PETG Why have you forsaken me?

After my initial try with it clogged and broke my TAZ 5’s nozzle, I replaced the nozzle (with a .4mm E3d style) and went on to print many wondrous and somewhat large and complex parts with PETG (as well as ABS and PLA). I love it’s strength and lack of warpage.

Using the same profile I printed several parts in previously, all of a sudden I now cannot complete any part I try to print in PETG. Don’t seem to have any problems with ABS.

The print will start beautifully, but after several minutes of printing will stop and I end up with the half-moon cutout in my filament. It doesn’t appear to be a jam as loading the filament back in immediately extrudes easily with just light hand pressure. Reloading it will result in another few minutes of printing, but will end up the same way. This did this on the first print on a new nozzle as well.

So far I have tried:

calibrating e-steps (these were off by 5mm, but ABS and PLA were still printing with excellent quality - now even better)
clearing and reloading PETG profile (obtained in these forums)
reducing tension to min on the filament (as described in these forums)
replacing 1st new nozzle with another new .4mm nozzle (worked exactly the same)
measuring over 30 meters of filament for diameter and averaging over 30 points

It’s still the same every time. This is very frustrating as it was working so well before.

Any insights?

Crank the idler pensioner bolts down so there is 8mm between the washers, start the print slightly further from the bed, check the filliment diameter and adjust if it is off in your printer interface, and try running around your house 3 times backward to appease the petg gods?

I have already tried the loose screws and super anality about the diameter, but not raising my Z. I’ll try it. Thanks.

I think it would be more likely I’d offend the gods if I tried a run, but at this point…

What brand of filament? The way I use to check filament drive tension is set where it should be, extrude a inch or two and then retract and look at the teeth marks on the filament. Are they to deep, distorting and causing a jam or too shallow as to not drive the filament reliably? You could have a section or roll of bad filament also causing problems.

Well, apparently raising the Z has accomplished something. Just had a 14hr. print finish, and it looks great. Thanks for the advice!

Now to try to print the thing that started all this.

George, it’s Esun PETG in Black. I haven’t had issues with any of their other plastics. Hopefully the thing was just printing a little too low.

the backwards running trick works every time!

Hmm, maybe I should have ran.

Went to print the object again ( a ukulele body) and it failed within the first few minutes, as before.

The first time I printed it was in ABS and looked like a modern art body. Next was in PLA but it had poor layer bonding and was fragile though complete. Tried it in PETG and got 60% before failure. Now it fails in a few layers. It is a rather thin part (maybe.8 thick walls) could that cause extrusion problems?

FYI from my experience a lot of things on ThingVerse do not print right. The one you are trying is to thin. The sad thing is you can not edit a STL file, you might be able to scale it in such a way that it would work. But I think you need to just move on to another project.

I don’t know if you do CAD or not, but TinkerCAD from Autodesk is a good place to start building your own projects. I tried it and 123D Design but found both programs were too limiting. Since I have used CAD in the past, like 20 years or so Sketchup was not for me, but I found Fusion 360 a better choice for me. Its free for hobbyists and startups.

I use the Autodesk Inventor STL importer. Clean the file up in Netfabb first, hit import, then convert it to an editable solid, change whatever needs changing, then re export as a new STL. Works about 90% of the time, depending on how thrashed the internals of the design are to begin with. Usually I can at very least get surface geometry sufficient to quickly rebuild the object.

I don’t know if the OP can even use a CAD program and I don’t have time to learn yet another program. Nice to know.

I experienced something similar right after I built a Mangrove extruder mount with the dual print cooling fans.

Is your print cooling fan over cooling the hot end? Most people slice an STL so that the fan is off for the first few layers and then come on at a low speed and works its way up. If the fan is blowing too directly on the hotend, it can cool the hotend enough to cause jams.

I’m pretty familiar with modeling in general. Did it for video game mods for years. I use a variety of products for it, but right now it’s mostly FreeCAD for mechanical things. Meshmixer has a few neat features as well for printable models. I have tried to thicken the walls of the model but there really isn’t a simple way to do it evenly. You can edit it though in FreeCAD by converting it to a solid and tweaking it. The body has a LOT of geometry after solidification though, and there isn’t a non manual way to do it. Would take forever.

It will fully print in PLA and is so close to being strong enough. There are a few working examples of it in PLA. It would actually print in ABS but it warped so much I stopped it before it finished. The 50% body I got in PETG is quite strong despite only being 1mm thick and would work beautifully if it had completed. I don’t think I’m gonna give up on it just yet.

I’m not running the cooling fan for PETG. I did notice that the mini fan for the hotend vanes was full of dust though. I’m wondering if it could’ve been a heat creep issue. I was able to get successful test prints of other objects since lowering the temp slightly and cleaning out the fan. I’m right at the margin of having enough on the roll to restart it…I’ll likely just wait till the new rolls come in. I think I’ll test it on some legos. :smiley:

Thanks for the replies, all.

Well, after printing out a half dozen or so nearly perfect Lego bricks, I decided to check my filament supply again and realized I had enough for the print after all. And…Success!!

The PETG is much stronger than the PLA and should work just dandy.

Just to close out the thread for those that come later, the problem was likely a combination of several things. Too low Z, too tight extruder clamp, and a bit of heat creep caused by a clogging hotend fan. Calibrating the e-steps probably helped too. I’m overextruding just a tad less now.

Thanks again for all the replies.