NOZZLE TOO CLOSE TO THE PRINT BED
If the nozzle is too close to the surface of the printing bed, there will not be enough space for plastic to exit the extruder.The hole in the upper part of the nozzle is substantially blocked, and then the molten plastic can not escape. A simple way to recognize this problem is to verify that, if the nozzle does not extrudes plastic for the first layer or two, but instead begins to extrude around normally to the layers 3 or 4 means precisely that the bed in the print starting position, it is too close to the nozzle hole. To solve this problem, you can use the very practical offset the G-Code that can be found on the G-Code tab of process settings of your printing program. This allows you to make very fine adjustments, just as the Z axis position accuracy, without having to change the hardware. For example, if you enter a value of 0.05 mm for the Z axis Offset G-Code, this move 0.05mm nozzle further away from the print bed. Keep this increased value by small increments until there is enough space between the nozzle and the build platform. The classic measurement of proper thickness is to insert a normal sheet of A4 paper that must pass without binding between the nozzle and the platen.