Nylon not sticking

[Jon Bondy]

I'm trying to print a nylon calibration cube on the black (garolite?) board that came with the printer.  The cube keeps curling up and lifting off.  The bed is set to 100 and the extruder to 240.  I tried scuffing up the board with sandpaper, but that did not help.  I could try hair spray, either on the board or on glass.

What is working for the rest of you please?

Jon

[Dave]

On Friday, December 27, 2013 10:48:30 AM UTC-6, Jon Bondy wrote:

I'm trying to print a nylon calibration cube on the black (garolite?) board that came with the printer.  The cube keeps curling up and lifting off.  The bed is set to 100 and the extruder to 240.  I tried scuffing up the board with sandpaper, but that did not help.  I could try hair spray, either on the board or on glass.

I never got the black garolite that shipped with the printer to work with nylon, even after belt-sanding it to rough it up.  I suspect (could be wrong) that the black material does not have paper or cotton fibers in it, and it's the cellulose in those fibers that binds to the nylon.  Or maybe the carbon black acts as a lubricant and releases the nylon.  Anyway, it didn't work. 

Nylon does not chemically stick to very much other than more nylon, so everything that works is a mechanical connection.  Glue, hair spray or whatever else is no help.  Nylon will print on natural fibers, though, so wood, burlap, paper, and even paper masking tape work.  It's a question of getting a nice flat surface that can withstand the warping load of the plastic.  Make no mistake; nylon will be pulling on your bed, even if it doesn't pull off.  Some folks have found that nylon sticks fine to blue painter's tape, but the tape won't stick to its substrate well enough to stay down, so the nylon pulls the tape off the bed.  Likewise with gluing down copy paper on glass or metal.

I am currently printing nylon on a different variety of garolite, the CE flavor, part 8491K23 from McMaster Carr.  I sanded it flat and left it a little roughed up.  Big, flat, blocky parts need a fair amount of brim to hold them down, but it works reasonably well.  One noticeable downside is that it dips in the middle, nearly 1 mm when heated to 60 C, so I can't make very large parts with a heated bed.  I am considering trying it cool for big pieces, at which point it's reasonably flat, but haven't had the need yet.  The reason our printers ship with borosilicate glass is because it doesn't warp (much) when heated on one side.  Most materials do.

The LE variety of garolite may stick a little better than the CE (reviews are mixed), but it's more expensive.  I figured I'd try the cheap stuff first, and haven't had a need to switch yet.    

Hope that helps,

Dave

[Jon Bondy]

I figured that for the calibration cube, I could just use blue painter's tape and a cold bed, and I was right.  I grabbed a brand new roll of nylon, sealed in plastic, with a desiccant inside, just in case some of the problems were related to moisture.  Turns out I was over extruding by almost 100 %.  Trouble is that now that I am extruding the "correct" amount, the walls look ratty and spotty.  I can see brief wisps of "smoke" which could well be steam, but how to explain this on filament directly from a sealed bag with desiccant?  Maybe I need to repeat this tomorrow with freshly "baked" nylon.

I ordered the recommended CE garolite.

Note that I live in Vermont, and the relative humidity this time of year is pretty low.

I want to love the nylon, but I'm not feeling it yet

Jon

[Rick Zehr]

I'm with you - it didn't do much for me either. Tried it = ho hum.

[Jon Bondy]

Unfortunately, there are some projects that seem to require nylon, so the quest continues

If you want to dry out Taulman nylon, do not put a spool of it in the oven.  The nylon filament does fine at 250 F; the spools do not!

[Dave]

On Saturday, December 28, 2013 6:37:56 AM UTC-6, Jon Bondy wrote:

Unfortunately, there are some projects that seem to require nylon, so the quest continues

If you want to dry out Taulman nylon, do not put a spool of it in the oven.  The nylon filament does fine at 250 F; the spools do not!

I've dried it at lower temperatures (near 200 F) for 20-30 minutes, though not on the spool, just a small batch at a time.  I suspect that even sealed nylon with a desiccant in the bag may still be moist.  The stuff really attracts water, and little desiccant packs can only do so much, especially if the plastic bag leaks, which they do. 

A job I'm working on at work right now involves desiccant in bags, and the customer is very serious about keeping their product dry.  The bags are metal foil, double-layered, and the desiccant packs are much heavier-duty than the ones that ship with our filament.  Keeping moisture out is hard to do. 

Extrusion settings on nylon have me stumped.  Too little and you string all over the place. Too much and fine features won't build because the filament isn't properly primed at the nozzle tip.  The ideal retraction setting varies depending on the move time between extrusions and the feature size of the target.  It's hard to find a good compromise for any shape with varying geometry, though I've made some nice-looking vases and such. 

Let us know what you find. 

Dave

[Jon Bondy]

Elmer's glue stick has helped the problem with the print not sticking to the bed, at least some.  The photos were take perhaps 10 minutes after the print was made, after the bed had cooled a bit.  There is not much structure in this calibration cube (1 layer on the bottom and sides) so the warping does not worry me.  Yet.

See photos.  The skirt had FOUR loops, and none of them came out close to correct; the hot end is essentially empty when the print starts, due to "drooling".  The walls of the calibration cube contain fewer holes (now that the filament has been dried), but the cube edge is clearly horrible.  I had to bump the extrusion multiplier back up from 0.59 to 1.0 in order to get something this good: with the "correct" extrusion multiplier, there clearly was not enough plastic coming out.

Any suggestions?

Jon

[Jon Bondy]

Just FYI, I am using one of the original all metal Magma J-Heads.  Whether this could be part of my nylon problems, I cannot say.  I have ordered some additional all metal hot ends, just in case

[John D]

Jon - what temperature are you printing?  I had decent results on GaroliteLE after drying the 618, and printing at 235c from a normal j-head.  I still had warping issues, but seeming better print quality.

[Jon Bondy]

I started at 235 and when the extruded nylon bead was not smooth went up to 240.  Is there any rule of thumb about how to determine the optimal temperature by looking at the extruded bead?

If I were to have a "bad" Magma on that particular printer (with the chamfers that prevented decent PLA printing) is it likely that this would cause problems printing Nylon? I know even the "bad" Magmas seemed to be able to print ABS OK.  I never fully understood why.

[John D]

Jon - I think it's voodoo - I just watch and see if I'm getting a consistent line at speed.  I would think you could use the thin wall test to see if what you are slicing matches what you are getting in reality - but I've not really used that method in a while.

I had the original "bad" magmas - not the j-head magma - and I never really got it printing well enough to leave it in the printer for any amount of time.  I think the chamfer was more critical with PLA but since Nylon and ABS are much more slippery it was not supposed to be as much of a problem.