I have the ROBO 3D R1 Plus printer. I have added a PEI sheet and the XXL printsolid lcd. My biggest issue with this printer is the bed leveling and z offset inconsistency. I have been battling this problem for around a month now. First problem is the bed leveling. I moved the nozzle to the left side of the bed and get the nozzle to where I can just slide a piece of paper under it and the moved the nozzle to the right side and adjusted the threaded rod with my hand so that the nozzle is the same height off the bed on each side. I started the print and when it was laying down the first layer it wouldnt print on the right side but would print on the left side(because the nozzle is too close to the bed on thr right side). I adjusted this by using trial and error turning the right threaded rod till it produced a consistent first layer. Which sound like the bed leveling program is jacking everything up, how can the X axis be level before a print and not during a print?? Secondly, I spent the last couple of days fine tuning all of the print settings for the different filament including the z offset. I printed some cubes and calibration ring and had it perfect at a z offset of -0.03. I let the calibration ring finish and then I removed it and started a new print, now the nozzle is dragging on the bed during the first layer!! I backed it up to 0 and it is still dragging on the bed. This also happens quite often. What could be the deal? It turns printing into an all day affair because what works one day might not work another.