I think carbon filament can damage the idler pully bearing in the extruder. I noticed this during de-assembling the extruder. The idler pully was pretty hard to turn. After removing pressing out the shaft of the idler pully, there where some filament which blocks the pully from turning properly.
After cleaning everything, i saw that the carbon fibers literally sanded away some of the shaft’s diameter (about 0.1mm). On the photo you see the gap on the shaft.
I’ve just cleaned out my extruder as part of regular maintenance and the idler was pretty gunked up. That wear is from the bearing and constant pressure on that contact point and to be expected. CF is a coarse filament but it’s not the issue here in my opinion.
Sure it is from the filament ?
I have not taken the P1 extruder apart yet but ALL my other extruders have a grove on the idler - it helps to grab the filament…
Not that your grove is meant to be there and you are chasing the wrong fox…
Yeah the last time I stripped it down I assembled it with a smear of superlube grease. It really didn’t like that, it’s been around 500hrs, the shaft has a fair wear spot on that side which I’m not really worried about but it will get replaced next time round. I gave it a little oil this time round. I’ve also been doing a lot more ABS etc lately which would also gum up the works, heat in that area would also be a big factor.
The wear accelerated when the grease went south, the shaft and bearing are a consumable and lifetime would vary with heat and mileage. There is a lot of pressure on that one spot and it’s performing ok imho. I did rotate the spot to the backside so it would last ok.
Agree to @Nebur: May it’s not even caused by the filament dust… It seems, the shaft is not hard enough. The bearing needles and the inside of the pully still looks ok. All parts of a bearing should be hardened!
They could use an old rusty wire for all it matters, the key factor is this part is a consumable and it WILL wear, it was designed to perform a function and it does it reliably. There is no advantage in over-engineering parts when they were going to wear out anyway, even your most exotic machinery has consumable parts.
This idler gear and bearing set performs in a high heat environment, and under a one sided pressure from a heavy set spring. The needle race is working with minimal lubrication and in majority of cases it is ignored in the maintenance routine, yet look around here and there are next to no mentions of it being an issue in service
This and the other parts which make up this printer were designed to a price point and reliability standard, I think they read the assignment.
Could you tell me the advantage in over-engineering this part? I think it works perfectly fine, the pressure on that side is naturally going to wear and yet it can still perform its function in providing tension to the filament in that pulley. I have reasonable experience and a long history (in another industry) with parts like this that work similarly and feel confident that there is no need to panic about the wear.
As for the dragons, that was a subtle dig at that particular topic. I feel this post is eerily similar in the direction its heading. BTW, I’ve rarely printed a dragon and yet can see the attraction for some.
I have raised a ticket, let’s wait on the response. I also asked for the possiblity to order the bearing and the shaft separately as this seems to be a consumable part…
I agree that these are consumables; thus, wear and replacement is not a problem but a feature.
Nevertheless, I would not expect so much. In the last months, I did a lot of prints using PETG-CF, and neither noticed a problem nor felt that it was strongly abrasive, such as PET-CF.
I am likely wrong and need to check up on the extruder.
In any case, it seems easily solved.
Just FYI: I received an response from the Bambulab Support, see below. I have ordered the replacement part which is actually not too expensive. The new one looks a bit different an has helical gearing.
Hello, thank you for contacting Bambu Lab Support.
We are sorry to hear that you are experiencing problems with your extruder.
Rest assured we will work to resolve the issue as fast as possible.
The shaft and bearing are not hardened. We do not sell them individually, but you can buy the gear set, which I recommend based on the wear here
