RPi 3B stuttering when printing small holes/circles

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1

What is the problem?
When printing with raspberry pi 3B using octoprint (touchui enabled), small circles/holes you can hear that instead of a continuous circle, it prints in "points" (like stuttering).
I seriously don't know how to describe this, so here are pictures how it looks when printed from RPi and from my PC.
I guess that this might be the same thing: https://github.com/foosel/OctoPrint/issues/450
What did you already try to solve it?
Nothing, as everything works great when printing it from PC (using Cura, but the same gcode). I really don't know what can cause it.
Additional information about your setup (OctoPrint version, OctoPi version, printer, firmware, octoprint.log, serial.log or output on terminal tab, ...)
OctoPrint: 1.3.10
OctoPi: 0.16.0
Printer: Kossel delta "clone"
Firmware: Marlin-AC-G-force9-AC
octoprint.log: octoprint.log (61.0 KB)

2

Because I can't post more then 1 image, here they come:
PC

PC_close
PC_close.jpg945×900 190 KB

3

PC

PC_norm
PC_norm.jpg2010×1740 655 KB

4

RPi

RPI_close
RPI_close.jpg858×848 176 KB

5

RPi

RPI_norm
RPI_norm.jpg2607×2085 1.04 MB

You can see that the nozzle stops and then continues.

I guess that the Pi just can't handle it.

6

Can you share the gcode and stl?

7

CFFFP_Circle test #3 (2).gcode (199.3 KB)

8

Circle test #3 (2).stl (200.1 KB)

9
  • Guess: The Kossel probably uses an Arduino Mega 2560 (8-bit) controller board
  • This is a delta printer which requires a lot fo mathematical conversions from cartesian coordinates

That alone is a recipe for shredding/blobbing/stuttering.

And then you've added extra processing needs to your Raspberry Pi 3B by adding the PIXEL/Desktop plus browser on top of this, possibly making the Pi unresponsive on its side of the communications.

Read through the many things that people did on those two long issue threads.