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General Mach Discussion / Re: lathe will not thread
« on: August 19, 2017, 06:46:45 PM »
Don't think the internal threading of Mach3 was ever changed in years or after version 3.042.034 and I use version .062 and have had no problems.
Info from Threading on the Lathe Manual:
A gcode file defining the axis moves along with related thread information is read by Mach3. The index pulse provides Mach with rpm data and the program controls the Z axis to a move appropriately from a dead start, accelerate to a defined distance, and then maintain a feedrate such that the cutting tool produces a spiral cut along a cylinder representing the lead of the thread. The start of the Z motion happens when and if a timing pulse is seen. If no pulse is seen the threading will not begin or continue. The timing pulse synchronizes the z axis location to the spindle rotation the same as closing of the half nuts on a manual lathe would do. So, the threading is activated with an index pulse.
The P in G76 should be the pitch and YOU define it. I will assume that you are using the original G76 command and not some altered one. If you use the wizard you should use the Calc Number of Passes button to check if you motor setting is appropriate for the rpm and pitch entered. Remember that with a stepper as the velocity is increased the torque decreases / there is less power available and you want some “headroom” left for cutting the thread. Also you have a choice in what code will be posted and that is covered in section 7.2 of the manual.
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NOTE:
If you are generating gcode from some program then that is different matter as the post processor needs to be correct for MACH3 LATHE.
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So from the manual info above, it seems that the index which triggers threading, is not seen by Mach3. Test that the index is working ( how to do is in the manual). Not familar with the Appolo 1 break out board, use of their plug in, or their screen set.
Do you have the index configured in Mach3? How?
Are you setting spindle rpm manually? ( don't want the vfd fighting the index info to Mach as that can become problematic)
FWIW,
RICH
Info from Threading on the Lathe Manual:
A gcode file defining the axis moves along with related thread information is read by Mach3. The index pulse provides Mach with rpm data and the program controls the Z axis to a move appropriately from a dead start, accelerate to a defined distance, and then maintain a feedrate such that the cutting tool produces a spiral cut along a cylinder representing the lead of the thread. The start of the Z motion happens when and if a timing pulse is seen. If no pulse is seen the threading will not begin or continue. The timing pulse synchronizes the z axis location to the spindle rotation the same as closing of the half nuts on a manual lathe would do. So, the threading is activated with an index pulse.
The P in G76 should be the pitch and YOU define it. I will assume that you are using the original G76 command and not some altered one. If you use the wizard you should use the Calc Number of Passes button to check if you motor setting is appropriate for the rpm and pitch entered. Remember that with a stepper as the velocity is increased the torque decreases / there is less power available and you want some “headroom” left for cutting the thread. Also you have a choice in what code will be posted and that is covered in section 7.2 of the manual.
-------------------------------------------------------------------------------------------------------------------
NOTE:
If you are generating gcode from some program then that is different matter as the post processor needs to be correct for MACH3 LATHE.
-------------------------------------------------------------------------------------------------------------------
So from the manual info above, it seems that the index which triggers threading, is not seen by Mach3. Test that the index is working ( how to do is in the manual). Not familar with the Appolo 1 break out board, use of their plug in, or their screen set.
Do you have the index configured in Mach3? How?
Are you setting spindle rpm manually? ( don't want the vfd fighting the index info to Mach as that can become problematic)
FWIW,
RICH
