Some 0.24mm and 0.35mm nozzle prints

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Some 0.24mm and 0.35mm nozzle prints

Postby orcinus » Mon Mar 10, 2014 8:48 pm

I've recently busted an Arcol.hu hotend i've been using for the past year or two and am trying out an E3D hotend.
The E3D has a 0.24mm nozzle, the Arcol.hu had a 0.35mm nozzle.

You might ask - what's the point of having a nozzle thinner than 0.5mm since it doesn't limit the minimum layer height.
No, it doesn't, but it limits the maximum XY "resolution" (actually, the minimum width of the extrusion "trace") at a given layer height.
For example, if you go significantly lower than 0.25mm with a 0.35mm nozzle at 0.1mm layer height, you'll overstretch the plastic and end up with a spotty extrusion.

Anywho, here are some prints with the Arcol (just before i broke it) and the E3D.
E3D prints are at 0.15mm width, Arcol prints are at 0.25mm width. Both are at 0.1mm layer height.
The bigger print on all photos where it's present is the Arcol, the smaller one is E3D.

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Re: Some 0.24mm and 0.35mm nozzle prints

Postby orcinus » Mon Mar 10, 2014 8:51 pm

The "folds" that look like vibration artifacts aren't vibration artifacts, but are part of the original model.
That would be: http://www.thingiverse.com/thing:245735

Image
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Re: Some 0.24mm and 0.35mm nozzle prints

Postby DonaldJ » Wed Mar 12, 2014 12:47 am

Nice prints, but help a Big Dummy (TM) out...

How do you get extrusion widths smaller than the nozzle diameter? Seems counter-intuitive to me.

Extrusion reminds me a lot of the old RapidoGraph pens; the steel tube jobbies that we used in the last century. Never got a triple-0 line from a #1 pen.
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Re: Some 0.24mm and 0.35mm nozzle prints

Postby secretgspot » Wed Mar 12, 2014 1:24 am

dang.. I bought e3d just because of this post.
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Re: Some 0.24mm and 0.35mm nozzle prints

Postby orcinus » Wed Mar 12, 2014 3:34 am

DonaldJ wrote:How do you get extrusion widths smaller than the nozzle diameter? Seems counter-intuitive to me.


Simple - you stretch it thin.
And therein lies the problem... You can't stretch it too far, because it snaps.

It's more like drawing a line with the cake-icing squeezy thingamajig, than a rapidograph.
If you extrude less then necessary, you'll end up with a "trace" that's thinner than the nozzle.

Of course, nasty things start happening once you go that route.
The "ring" around the nozzle orifice isn't flattening out the "trace" properly anymor, for starters.

Also, take the extrusion width values with a grain of salt - the *real* width of the extrusion is usually always wider than the specified one.
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Re: Some 0.24mm and 0.35mm nozzle prints

Postby orcinus » Wed Mar 12, 2014 3:37 am

secretgspot wrote:dang.. I bought e3d just because of this post.


Bear in mind it's... picky.
At least the 0.24mm nozzle combo is, haven't tested it with 0.35mm yet.

With this particular filament, i got really nice results.
Colorfabb's silver was much nastier (it's much thicker, doesn't stretch as well and tends to blob much more).
With some no-name orange filament i got really really smooth walls, which is too bad, as it doesn't do overhangs as well.

Also, as i've neared the end of the spool of the silver from the photos, i got a much rougher surfaces for some reason.

It's probably the nozzle - people consider anything below 0.35mm "experimental" for a reason...
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Re: Some 0.24mm and 0.35mm nozzle prints

Postby orcinus » Wed Mar 12, 2014 3:43 am

One thing i still cannot crack is, why i can't get the perimeters as glassy smooth as with the Arcol.
I can get more detail out of the E3D @ 0.24mm, but it gets obliterated by the comparative surface roughness.

Some bits of the Arcol prints actually look *sharper*, because the smoothness makes the shadows and highlights sharper, even though the features themselves are slightly duller.
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Re: Some 0.24mm and 0.35mm nozzle prints

Postby orcinus » Wed Mar 12, 2014 5:29 pm

Heh, i think i've figured out what was causing the surface roughness...

It seems the E3D nozzles aren't machined as smoothly as the Arcol nozzles.
There appears to have been some swarfy edges on one side of the nozzle, causing it to "dig into" the surface in one direction, but not the other.

I've sanded that down with some very fine sandpaper and realigned the hotend a little with some shims made from paper and kapton and it seems to have fixed the issue, at least as far as calibration cube tests are concerned. We'll see if it helps with more complex stuff.

As a sidenote, tried printing Taulman T-Glase (PETT) with it today.
Initial results were a nightmare.

It wasn't until i've tried printing at 260 deg C (instead of the normal 210-230) and STILL experienced delamination and uneven extrusion, that i've figured out i'm actually freezing the PETT immediately after it exits the nozzle. Turns out PETT freezes to solidity VERY quickly. That, combined with relatively small thermal capacity of the E3D nozzle (it's fairly thin) and my overdone cooling system (2x50mm fans, of which one is ducted and blows directly at the nozzle tip) resulted in a mess.

Switching the ducted fan off and reducing speed seems to have helped.
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Re: Some 0.24mm and 0.35mm nozzle prints

Postby DonaldJ » Wed Mar 12, 2014 5:38 pm

(For comparison purposes only, not an ORD Bot)

A while back I was fooling around with a 0.2mm nozzle, 50 micron layer height. Results are okay, but more trouble than they're worth. First few layers are tricky. I think it was PLA, with extrusion width of 0.2mm.

gear.JPG
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Re: Some 0.24mm and 0.35mm nozzle prints

Postby fma » Wed Mar 12, 2014 5:40 pm

Very impressive!
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