Nylon Problems

[jenjaw 0]

Hi,

I've been using the Taulman 645 nylon for a few weeks now and I am have 2 major issues with it.

Firstly, it keeps jamming in the nozzle. meaning after every few prints one will fail and I have to spend time sorting it, which isn't great on a time limit. Has anyone else had this problem or any idea what's causing it?

Secondly, the print quality is very bad, I've tried printing between 250 and 260 degrees with no improvement and changed the speed to faster and slower, but it still has a poor structure and is crumbling badly like in the image below. (I have to print on fabric for the research I'm doing)

Has anyone got any tips on how to improve the print quality? I've heard about drying out the filament but not sure how to do this quickly/safely?

Thanks!

 

[nick-foley 5]

I have a machine that is set up to print in 645 exclusively and we get pretty consistently great results. Some tips:

1) Your prints look fuzzy because the filament is spending too much time in the nozzle. You probably need to increase your extrusion rate. Also, this material does not like lots of small hops, since a section of filament will then spend a lot of time heating up in the nozzle before finally being extruded. Don't waste your time drying the material - we keep ours exposed to air and get solid, smooth prints every day. The only time we get foamyness is on the first few mm of filament in the skirt of each print, because the previously pre-heated nylon has absorbed a lot of water while molten.

2) Your filament is probably clogging because the diameter of the Nylon is too large. I haven't tried printing 645 on a fully stock machine - our "nylon machine" is a stock machine on which I've opened up the ID of the entire hotend assembly with a 3.4mm drill, and replaced the bowden tube with a thin-walled equivalent to give more clearance for the filament. We have never had a clog with nylon.

Anyway, our overall experience is that nylon isn't a particularly pretty material to print in, and it isn't a particularly great material for small/detailed prints, but it is an extremely useful material - it's strength, flexibility, and toughness enable amazingly high-functioning parts that totally transform what 3D printers are capable of.

 

[nick-foley 5]

Here are the relevant settings from our go-to nylon profile. If I were printing smaller things with more jumps I would probably drop the print speed 10-15mm/s and drop the nozzle temp 5-10°:

 

 

 

layer_height = .15

wall_thickness = 2

retraction_enable = True

solid_layer_thickness = 3

fill_density = 100

nozzle_size = 0.4

print_speed = 50

print_temperature = 255

support = None

platform_adhesion = Brim

filament_diameter = 2.88

filament_flow = 100.0

retraction_speed = 30

retraction_amount = 4.5

retraction_min_travel = 1.5

retraction_combing = True

retraction_minimal_extrusion = 0.5

bottom_thickness = 0.3

object_sink = 0

travel_speed = 150.0

bottom_layer_speed = 15

infill_speed = 50

cool_min_layer_time = 6

fan_enabled = False

skirt_line_count = 4

skirt_gap = 20

 

[jenjaw 0]

Thanks for the advice, I'll give those settings a go and see how that works. They don't need to be perfect looking prints but it would be nice if it printed some functional parts!

 

[jenjaw 0]

Right, I've tried a couple of prints using those settings which were better but still fluffy and not functional. I decided I'd try to dry out the filament yesterday, so now there is no hissing in the nozzle from moisture, but it's still producing sub-par prints:

It just doesn't seem to bond very well layer to layer and the outer shell seems to be made out of diagonal lines rather than a solid piece.

Any idea's on why this is happening still or how to fix it??

Thanks

 

[nick-foley 5]

You are getting serious under-extrusion. Probably due to clogging/jamming/friction in your bowden tube or hotend?

I would try removing the brass nozzle and pushing some of the nylon filament through your machine by hand, in an attempt to assess the amount of resistance your filament is experiencing. If it seems hard to move through, I would then further try to isolate the problem by separating the hotend from the bowden and trying again. I would then either replace the offending bowden with a larger ID tube (Mcmaster stocks several options - check the replacing bowden tube thread for P/N's) or expand the ID of the offending hotend with a 3.2-3.4mm drill.

If that doesn't seem to be the problem... it could be that your hotend isn't calibrated correctly and the temperature is way too low?