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IndustryArena Forum > CAM Software > Autodesk CAM > fusion 360 and GRBL
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  1. #1
    Join Date
    Mar 2011
    Posts
    333

    fusion 360 and GRBL

    I am trying to process my first F360 CAM for a GRBL/Arduino set up. I am using the Grbl/grbl podst.
    When I simulate in UGS(so it does not move the machine) I get an error:20 while sending M6.
    I did not think I was asking for a tool change. Also, when I try to run it the first thing the machine does is
    go to my home position but it overshoots and hits the hard limits then it is stuck.
    Question 1. I have the flood coolant disabled in the tool path so why is it generating the M6?
    Question 2. why is it sending the machine to HOME first thing?

    Here is the .nc file.
    %
    (xaxis idler cam)
    (T1 D=0.25 CR=0 - ZMIN=-0.5 - flat end mill)
    G90 G94
    G17
    G20
    G28 G91 Z0
    G90

    (2D Contour1)
    M9
    T1 M6
    S24000 M3
    G54
    G0 X4.0384 Y2.3612
    Z0.6
    Z0.2894
    G1 Z-0.225 F13.12
    X4.0386 Y2.3609 Z-0.2289
    X4.0391 Y2.3602 Z-0.2327
    X4.0399 Y2.3589 Z-0.2363
    X4.0411 Y2.3572 Z-0.2397
    X4.0425 Y2.3551 Z-0.2427
    X4.0441 Y2.3526 Z-0.2452
    X4.046 Y2.3498 Z-0.2473
    X4.048 Y2.3468 Z-0.2488
    X4.0501 Y2.3436 Z-0.2497
    X4.0522 Y2.3403 Z-0.25
    X4.0661 Y2.3195 F39.37
    G3 X4.1007 Y2.3125 I0.0208 J0.0138
    G2 X4.308 Y2.375 I0.2073 J-0.3125 F50
    G1 X5.375
    G3 X5.5 Y2.5 J0.125
    G1 Y4
    G3 X5.375 Y4.125 I-0.125
    G1 X4.308
    G2 X3.9832 Y4.3125 J0.375
    G3 X3.875 Y4.375 I-0.1083 J-0.0625
    G1 X0.875
    G2 X0.5 Y4.75 J0.375
    G1 Y7.5
    G2 X0.875 Y7.875 I0.375
    G1 X7.125
    G2 X7.5 Y7.5 J-0.375
    G1 Y0.5
    G2 X7.125 Y0.125 I-0.375
    G1 X0.875
    G2 X0.5 Y0.5 J0.375
    G1 Y1.75
    G2 X0.875 Y2.125 I0.375
    G1 X3.875
    G3 X3.9832 Y2.1875 J0.125
    G2 X4.1007 Y2.3125 I0.3248 J-0.1875
    G3 X4.1077 Y2.3472 I-0.0138 J0.0208 F39.37
    G1 X4.0939 Y2.368
    X4.0917 Y2.3712 Z-0.2497
    X4.0896 Y2.3744 Z-0.2488
    X4.0876 Y2.3774 Z-0.2473
    X4.0858 Y2.3802 Z-0.2452
    X4.0841 Y2.3827 Z-0.2427
    X4.0827 Y2.3848 Z-0.2397
    X4.0816 Y2.3865 Z-0.2363
    X4.0808 Y2.3878 Z-0.2327
    X4.0803 Y2.3886 Z-0.2289
    X4.0801 Y2.3888 Z-0.225
    G0 Z0.2
    X4.0384 Y2.3612
    G1 Z0.0394 F13.12
    Z-0.475
    X4.0386 Y2.3609 Z-0.4789
    X4.0391 Y2.3602 Z-0.4827
    X4.0399 Y2.3589 Z-0.4863
    X4.0411 Y2.3572 Z-0.4897
    X4.0425 Y2.3551 Z-0.4927
    X4.0441 Y2.3526 Z-0.4952
    X4.046 Y2.3498 Z-0.4973
    X4.048 Y2.3468 Z-0.4988
    X4.0501 Y2.3436 Z-0.4997
    X4.0522 Y2.3403 Z-0.5
    X4.0661 Y2.3195 F39.37
    G3 X4.1007 Y2.3125 I0.0208 J0.0138
    G2 X4.308 Y2.375 I0.2073 J-0.3125 F50
    G1 X5.375
    G3 X5.5 Y2.5 J0.125
    G1 Y4
    G3 X5.375 Y4.125 I-0.125
    G1 X4.308
    G2 X3.9832 Y4.3125 J0.375
    G3 X3.875 Y4.375 I-0.1083 J-0.0625
    G1 X0.875
    G2 X0.5 Y4.75 J0.375
    G1 Y7.5
    G2 X0.875 Y7.875 I0.375
    G1 X7.125
    G2 X7.5 Y7.5 J-0.375
    G1 Y0.5
    G2 X7.125 Y0.125 I-0.375
    G1 X0.875
    G2 X0.5 Y0.5 J0.375
    G1 Y1.75
    G2 X0.875 Y2.125 I0.375
    G1 X3.875
    G3 X3.9832 Y2.1875 J0.125
    G2 X4.1007 Y2.3125 I0.3248 J-0.1875
    G3 X4.1077 Y2.3472 I-0.0138 J0.0208 F39.37
    G1 X4.0939 Y2.368
    X4.0917 Y2.3712 Z-0.4997
    X4.0896 Y2.3744 Z-0.4988
    X4.0876 Y2.3774 Z-0.4973
    X4.0858 Y2.3802 Z-0.4952
    X4.0841 Y2.3827 Z-0.4927
    X4.0827 Y2.3848 Z-0.4897
    X4.0816 Y2.3865 Z-0.4863
    X4.0808 Y2.3878 Z-0.4827
    X4.0803 Y2.3886 Z-0.4789
    X4.0801 Y2.3888 Z-0.475
    G0 Z0.6
    G28 G91 Z0
    G90
    G28 G91 X0 Y0
    G90
    M30
    %

  2. #2
    Join Date
    Mar 2003
    Posts
    35538

    Re: fusion 360 and GRBL

    1) M6 is tool change, Coolant is M7/M8. Disabling coolant has nothing to do with the tool change.
    2) I think all Fusion 360 posts send the machine home first.
    You can always delete the G28 G91 Z0 line, and any line with an M6.
    Or edit the post.
    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)

  3. #3
    Join Date
    Jan 2005
    Posts
    1943

    Re: fusion 360 and GRBL

    M6 isn't coolant, it is a tool change. Grbl doesn't natively recognize tool change, but some Grbl interfaces do.

    G28 is a move to a predefined position. If you haven't set the G28 position then it is the same as your home position

  4. #4
    Join Date
    Mar 2011
    Posts
    333

    Re: fusion 360 and GRBL

    Quote Originally Posted by ger21 View Post
    1) M6 is tool change, Coolant is M7/M8. Disabling coolant has nothing to do with the tool change.
    2) I think all Fusion 360 posts send the machine home first.
    You can always delete the G28 G91 Z0 line, and any line with an M6.
    Or edit the post.
    how do you edit the post ?

    - - - Updated - - -

    Quote Originally Posted by 109jb View Post
    M6 isn't coolant, it is a tool change. Grbl doesn't natively recognize tool change, but some Grbl interfaces do.

    G28 is a move to a predefined position. If you haven't set the G28 position then it is the same as your home position
    How do you set a predefined position for the G28?

  5. #5
    Join Date
    Mar 2011
    Posts
    333

    Re: fusion 360 and GRBL

    ok I deleted the G28 line at the beginning and the M6 line.
    When I run the program it is cutting only .475 deep and the stock is .5. I zeroed the Z axis at the top of the stock before starting so why is it only cutting .475 deep?
    Also, it homes at the end of the cut which I think is ok but it runs into the limit switches and hangs with a hard limit error, why?

    Thanks

  6. #6
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    Jan 2005
    Posts
    1943

    Re: fusion 360 and GRBL

    There were more G28 commands at the end of the file. A G28 is not "homing". It happens to be going to the home position because no G28 offset has been programmed. "Homing" is a very different thing in that when homing the machine doesn't know where it is at and it is using the switches to find itself. That is homing. G28 is just moving to a location. Even moving to the same location as the machine home position is simply moving to the home position but is not "homing"

    To set the G28 predefined position you just move to the position you want it to be at and then send a G28.1 command. The G28.1 saves the current machine position location into the G28 offsets.

  7. #7
    Join Date
    Oct 2010
    Posts
    171

    Re: fusion 360 and GRBL

    Upload your f3d file here. It will be a lot easier for us (or at least me) to diagnose.

    PM

  8. #8
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    Mar 2011
    Posts
    333

    Re: fusion 360 and GRBL

    Quote Originally Posted by 109jb View Post
    There were more G28 commands at the end of the file. A G28 is not "homing". It happens to be going to the home position because no G28 offset has been programmed. "Homing" is a very different thing in that when homing the machine doesn't know where it is at and it is using the switches to find itself. That is homing. G28 is just moving to a location. Even moving to the same location as the machine home position is simply moving to the home position but is not "homing"

    To set the G28 predefined position you just move to the position you want it to be at and then send a G28.1 command. The G28.1 saves the current machine position location into the G28 offsets.
    is this something that is expected to be done manually or is there some switch I should set in Fusion somewhere?
    Seems weird that I should have to edit the .nc file before I can use it. Yes I am a noob.

  9. #9
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    Mar 2011
    Posts
    333

    Re: fusion 360 and GRBL

    Quote Originally Posted by ger21 View Post
    1) M6 is tool change, Coolant is M7/M8. Disabling coolant has nothing to do with the tool change.
    2) I think all Fusion 360 posts send the machine home first.
    You can always delete the G28 G91 Z0 line, and any line with an M6.
    Or edit the post.
    How do I edit the "post" so I dont have to manually change the g-code before I use it?
    Thanks

  10. #10
    Join Date
    Oct 2010
    Posts
    171

    Re: fusion 360 and GRBL

    Quote Originally Posted by tkms002 View Post
    How do I edit the "post" so I dont have to manually change the g-code before I use it?
    Thanks
    This might help: https://www.nyccnc.com/beginners-gui...rs-fusion-360/

  11. #11
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    Mar 2011
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    333

    Re: fusion 360 and GRBL

    Quote Originally Posted by precisionmetal View Post
    Upload your f3d file here. It will be a lot easier for us (or at least me) to diagnose.

    PM
    it is the same one as in this thread
    https://www.cnczone.com/forums/autod...ion-360-a.html

  12. #12
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    333

    Re: fusion 360 and GRBL

    Quote Originally Posted by 109jb View Post
    There were more G28 commands at the end of the file. A G28 is not "homing". It happens to be going to the home position because no G28 offset has been programmed. "Homing" is a very different thing in that when homing the machine doesn't know where it is at and it is using the switches to find itself. That is homing. G28 is just moving to a location. Even moving to the same location as the machine home position is simply moving to the home position but is not "homing"

    To set the G28 predefined position you just move to the position you want it to be at and then send a G28.1 command. The G28.1 saves the current machine position location into the G28 offsets.
    I am using UGS to interface with my Arduino/GRBL machine. Do I have to send G28.1 after setting a new 0,0,0 position other than home? Can I add a G28.1 to the beginning of the .nc file?
    Sorry, it just seems weird that the Grbl/grbl post needs to be modified to run on an GRBL controlled machine.
    I feel like I am missing something that would make this simpler.

  13. #13
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    Jan 2005
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    1943

    Re: fusion 360 and GRBL

    The Grbl postprocessor wasn't made by the Grbl developers. It isn't part of Grbl and they have absolutely nothing to do with the postprocessor. It is a Fusion postprocessor made by who knows who and for who knows what interface program. I have my own postprocessor I made for my interface program to use with Grbl, but my interface supports canned cycles, optional stop, tool changes, and more that Grbl doesn't support natively. So my custom postprocessor is a Grbl postporocessor that is contingent on using my interface, but is a Grbl postprocessor nonetheless.

    One more time.......

    G28 means ----- Go to predefined position

    G28.1 is how you set the predefined position. Where the machine is when G28.1 is invoked is the position it will go to whenever G28 is invoked. If it has never been defined it will be the same as the home position. It is persistent, meaning Grbl will remember it even after a power down or reset.


    You really need to do some research on your own. There are plenty of references on the internet about G-codes. The Grbl site tells which g-codes are supported by Grbl.

    https://github.com/gnea/grbl/wiki

    And the linuxCNC user manual will explain every one of those supported commands. http://linuxcnc.org/docs/2.7/pdf/Lin..._Manual_fr.pdf

    You can also just google them. Just googling "cnc G28" or "cnc G28.1" or any other g-code command will bring up a host of references.

  14. #14
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    333

    Re: fusion 360 and GRBL

    G28.1 is how you set the predefined position. Where the machine is when G28.1 is invoked is the position it will go to whenever G28 is invoked. If it has never been defined it will be the same as the home position. It is persistent, meaning Grbl will remember it even after a power down or reset.

    the above statement helps a lot.
    any idea why my machine did not wait for the z retract to head for home?
    after I remove all G28 commands from the file this does not happen. it still does a Z up by one inch then ends.
    Attachment 419874

  15. #15
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    Re: fusion 360 and GRBL

    G0 Z0.6 This line should raise Z to 0.6 above the top of the part
    G28 G91 Z0 This line will do a G28 but only the Z axis will move
    G90 This line puts it back into absolute positioning mode
    G28 G91 X0 Y0 This line will do a g28 but only X and Y will move
    G90 This line puts it back into absolute positioning mode
    M30 End of program

    In general a G28 by itself will move the tool simultaneously in all 3 axes from where it is to the G28 position.

    If an axis is on the line then only that axis will move and it will first do the move defined on the line and then go to the G28 position for that axis. So,

    G28 G91 Z0 will do a G91 Z0 move first. G91 Z0 is an incremental move of 0 units, so it won't actually move, but the G28 then makes it move the z axis to the G28 position, but only Z will move.

    G28 G91 X0 Y0 is same except in x and y I'll use another example though

    G28 G91 X1 Y0 would first cause a move 1 unit in the Y direction, and then x and y would move to the G28 position.

  16. #16
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    333

    Re: fusion 360 and GRBL

    ok it does not appear to be doing that
    If I take out the G28 commands then at the end of the program it moves the Z up .6 and ends
    if I leave the G28s in it goes on a straight line to the G28.1 position as if it is ignoring the G0 Z0.6.
    I have reproduced this issue twice now.
    Without the G28 the Z retracts to .6 above the Z zero position(top of the stock).
    With the G28s in it cuts a straight line from the last position of the spindle(bottom of the last cut) to the G28.1 position cutting through the stock on it's way.
    I am attaching both files.

    I have discovered in the POST settings in Fusion I can disable the addition of the G28's but I would rather figure this out.

    Thanks

  17. #17
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    Jan 2005
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    1943

    Re: fusion 360 and GRBL

    I ran the code with G28 through Grbl without modification and except for the M6 command, it runs as expected. When it gets to the final portion of the code it does the following:

    G0 Z0.6 Z axis raises to Z=0.6"
    G28 G91 Z0 Z raises up to the Z height for my G28 position
    G90
    G28 G91 X0 Y0 X and Y axes move to the XY position of my G28 location
    G90
    M30

    This is using my sender in "Basic" mode which simply sends the lines to Grbl with no modification. I used my single step mode so I could see exactly what each line is doing. So once again, the problem seems to lie with UGS unless there is a problem with your Grbl. What version of Grbl are you running?

  18. #18
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    Re: fusion 360 and GRBL

    Quote Originally Posted by 109jb View Post
    I ran the code with G28 through Grbl without modification and except for the M6 command, it runs as expected. When it gets to the final portion of the code it does the following:

    G0 Z0.6 Z axis raises to Z=0.6"
    G28 G91 Z0 Z raises up to the Z height for my G28 position
    G90
    G28 G91 X0 Y0 X and Y axes move to the XY position of my G28 location
    G90
    M30

    This is using my sender in "Basic" mode which simply sends the lines to Grbl with no modification. I used my single step mode so I could see exactly what each line is doing. So once again, the problem seems to lie with UGS unless there is a problem with your Grbl. What version of Grbl are you running?
    running GRBL 1.1

  19. #19
    Join Date
    Jan 2005
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    1943

    Re: fusion 360 and GRBL

    So with Grbl 1.1, all of the commands except the M6 line are accepted by Grbl natively. The G28 command should make it move up in the Z direction first before moving in the XY. It works on my install, so not sure why it isn't working correctly for you. The only thing I can think of is that UGS is somehow changing what is sent to Grbl. I don't use UGS, so can't help in that regard, but maybe you could try one of the other sending programs https://github.com/gnea/grbl/wiki/Using-Grbl

    Also, just a tip. It is always a good idea to do a dry run which can be accomplished by setting the Z=0 position to a location above the part such that the maximum z- move won't get down to the part, then run the job. The tool will move around above the part without actually cutting and you can watch its movements for anything that doesn't look right.

  20. #20
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    Mar 2011
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    333

    Re: fusion 360 and GRBL

    Quote Originally Posted by 109jb View Post
    So with Grbl 1.1, all of the commands except the M6 line are accepted by Grbl natively. The G28 command should make it move up in the Z direction first before moving in the XY. It works on my install, so not sure why it isn't working correctly for you. The only thing I can think of is that UGS is somehow changing what is sent to Grbl. I don't use UGS, so can't help in that regard, but maybe you could try one of the other sending programs https://github.com/gnea/grbl/wiki/Using-Grbl

    Also, just a tip. It is always a good idea to do a dry run which can be accomplished by setting the Z=0 position to a location above the part such that the maximum z- move won't get down to the part, then run the job. The tool will move around above the part without actually cutting and you can watch its movements for anything that doesn't look right.
    thanks I will give a different program a try

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