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Discussion in 'Control Software' started by Sonny Jeon, Aug 12, 2015.

  1. Stephan Schmidl

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    Thanks for your answers.
    Today I tried to mill gcode for the first time :)
    I got a gcode sent from a friend, an elevator for a DLG plane.
    When he mills it, the surface is smooth.
    My result was a bit frustrating as shown in the picture.
    There are visible jags, where normally should be smooth surface and lines!
    Any idea?
    Use universal gcode sender.
    Even in the prview it looked bad.
    Do I have to change something like resolution?
    Or is the Ox not accurate enough?
    Sometimes the gcode I used had 4 numbers after the point, e.g. X30.8755
    Thank you in advance
    Stephan
    PS.: I am an absolute CNC noob:)
     

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  2. Sonny Jeon

    Sonny Jeon Well-Known
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    OX CNCs should be accurate to at least 0.05mm. At first glance, I think you are seeing the roughing pass. A faster tool path that removes the majority of the material before doing a slower and finer detail finishing pass. This is typical. Also, g-code programs are not usually transferrable between different machines. They each are generated in CAM based on the particular parameters of the machine. It can either be too slow or too aggressive and break something.
     
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  3. Jimmybuckets

    Jimmybuckets Well-Known
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    Was thinking the same thing
     
  4. Stephan Schmidl

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  5. David the swarfer

    David the swarfer OpenBuilds Team
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    #365 David the swarfer, Jan 1, 2017
    Last edited: Jan 3, 2017
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  6. Serge E.

    Serge E. Journeyman
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    Without the limit switches, the machine cannot 'tell' when it hits the limit of the machine. So automated homing is not possible, nor is stopping if Gcode tries to send the head beyond the physical limits of your machine.

    What I did (and still tend to do when setting up a job, at least for X and Y) is to manually position (power off) the machine to the 'home position' for the job at hand... If you are cutting through the material (2D / 2.5D jobs), you can also set your Z to material surface and, if you are real careful, still keep your spoil board in good shape for a long time. Once all set, turn the power on and start your Universal Sender going. All should be good.

    I also made a reference point in my spoil board ... actually just off of it at the true 0,0 of myOX. It's in a corner aluminum. But I rarely use it.

    Since you don't have limit switches, keep a close eye on the job and be ready to pull the plug (emergency stop) if something is going wrong before damaging your machine or anything else nearby.
     
  7. Lemonhawk

    Lemonhawk New
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    GRBL has options for a Pause and a Resume button, but is there some gcode command that could be inserted in the gcode file that would cause GRBL to wait until the Resume button was pushed? What I want to do is pause while I clean the accumulated plastic cuttings off the tool and the part.
     
  8. Sonny Jeon

    Sonny Jeon Well-Known
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    The "M0" program pause command will do the job
     
  9. Stephan Schmidl

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    Well, I have got a question. I have got the Ox CNC with CNC x Pro v.3, dimensions of my machine 1m x 1,50m.
    I installed end stop switches and the machine is going home very nice. But: It shows "weird" coordinates for x and y -800 -1250.
    How can I manage it, that in Gcode Sender it shows 0,0,0 ?
     
  10. Sonny Jeon

    Sonny Jeon Well-Known
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    Answered this question on Grbl's issues threads
     
  11. Stephan Schmidl

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    Hi Sonny, maybe you could give me a hint? I didn´t find it :-(
     
  12. Metalguru

    Metalguru Veteran
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    Yeah, I couldn't find it either. This has been bugging me for months
     
  13. Sonny Jeon

    Sonny Jeon Well-Known
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    Sorry. Had the exact same question on the Grbl issues threads at the same time. Thought you were the same person.This is a common question and is available in the FAQ.

    Frequently Asked Questions · grbl/grbl Wiki · GitHub

    EDIT: Correction. You are the same person. Please do me favor and don't post the same question in multiple places. I now have had to answer your question twice. And Google Translate is your friend.
     
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  14. Lemonhawk

    Lemonhawk New
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    Sonny, thank's for your quick reply on using M0. I ran my machine for the first time actually milling out a plastic part and programming in a hold to clean the tool would make things go a lot easier. I suspect that tool choice and feed rate will also help. It was also obvious that I need to better methods to hold the plastic down as I think it shifted ever so slightly. But in all this I am impressed with the the software, especially GRBL and I do thank you for all your efforts!
     
  15. Sonny Jeon

    Sonny Jeon Well-Known
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    The nice thing about the new Grbl v1.1 is the new feedrate overrides. You can set your feed conservatively in CAM and adjust it with the overrides while it's running. You'll quickly get a good feel how fast your machine can cut the job.
     
  16. Lemonhawk

    Lemonhawk New
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    Tried the M00 hold/Resume and it work as expected! Thanks!
     
  17. Stephan Schmidl

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    Hi folks, I have got a question. Yesterday I had an issue with my OX Cnc. As I "forced" my machine to go into the home Position, I mentioned, that the y-axis runs normal into endswitch, but the x-axis didn´t. Tried several time sto reboot but then, I realized in Universal gcode sender, that the settings for the x-axis had been changed. When I retyped the Settings for the x-axis (26.666667/Nema 23 belt drive) all was fine again. Is it a known issue, that sometimes the grbl Settings vanish ?
     
  18. Sonny Jeon

    Sonny Jeon Well-Known
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    Grbl shouldn't randomly overwrite settings or lose them. It calculates a simple checksum to ensure saved settings data isn't corrupt. If it was, Grbl would try to restore all of your settings. Not just one. It's likely something was written to Grbl by the GUI or accidentally that altered it.
     
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  19. Metalguru

    Metalguru Veteran
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    Hi Sonny:

    I'm trying out the latest 1.1 code revision. I wanted to change the homing default to the front right on my machine. I recompiled the code with the Homing_Force_Origin statement uncommented, but it doesn't seem to have worked. Running a homing cycle sets the machine position to -$132, -$133 settings just like it did before. Is there something I am missing?

    Also, I wanted to disable the PWM output so I could use an SSR to control the router in on/off mode. But, uncommenting the compiler directive for this did not seem to work either. Pin12 remained the Z axis limit input, and Pin11 did not change state with M3/M5. I finally used the other option to make the direction bit Pin13 the on/off and it seems to be working properly.

    I believe I read somewhere that it is possible to disable the PWM and make it a simple on/off without changing the pin configuration on Pin12 and Pin11. Is this possible?

    MG
     
  20. Sonny Jeon

    Sonny Jeon Well-Known
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    Make sure all previous installations of Grbl are removed. And you are editing the correct config.h file in the Arduino library folder.

    I may have changed how max and min rpm works so you can't make PWM behave like an on/off with the default build. You used to be able to set max/min rpm equal to each other or both zero and the PWM would work like an on off.

    Probably the best way to go is disable VARIABLE_SPINDLE and alter the pin configuration in cpu_map.h.
     
  21. Ferreri

    Ferreri New
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    Hi,
    I have a bit of experience using grbl controlled machines, and, in that experience, it just works. Thank you for that!
    I've managed to acquire an old CNC mill that has a dead control board with a serial (db25) interface. I've worked out that the stepper drivers can be run using grbl (so cool to see a machine that last ran connected to a DOS program more than 20 years ago come to life). I tested each axis individually as I still need to work out the power management.
    My question: the motor drivers do not have an enable pin... What am I missing, giving up, or risking by leaving pin 8 disconnected?
    Thanks!
     
  22. Sonny Jeon

    Sonny Jeon Well-Known
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    If your motor drivers are built to stay on all of the time, then not much. Grbl turns off the motors in reset or alarm situation, but if you have your motor drivers shut off with an e-stop. You should be ok.
     
  23. Ferreri

    Ferreri New
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    Thanks for the quick reply. That's what I wanted to hear. Typically, I use a switch to cut all power for a true e-stop. Otherwise, feed holds are usually enough. I might use the enable pin to control some LEDs.
    Thanks again... Awesome work!
     
  24. Lemonhawk

    Lemonhawk New
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    Well without reading the manual, I tried a Gcode subroutine. Are there any plans to include this feature, or does this require a better processor?
     
  25. Sonny Jeon

    Sonny Jeon Well-Known
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    Subroutines and macro programming is not planned. It's not compatible with streaming, because variables change and you have to occasionally jump back to earlier parts of a program. Another reason is that it's very old and outdated. Modern programming languages, like Python, would do a much better job at generating g-code for Grbl to run.
     
  26. Stephan Schmidl

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    Hi there, I have got a question. Been using the OX CNC with an CNC X Pro V3 and GRBL installed. Control Software is Universal G-Code Sender.Yesterday it happened for the third time, when enabling the machine and connect to G-code Sender, the machine lost all of the GRBL Settings. Home cycle Settings, feed rate, eg....all of Settings were lost. Any idea?
     
  27. Sonny Jeon

    Sonny Jeon Well-Known
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    Can you explain what you were doing beforehand? And each time you noticed this happened? Are you writing any settings during a job? Altering work coordinate systems often? Etc.
     
  28. Stephan Schmidl

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    Well, it occurs, when starting the machine next day, after normal shut down, when the work is done. During a Job, I do not change any settings.I am a newbie, so I do my CAM work, send it to universal gcode sender and let the machine do the job. The projects I did so far, are circles, some curves, nothing Special or where the machine has to do some "brain" work :)
     
  29. Metalguru

    Metalguru Veteran
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    Hey Sonny:

    I have a couple of questions:

    1. Is there a way to save and load all the GRBL settings in one lump, with some kind of script or something? I build a lot of machines, and it would be really handy to have a way to preload all the settings for a particular type of machine.

    2. Is there a way to invert the polarity of the Spindle On/Off and Coolant output bits? I have some relay boards with active low inputs, but the outputs from the Arduino are active high...

    Thanks. Love your work. I takes a special kind of dedication to do what you do for the benefit of all us hobbyists.

    MG
     
  30. Sonny Jeon

    Sonny Jeon Well-Known
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    1. Yes. Create your own defaults in default.h. These define the initial settings on a fresh Arduino install. If Grbl has been loaded on to it once, you may have to command `$RST=*` to restore the defaults manually. Otherwise, you can use the simple_stream.py script to stream the `$$` settings just like a g-code file.

    2. Yes. See the config.h file. There are invert settings in there.
     

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