Messages

331

General Mach Discussion / Backlash Comp doing weird things.

« on: April 01, 2009, 08:14:01 PM »

I've got my BP clone CNC conversion up and running and I'm getting about .0005 backlash and want to use the Mach Backlash Comp function but when I turn it on and then move let's say Y5 in MDI, it spins fast for a second, then spins slow then spins at normal speed until it reaches the coordinates. What's going on here? Thanks.

332

General Mach Discussion / Re: Jerky motion...yes I've read the other posts :-)

« on: July 08, 2008, 03:26:59 AM »

I have a question, I've read not only here but other places that it's best to use an unregulated power supply. Why is that? It seems logical to me to use a regulated power supply that keeps the volts exactly at what the PS is rated at.

333

General Mach Discussion / Re: Jerky motion...yes I've read the other posts :-)

« on: July 07, 2008, 09:19:34 PM »

I know that, but I was still curious.

334

General Mach Discussion / Re: Jerky motion...yes I've read the other posts :-)

« on: July 07, 2008, 08:55:43 PM »

Greolt, what do you mean by switchmode? I'm used to the terms unregulated, unregulated doesn't keep the same voltage, regulated keep the volts the same no matter what.

Anyway, I was having the limit switch problem tripping, so I rewired the entire CNC with shielded cable (already had it on motors), made sure no wires laid on each other and kept the PS outside the enclosure so no 120V inside, grouped only like lines together. What a difference. I honestly believe it runs smoother!! The limit switch problem went aways and it's definately quiter. Thanks for everyone's help. It runs super smooth now.

335

General Mach Discussion / Re: Jerky motion...yes I've read the other posts :-)

« on: July 04, 2008, 02:09:46 PM »

Thanks a lot, I really appreciate it. Now I know what kind of noises they make. I just assumed if it was running prefectly you wouldn't hear the fluctuations in the motors they would run smooth, but now I know. Have a good weekend.

336

General Mach Discussion / Re: Jerky motion...yes I've read the other posts :-)

« on: July 03, 2008, 01:29:22 PM »

It's in the first post. Thanks I appreciate it. It's only a 6 minute program but I don't need to see the whole thing.

337

General Mach Discussion / Re: Jerky motion...yes I've read the other posts :-)

« on: July 03, 2008, 02:52:09 AM »

I reset the acceleration to what I consider a sweet spot. Not so abrupt but no real spin up. I think it works better that way. If any of you would like to I'd appreciate someone videoing their "tuned machine" to run my G-code with the spindle off so I can see the way it moves and the way the motors sound, that would help a lot. It must be steppers though, just seeing someone else's would do me a world of good. Thanks.

338

General Mach Discussion / Re: Jerky motion...yes I've read the other posts :-)

« on: July 02, 2008, 08:48:38 PM »

So I just cut a piece and eveything seems to working fine. One of you said to tune the acceleration to the highest I can without losing step, so I did that. Now when the motors move they stop abruptly, which is no big deal if that's OK. I remember reading somewhere to set the acceleration to smooth not abrupt or too slow to spin up. So I just wonder if the abrupt stops are going to cause a lose of accuracy. If it really doesn't matter too much I'm going to slow it down so it's not so abrupt becasue now it's at the maximum.

339

General Mach Discussion / Re: Jerky motion...yes I've read the other posts :-)

« on: July 02, 2008, 12:12:00 AM »

Gerry you are the man!! That worked, it's definately smoother, but I'll let you people be the judge of that. Here is a 12mb video of the new settings, same G-Code, same feedrate (I think) 36 IPM. I also went all the way on the acceleration on the Motor Tuning which was 37.5, the highest for my motor's velocity and I wasn't losing any steps just jogging around the table.

http://www.smokeproductions.com/cnc2.avi

I also did a driver test here are the results: Pulse Per Second in 25khz mode 23798, CPU Speed 2661, Apic Timing Constant 5592.

I'm not over 25,000 as someone mentioned should I try to remodey that? I'm not running Quick Time and I don't have any extraneous stuff running, it's a pretty clean computer.

I also did the diagnostic thing with my mouse and it stayed at 23,793. Time In Int. stayed mostly at 4 but occasionaly jumped to 10-11, all while running a G-Code.

P.S. I'm running 2.63, but I just upgraded from 2.45 but I had the same problem before that's why I upgraded.

I appreciate all the help you've given me.

340

General Mach Discussion / Re: Jerky motion...yes I've read the other posts :-)

« on: July 01, 2008, 11:25:58 PM »

Sorry Gerry didn't mean to mis quote you. I didn't know what you meant by settings page, but I just checked now and I see what you mean, I'm a little slow lately.

I'm still a little fuzzy, ok there are 2 CV things on the settings page and there are 2 CV things on the config page as well as another CV check box, so I turn off the ones on the settings page and the 2 on the config page but leave the regular CV enabled? Also what do the settings refer to: CV Distance, CV Feedrate, CV Dist. Tolerance, G100 Adaptive Nurbs CV? I will see if I can find the answer to the definitions too.

I will check my power supply and see but this problem has nothing to do with the change over it was there before.

I did try the CV on with the Sherline but no difference. I've tried all configurations I can think of and it doesn't seem to make any difference. I don't mind living with it as long as it's working and cutting what it's supposed to but like I said before I though it should be fluid as it goes through curves.