The adjustment, or at least the control, of the quantity of extruded filament is one of those operations with which everyone, before or after, must deal.
This examination becomes necessary if we find ourselves in the case in which our prints have an inconsistent shape, or in the opposite case if we were to deal with small or large colaturre of materials. For the more finicky, it is also a necessary test even in the absence of obvious problems.
The case in general in which this operation is perhaps more useful is when we are in the presence of constant lines on the surfaces of our print. In fact, a small overextrusion can be easily confused with the problem of wobbing. Going to identify the problem and adjust the extrusion at the beginning of the endless controls that we should put in place for the mechanical oscillation could be a stroke of luck.
Amount of extruded filament: Practical guide
The steps are very simple and we need very common materials.
We’re gonna need:
- Measuring instrument (ruler/measurement tape/caliper)
- Marker pen
- A printer-computer dialog program (we will use Repetier Host)
Connect the printer via the dialogue program to the PC, and make sure that the printer responds to your commands. Now take the instrument you use to measure and count 10 centimeters, precisely where the filament enters the extruder backwards and make a mark with the marker.
Using Repetier you instruct the printer to extrude exactly 10 cm and at the end of the operation look at where the marker mark has ended. If it has disappeared you will be in the case of overextrusion, on the contrary if you see it still far from the extruder entrance you will be underextruding.
In case your sign is right at the extruder entrance…well! Your test so far here!
In the previous 2 cases, instead, you have to adjust the number of steps that the thread-pusher motor (conventionally E) takes. Normally this value is found in the variable firmware settings from the built-in screen to the printer. For example, the marlin is placed under –control (control) —> motion (motion) —> Esteps/mm.
The E steps value should be revised downwards in the case of overextrusion and upwards for underextrusion. It is recommended not to exceed 50 points from one change to another, and of course repeat the test. Adjusting the shot until the mark you made will stop exactly at the entrance of the extruder (where you started to measure).
Amount of extruded filament Firmware Change
Once you have found the exact value, you just have to save it through the “store memory” function on the loaded firmware. If you do not have the possibility to save then you must proceed with the loading of the firmware with the new values just found. The steps of the engines to be modified (on Marlin) are located inside the configuration.h tab about middle of it.
It can happen that despite the perfect setting you are still in the case of under/over extrusion. And this can be given by various factors, including the filament used.
In this case, when you find the error cases (e.g. a given filament) you can go and act directly from the slicer flow quantity, which you can modify if necessary.