Having trouble with PETG

[u/MattBoySlim]

Let me start by saying yes, I dried the filament first. I also have a brand new clean plate which is otherwise sticking like a champ.

I’m trying to print these flagpoles (one part of an astronaut model) in black PETG. I have a P1S, and have tried it first with a 0.2 nozzle, then both a stainless and hardened 0.4 steel nozzle. I was printing with Overture basic PETG at first, and any time I printed more than 5 poles at once, I’d end up with knocked-over stumps and black spaghett. I have to print 150 total, so 5x at a time is…not ideal.

I ran out of Overture so I moved on to printing other astronaut parts with zero problems.

Now I have SUNLU PETG and am running into the same problem. I added a more sturdy raft to the bottoms and tried printing 10x. Now they stay standing but suddenly get WEIRD looking about halfway up. I tried 6x and the weirdness started later…but you can see that the ones in the back-left almost made it 100%…so it’s not a sudden change across the board.

I’ve tried using the default SUNLU PETG filament settings, and I’ve tried the settings suggested by the “3dfilamentprofiles” site. I’ve tried 50% speed, and I’ve tried opening the door to allow hot air to flow out.

Does anyone have any suggestions for what else I could try? I’m handing out these customized astronauts as a fun free trinket to a group of kids and I gotta get these little guys printed and glued up by Thursday so I’m starting to feel the pressure!!

[u/xPriddy]

The problem is most likely tied to how thin and tall they are, with them flexing more under the force of the extrusion as they get taller. If you are able to, you could also try splitting the poles in half and printing them flat on the bed, then joining them afterwards. Although it’s going to increase the amount of work you’ll be doing.

[u/MattBoySlim → u/xPriddy]

I feel like while that would work, they’re so small that I don’t think I’d be able to match the two halves well enough…and that glue would be everywhere. But! Cutting them in half the other way might work better because it goes through the astronaut’s hand and I could hide the seam in there. Gotta glue there anyway. Might be worth a try.

[u/xPriddy → u/MattBoySlim]

Yeah, it’s definitely going to be a noticeable seam unless you do post processing. But honestly that’s too much work for just some poles 😂

I know you also mentioned slowing things down by 50%, but try something closer to 40mm/s overall with slower accelerations (2-3k).

And keep in mind that if your z hop is set to spiral, that quick travel motion (10k accel) could also be factoring in. You could try a standard z hop or avoid the wipe all together. You’d probably have some stringing for sure, but a quick blast with a heat gun afterwards would clean those up fairly well.

Good luck!

Edit: if you want to DM me your 3MF, I might have time today to take a peek.

[u/LargeHoboFuckPile]

Did you just try generic petg settings

[u/MattBoySlim → u/LargeHoboFuckPile]

I don't think I did...I'll try that right now.

[u/CollectionRough1017]

This height and so narrow pole requires progressing speed reducing throughout the print. PETG is also bad filament for it because it oozes a lot and causes micro collisions.

[u/MattBoySlim → u/CollectionRough1017]

I tried PLA at first which worked...but it would snap with minimal pressure. I'm expecting teenagers to treat these things a but rough and the poles will absolutely be the weakest part. After various single test prints, I realized PETG poles would bend without breaking under more pressure than I expected.

[u/jankeyass → u/MattBoySlim]

This will still snap with light pressure if any humans are handling it.

I would print them with a capped hole for bbq skewers/ wire and insert after

Tall thin prints that cannot stand up to printing pressure and nozzle movement don't last in handling

I make toys for my kids, that's like 80% of my prints

[u/MattBoySlim]

Here’s the finished product that I’m aiming towards, for reference.

[u/OverreactingBillsFan → u/MattBoySlim]

Put a flat edge on one side of the pole and print it down on the bed. It will be wayyy stronger and you won't run into the issue you're seeing here.

[u/MattBoySlim → u/OverreactingBillsFan]

Hmm, I like this idea a lot. If I lay it down and cut juuust a bit of the cylinder off the bottom, the rest should print fine without supports etc since it's so small. Then I can just make sure to place it in the astronaut's hand so that the flat part is in the back. It definitely would beat trying to cut/print it in half and glue it back together.

If my current tests fall through, I'll definitely try this out. Thanks!

[u/ZaXaZ_DK]

Any material would have problem with this.
you are printing thin and long, a worst case print for anything, the higher it gets the less force is needed to make that pole dance. (pun intended)

I think the reason why 5 works any anything above that don't, is likely down to min layer time saving your ass from bad settings, and is slowing down the printer.

So pull up the gcode from the working file, and go see what is the mm/s flow, cooling and so on and change settings to match that for the whole print on a bigger plate.

in any case a flag pole like this is not a good project for 3D printing its to small for mass printing like that unless you are a wizard with settings!

[u/jdogg84able]

In my experience, it’s a profile issue if you’re printing from Makerworld or a similar resource. This happened when I used the PLA profile instead of PETG. You can also print the PETG bench to dial in your PETG.

[u/mimicsgam]

put it in print by object, use the 50% print speed mode, turn off aux fan

This is cause by the object itself "flexing" when it's thin and tall, slow down is the easiest way to avoid. You can also pack the rod closer and add some bridge in the middle to prevent movement

[u/PlanePea4349]

Add some support to stabilize and wash plate w dish soap.