Problems Printing Colored PET+

[Dave K]

I'm having extrusion and/or adhesion problems when printing PET+ but only the colored filaments. I have the problem with black and with white filament. The clear filament prints beautifully. Nylon (Taulman 618) is fine, and PLA is fine. My gut tells me this is a temperature related thing, but I'm not that good yet at diagnosing print problems so I'm throwing this one out for comments.

In the photo, area #1 looks OK. If anything, it might be a little over-extruded, but in any case it was printing well. Problems start at area #2 (same layer as #1), when printing over support. On the next layer up, it looks like underextrusion at area #4. It got a little better at area #3.

When the filament lays down the way it does in area #4, it doesn't adhere well (or at all) to the layer below it, so when the hot end passes over it on the next layer, it will drag through the loose filament, breaking some of it and really messing things up. That's why some of the filament looks dirty, because the nozzle got globs of filament on it that picked up bits of dark filament that were left on the sides of the nozzle, I think.

The prints start out consistently good for the first 10-20 layers, then for no obvious reason, I get those thin extrusions that don't stick down well, and it turns in to a mess. It will start laying down good lines again, but at that point the print is often messed up beyond "self-repair". And the problem typically recurs during the print even if it clears up on its own.

I can't upload the FFF file here, but if you're curious, it's in my dropbox here: https://www.dropbox.com/s/axn34ii7ipf96 ... micron.fff

The print in the picture was at 245C. I've also tried 250C, but I didn't want to go any higher. My clear PET+ prints the same STL great at 245C with almost identical settings. The extrusion multiplier is slightly above 1 in this FFF, but I've also had it down around 0.95 with no noticeable change in the problem.

Any suggestions appreciated!

[Dale Reed]

Dave,

How's the layer-to-layer bonding between parts 1 and 3, and between layer 4 and the layer under it?

It's rather bizarre in area 4, actually. Looking at the ends of the extruded lines, it looks like you are over-extruding -- see how there's a bulge at the end that sticks up? Likely that rapids or moves on the layer above this one would catch on these. Yet look at the parallel extrusions in the middle of area 4. Is that infill or is that supposed to be a solid layer? It seems pretty dense for infill (over-extruding?), but the lines are not touching edge to edge, so if that's supposed to be a solid layer (like area 1), it's either under-extruding or ????????.

I'd try bumping the temperature up another 5 degrees if the layer-to-layer bonding is weak --- that might flatten out some of the "roundness" of the extrusions if they are supposed to touch side-to-side, essentially making them more "square". But absolutely dial the extrusion multiplier down a bit. Probably want to run a calibration object with this new filament and see if the dimensions are 'on' or not before continuing with this complex object.

One more note. In area 2, see how the lines are not straight and parallel? That tells me they're not sticking to the layer under them as they are being put down, and just kind of laying on top and going where they want. So, yes, dial up the heat a bit -- bed and extruder.

jimc has way more experience with pigmented PET+ than anyone I know --- I've had some good results with the clear, but it takes some powerful anti-ooze settings to make it work. Sounds like you've got that figured out... but I'm anxious to see what jim has to say on this one!

Dale

[Dave K]

Dale - Layer to layer bonding is maybe a little weak between areas 3 and 1, but really not that bad. The filament at area 4 can be moved easily with the tip of something small (I'm using an x-acto knife). Odd thing is, areas 3 and 4 are the same layer, but I don't remember if 3 and 4 were laid down consecutively, or if it put one area down and then went off to other areas before coming back.

All of the layers are at 100% infill. It's the extruder filament guide and bearing mount part so I wanted it solid. I did have it at something like 0.96 extrusion, but I didn't take any photos of it. That might be a good idea, just to see what it looks like up close.

The attached photo is a part I'm printing now (the extruder motor mount) in clear PET+, which shows no signs of the same problem. It prints at 245C and is almost identical to the FFF I used for the white PET+. But, just to be sure, I think I'll try printing the white PET+ using the exact same FFF file just to get a baseline difference between the two. I'm pretty sure I did that already, but this is so odd I'm going to do it again just to make certain. Although, I may bump the temp up to 250C for grins.

Man, I can't believe how fugly my nozzle is. Maybe I'm used to seeing it like that, but it needs a good cleaning, bigtime!

[jsc]

One comment I can make, on that particular part, is that the print over infill section is supposed to do the inner ring perimeter, and then effectively bridge from the outside to the inside over that support. If the inner ring perimeter doesn't go down clean, then the bridging doesn't happen and you're effectively laying down loops of filament over the support.

My suggestion is to make sure the overhanging inner hole edge has liberal, maybe even complete, support, so that the perimeter loop goes down as a neat circle. You can do this manually, or use the new "extend support" feature.

[Dave K]

One comment I can make, on that particular part, is that the print over infill section is supposed to do the inner ring perimeter, and then effectively bridge from the outside to the inside over that support. If the inner ring perimeter doesn't go down clean, then the bridging doesn't happen and you're effectively laying down loops of filament over the support.

My suggestion is to make sure the overhanging inner hole edge has liberal, maybe even complete, support, so that the perimeter loop goes down as a neat circle. You can do this manually, or use the new "extend support" feature.

Thanks, I didn't even notice that feature. The clear PET print laid the loop down nicely, but the white PET didn't even stick, it just dragged the filament around while it was trying to print the perimeter loop. Next time I'll put a non-zero distance in that setting, just on general principles.

[jimc]

dave, the setting for the colored pet+ are different from the clear. it does need to run hotter. here is my fff for the black. it runs at 255. you wont have an issue running at that temp. also not for nothin but this also has a possibility of being a hot end thats a little tight or 1/2 clogged and needs a cleaning. especially if you have been switching plastic types alot. in consistent extrusion and just plain old weird extrusion problems many times can lead back to that. most of the time its not so much the nozzle as it is the brass barrel.

madesolid blk pet+.fff.zip

(2.32 KiB) Downloaded 459 times

[Dave K]

[quote="jimc"]dave, the setting for the colored pet+ are different from the clear. it does need to run hotter. here is my fff for the black. it runs at 255. you wont have an issue running at that temp./quote]

I'll give that a shot tomorrow, Jim. I've got a print going now with the clear PET+ and had to restart it with glue stick instead of hairspray to help keep it down...it's a thick part. If that temp change works for me, I'll be a very happy guy, because I love the PET+ clear so much, I bought the black and white, and I've got blue and green being shipped now. My enthusiasm got ahead of my testing

I think I'll try Dale's suggestion to run a calibration print before I try that particular print, as well.

[jimc]

try running that fff just as it is. dont change anything. just double check to make sure your filament dia is set correct and i would swap out your start and end gcodes with mine. other than that run all the settings as they are. i have some ooze control stuff in there that you dont. try it and let me know how it works out. i have not tried the white yet. i just had a roll come in. i have only used the black stuff.

[Dave K]

I hope to try that tomorrow, and I'll report back on the results.

[jimc]

Crap i meant swap out my start and end gcodes with yours. But you prob knew that.