Filament Breaking Issues - Bambu P1S

[Kainz]

Ok long story time.

I left my old workplace a while back, and passed some of my job to a young lad who was new to all this. One of the aspects of my work was 3D Printing on a Flashforge Guider 2 that I looked after very well. Our company prints very basic small parts, that are part of our main product lines. So I used to buy just one type of 1.75mm PLA from Verbatim.

Fast forward to 2025 and I return to company after a years haitus. Place is an utter train wreck, there is now a P1S and an AMS system for no apparent reason and a new Guider 2 because the old one 'broke'. Both of these printers and my old one seem to have broken filaments in the hot end, which he couldn't resolve so he just bought new machines leaving the old ones sitting there. The P1S is unused and the company has been using up the pre-printed parts that I made when I left.

I have inherited these two machines and an absolute ton of Bambu PLA reels that hasn't been well looked after - they're all opened and just sitting on the manufacturing floor. He has also bought a Creality drying box thing for the reels but it is unused.

On Friday I decided to acquaint myself with the P1S and took the extruder apart. Luckily there was a broken filament but in the hot end. I put it all back together and heated the hot end to 240c whilst feeding new filament in and reducing the temp to 220c once extrusion had begun. Sorted.

I printed out a lightweight plane model as a test (so I could throw it at him) and all was well. I then tried to print out a Grumpy Cat model as a second test as I wanted print consistency. Bambu Studio then flashed up a broken filament error again. So I reheated the hot end as per above, and fed some filament through and tried again and all was well.

I am out of the loop with these new machines as I am used to the Guider2 but why am I getting breakages after a single print session? I'll do some more testing tomorrow when I'm back at work but could it just be that the PLA reel is brittle?

 

[Bluecube]

Looking at the PLA reels would certainly be my first port of call especially as the opened reels have been sitting about for goodness knows how long. If you can easily snap the PLA on the reel just be bending it then you’ll know what the problem is.

 

[Kainz]

Looking at the PLA reels would certainly be my first port of call especially as the opened reels have been sitting about for goodness knows how long. If you can easily snap the PLA on the reel just be bending it then you’ll know what the problem is.

I haven't touched them yet, thank you I'll do that first thing in the morning. When I used to use the Guider 2, I always kept spare reels boxed up with desiccant within.

 

[b0rn2sk8]

Wet PLA is very brittle and breaks very easily.

Also check for wear on the extruder gear, if they have been using filament with carbon fibre or glass fibre, it will wear the stock extruder gear and nozzle pretty quickly.

If you can resolve the issue, the P1S is a very capable printer and usually very reliable.

 

[Kainz]

So an update - Yes 3 out of the 4 reels in the AMS were brittle. I just worked my way through each reel snapping segments off until it wouldn't snap. I figured the inner spool would mostly be fine and it was. I fed all 3 into the AMS once I was happy with them and all has been well since then with regards to printing jobs one after another.

Still got another 9 reels sitting up high on a rack to look at though :/

I am very impressed with the machine (apart from the awful screen and UI) and the Bambu studio program really. So much so that I've been thinking about an A1 for myself. So far at work I've been working on a gridfinity setup for our tool chests which have been a mess since I got back.

 

[Tackle_Berry]

I have noticed that I end up with 20-30cm of brittle filament, on rolls that have come out of the AMS and sat for a week or so (even rolls stored at 20% humidity). I believe it’s from the AMS where it feeds the filament, the gears leave little teeth marks / indentations. I typically just snip 20-30cm off any rolls that have been sat for a while before re-entering them in to the AMS.

 

[IanAG]

The P1S itself isn’t so bad, but broken filament in the AMS is a pain to take care of! I haven’t been taking chances since the 2nd time and actively dry more often than not if I come back to old filament. Desiccant alone isn’t always enough.