Nylon PRO printing problems
This may have been covered elsewhere, but after searching, I've not found an answer.
I have been trying to print with Matterhackers 1.75 PRO Series Nylon (black), and have yet to produce a completely satisfactory print on my Creality Ender 3. At first, the main problem was significant "stringing," so I have been tweaking my slicer (Cura) settings to try to eliminate that issue. I have now apparently eliminated (for the most part) the excessive "stringing" by upping the retraction distance to 7mm, opting for a Z hop, setting travel speed to 120mm/s. The bed is level, using TH3D EZABL, I've calibrated my extruder e-steps to insure that extrusion is accurate, bed heat is 60° C, and hotend temp is 260° C.
Now, I get a great first layer, seemingly no issues with layers 2 and 3, but by layer 4, I start getting the "spaghetti monster" and the layer appears to be delaminating significantly.
What can I do to alleviate this situation? I spent $55 for what has essentially been a great headache. I have had no issues printing with PLA. I dried the nylon in an oven per Matterhackers directions, the filament is stored in a drybox at 20% humidity. What's going wrong?
Have not printed Nylon Pro But lots of other Nylons from Taulman (Bridge, 640, 910) to Hobbyking PA/Nylon which kinds is fishing line. Here a couple of things
1.) You got to have the filament dry. Get a print dry or convert a food dehydrator. Run the filament out of the print dry as even if you put it on the spool holder out in the "wild" you will pick up moisture in less than 1 hour to the point to cause stringing and layer adhesion problems. extrude some with the gantry up so you can look at it and if you see steam or hear crackling stop right there and dry it
2.) Garolite is the best for bed adhesion with a little gluestick and I found higher bed temps than 60 are needed for large items.
3.) Go slow with the print speed. I have not found a nylon yet that has good layer adhesion above 30mm/s with a .4 nozzle and that is Taulman bridge which is the easiest to print of the ones I printed so far. If you use slic3r or cura go to volumetric and start at 11 mm3/sec if you have an E3D V6 full metal hotend.
I assume you have upgraded your hotend on your ender as 260 is too hot for the PTFE tupe inside your hotend as it is a clone and not full metal and should not be run above 240
set the layer width to 120% nozzle diametr (.48 with a .4 nozzle) and keep the layer height at or below 50% layer width. I print Nylon with a .8 nozzle and a layer width of .96, extrusion multiplier .93 to .97 depending on what Nylon, volumetric max between 9 and 11 mm3/sec bridging at 120%. Make sure the fan is off as it messes with layer adhesion. IF you got to print something small slow down the print but try to not turn the fan on if necessary and you get the "molten candle" effect put a stick or 2nd item accross the build plate to give your print time to cool down. An enclosure helps too
mpirringer: Thanks for the input. I have dried the filament in an oven at 160° F for 3 hours, put it in an airtight box with dessicant, humidity is stable in the box at 20%. I have a TH3D "tough" hotend that has no issues with 260 C. I don't have any issues with bed adhesion; I use PVA glue and a glass bed at 60 C. I will try slowing down the speed, but it's not fast now. The 120mm/s is travel speed to try to avoid stringing. Lately I have not had the stringing issue; it's just layer adhesion above the 4th or 5th layer. I get very good 1st layer and 2-3, so I'm wondering if it's just the print speed that's an issue.
Okay, changed the print speed to 30mm/s for all layers. Layer width is .15. No fan (have never used a fan for Nylon, as that's not recommended by anybody). Hotend temp is 260 C, bed temp is 60 C. Again, no issues with bed adhesion.
Retraction distance is 7mm, retraction speed is 60mm/s, travel speed is 120mm/s. I am not experiencing much stringing, but still have a problem with upper layers delaminating and/or creating the "spaghetti monster". It's as if the filament is getting too cool at the upper layer levels, but indoor temp here is 70 F. Filament feeds directly from the drybox to the extruder, so there's not much exposure to outside air. Filament has been dried in an oven at 160 F for 3 hours prior to being placed in the drybox. Drybox humidity is stable at 20%. I have tried everything that has been suggested by various "experts," and nothing seems to have worked. The only other thing I haven't tried is putting the printer in an enclosure, which is not feasible at this time.
Can someone recommend slicer settings that might solve this problem?
I will add that my extruder has been calibrated such that when asked to extrude 100mm of filament, that's exactly what you get, so there shouldn't be a problem with over/under extrusion. Bed is level as I have been using the TH3D EZABL sensor. I get great skirt, first and second layer, but it seems that layers after 3 or 4 just don't stick at all.
Some materials like to be under/over extruded a bit. For example PETG likes about .93 to .95 of the measured calibration. IF you run it at 1 you get a "Bumpy ride" Some materials like Many nylons have measurably worse adhesion at different layer thickness. One good indication is to print an L laying down or half a box without top. Make the wall 2-3 layer widths wide and then one a little wider. So for example with my .8 nozzle and a layer width of .96 I make and L that is 1.92 thick and one that is 2.4 thick. Then I print them about 10mm hight. The legs are 50mm long. Then you take them and measure them with a caliper from the top, from the end close to the end and where it makes the corner. Idealy both come as close as possible. The 1.92 should be dead on as the walls are touching and you get the filament go fill where it can. i prefer a tiny bit over so 1.93 is ok. Then you print a square sheet about50x50 5 solid layers thick so if you are running .2mm layers you make it 1 mm. Now you can inspect the surface and see if you get any ripples which could make the nozzle get stuck on. if you do you dial the extrusion down or introduce a Z hop.
sometimes you just have to find a happy medium. Going to volumetric I eliminated the taper effect where it was thicker at the corner and end than in the middle. If you just get a bulge at the end of the wall then your printer has a tough time making the corner and you should turn the mm/sec down or introduce a fillet into your design. So I consider the measured value of the filament as a starting point. and I can't say it often enough some materials like Nylon, HIPS, PETG etc dont like a fan when it comes to layer adhesion some dont even like a draft coming from someone breathing to close to it hence enclosures (cheapest is to drape a clear garbage bag over it
I'm not using a fan, except for the fan that exhausts from the heat break. There's no cooling fan on when I print at all. Should I not even run the heat break fan?
I'll try the garbage bag trick.
You have to run the heatbreak fan. Let me know if slowing it down helped. And maybe call matterhackers tomorrow