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Precision Nozzle

PostPosted: Thu Mar 21, 2013 2:55 pm
by Digitalmagic
I gave a try making my own nozzle, discovering the *pleasures* of precision machining.

Here is my first prototype.
I experienced the many hurdles to jump, and understand a little better how to craft a precision nozzle.
So, I start from this first cut, trying to design different nozzle sizes and other characteristics, to match existing hotends.

Custom brass 0.35 nozzle

Re: Precision Nozzle

PostPosted: Fri Mar 22, 2013 1:31 am
by Digitalmagic
Or rather: Details about nozzle.
A first goal is not to have to choose between 0.35mm and 0.25mm, so to say.
I managed to get 0.30mm and 0.28mm to get finer extrusion.
Actually, printing will tell me if 0.30mm/0.28mm with 0.1mm layer is of interest.

In the showed design, I did a mistake using M8 instead of M6, so I make them again with M6, and I use 118° cone instead of 90°

About heating and temp sensing, I build a specific test bench with a PID to study the detailed thermodynamic, varying design and thermistance/thermocuple position.
About thermal barrier, I opt for original solution, there is really a commonly bad functional analysis about nozzle/hotend/coldpart that I read on forums.

Polycarbonate printing (300°) is on the goal list, too.

Re: Precision Nozzle

PostPosted: Thu Mar 28, 2013 11:51 am
by Digitalmagic
Here 4 nozzles I machined: 0.35mm, 0317mm, 030mm and 0.28mm
Threaded for M6
0.35 - 0.317 - 0.30 - 0.28 nozzles

Now, I can screw then on my printer hotend, do they extrude well? Will see.
Then, am gonna to print the same object, with adequate features, to see which nozzle diameter is interesting to have, below 0.35mm, without recurrent clogging problems.

The lathe has a slightly bad alignment, showing a small eccentricity, (mine is huge) but is not a real issue at this stage.

(Sorry for the picture, trying to shot a better one soon, to clearly see the extrusion channel hole.)

Re: Precision Nozzle

PostPosted: Sat Mar 30, 2013 8:32 pm
by Digitalmagic
I successfully extruded some 1.75mm ABS with the custom 0.30 nozzle, mounted on a makergear heatcore.
The extruded spaghetti is 0.35mm, comparing with 0.41mm when using a 0.35 nozzle.

Now, am gonna print the same part with 0.35/0.30 nozzles to see the detail enhancement.
With slic3r 0.99 released today, allowing multiple layer heights, it is even more interesting to have dualstrusion to combine layer height and nozzle diam to refine part printing.

EDIT: I printed successfully with my 0.28mm nozzle a simple part with flats and rounds to clearly see the layers.
I printed the same part, with same settings, using a standard 0.25mm nozzle (not mine) to compare.
The 0.28mm gives a quite close result, with more small peaks here and there, but very satisfactory.

I did not get any clogging with my custom nozzles, though I always try to lower extrusion temp at the lowest (205°C / 204°C) when infills aspect starts to look weird.

Now, am preparing 0.25mm and 0.20mm nozzles to explore the ability to fine print.
The printing test am looking for is to match the nozzle diameter with layer height, like 0.20/0.20 0.15/015 and if it extrudes, 0.10/0.10.
I don't think "vanilla prints" need this level of fine grain, but it is interesting to know it is possible, perhaps for some parts requiring mechanical/artistic details.

Also, there is a new trend of "acetone spraying", which can really turn low res part into an apparent more detailed part, with a shiny look.
This trend is clearly at the opposite of fine printing, printing faster, and offering a good post-processing finish, though.

Fine printing on one end, and acetone spraying on the other one, just widen the printing capabilities.
(And multitrusion, BTW)

Trying to add comparing pics soon.