARE OFF.

Craig
My wife left with my best friend...
     and I miss him!
Re: What kind of bit/end mill should I be using?
« Reply #26 on: September 05, 2018, 11:36:47 AM »
Someone on here suggested an O flute for aluminum. I tried cutting at 18,000 RPM 90 IPM @ .005 Depth per pass, and it gave a pretty good cut, the downside being 54 passes per piece.

What does it mean when I am creating dust instead of chips? Is this good or bad?

Offline ger21

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Re: What kind of bit/end mill should I be using?
« Reply #27 on: September 05, 2018, 11:52:41 AM »
Your depth per pass is way too low. Having said that, the actual depth you use depends on the rigidity of the machine.
You should be cutting at least .05 - .125 per pass.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
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Re: What kind of bit/end mill should I be using?
« Reply #28 on: September 05, 2018, 02:38:16 PM »
Hi,
I'd be trying to cut the panel in one pass, ie top layer aluminum, the core and the bottom layer aluminum all in one go.

Craig
My wife left with my best friend...
     and I miss him!

Offline ger21

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Re: What kind of bit/end mill should I be using?
« Reply #29 on: September 05, 2018, 02:54:00 PM »
He said 1/4" aluminum? There's no core or layers?
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html