BF20 / wmd30 / Grizzly 0704 CNC Conversion

[ellik]

Check my comment below the video... its still processing, just checked. Maybe i should upload it again.

Video doesn't work my friend.

[LeeWay]

Got the Z axis moving tonight... wow.. The 1200oz stepper at 5A, 72V has no problems throwing the head up and down at 220ipm at 0.064G, (acceleration set at 25 in mach) A reasonable speed is 180 ipm at 0.13G ( acceleration set at 50)

The 640oz is almost as quick and runs reliably at 180 ipm as well.

Bottom line the 640 is a very good mach for this mill.

Here is a quick video of the 1200oz in action at 220 ipm.



(Still being processed when this message was sent)

EK

I mentioned in post 113 that I thought you would have no trouble.
I was apparently wrong. Your video don't play. Still.

Something else to consider is the impact to the system of using a higher acceleration. Mine are withing the 10 to 20 range IIRC.
Mach does a good job of letting a machine run smooth. I think a slower acc. helps with everything involved and doesn't cost a lot of time.

[Enraged]

video works if you click through to youtube, its just the embedded version that isn't working.

[LeeWay]

Still tells me video is not finished processing.
My vids only took 15 min at most.

[ihavenofish]

Video doesn't work my friend.

hence the "still being processed" comment. check back in an hour or so.

[LeeWay]

hence the "still being processed" comment. check back in an hour or so.

I'm just a curios guy. Impatient to boot.

[ihavenofish]

I'm just a curios guy. Impatient to boot.

me too, ive clicked it about 10 times...

[ellik]

Processing done but sill issues. I can play it from here though

http://www.youtube.com/user/erlendurk

btw: The Y stepper, a 640oz NEMA 34, is also wicked fast. For fun I tuned it up 300ipm but at rather slow acceleration (0.05G). A more reliable speed is 200 at 0.1G (40 in mach)

[ihavenofish]

haha, yeah, thats peppy. i like it.

[LeeWay]

Speed looks familiar. Looks good.

[Enraged]

speed looks great! I'm considering servos for mine, but those steppers sure move quick.

[LeeWay]

They do with Gecko's.
I have not went with servo's anywhere because of unfamiliarity with that system.
These big steppers are easy and awesome.
No problems.
Might be a different case if we were talking a router where speed on a large axis is an issue, but for smaller bench top stuff, it works.

[ellik]

Combined Backlash in Y is 0.0025, that's more than I was hoping but the coupling is the weak link there, el chipo Lovejoy coupler.

Memo to self... make sure the couplers are tight (and use lock-tight) before running stupid fast test jobs at 150ipm... things tend to get loose

[Starleper1]

IMO Lovejoy couplers are junk for CNC. I tried to use them on my one mill and had horrible results. Get the disc style or equivalent.

[gd.marsh]

One more thing about L J's

You might also want to run a tap all the way through the set screw pilot holes on those couplers .. I had one that was binding the set screw in unformed threads at the bottom before it ever really clamped down on the shaft .. took me a while to figure out what the heck was going on ..

Gary

[photomankc]

Works fine, youtube just had not processed it yet.

[arizonavideo]

Nice speed on that Z

Just for fun you might try to run the roadrunner G code in Mach3. If you run the Z as the Y axes the head will get a real workout. Set the over ride to 250 too.

I found that I had to lower the acceleration quite a bit to not fault my servo.

[ellik]

After connecting the home switches I noticed the 12000oz Z stepper was losing steps, about 0.002 on each test. Turns out it has terrible resonance issues at certain speed and when accelerating through that speed range it losses a few steps. The 640oz motor on the other hand has no resonance problems at all. First I thought it might me be driver so I swapped it out but with no effect. There is a NEMA 42/34 switch on the driver that helps with resonance but it had little effect, neither did the trimpot adjustment.

Any ideas, or is this normal for a big motor like this?

[LeeWay]

I think it is a known issue with these, however I have not seen the issues. I have set my acc. a bit slower and even at 300 IPM, I have no issues. Too damn fast, but other than that, it runs with no missed steps reliably.
I have the same 1200 oz on my X axis and maybe 470 oz on the Y. Both are set the same and run the same.
Had a short in my other 470 motor on X and I had some 1200 oz motors waiting to get installed on my newer conversion. No problems after install. Ran them typically rather than increased everything for a larger motor.

[ellik]

More videos

180ipm, 0.1" travels
"http://www.youtube.com/watch?v=2ABMxQ0--Vk"]YouTube- DSCN1162.AVI

"http://www.youtube.com/watch?v=qbcUEvVc6mo"]YouTube- DSCN1163.AVI

"http://www.youtube.com/watch?v=n0g98NQVsWE"]YouTube- DSCN1164.AVI

At this point the coupling on the Y axis got loose, you can hear it...
"http://www.youtube.com/watch?v=Il4H9hzMSW8"]YouTube- DSCN1166.AVI