When objects seem to have bad dimensions or if the printhead or table shows jumps during printing. Which shows like this:

Mechanical issues

• Belt is defect
• Pulley not properly fixed on motor shaft
• In some cases there can be some piece of filament between the belt and the pulley, causing shifts.
• Check for the Tec 4 if the extruder assembly is not rubbing against the aluminum profile, there should be approx 1mm clearance. If not reposition the linear rail of the x-axis.

Electrical issues.

Endstop circuit is not functioning properly. Actually only for the 3.1, the opto sensors are continuously monitored. So if anything is defect, it will show on the object. When the sensor is defect, the printer thinks the sensor is continously triggered. Since the printer is not allowed to move past the endstop, it will only do movements in positive direction. 

Motor circuit is not functioning properly.

In this case the following can be the issue.

• Motor cable is broken.
• Connector on motor on on mother board is not ok.
• Stepper driver can be overheating, double check if the potmeters are set according to the manual
• Too little power is going to the motor. Please double check potmeter

Slicing/software issue

When there are large overhangs and the object is not able to cool down sufficiently fast, the object can curl up a little bit. When this happens the nozzle can bump into the object causing a shifted print. To prevent this, you can:

• Change the design
• Reorient object
• Print multiple objects so it can cool down before the next layer is printed.
• Lower print-temperature a bit.