eSun ePA-GF - weird hue changes on layers  

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jmone
(@jmone)
Estimable Member

I've had great success with eSun's ePA-CF (Nylon Carbon Fibre) and just got a roll of their new ePA-GF (Nylon Glass Fibre).  I did a print straight from the pack and it was the expected cream colour but it was also clearly no fully dry as the finish was a bit "wooly" and stringy.  So to dial in my settings, I started playing with Temp, Retraction settings after drying the filament for 12hrs @ 70c. 

Oddly, I now have prints that are more yellow but there are also bands of different hues.   These bands align across prints so it is not uneven drying of the filament itself (though I have put the roll into my 0%RH dry cabinet and will then dry again @ 70c).  I figured it must be temp related but it is the same @ 240c, 250c, 260c.  Given these bands line up across prints, and seems to be related to changes in geometry of the Benchy, I'm guessing my filament is still not dry enough...... or there is some combination of Fan, Speed, Temp at these layer heights.

Here is a pic (from Left to Right, Dried 240, Dried 250, Dried 260, Straight from Packet 260)

Posted : 01/11/2019 9:49 pm
aureumlocus
(@aureumlocus)
Eminent Member

Hmmm. Interesting.  I have just received a roll of ePA-GF and will report here once I have tested it.

Posted : 02/11/2019 5:10 am
jmone
(@jmone)
Estimable Member

So getting there - Did a few cycles of Heat to 70c for an hour or so --> Vacuum Chamber.  Much dryer now.  I can still pick out some changes in colour but if it was like this out of the box I would not have noticed.  I'll give it another round tomorrow but it is pretty well sorted now.  Like with the eSun ePA-CF, this ePA-GF is tough (hard to even snap of the funnel), a bit of flex, little stringing.  Overall another good engineering filament option. 

Posted : 02/11/2019 7:04 am
aureumlocus
(@aureumlocus)
Eminent Member

@jmone

Excellent. I’ll make sure to cook mine overnight at 70 degrees C before I try it out. If I get discolouration it will be a good indication that it’s not dry enough. 

This post was modified 1 month ago by aureumlocus
Posted : 02/11/2019 10:05 am
jmone
(@jmone)
Estimable Member

...also stringing is pretty much gone once properly dry.

Posted : 02/11/2019 9:28 pm
jmone
(@jmone)
Estimable Member

...and here it is fully dry.  Printed with the same profile I have for the ePA-CF (attached).  Nice.

3DBenchy_ePA-CF

Posted : 08/11/2019 11:42 am
aureumlocus
(@aureumlocus)
Eminent Member

OK,  That's very interesting.

I just got a commission from a client who wanted Nylon.  It's a big solid print.  I dried the ePA-GF overnight in a dehydrator at 70 degrees and still got the result attached.  A bit disappointing but as it is a functional print the colour banding is OK.  I am thinking that overnight in a dehydrator wasn't enough time to fully dry the filament. It's also possible that the banding is from artifacts in the model.

I am starting the second one now after another 24 hours drying so we'll see what that looks like in 10 hours time...

PS: The Nylon is super strong.  removing supports took me over an hour with pliers, flush cutters and a modelling knife.  Blood was spilled!

This post was modified 1 month ago 3 times by aureumlocus
Posted : 08/11/2019 10:13 pm
aureumlocus
(@aureumlocus)
Eminent Member

Oh, and no stringing or warping observed.  I did have a 20mm brim though, and this is a rounded part so no square edges to cause problems.

Posted : 08/11/2019 10:27 pm
jmone
(@jmone)
Estimable Member

Yeah it looks like it is not fully dry yet.  I had to do several cycles of dry @ 70c, put in Vacuum Chamber + then kept it in my 0%RH dry cabinet.  Now it prints well and without any colour banding.  I don't think the finish is a good as my ePA-CF with the same settings but as you say there is no stringing, warping, bridging is pretty good..... and it is as tough as nails!

This post was modified 1 month ago by jmone
Posted : 08/11/2019 10:46 pm
jmone
(@jmone)
Estimable Member

"it's also possible that the banding is from artifacts in the model."

That is what I also thought at first, but they disappear completely with dry filament.  

Posted : 08/11/2019 10:51 pm
aureumlocus
(@aureumlocus)
Eminent Member

@jmone

Thanks. I agree with you. It’ll be interesting to see how the current print comes out. I’ll know in a couple of hours. I don’t have a vacuum dryer or 0% RH cabinet (yet) so I’ll just have to see how long it takes with a modified food dehydrator.
I am printing directly from the dehydrator while it is running using PTFE tubing and  ‘reverse Bowden’ fittings on one of my printers. 

I’ll keep you all up to date. 

Posted : 08/11/2019 10:51 pm
aureumlocus
(@aureumlocus)
Eminent Member

@jmone

That’s good to know. Thanks. 

Posted : 08/11/2019 10:52 pm
jmone
(@jmone)
Estimable Member

Sounds good - I also do all my prints from the Dehydrator (with the door on of course!)

Posted : 08/11/2019 10:57 pm
aureumlocus
(@aureumlocus)
Eminent Member

@jmone

That’s a great looking setup. 

Posted : 08/11/2019 11:00 pm
aureumlocus
(@aureumlocus)
Eminent Member
jmone
(@jmone)
Estimable Member

Thanks - that was an older pic, this is more what it looks like with the Dry Cabinets.

My prints now look like the top half (more yellow than the tan bottom half).  The layers look better however than in your first print.  I also found that the prints are stronger the drier the filament is as well.  

 

Edit - I also UV Tinted the glass on the doors

This post was modified 1 month ago by jmone
Posted : 08/11/2019 11:07 pm
aureumlocus
(@aureumlocus)
Eminent Member

@jmone

this cabinets look amazing.  What are they and where are they from?  

Yes, my second print is definitely looking better.  Looks like a two-day drying process is needed.  The layer height is 0.3mm with a 0.6 nozzle so they are always going to be distinctive.

 

This filament was straight out of the sealed pack from eSun.  Like my ePA-CF it was wet from the supplier.  It's probably expecting too much for the Nylon not to absorb water from the environment through the standard plastic packaging.

Posted : 09/11/2019 12:10 am
jmone
(@jmone)
Estimable Member

I'm in Oz and got them here - https://www.photoequipmentstore.com.au/edry-ultra-low-humidity-250l-dry-cabinet-sl-206ca-100-made-in-taiwan/

There are a range of sizes, dehumidifcation capabilities, and costs.  I did a bit of a write up / review of a few different models - https://forum.prusaprinters.org/forum/english-forum-general-discussion-announcements-and-releases/edry-cabinet-testing-and-thoughts/#p134090  

Posted : 09/11/2019 12:32 am
jmone
(@jmone)
Estimable Member

I just think it does not take much absorption for Nylon based filaments to print poorly, and your right... a desiccant satchel in a plastic bag will not work.  

Posted : 09/11/2019 12:34 am
aureumlocus
(@aureumlocus)
Eminent Member

@jmone

Cool.  I'm in Oz too. Thanks for that.

Posted : 09/11/2019 12:52 am
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