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VCarve GRBL Post Processor Mods

Discussion in 'CAM' started by sharmstr, Aug 21, 2019.

  1. sharmstr

    sharmstr OpenBuilds Team
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    Here I will be listing out my VCarve GRBL post modifications.

    To get started, open VCarve, click File, then Open Application Data Folder. This will open a new window. There are two folders you want to make note of. PostP has all the built in processors. My_PostP is where you'll put your modified post file. **Note: If any post processors are placed in the My_PostP folder, they will become the *only* ones displayed in the Post-Processor list.

    Open the PostP folder and copy Grbl_mm.pp to your My_PostP folder. After copying the file, rename the copied file to OB_grbl_mm.pp. Open OB_Grbl_mm.pp with your favorite text editor.

    The first change to make is to the "POST_NAME" variable.

    Change

    Code:
    POST_NAME = "Grbl (mm) (*.gcode)"
    To

    Code:
    POST_NAME = "OpenBuilds Grbl (mm) (*.gcode)"
    This will change the display name that you will see when you select your post processor in the VCarve UI.

    Second change; remove tool call

    Find the following line

    Code:
    "T1"
    And put a + sign in front of it. It should look like this when done

    Code:
    +"T1"

    Save the file. Restart VCarve for it to take effect.

    That's it for now. I'll update this once I have a chance to really dig into this.
     
  2. jtovar78

    jtovar78 New
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    Made that change on mine. Got an error for no closed quote on post name. Added close quote and it appears fine now. Thanks for the info.
     
  3. sharmstr

    sharmstr OpenBuilds Team
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    where did you add it? My code above has a closed quote so I'm confused.
     
  4. jtovar78

    jtovar78 New
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    Uh, disregard my previous comment.... I was reading your post on my phone and it apparently cut off the end quote. :oops:
     
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  5. JacobE1988

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    What is the purpose of this command?

    I also recommend adding "M5" to the Footer is using a VFD Spindle.
     
  6. sharmstr

    sharmstr OpenBuilds Team
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    T commands are tool changes. T1 is tool 1. Other Codes

    M5 is already in the footer.

    Code:
    +---------------------------------------------------
    +  Commands output at the end of the file
    +---------------------------------------------------
     
    begin FOOTER
    
    "M5"
    "G0[ZH]"
    "G0[XH][YH]"
    "M2"
     
  7. JacobE1988

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    In mine it was missing.. I don't know why it's different from yours. But it's just a little thing to have people keep an eye out for I guess.
     
  8. JacobE1988

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    Aspire Gcode question - Why doesn't the post processor for Grbl use G2 and G3 codes for arcs/circulation? It would create fewer lines of code, smaller files, and easier processing. Just curious if anyone knows.
     
  9. Alex Chambers

    Alex Chambers Master
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    It depends on how you defined curves in Aspire. I'm not a Vectric user (yet) - have just tinkered with the trial versions - but if I remember correctly drawing curves as splines means it won't generate G2 or G3 code. Ie it is your cad not your post processor that determines this.
    Alex.
     
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  10. Alex Chambers

    Alex Chambers Master
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    Re the My_PostP folder, if you save your modified post processor somewhere else you can install it as a new post processor in the main post processor folder - just make sure that you change the name as @sharmstr said so that you can identify it later from the list.
    Alex.
     
  11. CDNSmitty

    CDNSmitty New
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    I jsut did this and it worked for me just fine. Thanks for the help!
     
  12. Slandis

    Slandis New
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    Is there an easy way to add tool changes? When I try and and output all visible tool paths i get the error that my post processor does not support tool changing.
     
  13. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Grbl itself does not support Toolchanges. Some hosts step in and handle it for you, but because officially Grbl does not, most Posts for Grbl also does not do toolchanges.
    Save each tool as its own file and run them one after another. Not much more effort than working a toolchange routine, and sometimes even feels more "in control" as the machine isn't just paused and waiting on you to do something wrong (;
     
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  14. Slandis

    Slandis New
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    Ok that's what i figured I would have to do. Thank you.
     
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