A Z axis that rises into the upper limit during Mach3 “Run From Here” is not necessarily following the CAM clearance plane. In the documented case, the clearance plane was 0.250, but the actual cause was unset Mach3 Safe Z settings. Configuring Config > Safe Z resolved the problem.
Separate CAM Clearance From Controller Motion
RhinoCAM generates the cut file, but it does not know that the operator selected “Run From Here” inside the control software. Diagnose the restart motion in Mach3 before changing CAM parameters.
| Item | Evidence | Engineering decision |
|---|---|---|
| Clearance plane | Set to 0.250; units were not stated | Do not assume this value controls Mach3 restart motion. |
| Unexpected motion | Z traveled upward to the upper limit after Cycle Start | Inspect controller restart and Safe Z configuration. |
| Confirmed correction | Safe Z settings had never been set | Configure Safe Z in Mach3. |
Check Mach3 Safe Z
Open Config > Safe Z and inspect the existing configuration. The evidence does not identify the required Safe Z value, coordinate mode, machine travel, or units, so derive the setting from the actual machine coordinate system and available Z travel rather than copying the 0.250 clearance-plane value.
Configure and Verify Run From Here
- Confirm that Mach3 is executing the “Run From Here” operation and that the CAM clearance plane remains 0.250 in its stated but unspecified units.
- Open Config > Safe Z and configure the previously unset Safe Z settings for the machine.
- Verify the restart under controlled conditions while watching Z direction and position. Stop the cycle if Z again approaches the upper limit.
- Confirm that Cycle Start completes the restart motion without activating the upper limit switch.
If the fault remains, retain the separation between CAM and controller behavior: review Mach3’s restart motion and Safe Z configuration before altering the RhinoCAM toolpath. Machine-specific values cannot be determined from the available evidence.
FAQ
Why does Mach3 Run From Here send Z to the upper limit?
In the documented case, Mach3 Safe Z settings had never been configured. Setting them under Config > Safe Z stopped the upper-limit travel.
Does a RhinoCAM clearance plane of 0.250 control Mach3 Safe Z?
The evidence shows that the 0.250 clearance plane did not prevent the restart fault. Treat the CAM clearance plane and Mach3 Safe Z as separate settings unless the machine configuration proves otherwise.
Where is the Safe Z setting in Mach3?
Open Config > Safe Z. Determine the correct configuration from the machine’s coordinate system and Z travel because the required value and units were not provided.