Drying Nylon

[Jane And Rog]

I'm trying to print some PA6 (no CF or glass) but the bridges are awful. Layer strength and overhangs are pretty good. After a lot of trial and error with little improvement, I'm down to the problem being that it's not dry, despite having been at 75C for ±48 hours: the hottest as my cheapo SpacePI goes.

Does anyone recommend a dryer that gets hotter? PaulandChrissy you mentioned earlier that you print Nylon...

 

[PaulandChrissy]

Hi
I normally dry nylon for 48hrs at 65c. Immediately after that start printing. You need to feed the filament into the printer directly from the dryer. You can’t let the spool stand. It will absorb moisture in just 30minutes and print poorly again.
If you purge the filament through the hot end you shouldn’t see any steam or water bubbles spitting.
The new Creality dryers are very good. I’ve been using a double wide version for a month, and it’s really good.
I’ve only used nylon with CF.

Hope this is helpful. PaulandChrissy

 

[Jane And Rog]

I can’t see or hear any moisture as I extrude it but… the bridges are crap.

The new Creality is the dryer I have (single though). I’ve had this stuff in there on the PA setting (65C) then turned up to 75C for an age. I am running it straight from the heater to the printer through a PFTE tube.

Looks like some brands (eg Polymaker and Qidi) suggest more like 100C for nylon- although Prusa recommend 90C which I guess is what you use. I can’t find any reasonably priced dryers that go that high so my next experiment is to put it in the oven at 100C for a few hours. Luckily Jane doesn’t read MotorHome fun so she won’t be aware of that.

If it doesn’t work after that, I’ll put it in the bin for a long time.

 

[PaulandChrissy]

If you wanted to send me your gcode, I could take a look. What printer do you have.

 

[Jane And Rog]

Qidi Plus 4 so far I’m just printing the Orca temp tower.

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[PaulandChrissy]

Nice printer.
Have you got some pictures of your test print. Would still be good to see your Gcode.

 

[Jane And Rog]

4 hours at 100C and it’s still not great. Maybe a little better. I’ll try 120 next week after I’m back from a short break then I’ll assume there is actually something wrong with this stuff.

Will send the Gcode in a PM.

 

[PaulandChrissy]

What’s it like higher up when the temperature is lower. The CF Nylon I have has a nozzle temp of 240 to 260. Your tower in the picture has only 275 to 270. Toooo hot maybe. The 270 looks better than the 275. Could be better as the temp reduces.

 

[PaulandChrissy]

Looks to me that your nozzle temp is tooo high. The results i suspect would be better higher up the tower as the temperature is lower. Your fan speed looks healthy in the gcode. Try lower temps.

 

[Jane And Rog]

That’s a good point. Filament says 250 is lowest temp but when I tested that layer adhesion wasn’t good. This was a smaller tower around the 270 mark I’d selected as best from that.

I’ll try a new tower at a lower temp after the drying.

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[PaulandChrissy]

I would say 265 could be your sweet spot based on your tower. Don’t expect a super clean result. Remember nylon is very oozy to print, a bit like TPU. CF nylon is more stable. Also when printing regular parts and not torture tests bridges are not an everyday thing.
Safe Travels PaulandChrissy

 

[Jane And Rog]

Agreed. The two things I want to print with this don't even need bridges at all - never mind this long - I just wanted to get it "right".

I also printed a test from 280 all the way down to 240. The top half split into layers as I pulled it off the build plate

Thanks for the advice.