Extrudeing in bursts, and suddnely printing to the side of the print

Hi! I have to curious problems with my ormerod 2.

It is extruding in bursts, making a sortof spoted patern on the skirt, and making a very bumpy, uneven print. Its like it extrudes, then pauses, the extrudes again, every other second or so. What can be causing this?

The other issue is that it will somtimes offset the print in x and y direction in the middle of the print. If im printing a flat heart for example, it will sometime suddenly start printing the heart offset to the original posistion. The shape will still be right, and the height will be right, but parts of the shape will be in the air. This only happens sometimes, and i cant relly find and method to the madness. Any sugestions?

Thanks in advance, alla help is appreciated

Your first problem is due to the Z zero height being too low. Adjust your Z homing position to be 0.1mm or so higher than it is at present. If you place a sheet of copier paper under the (clean) nozzle and execute the command "G1 Z0" the paper should be gripped, but you should still be able to move the paper fairly easily while feeling a slight vibration through the paper. You can adjust the Z height while moving the paper using the web interface or pronterface, and when the height is correct execute the command "G92 Z0" which will set it to zero. Be careful not to press down on the bed when moving the paper.

Your second problem is due to either a slipping belt, slipping pulley or a stepper motor skipping a step. Make sure your belts are tight, and the grub-screws on the motor spindles are aligned with the flat in the spindle and are tight. A skipping motor is usually caused by the nozzle hitting a part of the print that has curled up or developed a blob. You should be able to see and hear when a motor skips a step. There are different cures for curl-up and blobbing.

Dave

Thank you! Great help