512,671 active members
3,105 visitors online
Register for free
Login
Page 8 of 10 678910
Results 141 to 160 of 185
  1. #141
    Registered
    Join Date
    Jan 2007
    Posts
    325
    Ok, Dave and I just had a nice chat and at this point we do not believe backlash is the culprit.

    This is good news to my ears.

    So, I will continue with construction of the new box (as soon as I make room in the garage to work on it )

    BobL.

  2. #142
    Registered
    Join Date
    Jan 2007
    Posts
    325
    Quote Originally Posted by ger21 View Post
    It's not backlash. Backlash isn't cumulative, so even if you have 1/4" of backlash, it will still return to zero, provided you return there from the same direction that you used when you first measured.
    By moving to a SmoothStepper, I would have though that any Mach3 issues would be eliminated.

    What is your acceleration set for in the Z axis? Most of the time, the Z gaining position is due to the acceleration being too high.

    Other than that, the only other culprit would be some electronic issues.
    Gerry, I agree with everything you've said. My first though on the backlash was that it shouldn't be cululative but with the other guys problems in that area I wanted to confirm it myself.

    As far as the Z acceleration I can't give you numbers but I can tell you I tried everying from V=100IPM / A= 15% down to 2 or three percent and then with V= 30IMP and acceleration set from 5 to even lower and lots of places in between. A points the Accel was so low it would drift to a stop. I know that not good/accurate info to go on, but through all of that the error was always similar (I say similar because I just eye-balled it after the run). I would think it should have changed in there somewhere, or at least it's a would be a big clue staring me in the face I don't recognize.

    BobL.

  3. #143
    Community Moderator ger21's Avatar
    Join Date
    Mar 2003
    Posts
    34660
    Any chance the Z axis is binding, or the couplers are moving?
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  4. #144
    Registered
    Join Date
    Jan 2007
    Posts
    325
    I don't think the Z is binding, plus I wouldn't think that would have the concistency displayed.

    The coupler isn't moving. I marked it first off way back. It hasn't moved.

    I started out with POS motor cables from the big box store. 18ga. with foil shield. Suspected them first off. Removed them, put braided sheilds on them, re-ran them, problem the same. I have replaced them with Igus 16ga. PVC jacketed motor cable at the reps recommendation. Problem exactly the same.

    I started out with PP cables. Changed them. Have since replaced them with an Ethernet SmoothStepper. First had a cat5 unsheiled cable connecting them, then a nice sheilded cable. Same results both times.

    I even wrapped all the ribbon cables in the control box with aluminum foil and grounded it. No change (since removed).

    I have removed everyting in the control box except that needed for movement (the SuperPID is still in there). No change.

    I've tried motor tuning, pulse stretching, Sherline mode, half stepped them, 10 micro-stepped them, verified motor wiring, verified pulse setting with the geko manual, swapped drives, and other stuff I'm sure.

    I'm stumped. Please keep asking though as you never know which question will be the right one.

    BobL.

  5. #145
    Registered
    Join Date
    Jan 2007
    Posts
    325
    Oh, I could mention the Z screw was easy enough to turn with two fingers no problem (motor removed of course).

    BobL.

  6. #146
    Registered
    Join Date
    Jan 2007
    Posts
    325
    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.

  7. #147
    Registered
    Join Date
    Jan 2007
    Posts
    325
    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.

  8. #148
    Community Moderator ger21's Avatar
    Join Date
    Mar 2003
    Posts
    34660
    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.
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  9. #149
    Registered
    Join Date
    Jan 2007
    Posts
    325
    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.

  10. #150
    Registered
    Join Date
    Jan 2007
    Posts
    325
    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.

  11. #151
    Registered
    Join Date
    Jan 2007
    Posts
    325

    Z now off in the other direction...

    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.

  12. #152
    Registered
    Join Date
    Jan 2007
    Posts
    325

    I'm not sure whats going on anymore...

    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.

    Click image for larger version. 

Name:	Aztec Calendar at .05 start depth.JPG 
Views:	53 
Size:	263.8 KB 
ID:	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.

  13. #153
    Gold Member
    Join Date
    Apr 2004
    Posts
    4918

    That could be backlash error

    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 View Post
    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.

    Click image for larger version. 

Name:	Aztec Calendar at .05 start depth.JPG 
Views:	53 
Size:	263.8 KB 
ID:	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.

  14. #154
    Registered
    Join Date
    Jan 2007
    Posts
    325
    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.

  15. #155
    Gold Member
    Join Date
    Apr 2004
    Posts
    4918
    Quote Originally Posted by boblon View Post
    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.]

    Andrew Werby
    ComputerSculpture.com — Home Page for Discount Hardware & Software

  16. #156
    Registered
    Join Date
    Jan 2007
    Posts
    325
    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.

  17. #157
    Registered
    Join Date
    Jan 2007
    Posts
    325

    Success !!

    Ok, after MUCH trouble getting a fresh load restored to my shop PC I've got it back hooked up, at least enough to get the motors running.

    I restored the OS from the first time I set it up. No updates were applied. I removed the old Mach3 folder and did a fresh install of the latest dev release of Mach3. I loaded the latest ESS plugin.

    I build a new profile from scratch, every pin/port and motor setting. I haven't even tested the home switches yet and currently have the motor tuning set conservatively.

    I just finished running my test files that jogged each axis one inch and back 50 times. Previously each axis was off around 10 thou. after this.

    Well, each axis returned to zero on the indicators (analog for the X and Y, digitial for the Z).

    OMG !!!

    I don't want to get too excited after all I've been through. The guts of my original control box are spewn about like a grenade went off in there. Only minimal hookup remain. Weeks and weeks of frustration, so I'm not ready to count my chickens before they hatch fully.

    But ya know what? I don't care, looks like the damn think is finally working :banana:

    Gerry, thanks so much for the suggestion. I have to admit I really didn't have a lot of faith in this but your experience holds a lot of weight with me. Thank you, Thank You, THANK YOU

    Ok, I'm going to quit bragging before I anger the gods. I'm going to go play some more and see about getting the home switches working.

    Cheers all, beers on me :cheers:

    BobL.

  18. #158
    Community Moderator ger21's Avatar
    Join Date
    Mar 2003
    Posts
    34660


    As soon as you get everything set up, make a backup copy of your .xml file.
    Mine has gone bad twice in the last year or so. In both instances with mine, it wouldn't home correctly, either moving the wrong way or moving a fixed distance and stopping. Using the backup .xml file got it instantly working again.
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  19. #159
    Registered
    Join Date
    Jan 2007
    Posts
    325
    Well, the news is not all good.

    When I went back and ran the test jobs (cutting air) the z axis drifted again

    BobL.

  20. #160
    Registered
    Join Date
    Jan 2007
    Posts
    325

    Next Steps?

    Ok, I've got a clean load on the PC and a clean load, clean config on the software. I don't want to get wrapped around the axle again.

    So, when I get back to the shop I'm going to re-run the Cycle50 test on each axis just to make sure that's all good.

    Assuming that checks out, there's a couple of other things I want to verify but what I'm really thinking of doing at this point is to just go ahead and get the other control box going, move over just enough to achieve movement, and begin testing from there.

    I don't want to chase a ghost and this way any trouble shooting necessary will at least be done in a more permanent box.

    Will keep you posted.

    BobL.

Page 8 of 10 678910

Similar Threads

  1. New 4x4 XYZ Gantry Build
    By WillsCNC in forum XYZ Gantry Routers
    Replies: 140
    Last Post: 11-08-2011, 01:58 AM
  2. Wanting to Build a 4th Axis / Rotary
    By CNC-Joe in forum Benchtop Machines
    Replies: 19
    Last Post: 05-25-2011, 10:27 AM
  3. Heavy large scale gantry mill/router/3d carving 5 axis build
    By Tristar500 in forum DIY CNC Router Table Machines
    Replies: 20
    Last Post: 03-18-2010, 12:07 PM
  4. First build! 3-Axis Gantry-style CNC
    By TheBakachan in forum DIY CNC Router Table Machines
    Replies: 25
    Last Post: 04-18-2009, 02:10 AM
  5. Rotary 4th axis build componants & tech ?
    By Cruiser in forum Uncategorised MetalWorking Machines
    Replies: 15
    Last Post: 09-04-2007, 10:59 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •