Hi. I have a P1S with around 3800 Hrs on it. Over the last month I have noticed some under extrusion happening, mainly top surfaces and the odd spot on the walls of prints.
it has gotten to the point I can separate the layers and walls easily.
Print Settings are as follows on the part shown
Walls: 5
Infill 35%
No changes to other Settings.
Bambu labs stock settings for PLA Matte
since trying to fix this I have done the following maintenance.
Replaced Nozzle ( old one had 1000 plus hrs on it.)
Cleaned and Lubed the Z axis
Tensioned the Belts as per Bambu Labs Wiki.
Took the Extruder out and did a full tear down and clean.
Replaced the Thermistor and Heat probe as they were showing signs of wire breakdown.
None of the above has helped.
once done I tried to calibrate the filament I use again.
did the K Value flow test in Bambu studio entered the value that looked the best (0.015) and saved.
Then I did the Rough calibration of the 10 Swatches. Number 20 was still under extruded…
I then did the Fine calibration, 0 was the best but slightly under extruded Same as the 20 from before.
After all this I have a Extrude ratio of 1.176.
in the past It has always been 0.98 and I have had hundreds of amazing parts.
Looking for ideas at this point.
Bambu Labs Just says I have Extrusion issues… I have followed there calibration steps and have ended up here.
Perform the pressure advance calibration in Bambu Studio. I only use the first step which is the line method. I set it to print a range from 0.010 to 0.045 in 0.001 steps. Look at the lines with a magnifier glass to find the line that has the most consistent width all of the way across the line. That is you K-value.
I use this to fine tune the over/under extrusion. https://www.thingiverse.com/thing:1622868
Follow the directions carefully for slicing, etc. I recommend downloading his spreadsheet to do the calculations for you and to save for future reference. Use calipers to take measurements for the spreadsheet. I print four samples each time to get a decent statistical sample. It does not take long or much filament. If you print anything with close tolerances, they should fit nicely.
You clearly have issues but f the issues are the same with a new hotend it means they are upstairs.
Don’t mess with settings and such, rule out what you can first >
Try a new/different hotend - tick…
Take the extruder apart, clean and lube it - tick
Check or for the time being replace those teflon tubes - ?
If AMS is used, does the same happen the same with all four slots ?
If you ruled out hardware related issues like build up on the extruder wheels, dried out lube on those shafts and the filament moves freely and without too much restriction >
What about the print temp ?
Does the filament come out during a manual extrusion as it used to ?
A new hotend should rule out all problems with dried out thermal compound, contact issues and such.
But if you would, for example, see the outcoming filament is quite stiff rather than being more gooey/liquid at the default temp it could indicate a faulty board is to blame.
You said you replaced thermistor and heater, so I have to assume you did not replace the entire hotend?
You can’t leave old compound in the hole for the thermistor and you have to make sure not to use too much on the heater…
Try to find a thermometer or temperature probe you can get onto the hotend, preferably on the side opposite to the heater.
Set the temp to lets say 40ºC and check if you can read the same on your probe/thermometer.
Use increments of 10 to keep checking but do not go over what your thermometer can handle…
A difference of 3 to 5 degrees is within tolerances but if your hotend claims to be at 120º while your probe make clear it is barley 90º …
Did you end up completely replacing the gears or just cleaning them? I’m having similar problems (3000 hrs) and have done most of the following, but instead of replacing I have just cleaned. Thanks!
