Hi there,
I’m having trouble with my P1S with 2 AMS systems.
My prints are fine when only 1 filament is used, but as soon as filament swaps are required my prints display under extrusion.
I’m under the impression nozzle is taking too long to prime and build up pressure.
This happens over multiple diameter nozzles and even brand new nozzles.
Here I’ve used 0,4 and 0,6 brand new nozzles and it’s clear as soon as filament swaps are involved the prime tower is brittle and can be snapped in half with little force.
The only modification I currently have installed is a revo panda hotend, the error is present in stock bambulab hotends, even brand new in multiple diameters.
Any ideas of what’s going on?
I’ve changed all PTFE tubing and extrusion gears to no avail.
I don’t think this is a calibration issue since it appears to be isolated to when there are filament swaps from the AMS. I don’t own and AMS so I would be of no help here.
However, I can guess and wildly speculate along with the best of them.
We know that under extrusion occurs when not enough filament flows into the hot end. In this case we are told that the under extrusion occurs after a filament sway. So ergo, something during filament swaps is binding or impeding the flow of filament. My first point of investigation would be the spool rollers first to make sure they are clean and the PTFE tubes next.
What was not stated was if this happens with all spools, what kind of spools, if it happens in each spool cavity… details matter…
Also, troubleshooting 101 before one does anything. If there are any modifications to any complex system. Return the system back to it’s original state and then diagnose from here. The fact that this has a non-factory nozzle is one place that should have been stop #1 on the troubleshooting tour. Otherwise we are violating rule #1: Change only one variable at a time.
Hey Olias, thanks for chiping in here, I appreciate it.
You’re right, details matter.
-This happens with all spools, all AMS slots, both AMS units, they weren’t purchased at the same time so they have different wear.
My first point of investigation would be the spool rollers first to make sure they are clean and the PTFE tubes next.
Spool rollers have been removed,cleaned and swapped.
PTFE tubes have all been replaced for new ones.
Return the system back to it’s original state and then diagnose
I have returned the system back to it’s stock nozzles and back to revo again to troubleshoot. Issue persists.
Maybe I should’ve stated this information more clearly in my original post.
ince I’m not familiar with the AMS mechanics, I can only suggest a few key areas to focus on. Have you inspected the extruder nozzle for wear? When was the last time you replaced it? A good first step might be to disassemble it and clean the area with an air duster.
As a diagnostic measure, you could create a cube primitive and vary the color at specific heights to see if the under-extrusion can be reproduced in a controlled setting. For example, a 25x25x100mm cube could serve as a test model. You can also try this with a cylinder or a cone, but a cube is a good starting point. A cone primitive test subject would be equally revealing as the speed would taper as the height changed. Try cube first though as it is the simplest test scenario.
Example model heights these are just suggestions and of course you can vary these(all numbers are mm):
First test set:
Layer at first color change
Height of First Color change
Height of Second Color Change
model_1
10
20
50
model_2
20
20
50
model_3
40
20
50
model_4
60
20
50
model-5
80
20
50
Second test set:
Layer at first color change
Height of First Color change
Height of Second Color Change
model_1
10
20
50
model_2
20
30
50
model_3
40
40
50
model_4
60
50
50
model_5
80
60
50
Third test set:
Layer at first color change
Height of First Color change
Height of Second Color Change
model_1
10
20
20
model_2
20
20
30
model_3
40
20
40
model_4
60
20
50
model_5
80
20
60
These hypothetical test scenarios aim to isolate the behavior and determine whether it is confined to a specific model span. For example, observe whether changes occur at 20mm of filament or vary at 30mm. Consider whether height influences the behavior. If all models remain unaffected below 30mm, this may indicate a mechanical issue with the Z-axis lead screws rather than an extruder problem. Conversely, if a 30mm span of color change eventually stabilizes at, say, 50mm, it could suggest “stiction,” where initial resistance due to filament inertia levels off as the filament moves. This would indicate extruder wear, grip issues, or possibly an extruder motor problem.
Thanks for your insight.
I printed the tests as suggested and they have me perspective.
All prints looked the same so the error had to be from some action taken during filament change.
Turns out the cutter arm wasn’t as smooth as should.
Re-seating the cutter arm and lubricating the pivot point resulted in a much better multi colour experience.
Thanks for following up with your solution and sharing it with the community. This truly adds to the body of knowledge and helps everyone. I learned something new. It would never had occurred to me to troubleshoot the cutter.
