3D resin printer using nanoDLPvref
So I am having some issues with my 3D resin printer.
Just finished setting it up with its new 4K LCD, and better UV with nanoDLP. Well, it is a Wanhao D7 Plus but I have stripped out all the electrics bar the motor and end stop. See the kit list at the foot. All the mechanics are D7 Plus still.
I managed to calibrate my resin at various cure times and had some 30 ish successful prints. However, over the past week and with great frustration it has suddenly stopped working. The print is fine for the first 2mm, and then I start getting the telltale bang as the motor strains against something. The print is perfect up to that point, but it always stops at 2mm. I have tried forcing up and down as it is not clear in which direction the motor strains, but it makes no difference. It appears, not verified that it is turning but missing every few turns, so becomes out of sync in the process as it is # turns/pulses that it knows as its height.
The model might have been sticking to the fep, so checked that. There are no gummy bears so it is not sticking to it. The fep was a bit looser than normal, so could raise the lift height or change the fep. I chose the latter, but it made no difference.
It has been suggested that it is the vref on the skr/RAMPS and was directed at this https://marlinfw.org/docs/gcode/M906.html but it all means nothing to me and not sure what I should enter for the Wanhao motor or my new 0.9 one? And why should it start to fail now, after about 30 successful prints? The build plate moves freely outside printing.
So I need your help, please: What do you think the issue is and how to fix, and do you think it is the vref and if so, does anyone know how to configure it, please? M906 something???
Existing Wanhao D7 1.8 motor, though changing that to NEMA 17 0.9' Step Angle Stepper motor (400/rev) 1703HSM168A - 50oz - 1.68A 5.5 4K 2160x3840 LCD Remove Backlight with glass protector LS055D1SX05(G)
64 pin 20cm Ribbon
4k HDMI board and MIPI Driver
Raspberry Pi 4B
SD Card - 32Gb
SD Card to USB reader
Meanwell LRS350-24 LED DRIVER, DC24V 350W
BIGTREETECH SKR Mini E3 V1.2 Control Board 32Bit with TMC2209 UART Driver 3D Printer Parts Cheetah for Creality Ender 3
Youmile LM2596S Dual USB Power Supply Module Step-Down Buck Adjustable 3A DC-DC Port 15 - 4
Kyrio DC USB Brushless Cooling Fan 5V 4010 3D Printer Fan 40mm x 40mm x 10mm x 2
WINSINN 60mm Fan 24V Brushless 6010 60x10mm - High Speed (Pack of 4Pcs)