In case it might be handy:
http://www.wallacecompany.com/machine_shop/LinuxCNC/fourth_axis/
My next task was to try to clearly define what the plot should look like. A working example to copy would be nice.
On 08/25/2017 12:53 AM, 王若溪 wrote:
Hi forks, I'm using LinuxCNC with my 4 axes (A axis rotate along X axis) mill and I want to make back plot in Axis GUI reflect the path of tool reference point (tool tip) relative to the workpiece correctly. i.e. The tool reference point (tool tip) should rotate about the A axis hinge point, which has a fixed G53 Y, Z coordinate when I'm jogging A axis. If I set "GEOMETRY = XYZA", the tool tip always rotate about the current point, which is not correct. If I set "GEOMETRY = AXYZ", the tool tip rotate about the origin of G53 coordinate system. Then I had to offset the min/max/home of YZ axis to make G53 origin coincident to A axis hinge point, which is kinda dangerous because many CAM software defaults to do a "G0 G53 X0 Y0 Z0" in the beginning of an operation, which would crash my spindle into the table. So what's the normal practice when making an NC system for 4,5 axis machine? Do I have to add non-trivial kinematics so that the back plot is correct when "GEOMETRY = XYZA"? Or can I redefine the tool length compensation value to be (Z coordinate of A axis hinge - Z coordinate of tool tip) when machine is at Z home/max, which is normally a negative value, so that I still set Z home/max = G53 Z0 but get correct back plot when tool length compensation is applied? What is tool length compensation typically defined, BTW? Wow, there are a lot of questions. I'm new to mill with rotary axes, any hint would be appreciated, thanks. ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
-- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/ ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
