The offset calibration concept is:
1. Measure the farest Z position: (steps) between the Z home and Z max position. It can be different in 1/10 mm so we have to check it.Because the build plate can move if the power goes out we have to know the max steps to get back the proper position when the print resumed.
2. Find the edge of the build plate. In assembly the Z console can be on an unknown position from the extruder. When the nozzle touch the front edge of the build plate it stores the position.
3. Measure the distance between the BL touch switching height and the nozzle build plate touch. We touching the build plate several times to avoid wrong measure
4. Two head Z distance. This has two phases.
- Phase 1 measure the distance (in Z) between the two heads. If it is under +-0.1 mm the calibration will continue with next step. If not the Phase 2 starting.
- In Phase 2 we ask the user to loose the extruder heatbreak, it will drop out the nozzle. It can move freely up and down. Now we push up the nozzle with the build plate to Z0 position and ask the user to secure the heatbreak. After it we check if the Z level between the two extruder is under +-0.10mm and store the value for dual head printing compensation. If not, we ask the user to redo the process.
5. XY callibration. The two head are cannot be aligned on X Y plane fully. We have to know what is the difference. There is a hole in the front middle of the buildplate where we touching the hole edge with the nozzle. Both extruder. It give us the XY difference, compensation value.
Assisted bed leveling:
1. We measure the 3 point of the build plate.
2. Start dropping the BL touch. We ask the user to turn the bed knob, until the distance between the BL touch switching level is below +-0.1mm - we already know the distance between the BL touch and the nozzle from previous measure.
3. After the 3 point measure we check the distance again, if it is under +-0.1mm we finish else we go back to point 2.
Mesh bed leveling:
We heat up the build plate to 60C and then 80C and 100C. With the BL touch - we already know the BL touch, nozzle offset from the previous process - we measure the distance between the build plate and the BL touch (3 mesh). Mainboard makes a mesh surface and during the print it compensates the Z level according to the mesh. We always use the closest mesh table for the bed temperature during the print.If two head is printing in parallel or mirror mode the average value of the two print point will be used for compensation.
The FMS sensor on the top of the hotend is turning as the filament pushed in to the tube. We extrude 50mm filament and we check if the FMS measured the correct value.