Hello Guest it is August 08, 2020, 05:55:35 AM

Author Topic: homing accuracy  (Read 9888 times)

0 Members and 1 Guest are viewing this topic.

Offline RICH

*
  • *
  •  7,411 7,411
    • View Profile
Re: homing accuracy
« Reply #10 on: September 04, 2008, 05:44:31 PM »
BEN
Are you using MACH Mill to run your lathe?
RICH
Re: homing accuracy
« Reply #11 on: September 05, 2008, 09:36:18 AM »
Hood,

I did restart Mach. Axis still would not run. Restarted computer and the axis is working again. Nothing else was checked, moved, adjusted. It is hard to believe it is hardware if it will run for hours sometimes weeks and then just quit. I have other things that come at work so sometimes the lathe sits for a couple days and the drives will work. Then I go to use it and it stops. A couple weeks back I ran it 2 or 3 days in a row no problem. Since then I have plugged in an ethernet network connection would that cause intermittent problems?

I did see a reply asking about if I run Mach Mill to run the lathe. No, I run a program that the lathe supplier provided (XML file).

B.E.N.

Offline Hood

*
  •  25,846 25,846
  • Carnoustie, Scotland
    • View Profile
Re: homing accuracy
« Reply #12 on: September 05, 2008, 10:01:29 AM »
I dont think it is a software problem if the DRO move when you jog. It copuld be the parallel port that is a problem so next time it happens test that the pulse is coming out on that axis Step pin with your voltmeter set to milivolt range.
Hood
Re: homing accuracy
« Reply #13 on: September 05, 2008, 12:02:26 PM »
Hood,

I set up to do the repeatability test again on the Y-axis. It ran 6 minutes with a variation of about .0006 inches. I was cycling .350 inches. Just past the 6 minute mark the stepper motor did its twiching and pushed the dial indicator out of the way. I ran a drive test right away all the displays looked normal but there was no line on the graph. 23731 to 23733, 547 and, 4192. The motor tuning settings are 23.94 in/min. 2.98 in/sec2. FRO is at 6. I have G17, G61, G90 and , G94 on the first line of the program. I am using G01 to go to the dimensions.

I stopped it when it hit the dial indicator. When I hit the start again all that would run is the elapsed time.

I will hook up a millivolt meter on the drive and run the experiment again.

B.E.N.

Offline Hood

*
  •  25,846 25,846
  • Carnoustie, Scotland
    • View Profile
Re: homing accuracy
« Reply #14 on: September 05, 2008, 12:05:20 PM »
Did you have Mach shut down when you run the drivertest, if not you will not get a line, Mach needs to be shut down.
Hood
Re: homing accuracy
« Reply #15 on: September 05, 2008, 01:18:24 PM »
Lathe ? Y axis?

Ed
Ed VanEss
Re: homing accuracy
« Reply #16 on: September 05, 2008, 01:54:47 PM »
Yes,

The vendor of the lathe provided me with an additional stepper and drive to run the tailstock. I do have occasion where I will use the other axis.

That gives me an idea though, I will run the tailstock off the Z-axis drive and see if anything bizarre happens. Maybe it is the extra stuff for that stepper that is the problem?

B.E.N.
Re: homing accuracy
« Reply #17 on: September 05, 2008, 03:19:09 PM »
Hood,

I moved the y-axis cable to the Z-axis, replaced the y's with z's in the repeatability program and ran 15 minutes without even a hesitation. Tweaking the velocity and accel I was able to improve repeatabilty to about .0003 in. I would get an occasional .0005/6. I am going to move my tooling back in place and try to make some parts. If all goes well I will contact the lathe vendor and ask about the XML file and the Y-axis settings.

Thanks for the support and have a great weekend. Hopefully you won't here from me on Monday.

I did shut MACH down and got the graph on driver test.

B.E.N.

Offline Hood

*
  •  25,846 25,846
  • Carnoustie, Scotland
    • View Profile
Re: homing accuracy
« Reply #18 on: September 05, 2008, 03:48:42 PM »
B.E.N.
 Was the line in the drivetest nice and straight?
Hood

Offline RICH

*
  • *
  •  7,411 7,411
    • View Profile
Re: homing accuracy
« Reply #19 on: September 05, 2008, 05:28:37 PM »
B.E.N
Hopefully you will have things sorted out by Monday and the following becomes mute.

It seems intemittent and when that is the case it's nice to try and duplicate what is happening. If you can.
So if some particular combination makes it occur keep things the same. That at least allows you to do some logical
checking / disciplined checkout. The checkout should be at a high level and try to pinpoint to major section / component of the system.

Follow the signal path at the start and at the receiving end. If the program keeps running and no steps are going out the PC that's one thing, but if the steps are going to the Geco drive and not the steppers that points to something else ( like maybe a voltage problem).

But since you swapped the drives and seemed like some success, i would ask what if any difference exists  in the
MACH tuning & settings for the Z axis as compared to the y axis and also any difference in the current limiting resistors?
Any difference in motor temperature after running?

One thing at a time and evaluate. Don't go jumping around or you won't be able to put some intelligence against
the problem. This way you scratch your head instead of pulling hair from it!

RICH