Before starting to calibrate the BLV Cube, we need to make sure that the sensor is working and that homing and mesh compensation are working.
The installation of the sensor is really easy but I still had some problems. First of all, for some reasons, the nozzle supplied in the kit was longer than expected. The results was that the nozzle would it the table before the sensor was trigger.
I got myself from BLV tested Hot End from the Mellow Store on Aliexpress. It is about 0.5 mm shorter, than the one I got in the Kit. This time the sensor is triggering but there is only 0.1 mm clearance. This was definitely not enough for me, I had the feeling it was going to hit the bed at every homing and I was living with the finger on the emergency stop ! 🙂
I redesigned a X Locker for the IR Sensor where I drop the IR Sensor by 1.5mm. You can find the STL on thingiverse. After printing and mounting, the sensor is definitely lower !
To calibrate the sensor, there is a macro on the SD card made by BLV, making the calibration really easy. I did it the same way but manually and got the following code with an offset of 1.7mm. It is not bad as it is recommended to have around 1 mm. Maybe I will update the model to raise the sensor by 0.5mm to get around 1 mm offset.
M558 P1 C”zprobe.in” H5 F120 T6000 ; set Z probe type to unmodulated and the dive height + speeds
G31 P500 X-2 Y-16.4 Z1.7 ; set Z probe trigger value, offset and trigger height
M557 X15:285 Y15:285 P5 ; define mesh grid
After that, everything is working fine, homing is perfect and the mesh calibration is working.
A word of caution, if you use the duet calibrator on the web, it will set you G31 at P25. It is a safety precaution making the sensor detecting the table from really far away, avoid any collision but the accuracy is really bad. P500 is the value you want, which will detect the surface at around 3mm.
Another word of caution, the sensor is really low and close to the object when printing. If you nozzle is not clean or you have blob of material building up, the sensor may collide with it and get damaged. So keep it clean and keep your BLV Cube calibrated. This is going to be the next step !
Happy printing !