The motor on Materium is a geared planetary stepper motor.
During extrusion, skips may happen. Also known as ‘stall’.
Skips are normally audible (making a quick skidding noise) and visible (Manual Dial taken aback when it should be forward)

Skips happen because the load is too big for the stepper motor, or the motor becomes weak at elevated temperatures.
When it isnt because of the motor getting too hot, this means the load is too big.
When diagnosing, it is important to differentiate between a Clog and a Resistance that is causing the skip.

A Clog is foreign object or unmelted material shutting off the final nozzle orifice inside.
The solution is to open up the nozzle, clean it, and reattach.
When a clog is left unattended, massive pressure builds up inside the nozzle.
Materium generates enough pressure to rip open a crack on the brass nozzle walls.
Another scenario, it will leak through the threads when nozzle is not tightened properly (see : Nozzle Maintenance)
Simply swap the nozzle.

Another unfamiliar cause is Resistance.
When temperature is too low for a certain material, the screw doesn’t have enough torque to rotate and push because the material ‘grabs’ it.
Another big cause of ‘grabbing’ Resistance is the presence of melt on the Feed Zone (upper part of the barrel) where it should NOT be hot. (see : melt zone). A reminder : pellet extruders operates with a temperature gradient; top cold, bottom hot. Without this, or if you assume everything needs to be hot, extrusion will not happen at all.
Or when a non-melting material is loaded, the screw may turn up until only a certain point then skips.