So it turns out, it’s the flat shape of the e3d v6 style nozzle that drags up filament as it moves, in case of PETG. My nozzle dia is 0.4 and the line width is 0.44. but the diameter of the flat portion of the nozzle is 0.8mm. The filament then burns and leaves yellow chunks on my prints.
I could have gotten a pointed head nozzle, but I didn’t have any and solved it by using a sandpaper and a drill to make the nozzle point.
Below are 2 prints with same settings. Before and after
Pretty interesting material to print with. It’s a stiff filament when you print it, but upon dissolving with water, it becomes flexible. Pretty sure it’s a 2 part plastic, one flexible like TPU and other PVA.
I’ll say it again. Alloy 910 is crazy strong and prints beautifully withBGM direct drive + all metal V6 setup. I threw it on the ground several times, like I was bouncing a ball, and not even a single crack. Only after putting all my might into it, did it crack and a small piece flew away. I have had ABS(from industrial machine: Stratasys) crack just by falling off the table.
I have read that polymaker polymide is even stronger than alloy 910 and well, even more expensive. I kind of want to go in the other direction and try some cheaper nylon and see if they are better than PETG. Do you guys have any experience with that? Here are some I found on Amazon:
Why the heck doesn’t sunlu ship to California? Anyone? lol
Probably doesn’t have the label yet that “this product may release carcinogens in the state of CA”, haha. BTW, do other filaments come with that label?
Oh weird. Nope not that I have seen lol
Irritating because it has good bang for the buck
Hey, I’m struggling to be able to print TPU with a 0.8mm nozzle. I might be able to print the perimeters on the first layer but soon enough the nozzle will clog up and the filament will either come out under the gear, or will just not feed in.
I have so many things I want to print for my board in TPU.
note: I haven’t tried 0.4mm nozzle, maybe I should but I have seen people advising that bigger nozzles are easier.
@mishrasubhransu it seems like you have a bit of experience with TPU. Please!? 
Sure. Glad to help. Can you post some pics of your setup, what filament do you use and also pics of your failed prints.
If it crackles then it most probably has some decent moisture content. Next time you print, pop the spool into the oven at just 60C(140F) for half hour or so.
Also print at higher temp. Go up to 235C.
Some really insightful tests done by Stefan(cnckitchen) on the extrusion width. Extrusion width basically is the width of the filament laid by the printer. If you use 0.4mm nozzle then 100% extrusion width is 0.4mm wide line. A 140% extrusion width is 0.56 mm. Seems like the layer adhesion goes up with the extrusion width, as much as twice 
However dimension accuracy is iffy at 200%. A 140% extrusion width seems to be the best. Another advantage is decrease in print time. I think it’s a win win. I have got to try this.
You can try reducing retraction as well but would change one thing at a time and do a small test run.
Occasionally can run into issues with the melted filament pulling back and sticking on ptfe or whatever is in the cold side of the hot end.
If it’s low durometer TPU it’s more likely to wind back on itself in the extruder as well.
Oh yeah, totally forgot. Start with 0 retraction. Let it string and goop. Temp 230. Reduce retraction after first print only in small increments 1mm(Bowden), 0.1mm(direct drive)
Show us how it looks.
This is actually an early effort (normal E3D Titan with Volcano, not the current Aero) and probably most successful to date (15mm x 15mm x 15mm).
As far as what filament: I’m in New Zealand, so I’m a long way away from decent branded filaments. It’s called “Marvle3D”. If it’s an issue with filament quality then I’m prepared to pay the expensive costs of shipping from US/EU but I’m not convinced.
I haven’t got any pics of setup. Tevo Tarantula Pro which prints very well with PLA. I also have a CR-10s Pro that I using for finer work, which I will convert to a more modular system so I can swap nozzles out easier.
Also: I have E3D hardened-steel nozzles coming. I wonder if my 0.8mm brass nozzle is wearing out.
(thanks @mishrasubhransu!)
Clearly underextruding. Like I suggested, remove moisture put heating it in oven and then try to print at 230 with 0 retraction.
Can you show where the filament comes out from?
Ok, it’s technically this company here https://marvle3d.co.nz/search?controller=search&s=tpu but it’s on a site called “trademe.co.nz” which is essentially a local version of EBay.
Have been printing with 0 retraction. Will try higher temps.
It’s been under-extruding since day one so I doubt it’s moisture. My oven is broken so that’s why I haven’t cooked it yet (good advice none the less).
What speeds to you print at with big nozzles?
Also: what TPU do you print with? I might just pony-up and buy a roll from overseas.
Anyone have a good test for print strength? I have used a temperature tower to dial in PETG and I have used this print test to dial in settings:
Neither of these tests the strength systematically, although you will know if it is bad.
Print a hook and see how much weight it can hold.
Just putting this out there but i had issues with cura and i switched to prusa slicer and its fucking amazing
Give some more detail here. What issues did you have? Did you copy the EXACT settings from cura? What versions?
Newest version of cura, horrific layers, went to stock settings worked and started to not work and i was done with cura and when to prusa slicer and kinda made my own profile
aka me running from my problems
I highly doubtful it’s the filament. I think the nozzle just has a clog. Replace for clean nozzle then.
