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I'm new in the 3D priting and I bought a BIQU B1 printer :-)

I printed the Pokemon with the white filament that come as a sample with the printer (PLA) and after that I bought the Inland PLA+ and PETG+ from Microcenter. The first thing that my son asked me to print is the toaster. Well, I tried to print three times with the PETG+ filament and always I end up after one or two layers with oozie everywhere and I had to stop printing. I replaced the filament with the PLA+ and now it's printing correctly (It's 91% complete right now :-) )

So, I set the correct temperator for both filaments:

  • PLA+ 205/60
  • PETG+ 230/70

I'm thinking that for this type of object (torture toaster) it doesn't work with PETG because of the complexity.

Is that correct? If not, what I could be doing wrong with PETG+ filament?

Trish
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Rafael Koike
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2 Answers2

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From what I can tell, the BIQU B1 is an Ender 3 clone with a similar extruder, which probably has really poor grip on the filament. This is bad with PETG, which tends to slip, and once it starts slipping, it will grind and make the problem worse. On top of this, it probably has a PTFE-lined hotend precluding printing PETG at the higher temperatures it would do better at, so the extruder is probably fighting excess resistance to pushing filament through the hotend. In short, I never had good experiences trying to print PETG on my Ender 3 when it was stock, and I'm not surprised if you have similar problems on a similar printer.

With that said, there are some things you can do to improve the problem.

  1. Dry the filament. Unless it's been actively dried in the past 24 hours and kept away from humid air afterwards, or stored in a serious drybox, PETG is always wet. PETG is very bad about not resuming well after retraction when it's wet (my theory: the water absorbs all the heat in its phase transition to vapor before the heat can properly melt the filament) and this will tend to produce the condition where the extruder starts slipping, leading to game-over.

  2. Go slower. 30-40 mm/s at 0.2 mm layer height and 0.4 mm line width is about the highest you can expect PETG to do well at on this kind of extrusion setup.

  3. Tune your retraction length down as low as you can take it without oozing/stringing, and your travel speed up. Travel speed (and acceleration) should be set as high as your printer can handle. This is a win-win situation: your prints finish a lot faster and there's less time for the retracted material to cool down while traveling, which would make it harder to restart extrusion after travel. It also reduces the risk of oozing/stringing.

However you might just find that printing with PETG is too much of a pain without an upgraded extrusion system. For prints where PLA is an appropriate material, consider just using PLA.

R.. GitHub STOP HELPING ICE
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Like mentioned, one of the most important things with PETG and other materials such as PLA with woodfill, Nylons, some other materials usually with similar properties to PETG, drying is your friend. The main reason being is that the materials listed above are all hygroscopic. They have a tendency to absorb moisture in the air very well and it should almost be a regular thing to dry it for some ours before printing it. Some materials like Nylon cant be used even after just three days of sitting in open air.

The issue arises when you are printing and the moisture trapped in the filament is super-heated. If you print some and its been out you will get those pops and cracks while its printing, that's the result of the moisture heating and the water bubble exploding making cracks, leaving inconsistent layers and sometimes small craters.

I wouldn't say that the toaster is impossible but its a challenge, as it should be. The premise of the toaster is to challenge your printer and give you and insight into how your printer is working, in terms of your settings. Printing this model will be great to see how well your retraction, bridging, tolerance, and temps are. While I would generally say try it out, it does take some time so going with some easier prints like retraction cubes, temp towers, and simple bridges may be better and easier on filament use when starting off.

If the extruder is slipping, attempt to add a slight more tension but not too much. As mentioned before, it really is a better thing to grab a cheap aluminum kit from Amazon or a hobby store online. The reason being is that the idler will no longer be a smooth roller bearing but instead have teeth as well to help hold on, the aluminum is also much stronger and can hold up in the case you get a jam for any reason.

Justin s
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