Extruder microsteps

General Discussion
1

Hi,

This more than a question, is a rookie clarification.
As I have mentioned other times, it is from a semi-configured CoreXY printer, a RatRig v3.

This printer has an image prepared with Klipper and Mainsail, prepared for the hardware you mount.

Been printing ABS and PETG, fine, but I’m having trouble with PLA.

The problem is that it starts to print fine, and at a variable height between 3 and 10 layers maximum, it stops extruding… only extruding, the rest of the printer continues executing the gcode of the file.

I’m testing things, and was to ask, if a default configuration option that I changed, could be the cause of this problem.

In the default configuration, “factory”:
[extruder]
…
microsteps: 16
…

and I, in order to have more resolution, change it to:

[extruder]
…
microsteps: 64
…

The question is, this change. Could it be the cause that after a few layers it stops extruding?

What would be the reason? (talking for talking), maybe when raising the microsteps, the extruder motor heats up and stops working?

and… with the default configuration, 16, is it enough? the extruder has more steps per mm than an axis motor

Thx…

2

If you have a stand alone driver, you have to set this microsteps with with jumpers at the stepper driver. (You did not mention what stepper driver you use and how it is run)
So if you don’t do this, you will have a 4 times (400%) over extrusion.

Usually 16 microsteps are enough for a extruder.
A common stepper has 200 full steps per revolution. That makes 3200 microsteps.

For a hobbed gear with i.e. a circumference of 21 mm the resolution is
21 mm/3200 = 0.0065625 mm

If you have a geared extruder, this resolution will be much smaller

In addition, smaller the microsteps are, the higher the current must be.

3

Drivers are TMC 2209

4

As stand alone or in UART mode?

5

In stand alone… Think. Not sure