'Noodley' looking filament bits near overhangs

Just got my Lulzbot Mini last night.

The 1 m HIPS that came with it printed the rocktopus pretty much perfect on the suggested cura medium hips quick preset. The back of the rocktopus head has very similar overhangs as this part and there is no evidence of this at all on the hips print. Being bright yellow I was not able to get a decent pic of it.

I had some ABS from Frys that I picked up on the way home (I have some lulzbot ABS coming as well, but I could not wait). The stuff is Shaxon brand. http://www.frys.com/product/8023384?site=sr:SEARCH:MAIN_RSLT_PG

It extrudes fine and prints most thing really darn nice. It is not doing well on overhangs though. When I try that I get these ‘noodley’ bits where it looks like the far outside wall filament is laid down and before it fully cools, it ‘flops’ off the layer it is on towards the outside of the model.

The engineer in me says this is a cooling/heat issue, but I am not sure if it is too high or too low. My brain can make arguments for both, temp could be too high, allowing that filament to fall out of place when it should be more firm, but the temp could also be too low, maybe the filament would ‘stick’ better in place if it was hotter and more liquid.

I am using the CURA lulzbot mini medium ABS quickprint preset in the picture. That appears to be 240 C nozzle and 110 C bed. I can’t get any more details out of the program it seems, when I try to switch to advanced to see the settings, I always see the same default numbers no matter what quickprint presets I have selected. I get the same issue on high setting. I don’t know the layer height exactly, but doing the math by knowing the model height (20mm) and looking at the slice view, it looks like about 0.25 mm layer height.

Tonight I will try firing up advanced mode for the first time and play with nozzle temp. My gut says to try 235 C.

What do you guys suggest? Have you seen this issue before?

Some more detail, this was printed with the checkbox for support structure checked, but I got very little support added to the print. Just a little bit under the very start of the head protrusion.

It was this file, shrunk down to 20mm height with locked proportions:

We have a bunch of print profiles here, that you can load in Expert mode:


That print looks very small. It would probably benefit from a finer layer height. Would be interesting to hear how it prints with our filament vs. Fry’s.

Quite a few people on reddit have said the shaxon filament is junk. So far my best results filament has been the cool gray pla from prototype supply.

Any suggestions on a good and filament for reasonable price? I have an unopen spool of lulzbot abs, but it is too expensive for regular use

The problem was the filament was too hot and not cooling enough.

I was using the default cura mini fine profile on the support page.

I turned the model around on the print bed so the face was facing the fan, and then I upped the fan settings from min/max 40/60 to 60/80. I also dropped the nozzle temp to 235.

For this filament I find those fan settings the best.

Pic attached is the same model, but this time even smaller, 15mm tall, and not 20, but you can see the overhangs worked much better. Far less issues with the support sticking as well.

This was because of the shaxxon black filament from frys.

  1. It is not pure, or maybe just nonstandard ABS, as it did not dissolve in aceton (just became black sludge, but did not dissolve)
  2. It required lower nozzle temp, higher fan, and lower bed temp than the ABS mini profiles on the site. 235 nozzle 100 bed 60-80% fan worked decent for me.
  3. It would not acetone smooth AT ALL. It would still get soft enough to acetone weld.

When I went to the ABS natural from lulzbot site, the ABS mini profiles on the site worked great with no tweaking. Wonderful overhangs, no noodley bits, and no warping of the first few layers.

I hear the black shaxxon from frys is worse than the other colors. I will probably try natural when my black runs out. Right now my black is great for things where I want larger, functional parts, and I will use the lulzbot ABS for detail work where appearance is important. The black shaxxon appears a little bit less brittle than the lulzbot abs.

Thanks for the update.

So I was having a great time printing Shaxon 3mm Black ABS. Great results almost always unless I screwed up my model placement. The trueness of the filament was really good too. 2.90 average. The only part that warped on me was a 140mm fan cover but I had a draft. I used a blanket and fixed that and hopefully the box that fan shroud is for turns out!

Now on to the neon yellow and red Shaxon 3mm ABS. I had all my parts print with a consistent concave bevel along the lower ~10mm edge. I printed so many things with temps ranging from 120 to 140 with horrible results during the same ~10mm layers. Everything else above was perfect! I started to think things were building up properly because that’s around the time the fan kicks on. But I’m printing ABS?!?!?!

After a whole box full of failed prints and a few weeks of lost time I called support and they really leaned on the filament so I tried my prints in Black and it worked great! So I read a few posts about Shaxon on here and I was having the same conclusion that this had some PLA & ABS properties where it liked a lot of cooling with PLA but a high temp with ABS. I’ve never printed with ABS but I know some stuff about plastic and have watched/read enough about it to have a vague idea as to what it’s about. 3 spools of ABS and counting.

The FIX for me!
I live in AZ so I have a good ambient temp and low humidity so YMMV compared to my results. All I did was keep 240 for the nozzle and 110 for the bed with the default fan settings but I removed the blanket to allow normal cooling with no specific cold air flowing on it like from a ceiling fan turned on more than medium and no AC. The red and neon yellow are printing perfectly now. I’ve already printed out several 5 hour high detail models with extreme angles and support. I did also set support to 20% vs. 15% which is part of the improvement.

This Shaxon colored ABS seems different than the black. It has a more brittle property to it rather than a stretchy/bendy property like real ABS but it still turns white when stretched/bent too far. It’s also more what I’d say candy like than plastic like which might explain the PLA theory. I recall G.I. Joe and TMNT toys from when I was a kid had a similar property particularly with how it breaks. 80s kid :wink:

But yeah that’s my experience and maybe it will help someone else out too. BTW Fry’s is keeping their Shaxon on the shelves long enough to sell out and they’re not re-stocking any black ABS. Seems like the consumer internet won that battle!