I got my first spool of nGen today and did some tests. Very mixed results, your comments are welcome:
First, a layer bonding test (Thingiverse Object). One of the advantages of nGen should be very good layer bonding, especialy thin cylinders break easy with PLA.
Orange is PLA, blue is nGen. There are two nGen tests, because my first test part broke very easily inside the cylindrical part itself where the PLA one wasn’t breakable without pliers. So I printed a second one with fan speed limited to 50%, now it’s rock solid. nGen doesn’t like too much cooling.
As you can see, the PLA peeled off on the top layer whereas the nGen ripped off all 3 top layer completely. Nice one!
But, as you can also see when zooming in, there are some gaps in the blue parts and signs of over extrusion in other places. It seems that nGen has serious problems with higher print speeds, also the infill comes out more stringy than the PLA one. That’s very bad…
Second test was overhang and curling edges. Both parts are printed with 0.1mm layer height, exact same settings. Every 3mm in height, the angle lowers by 5 degrees, starting with 40. Both prints failed at 25°, but nGen has a sudden change in quality while PLA has a more smooth transition from “good” to “bad”. Much more intresting is the corner from the vertical wall to the overhang area: While the PLA starts to curl at 35° (which renders the achievable 25° overhang unusable), nGen has a clean edge until 25°. nGen is the clear winner here.
Last but not least, I have strange looking cold pulls with nGen:
My PLA pulls come out clean every time, the nGen pulls have always a black ring where the heatbreake is. No idea why, maybe leftover from PLA prints? But in the meantime I used ~2m of nGen, still looks like that…
Result up to now:
- Very good layer bonding
- Very low tendency to curling edges, so hard overhangs will come out much nicer, especialy at low layer heights.
- Top surface quality is bad, voids between perimeters, sometimes small gaps in top infill (I printed 3 test cubes, it varies but don’t know why. Nozzle is clean). Nogo if I can’t work around that.
- It’s 2x the price from eSun PLA. If the quality problems can be solved, I think that’s OK for prints like figurines where overhang angles are a problem or if you need the strength.
I have to correct some of my statements from the first post. I did a lot of tests since my first nGen prints and now I like it (except the price) 
I could write a long post about all the interesting details when printing with nGen, but I know nearly nobody would read it.
So here is the short version, things that are important when printing with nGen:
.) Infill: Print at 0.7mm width minimum. My default width of 0.48mm with a 0.4mm nozzle wasn’t working stable. Or print with grid pattern instead of rectilinear.
.) Make sure your nozzle is completely clean. If you see voids in your prints as I did, it’s due to old filament of another kind (PLA for example) that’s burning and blocking the flow. If your cold pulls are OK and you are seeing voids, print a few more objects. Most likely the small particles will come out over time.
.) Cold pulls are impossible with nGen. Use PLA for this purpose.
.) Bridging flow factor is very important to get a good first solid top layer. Set it to 1.2 if your slicer has that option.
.) nGen sticks quite well to the print bed, much better than PLA. So if you don’t want to wait until the bed has cooled down after a print, you can also print with 75°C bed temperature for example - very likely even lower.
.) If you are used to print with PLA before, limit your fan speed to about 60% until you have a better feeling for the setting. Normal PLA cooling isn’t neccesary and will lead to weak prints.
.) A pressure control feature is nearly a must, because nGen is quite flexible. Without it, you will have severe underextrusion at the first part of a print line leading to gaps between perimeters for example. If you use my Marlin FW code, set K factor to 150.
.) If a clean top surface finish is needed, print 4-5 top layers (for a 0.2mm layer height). While 3 layers are OK with PLA, nGen needs a bit more due to the more sagging first top layer after infill.
I’m getting now very clean prints, no voids in perimeters or infill any more. The parts have a great layer bonding and are quite flexible - I guess it’s compareable to ABS. Due to my hand-braking objects test, I would say it’s not stronger than PLA. But it should be much more tolerant against a shock like droping a print on the floor.
In the end, I would say nGen beats PLA in nearly every point with only two things to consider:
.) If you need stiff parts, PLA is the winner
.) nGen is 48€/kg, ESUN PLA is about 23€/kg. That’s a hughe difference…
.) Based on my experience now, I guess PLA is a bit better if you need excessive bridging. But for real models, that’s mostly not the case.
ColorFabb: Make nGen cheap and I will sell all my PLA and change completely 
