RE: Underextrusion and transport problems of the filament
Yes, long time ago I opened the planetary gear because of a similar malfunction (underextrusion) of the extruder. But the reason for the previous malfunction was the blocking of the filament coil, which finally caused a stucking of the filament in the nozzle which couldn't be removed anymore.
The failure in the past occured during a 10 h print job. The printer completed the print job but appr. after 5 h the filament coil didn't rotate anymore and the stucking of the filament in the nozzle began. So I had to replace the nozzle. I don't know if this previous failure has any impact on the current malfunction. In the meantime I printed a lot of other parts successfully. I will check the gear and the presence of the washer. I think, afterwards I have to recalibrate the gear, isn't it?
Thank you for your advice!
RE: Underextrusion and transport problems of the filament
Be aware that when you open the planetary gearbox you should run the gearbox calibration after reassembling it.
RE: Underextrusion and transport problems of the filament
Yes, I launched the recalibration and after the recalibration I printed a lot of parts without any problems and in good quality.
Today the spare parts from PRUSA arrived. The sent me a new hotend replacement including the nozzle. Tomorrow, I'll install the new hotend and stepwise will introduce your proposed changes:
- check if washer is install correct
- set the print file to the old standard settings
In order to be able to find the real root cause, I'll introduce only on measure per step and will check the improvment of each measure if any.
Regards Bernd
RE: Underextrusion and transport problems of the filament
I missed to mention following changes:
- change supports to snug version
- raise nozzle temperature by 5 K
RE:
I missed to mention following changes:
- change supports to snug version
- raise nozzle temperature by 5 K
You raised the nozzle temperature by 5° Kelvin? That's the same as 5C anyway so I guess it's a typo. Would have been an awesome sight if you raised it by 5000 degrees.
RE: Underextrusion and transport problems of the filament
I shall be precise as an old engineer. The absolut temperature scale in Europe and a lot of other countries is °C. Relative temperatures are defined by the unit K - Kelvin. Don't mix it up with the absolute temperature scale K, which starts at a value of -273,15 °C. So the right rate of temperature rise proposed her is 5 K - a relative value e.g. starting at 220 °C --> 225 °C.
RE: Underextrusion and transport problems of the filament
First of all - the problem is solved
Root cause: Finally there were two root causes indentified and it isn't possible to conclude, which was the decisive one:
1. There was a 3 mm piece of filament in the area of the traction wheel in the extruder which could cause significant friction
2. The washer between the motor shaft and the planetary gear wasn't at it's right position. It is not possible to identify when this displacement of the washer happened. Nevertheless after opening of the gearbox, the washer wasn't on the motor shaft.
Cleaning of the traction wheel of the extruder and its surrounding and the right placement of the washer solved the issue. I was able to print the big frame 190 x 190 mm without any failure.
May I say Thank You to the 24/ 7 Prusa hotline. Colleagues of the hotline guided me systematic through the failure analysis especially many thanks to Victor who spent a night session to solve this issue stepwise. We exchanged a bundle of pictures, videos explanations and items for discussion. It was a perfect and systematic coopereation. And as an old engineer (age close to 70) I like this quiet, stepwise approach very much even if there a tests made which seems to be from the "stomach feeling" not the root cause.
As well Thank You to all of you here in the Forum who assisted the analysis with their experience and helpful advices.