Very low acceleration during printing

[MihaiDesigns]

I'm running a speed test and trying 15K acceleration for infill print moves. X, Y, and E axes all have acceleration limit set to 15K, and print moves are set to 15K acceleration. The interface reports the correct settings. Printing speed is close to 300mm/s. It looks right in the slicer preview (PrusaSlicer). There's no minimum layer time set.

However, during printing it looks more like under 2000 acceleration. I can't figure out why.

[droftarts]

@MihaiDesigns check that acceleration is not limited by any M204 setting (slicers have a bad habit of putting these in, reducing all your accelerations) - send M204 to see how it is currently set.

Ian

[deckingman]

@MihaiDesigns It's likely as @droftarts has said but also check jerk - especially extruder jerk. You can set extruder jerk to silly high numbers and it won't have any adverse effect, but low extruder jerk will, especially if you use pressure advance.

[MihaiDesigns]

@droftarts yes, I did check M204 and the firmware reports it correctly. X, Y, and E are all set to 15K acceleration.

[MihaiDesigns]

@droftarts indeed it was the E jerk. I had it set to 4. I assumed a high E acceleration would take care of it, but it seems not.

Edit: For clarification, I meant 4mm/s, which is 240mm/min.

[Phaedrux]

E jerk can be set very high for most extruders. Try 3000 to 6000 mm/min.