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Thread: Baffled

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  1. #1
    Join Date
    Nov 2008
    Posts
    19

    Baffled

    Hi everyone

    I have a serious problem this is the secound third and forth time it happens.
    I have a homemade CNC machine and running Mach3.
    Here is my problem.... i use Cut3D to create my toolpath and so on, after i bring it in Mach3 get the machine to start cutting the rough path no problem there, but here it comes it starts to cut the finishing pass gets half way thru and then its like it has a mind of its own it starts to cut off the parrtern and starts to dig into the actual patern where it should be finising, totally destroying my project.

    Can someone please help me if you need more info i will be happy to supply it.

    Here is some info

    The steppers.....X & Y are Eastern Air Devices....6.0 V....4PH.....1.76 A....1.8 Deg.... Type LA23D6K-23
    .....Z is a Astrogyn......Mini Angle Stepper....Type 23LM-C701-01.....P/N RH7-1048 04....5.2 B....1.4 A....1.8 Deg

    As for the control box i have no clue what make it is or anything it has no name on it at all.
    These are some questions that was asked

    Screws (Ballscrew, Acme, Threaded Rod) ? Threaded Rod
    Do you have anything magnetic in the close vicinity of the machine cables? No
    How hot are the steppers getting while cutting? They actualy stay pretty cool
    Does your control box have sufficient cooling? Unknown

    I have checked all wire connections all are good and tight
    Attached Thumbnails Attached Thumbnails CNC.jpg   CNC1.jpg   Control Box.jpg   Back of Control Box.jpg  

    Inside of CB.jpg   Inside of CB1.jpg   Inside of CB2.jpg   Inside of CB3.jpg  

    Inside of CB4.jpg   X Stepper.jpg   Y Stepper.jpg   Out of range.jpg  


  2. #2
    Join Date
    Mar 2008
    Posts
    3655
    Is this a new problem that cropped up after previous normal cutting, or has it been this way since you started cutting with it?

    CR.

  3. #3
    Join Date
    Nov 2008
    Posts
    19
    Crevice Reamer
    I have done a total of 9 paterns the first was good the secound srewed up the 3rd and 4th good 5th screwed up 6th and 7th good 8th and 9th screwed up.

  4. #4
    Join Date
    Mar 2008
    Posts
    3655
    Ok! This is unlikely to be a mechanical problem, but check the tightness of all shaft couplings anyway.

    My best guess is something in the computer or windows is interfering with Mach control. Are you running Vista? Vista is flakey. Change to XP or 2000.

    Check that all background tasks like screen saver, virus scan, AOL etc. are turned off and their programs removed.

    What computer are you using? Desktop or laptop? How fast is it? How long is the parallel cable?

    CR.

  5. #5
    Join Date
    Nov 2008
    Posts
    19
    Crevice Reamer

    I have checked the motors no slipping all connections are tight
    I have a Compaq pressario pentium 2 300 gig hd 2 gig of memory the only software in the system is Windows XP pro and Mach 3.

  6. #6
    Join Date
    Apr 2007
    Posts
    8082
    Does it always run correctly in simulation mode in Mach3? If yes, then it is a hardware problem that will be related to one (or more) axis.

    Suggestions:

    1. Run it without cutting anything and see if it still has problems. (Y/N)
    2. Determine which axis is having problems. (x, y, or z)
    3. If just one axis is having problems, it could be binding in the mechanics, or a problem with gantry racking. (Y/N)
    4. If you have the limit switch wiring snugly bound with the stepper motor wiring try separating the limit switch wiring away from the stepper motor wiring to see if there are crosstalk issues causing the problem.
    5. If #1 - 4 above are ok, then swapping stepper motors or cables to the motors may become necessary.

    CarveOne
    CarveOne
    http://www.carveonecncwoodcraft.com

  7. #7
    Join Date
    Jul 2007
    Posts
    265
    This happened to me one summer and I couldn't figure out what it was either. If I remember correctly it was caused by an overheating controller. I hadn't yet installed any cooling on the controller and the machine was heating up the room enough from working for a while to actually overheat the controller. I opened a window to let cool air in and that fixed the problem then. I have sinced installed heatsinks and a fan on the board.

    What mine did was run normally and then suddenly lose lots and lots of steps, making it look like it was moving around at random. What was really baffling was that it seemingly happened at the same spot every time.

  8. #8
    Join Date
    Mar 2008
    Posts
    3655
    Quote Originally Posted by meflis View Post
    Crevice Reamer

    I have checked the motors no slipping all connections are tight
    I have a Compaq pressario pentium 2 300 gig hd 2 gig of memory the only software in the system is Windows XP pro and Mach 3.
    P2 might not be fast enough for Mach. Is that a laptop? Power save might be a problem.

    Mach3 Minimum Requirements:
    Windows 2000/XP Operating System
    1Ghz CPU
    512MB RAM
    Non-integrated Video Card with 32MB RAM
    Basic Computer Skills (ability to copy/rename files, browse directories, etc)
    Desktop PC if using the Mach3 Driver (Laptops are not supported because the power saving features of the chipsets disrupt the pulse stream)

    How long is the parallel cable?

    CR.

  9. #9
    Join Date
    Mar 2003
    Posts
    35538
    Try cutting your accel and velocity in motor tuning by 50% and see if it cuts OK.
    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)

  10. #10
    Join Date
    Nov 2008
    Posts
    19
    the paralell cable is standard 6 feet

  11. #11
    Join Date
    Nov 2008
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    19
    I have tried at 50% all the way down to 30% still the same

  12. #12
    Join Date
    Nov 2008
    Posts
    19
    RE:
    Suggestions:

    1. Run it without cutting anything and see if it still has problems. (Y/N) No
    2. Determine which axis is having problems. (x, y, or z) Sometimes X and other Y
    3. If just one axis is having problems, it could be binding in the mechanics, or a problem with gantry racking. (Y/N) i have watched it and did not notice any skipping
    4. If you have the limit switch wiring snugly bound with the stepper motor wiring try separating the limit switch wiring away from the stepper motor wiring to see if there are crosstalk issues causing the problem. No limit switches
    5. If #1 - 4 above are ok, then swapping stepper motors or cables to the motors may become necessary. Have swithed X and Y no difference but have not changed cables

    CarveOne

  13. #13
    Join Date
    Jul 2007
    Posts
    48
    Do you have the motor supply and the PC plugged into the same outlet? $40 computer UPS solved my problem. Computer plugged onto the UPS outlet and motor supply into the surge supperssor outlet. Problem was motor noise getting into the PC and disturbing it at random times

  14. #14
    Join Date
    Oct 2008
    Posts
    1147
    I'm currently building a cnc so I'm no expert but I do work in IT and your pc specs are severely below standards. You are expecting a lot from a p2 300mhz. I would suggest you try using another pc to see if the pc is the problem. You may have the memory but your CPU is a huge bottle neck.

  15. #15
    Join Date
    Apr 2007
    Posts
    8082
    Quote Originally Posted by meflis View Post
    RE:
    Suggestions:

    1. Run it without cutting anything and see if it still has problems. (Y/N) No
    2. Determine which axis is having problems. (x, y, or z) Sometimes X and other Y
    3. If just one axis is having problems, it could be binding in the mechanics, or a problem with gantry racking. (Y/N) i have watched it and did not notice any skipping
    4. If you have the limit switch wiring snugly bound with the stepper motor wiring try separating the limit switch wiring away from the stepper motor wiring to see if there are crosstalk issues causing the problem. No limit switches
    5. If #1 - 4 above are ok, then swapping stepper motors or cables to the motors may become necessary. Have swithed X and Y no difference but have not changed cables

    CarveOne
    Your answers will help figure this problem out. In #5 you have switched two motors on axes that show a problem. This gives inconclusive results since if they have the same problem you won't necessarily see any change after swapping them. If nothing else anyone suggests fixes the problem try switching the z motor with the x or y motor since the z axis hasn't shown any problematic moves.

    All of the suggestions I've seen so far have been good ones to try.

    Motor tuning in Mach3 won't necessarily be the same settings for each axis due to loading and friction levels for each axis. If you are using delrin couplers or other fairly stiff couplers the motor shaft alignment to the lead screw is critical. Loosen the bolts of the motor mounting plate of the x and y axis just a little to see if letting the motor "self align" will help. These couplers are not as forgiving as a simple rubber hose style coupler.

    CarveOne
    CarveOne
    http://www.carveonecncwoodcraft.com

  16. #16
    Join Date
    Dec 2004
    Posts
    1865

    Problems?

    That looks like an awfull lot of stuff in a small enclosed plastic case. I was having weird problems with my big mill. In a metal cabinet with a lot more room too. I ran it with a small 10" room fan blowing directly on the electronics and solved the weird problems. I will install heatsinks and cooling fans as soon as I have time. The drives weren't even that hot to the touch but I didn't take a temp reading so I don't know how hot they actually were.
    Give it a try.

    Mike.
    Warning: DIY CNC may cause extreme hair loss due to you pulling your hair out.

  17. #17
    Join Date
    Nov 2008
    Posts
    19
    Here is something someone told me in the Vectric Forum.....

    yes now we know it is not the motors, the object is to work backwards until the problem is apparrent, now we need to switch drive's and that is just a little more tricky

    the drives are the three boards shown in photo
    you may want to come over to cnc zone where there are others who can help as well, i have yet to have a software prolem when loosing steps
    Attached Thumbnails Attached Thumbnails CB.jpg  

  18. #18
    Join Date
    Apr 2007
    Posts
    8082
    I really don't suspect the motors themselves. Something else electrical or mechanical is more likely.

    CarveOne
    CarveOne
    http://www.carveonecncwoodcraft.com

  19. #19
    Join Date
    Jul 2006
    Posts
    2
    I had a similar problem. The connector to my z-axis was shorting out. I replaced the connector and now it works perfectly every time.

    If you are having random issues it may well be some loose wiring as I had or E-M interference as mentioned previously.

  20. #20
    Join Date
    Nov 2008
    Posts
    19
    Hello everyone and thank you for all your support and advice, finally it's working great , after all it was my computer system that was causing the problem
    Again thank you all

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