fusion 360 and GRBL - Page 2


Page 2 of 2 FirstFirst 12
Results 13 to 20 of 20

Thread: fusion 360 and GRBL

  1. #13
    Member
    Join Date
    Jan 2005
    Location
    USA
    Posts
    1849
    Downloads
    2
    Uploads
    0

    Default 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.



  2. #14
    Member
    Join Date
    Mar 2011
    Location
    USA
    Posts
    306
    Downloads
    0
    Uploads
    0

    Default 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.
    fusion 360 and GRBL-bad-exit-jpg



  3. #15
    Member
    Join Date
    Jan 2005
    Location
    USA
    Posts
    1849
    Downloads
    2
    Uploads
    0

    Default 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.



  4. #16
    Member
    Join Date
    Mar 2011
    Location
    USA
    Posts
    306
    Downloads
    0
    Uploads
    0

    Default 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

    Attached Files Attached Files


  5. #17
    Member
    Join Date
    Jan 2005
    Location
    USA
    Posts
    1849
    Downloads
    2
    Uploads
    0

    Default 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?



  6. #18
    Member
    Join Date
    Mar 2011
    Location
    USA
    Posts
    306
    Downloads
    0
    Uploads
    0

    Default 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



  7. #19
    Member
    Join Date
    Jan 2005
    Location
    USA
    Posts
    1849
    Downloads
    2
    Uploads
    0

    Default 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.



  8. #20
    Member
    Join Date
    Mar 2011
    Location
    USA
    Posts
    306
    Downloads
    0
    Uploads
    0

    Default 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



Page 2 of 2 FirstFirst 12

Tags for this Thread

Posting Permissions

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


About CNCzone.com

    We are the largest and most active discussion forum for manufacturing industry. The site is 100% free to join and use, so join today!

Follow us on


Our Brands

fusion 360 and GRBL

fusion 360 and GRBL