Most 3D printers use an open loop control system. To be fair, they don't have feedback on the actual position of the nozzle. The printer simply tries to move the sprinkler to a location and hopes it will get there. Most of the time, this is possible because the stepper motor that drives the printer is very powerful and does not have a large load to prevent the nozzle from moving.

Then, if something goes wrong, the printer won't find it. For example, when you print, you suddenly hit your printer, and you may cause the nozzle to move to a new location. The machine has no feedback to identify this. So, it will continue to print as if nothing happened. If you find that the layer in the printer is misplaced, it may be due to one of the reasons listed below. Unfortunately, once these errors occur, the printer has no way of finding problems and dealing with them.