Taking the CNC Plunge

wrmiller19 said:
Congrats! Looks like you finally got this thing up and running. :)

Your efforts have given me further justification to never touch CNC... ;)
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My goal from the beginning was to learn CNC. Still have a ways to go. Have to admit it's been a bigger challenge than I anticipated but with the help I received from forum members I was able to work through the issues. Special thanks to jbolt, jumps4, Jim Dawson and others for their guidance and support.

This thread isn't done by any means. I'm still a rookie.

Tom S.
 
I do like the no-fog system I made but I did learn this weekend that it is not sufficient for 5052 aluminum at high speed. It was impressive to watch a 1/4" carbide end mill at 6k load up and melt a path through some 1/8" 5052 sheet at 17 in/min. Flood coolant worked much better.
 
jbolt said:
I do like the no-fog system I made but I did learn this weekend that it is not sufficient for 5052 aluminum at high speed. It was impressive to watch a 1/4" carbide end mill at 6k load up and melt a path through some 1/8" 5052 sheet at 17 in/min. Flood coolant worked much better.
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I'll keep flood coolant in mind when I'm building the enclosure. So you were plowing instead of cutting? Lol
 
For CNC I vote flood coolant and not some dribble pressure but a good proper blast to knock the chips out of the way. Remember to plumb a hose with a nozzle for machine clean up, that's one really nice thing about flood coolant you can hose down the entire machine which makes quick work of cleanup. Another is not having to worry about anything rusting. About the only place I had rust issues was under the Kurt vice.
 
jbolt said:
I do like the no-fog system I made but I did learn this weekend that it is not sufficient for 5052 aluminum at high speed. It was impressive to watch a 1/4" carbide end mill at 6k load up and melt a path through some 1/8" 5052 sheet at 17 in/min. Flood coolant worked much better.
Click to expand...

I was once milling a mold in some wood on my cnc mill...with the end mill rotating backwards, it was smoking and making a mess and I was cussing thinking I had bought a bad end mill...DOH!
 
It was more like friction milling. A cocept that never took off.

I like the mist for drilling and light work so I dont have to keep the enclosure closed.
 
Did you figure out the motor heating issue?

Jay
 
jbolt said:
Did you figure out the motor heating issue?

Jay
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Not yet. Wife and I have been out of town for the last two weeks. Will get to it today.

I thought about this a lot the last two weeks and it hit me that my power supplies are running on 220V. Could it be the driver dip switches are set for 110v thus drawing twice the necessary current? Seems to me I read in jumps4 build he had the same problem with the motors drawing way too much current.

Been watching your router build. The finished product looks nice. Hope you figure out the electronics soon so you make make chips.

Tom S
 
Changed the dip switch settings to the next lower amp rating and the X and Y axis motors are still overheating. Set them two amp ratings lower and motors still running extremely hot; so hot you can't hold your hand on the motor for more than a second or two. The power supply rated output is 60VDC at 5.85A. I checked them with a voltmeter and both were 61.4VDC without the motors turning and 69.6VDC when running g-code. These power supplies have an adjustable voltage setting so I turned them down as low as they would go. The X axis PS is putting out 63.6VDC and the Y axis 61.8VDC. The voltage didn't change between static mode and run mode. Not sure if my initial readings were bad or the readings after the voltage adjustment are bad. Could the high voltage situation be the cause of the motor heating problem? As it is now I'm reluctant to run g-code for more than 45 minutes.

BTW - I cut a 2" nominal hole is some 3/8" thick aluminum plate and am extremely pleased that the is less than .001" out of round. Hole size was a bit off at 2.005" but I think I can fix it by recalibrating the steps/per.

Tom S
 
Take a look at the idle current setting on the drives. It sounds like they are not switching down to idle current. That is way to hot, something is not right. The high voltage may be the cause, but the drives should limit the current.

Measure the end mill you are using. If it is oversize 0.0025, your hole would be oversize by 0.005. Most end mills are not exactly on size. You are correct in that you may need to fine tune the calibration.
 
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