Using RC Brushless motors as spindle

[Jonathan]

It's alive!

Heated the angular contact bearing in oven, cooled the shaft and it dropped straight on.
Bit of a fiddle to get the rest together, but it went ok.

I've run it up to 3100rpm (24v) and it sounds fine. Slight noise from the bearing but I don't think that's significant.

I also measured the runout and it's less than 0.01mm.

Will post some more pics in a minute.


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[blackburn mark]

It's alive!

Heated the angular contact bearing in oven, cooled the shaft and it dropped straight on.
Bit of a fiddle to get the rest together, but it went ok.

I've run it up to 3100rpm (24v) and it sounds fine. Slight noise from the bearing but I don't think that's significant.

I also measured the runout and it's less than 0.01mm.

Will post some pics in a minute.

Nice one jonathan !!!! iv waited a long time to see this beast
it should have enough power to make a walnut wip out of your Y axis :)

[Jonathan]

Nice one jonathan !!!! iv waited a long time to see this beast
it should have enough power to make a walnut wip out of your Y axis :)

That makes two of us.
Make a walnut what?! But yeah, running it off two 12v 92Ah batteries for the moment. Not got a power supply which would supply anything like enough for this. Idling at 3100rpm it consumes 94w. 45w ish at 1500 rpm... that implies almost 200w just to spin the thing at full speed let alone cutting!

[blackburn mark]

I ran the motor in for about 5 mins on 12v, soon got bored of that

i wouldnt worry about it jonathan, just use it as you would and keep tabs on how hot the bearing housing gets, i still check mine now and again as im using them, its ony my high speed spindle that shows any signs of struggling and thats only if i push it to 30000/40000 rpm

phils point is confirmed as all three spindles produce less bearing heat as time goes by

[Jonathan]

i wouldnt worry about it jonathan, just use it as you would and keep tabs on how hot the bearing housing gets, i still check mine now and again as im using them, its ony my high speed spindle that shows any signs of struggling and thats only if i push it to 30000/40000 rpm

phils point is confirmed as all three spindles produce less bearing heat as time goes by

I ran it at 3100rpm for 20 mins. The angular contact bearing was very slightly warm - helped no doubt by all the aluminum around it. The stator got a little warmer, still nothing to worry about.

Managed to get 1.5kw out of the motor without it complaining.

I'll have to buy one of these soon to run it at 6200rpm:

http://www.hobbyking.com/hobbyking/s...dProduct=10944

or maybe

http://www.hobbyking.com/hobbyking/s...idProduct=4691

Either way it's a lot of money.

[M250cnc]

Jonathan

Use a fine oilstone to de burr the slits in the collets as they can have tiny burrs which can be a cause of runout.

When checking the runout it the collet mark the high or low point so you can see that they are in the same place vertically when you measure both positions.

Phil

[M250cnc]

Jonathan i have just seen the pictures of a sample of the cut produced by your machine with the spindle.

All i will say is you have balls of steel.

Phil

[Jonathan]

Jonathan i have just seen the pictures of a sample of the cut produced by your machine with the spindle.

All i will say is you have balls of steel.

What did I do wrong this time?

Part was securely mounted...it didn't move. I raised it up to stop the Z axis bending too much and took light cuts.


Thanks for the tip about deburring the collets - I'll try that.

[M250cnc]

Sent you a PM

Phil

Sent from my HTC Desire using Tapatalk

[discoball]

Hello
sorry for my bad english but you'v understood:i am french
i was very interested by your post
and am planning to put one BLDC motor on my home made CNC
can i ask you what kind of alim (not batteries)are you using for these motors and controller?
something like 24 or 48v and 40amp
i would be able to make one if i had a plan
thank you for your reply
Discoball