The printer is new, I just received it late last week. I’ve used an X1C a considerable amount, so I’m not new to the Bambu ecosystem, though historically I’ve owned Prusa printers.
This failure looks like a low temperature issue to me, almost like it is printing PETG with PLA settings. You can’t make it out in this photo, but the bottom 2 to 3 layers were glossy, then the finish changes to matte and the print is crumbly. While printing in this poor state, I’ve confirmed that the bed is reporting 70°C and the nozzle is reporting 250°C.
The setup in this state is the PETG is loaded in AMS slot 3, right nozzle. The AI assistant is reporting that the feed path for spool 3 has a high resistance.
I moved the spool to slot 4, received the same warning, and had the same failure. I am using the PTFE tube that came with the AMS, I haven’t trimmed it. But I’ve read that the max PTFE length is something like 8.5 meters, so it is certainly not too long. It has a couple loops in it, but the loops are wide and natural, not forced. I haven’t finalized the position of the AMS, and I’m waiting for a second one to arrive, so I haven’t trimmed the tube on this one yet.
I’ve moved the spool to the left nozzle (no AMS) and it seems to be printing as expected. This suggests, but doesn’t guarantee, that this is a nozzle or an AMS issue. Could either of these two things be an issue?
The first time I loaded this spool into the nozzle, it broke on retraction. I spent a couple of hours trying to clear the blockage and finally cleared it by removing the nozzle and then everything in the extruder and path basically fell out. I reinstalled the nozzle and the sock.
I printed TPU from the right nozzle. Surely the nozzle would be purged multiple times over after getting as far into the print as shown in the image below, right? And if not, why are the first few layers look perfect and glossy?
I think my next steps are to print the filament in the right nozzle without the AMU in the path. What else might this be? Can an improperly installed nozzle result in the temperature reading higher than it really is (meaning the nozzle is cooler than reported)? Would that only happen on the first few layers?
I am not certain that it is properly seated, but I think it is. The clamps that hold it in place felt like they clipped properly, and it is at the right height as the drip-blocker moved back and forth properly.
At this point, the left nozzle (no AMS) printed successfully. However, the matte finish did show up on the surface after a few layers. The matte finish is likely a red herring, or it may be indicative of a bad spool of plastic?
I’m now printing on the right nozzle, AMS bypassed. The first few layers are going down well and I see that the temperature setting is at 255°C instead of 250. It is also showing a matte finish after the first few layers. I’m getting some stringing around concave curves, like poor layer adhesion? This may be a case where I just need to increase the temperature for this spool… but it is also printing much better than it was from the AMS.
I think this is just going to take some trial and error. I need to figure out the AMS high resistance issue (saw some problems with buffers on new printers a few years ago) and just do some testing with this particular spool.
I bumped the temperature up to 260, it’s glossy again, but the print quality dropped immediately and I’m getting all sorts of layer adhesion issues with stray lines goin everywhere.
Edit:I take it back, this print is also awful, and it was awful before I bumped it up to 260. Terrible layer adhesion. I’ll try a different PETG filament and see how it does.
The X1C is an office printer, and I’m “working” from home today, but I have my Prusa spitting out a PETG Benchy. That’ll be done in about an hour. In the mean time, I printed these tools in another spool of PETG. They turned out OK, but there’s still some issues. Definitely not the quality I’d expect from this printer.
There are obvious layer adhesion issues in the tool’s handle. The hexagon is something I printed the day the printer arrived and it looks wonderful, fuzzy skin outside and the inside. It’s the same spool of blue. I’ll pull the nozzle, clean it the surfaces with alcohol, and put it back in place.
When watching the previous print, I noticed the nozzle temperature swinging +/- 10 degrees. The first few layers are glossy, but I only see the outer perimeter. I have no idea what the inner perimeter on the second and third layer look like. But since the bottom of this handle is rounded, not just chamfered, it prints VERY slowly, giving the nozzle plenty of time to heat the plastic. The swingy temperatures and poor layer adhesion kinda suggest this is a temperature/nozzle issue at this point.
Benchy on the Prusa has 40 minutes remaining, but it is looking nice so far.
That is really a lot. You might want to have a look at the initial layer temperature. It might be that this is explaining the large temperature differences.
The H2 series is known for it’s strong cooling, also by the auxiliary fan on the left.
You might have a look at a deflector for that fan.
When layer times differ a lot, those lines are quite common with PETG.
I pulled the nozzle off the Bambu, cleaned it with alcohol, and put it back in. However, despite being latched in place, I found that I could wiggle the nozzle just a bit. I reseated the nozzle two or three time before it finally seated properly and was completely immobile. I took photos before I removed it and after I seated it properly, and I can’t tell a difference from looking at it. But I know now how to verify that the nozzle is installed properly.
I am 99% certain that the problem is that the nozzle wasn’t making great contact with the heater, so the nozzle was much cooler than the heater. This also explains why I’d see the temperature swing so much when the prints were running poorly, the thermal mass of the nozzle wasn’t helping the heater regulate temperature.
The tools also printed wonderfully this time! Chalk this one up to a learning experience, and hopefully my failure and troubleshooting helps someone else in the future.
Nozzle before I removed it
Note that you can see three “ribs” of the heat sink, and I THINK this is improperly installed.
I think for my next print, I need to start working on a filament respooler. I have about 20 spools of Atomic Filament that aren’t compatible with the AMS.
When watching the previous print, I noticed the nozzle temperature swinging +/- 10 degrees. The first few layers are glossy, but I only see the outer perimeter. I have no idea what the inner perimeter on the second and third layer look like. But since the bottom of this handle is rounded, not just chamfered, it prints VERY slowly, giving the nozzle plenty of time to heat the plastic. The swingy temperatures and poor layer adhesion kinda suggest this is a temperature/nozzle issue at this point.
