Sprite Pro Extruder stops attempting to extrude during (certain) prints

Ender-3 V3 Printers
1

I took the jump and upgraded my Sovol SV01 Pro’s stock extruder to a Sprite Pro using the Sprite Pro Extruder Kit a few months ago. The Sovol SV01 Pro uses a Creality v4.2.2 motherboard. I had to make a few tiny tweaks to the firmware, but nothing major, and got it working relatively easily.

However, ever since I’ve switched out the extruder, I’ve noticed the Sprite Pro will stop printing at a (seemingly) random point in certain prints. Some models come out perfectly fine, while others fail every time, in the exact same place of the print. Usually (if this happens), this will happen in a specific point on the very first layer. I’ve only seen one model where it happened about halfway through the whole print.

It’s not a clog - at some point, the extruder motor just stops trying to spin. I’ve taken a video of this in action: https://youtu.be/7Kv4Al2VCdI. You can see the extruder just stop at around 2:53. The print head continues to move around the print (and some melty filament continues to “leak out” of the extruder), but the extruder doesn’t push any more filament out. If I “pause” the print after this happens and send the GCODE commands to extrude/retract filament, nothing happens. If I fully stop the print and then try to extrude/retract, it works as expected (without needing a full cool-down period).

The extruder motor is not hot/overheating when this happens.

I am printing through OctoPrint. I never saw this issue until I swapped the extruders, so I’m fairly certain it’s an issue with the new extruder/my firmware, not OctoPrint.

I have tried tweaking various firmware/GCODE settings (lowering jerk, disabling retraction entirely, etc.), but this still seems to happen.

I have reached out to Creality Support, but have not received any help from them yet. I’ve ordered a replacement cable since I’ve heard they can be super finicky, but since it always fails in the exact same place on a given model, I’d be surprised if that truly fixed it.

Anyone have any insights/things for me to try between now & the end of December (when the new cable is expected to arrive)?

2

You might look into the extrusion limit.

3

What do you mean by “extrusion limit”? Is this flow rate?

4

Nope.
I think it is in the slicer.
Extrusion limit

5

I’m using Cura Slicer, but don’t see an option for that. Which slicer has that option? And what does it affect?

6

I can’t find it; it may have been in an older version of Marlin or Klipper. I think it was a part of the safety feature.

I think it would work this way: a long run of extrusion would cause the hotend heater to be set at a high PWM to keep up, then stopping the extrusion would cause the heater to overshoot and possibly catch on fire.

7

I think I have solved this, for anyone who comes to this thread later. It appears to have been a firmware issue - I re-downloaded the latest Sovol SV01 Pro firmware and made changes only to the e-stops and the nozzle offsets. I forked that repo into my own with just my changes for anyone interested.

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