Z Axis home position [solved]
Posted: Sun Nov 06, 2016 6:58 pm
Just got my Acrylic Prusa I3 pro B working and tried my first test print.
I homed all axes and leveled the bed then loaded my stl file, sliced with Slic3r and hit print.
The printer tried to print the first layer about 2 mm above the bed - disaster. Searching the forum I found a number of posts regarding strange homing behaviour on the X axis. So I started to plough through the firmware source. In the file "Configuration_adv.h" I found this section:
The idea of this is that, if homing is done at high speed, the axis might overstep the switch actuation position with inertia so it retracts and tries a second time more slowly. The software assumes that the retraction is enough to de-activate the end-stop switch. If the switch is not de-activated by the retraction the software assumes that it has reached the activation point and stops any advance.
Changing the last line to
and reloading the firmware fixes the problem.
It must be about time that Geeetech updated the firmware on the website and installed in supplied kits to fix all known problems - please.
Russell.
I homed all axes and leveled the bed then loaded my stl file, sliced with Slic3r and hit print.
The printer tried to print the first layer about 2 mm above the bed - disaster. Searching the forum I found a number of posts regarding strange homing behaviour on the X axis. So I started to plough through the firmware source. In the file "Configuration_adv.h" I found this section:
Code: Select all
//homing hits the endstop, then retracts by this distance, before it tries to slowly bump again:
#define X_HOME_RETRACT_MM 5
#define Y_HOME_RETRACT_MM 5
#define Z_HOME_RETRACT_MM 2
The idea of this is that, if homing is done at high speed, the axis might overstep the switch actuation position with inertia so it retracts and tries a second time more slowly. The software assumes that the retraction is enough to de-activate the end-stop switch. If the switch is not de-activated by the retraction the software assumes that it has reached the activation point and stops any advance.
Changing the last line to
Code: Select all
#define Z_HOME_RETRACT_MM 5It must be about time that Geeetech updated the firmware on the website and installed in supplied kits to fix all known problems - please.
Russell.
