Oh, I could mention the Z screw was easy enough to turn with two fingers no problem (motor removed of course).
BobL.
Printable View
Oh, I could mention the Z screw was easy enough to turn with two fingers no problem (motor removed of course).
BobL.
A couple of more things.
The computer and Mach load was the same exact configuration running my old machine, at first. The addition of the ESS required a version update. But in all cases the error was close enough to call the same.
I generated the CAM files using Aspire, two version actually as I upgraded in this time and regened the files. I also tried some older files previously generated AND cut on my old machine without issue. Same type of error in all cases.
BobL.
Might add the machine only has the motor cables and sensor cables in the cable chain right now. (I need bigger cable chain).
I removed everything from the Z (dust collection, router and power cable) to remove weight. Same same.
BobL.
I've never heard of anyone needing to use shielded motor cables. That would have been the last thing that I'd have tried.
My guess is the breakout board or drives.
Try wiring the Z axis drive and motor to the X or Y terminals on the breakout board.
Swap all components around to see if the error follows a specific component.
I'd also give Steve a call at PMDX.
This one is unlikely, but create a new Mach3 profile from scratch.
Lol, I thought the motor cables needed sheilding. Oh well, won't hurt.
I did not try the Z on another axis between the BOB and the drives as I am using a PMDX motherboard to mount the Gekos to. This board (PMDX-134) connects to the PMD-126 via ribbon cable.
I did physically swap a Geko out but nothing looking from/to the BOB.
I'm not sure if the PMDX-126 could cause this but was hesitant to call about it due to the condition of my control box and stuff.
I could run some wires to the geko's to swap those Gerry. Will have to wait until Sunday though as that's my next shop day.
Thanks everyone for the help, I appreciate it.
BobL.
Running through everything in my mind I remembered that when I was taking measurements with a digital multimeter ( I don't have a scope) I noticed a small amount of AC on the 50V supply when measured with the meter. Is this worth pursuing?
BobL.
I didn't have as much time in the shop as I planned but I was able to re-wire the Z and Y axis and do a couple of quick tests.
What I did was swap the Z and Y motor cables at the Gekos. Moved the current set resistor and swapped the step/dir port/pins in Mach setup.
The Z is now below the original Z zero after a test job. It was above the Z zero in the other tests.
I first did a quick short job with the last set speed and velocity then changed them and ran a longer job.
Same resulsts, Z ended lower than it started.
I don't know if the Y axis was affected and I haven't taken any measurements.
Tomorrow I will double check the wiring and try to see if the Y axis was affected or only the Z.
BobL.
All day while waiting to get home and run some tests I started thinking just how many things I've changed and all the settings I've tried. I figured it was time to go through everything and reset everything to what a 'default standard' config would be, ensure everthing was set per the manuals and even double check the wiring while I was at it.
Well, I came home and figured I'd set up a dial indicator and measure the Y axis (which was the Z axis logic/driver path. Well, it was off.
I have to admit here that I never did take any precise measurements of the X or Y travels. The progression went like this.
I got the machine set up and wanted a job to give it a workout. I chose the Aztec calendar floating around this site.
Attachment 161119
I set up a V-carve toolpath and loaded up some MDF for cutting. That's when I noticed the Z was changing. Over the course of a couple of weeks I continued to check/tweak some things and re-run the job after re-referencing to my home switches. Many, many times I turned everything off then came back later and turned it on, re-zeroed and re-cut the job with the workpiece never having been moved. I marvellled at how repeatable the switches were as other than the Z everything recut at the correct position. The jobs were run for various lengths of time never quite finishing before I would kill it.
This is with a design with lots of circles and sub-designs in circular arrays. The recuts along the X and Y were always right on so I never checked them.
So I don't know if things have changed or if this was always there. Frankly I don't see how it could have rerun the job so perfectly if it was off that much and varied with the job run time, but I don't KNOW that.
Anyhow, that's the story. Now for todays results.
I set up a dial indicator on each axis and referenced it. Then for each axis I ran a file that moved that one axis 1 inch and then returned. I repeated this cycle 50 times. Then moved it back to the reference point and took a reading.
Each test cycle was run twice on each axis and each run was within a thousandth of the each other.
Y Axis: 10,11 thousandths in the negative direction after run
X Axis: 21,22 thousandths in the positive direction after run
Here's the surprising one
Z axis: 0,0 after each run.
So, I'm not sure what this tells me but I'm thinking I do need to do a reset to baseline and proceed from there.
Any thoughts?
BobL.
Depending on how you were measuring with your dial indicator. If it was loaded on one side of the threads when you made your original measurement, and on the other side when you made your final one, that would mean you've got ,011" backlash in X and .022" in Y, which isn't impossible to believe. If it cut your calendar correctly and each path was directly on top of the other, then that seems like the most likely explanation to me.
You still need to figure out what's causing the problem in Z, though. Have tried reducing your velocity and/or acceleration and running the test part again?
Andrew Werby
ComputerSculpture.com — Home Page for Discount Hardware & Software
Quote:
Originally Posted by boblon
Andrew, the concensus is that it is not backlash as the error is cumulative. Before I ran the file that moved an axis back and forth 50 times I would move the X (or Y) axis one inch and then back to 0. Each time I did this I could see the error accumulating.
I did some backlash measurements on the Z and it at .001 or less.
Thanks for the post.
BobL.
[In that case, I'd say it's either a mechanical problem, like a coupler that's slipping a little each time you change direction, or it's a software problem, like an inaccurate steps/unit setting. Lost steps will accumulate as well, but not as regularly.]Quote:
Originally Posted by boblon
Andrew Werby
ComputerSculpture.com — Home Page for Discount Hardware & Software
Adrew, I marked and have been checking the couplings, they are not slipping. The steps per have been checked many times.
And your right, there is some kind of consistency in the errors but I don't know enough to know what that clue is telling me.
Gerry mentioned creating a new Mach profile from scratch. I have not done that (yet).
I am curious though if creating a new Mach profile has actually cured issues like this.
BobL.