printing nylon

[alaris2 1]

The internet is a mine of misinformation. it's amazing how fast an individual can persuade people to part with money by telling them he has something new, has cornered the market and how dangerous it would be to buy from anywhere else. so you should give him all your money. tracing the scare stories nearly always leads to one source - the person who stands to benefit most.

fools and money etc.

nylon seems to be one of these areas. I've been printing with nylon for some time now and would therefore recommend:

1) buy the cheapest weedwacker nylon you can lay your hands on. the cheaper the better. some expensive brands may try to add impurities to improve endurance (you'll always be able to spot these, because they claim to be '50% better than the ordinary line').

2) 2.4mm line is fine for the UM. if you buy 3mm you may find the tolerance isn't great and it might get stuck in the bowden tube. usually 3mm = 3.05mm for strimmer line, whereas 3mm=2.84mm in our world.

3) a temperature of 240-260 is about right, no higher.

4) retraction doesn't work well with nylon, expect to have to clean up afterward. an all metal hot-end allows you to control the hot zone and improve retraction, the UM V1/V2 hotend is better suited to PLA.

5) you NEED a hot bed. nylon curls like a cheese sandwich otherwise. ignore the silly advice about printing on cardboard, it makes a negligible improvement, is a pain to set up and takes ages to clean afterwards. just get a hot bed.

6) by all means spend hours cooking your nylon before printing to remove moisture. or just print it regardless and live with the fact it will hiss and spit a little occasionally - it won't make much difference to the final model.

in short, don't imagine you MUST buy nylon from expensive sources and ALWAYS question the scare stories.

buy from your local hardware store, or from, eg.amazon.

something like this (but in 2.4mm)

http://www.amazon.com/dp/B001BKZT1S/ref ... T1_SC_dp_1

or this (again you want a thicker variant)

http://www.amazon.co.uk/Black-Decker-A6 ... 888&sr=8-3

 

[joergen 2]

Excellent, it confirms my suspicions :-)

One quick question: what temp for the hotbed (assuming nylon sticks to hot glass and kapton)?

[IRobertI 520]

How's the smell of that stuff? From what little I've read it's pretty nasty stuff?

[alaris2 1]

allegedly, nylon sticks to nothing except other hot nylon (if you believe what you read)

but experience shows that if you skwish it hard enough onto a surface it will stay there for a short time (which is why people early on recommended cardboard)

I can print on the blue tape.. but only for about 5 layers before it starts curling off!

hence the hotbed is a necessity - I've not tried hot glass I'm afraid, but kapton tape seems to work OK. I also tried printing directly to metal, which works if the surface is roughed a bit first.

you're right that temperature is the key thing tho - you won't stick to anything if it's cold. and combined with raising the air temperature has given the best results so far (a chambered approach with turkey bags or whatever else you have to hand). best results I've had were with ambient temperature about 35C (as warm as I could get it with a hair dryer and turkey bags) and hotbed at 105C (+-10C cos my temperature readings seem a little off for the hotbed atm and I can't get it any hotter than this :(

this isn't perfect, there's still a little curl, but it's no worse than printing cold PLA so might be 'good enough' for most people.

I'm revamping my hotbed to go hotter right now and suspect the 'right' temperature is more like 120-130C - I'll let you know with some photos of my success (or otherwise)

(note - the necessary temperature seems to be much higher than the quoted glass transition temperatures)

regarding smell - not really. this is one of those urban legends that get propagated as scare stories, usually with names of chemicals like hydrogen cyanide. as with nearly all plastics, you want to avoid setting fire to it, and also avoid reaching the thermal decomposition temperature (about 310C) or you will get some nasty smells indeed. a good extrusion temperature is more like 240-260C.

to say there is absolutely no smell would be a lie, but it smells no more (or worse) than PLA or ABS. as with PLA, lower temperatures = less smell.

that doesn't mean I'd recommend sitting there sniffing it or working in a very enclosed space - I vent my UM by opening the window occasionally regardless of what I'm printing with. PLA fumes give me a headache if I sit in them for a few hours, whilst others claim the smell is like 'maple syrup'. no accounting for taste i suppose

the only thing 'weird' about nylon is the hissing spitting noise the hotend will make (apparently water turning into steam in the head) - it doesn't seem to do any damage or ruin the print, but it sounds disconcerting at first. since i've only really used the nylon long term on my metal hotend, I can't say if the more enclosed space in the V1/V2 hotend will have long term problems with steam - you might get more popping or pressure build up perhaps?

[IRobertI 520]

Thanks for the info. Good stuff. Maybe come summer I'll give it a shot myself as I can't really keep a window open now, too damn cold here in Sweden I need to get a hotbed first though which is on my to do list right after getting rid of the short belts (parts on the way).

[joergen 2]

allegedly, nylon sticks to nothing except other hot nylon (if you believe what you read)

but experience shows that if you skwish it hard enough onto a surface it will stay there for a short time (which is why people early on recommended cardboard)

I have been reading more of Taulman info about the nylon they are selling, and there is enough really good info to push it way beyond pure marketing speech: http://www.taulman3d.com/specifications.html

The info i got from it that it will stick to cellulose fibers in some way while hot (which explains cardboard and wood as printing platforms) and electronics boards (using the 1/10in holes as grips). I can see glass as a problem, since there is no fiber-like molecular structure Nylon could hold on to, and no carbon, only silica... other than van de vals forces... but maybe it's enough, since nylon has a Tg of 47C? kapton tape could work, since nylon and kapton share the same precursor (diamine), but I don't know if that helps for bonding those 2. can some of the chemists confirm/dispel this?

the other point he makes is about fillers in trimming lines, since they are not always pure nylon, but have calcium, and/or glass and carbon fibers, for bulk and improved cutting performance. I haven't played with trimming lines yet, but my gut feeling is using a larger nozzle (i.e. >0.5mm) will help avoid clogging, since the fillers are more likely to be pushed through. but thanks for your point on using 2.66mm line (0.105in), as this should feed without issue into the UM. one caveat would be the "funny" shape some of the lines have (square, star, hollow center etc) makes it necessary to be creative with the e-steps/mm setting, or play with the flow rate/packing density setting in your favorite slicer.

Related to this, they included even some info about dyeing Nylon: http://www.taulman3d.com/colors.html which I found tremendously interesting for my product development.

[alaris2 1]

The Tg is variously listed as 47, 53, 57 and 75C. some of this will be due to different variants of nylon and/or impurities added. however, even with the hotbed much hotter than this, I still can't completely eliminate warping. that's a bit different from PLA and ABS where the Tg seems related to the hotbed temp.

Do let us know if glass works (presume you're using borosilicate?)

I avoid the funny shape line myself (star shape for example) because the extruder isn't really designed for it, but it may still be useable. the cheapest stuff seems to be circular(ish), works fine, and if there are any 'fillers' they melt and go through the nozzle without a single blockage in the 2-3 months I've been using nylon

the colors info is really very good - I tried sharpie pens early on and they work but not very well. this looks much better so I'll try this next. but the info varies across the site, from very good and technically correct, to pure sales statements like "If you're not printing nylon with taulman's 618, you're printing nylon with one of his rejects!" - as with all persons hawking their own goods, caveat emptor

[chemwhite 0]

I have been printing the Taulman nylon on Kapton tape. It sticks so well that it can be difficult to get off. Often some of the tape will stick to the part, requiring new tape to be put down before the next print. Anyway, this has solved the warping problem for me - WITHOUT a heated bed.