Playing with the air nozzle design
I have played a little with the design of the air nozzle (Model R3) to try to improve its properties. I saw a video clip where they had placed a water bath under the nozzle to show how the nozzle blew. I did the same with Prusa's air nozzle and compared it with my own design.
The hit-surface of the Prusa air nozzle was very wide as it blows forward / down through the holes, and this air is not directed towards the tip of the nozzle.
I designed my air nozzle to blow more towards the tip of the nozzle where the filament is hottest. The result became a more concentrated hit surface and cooling below the nozzle.
I have not found any good model to test my air nozzle, but I do not think it's worse than the original.
My pictures below show the results of the two air nozzles.
Am I completely wrong with my theories or should my nozzle work better than the original?
Bear MK3 with Bondtech extruder
Re: Playing with the air nozzle design
Have you printed any test pieces showing, for example, reduced stringing or improved bridging performance?
Re: Playing with the air nozzle design
I've printed some models that look very good, but I'm looking for a model that requires good cooling.
Thank you for the tip about strings.
I will print a model that I tested earlier and that gave some problems with strings (PETG).
Bear MK3 with Bondtech extruder
Re: Playing with the air nozzle design
Now I have managed to do some flow simulations on the air nozzles, Prusa R3 and my designed nozzle. They differ in the design of the air outlets. On Prusa's nozzle, the front outlet are directed forward/downward, but I have directed them inward/downward.
What's right or wrong I do not know yet, but I think the air should be directed down against the tip of the nozzle.
On my air nozzle, the air is directed too much forward, so now I will redesign it so the air will be directed more towards the nozzle tip.
I'll add some pictures of the first simulation.
Now I have managed to do some flow simulations on the air nozzles, Prusa R3 and my designed nozzle. They differ in the design of the air outlets. On Prusa's nozzle, the front outlet are directed forward/downward, but I have directed them inward/downward.
What's right or wrong I do not know yet, but I think the air should be directed down against the tip of the nozzle.
On my air nozzle, the air is directed too much forward, so now I will redesign it so the air will be directed more towards the nozzle tip.
I'll add some pictures of the first simulation.
Bear MK3 with Bondtech extruder
Re: Playing with the air nozzle design
And some more pictures...
Bear MK3 with Bondtech extruder
Re: Playing with the air nozzle design
I have taped up the centre of the Prusa one due to the uneven cooling. It seems to cool one side of prints more giving uneven surface finish between sides of a print. That can be seen when the print orientation is changed.
Re: Playing with the air nozzle design
It seems to cool one side of prints more giving uneven surface finish between sides of a print. That can be seen when the print orientation is changed.
Does it cool better on the left side?
A bit better, but not perfect. I may go back to the drawing board again.
Bear MK3 with Bondtech extruder
Re: Playing with the air nozzle design
You can snag a test object off thingiverse that tests specifically for stringing and see how well each duct works. I am sure there are more than one out there on thingiverse.
Re: Playing with the air nozzle design
I will print different test models later, but first I will design an air nozzle that will provide a good result in the simulation.
Bear MK3 with Bondtech extruder
Re: Playing with the air nozzle design
Dude, this looks realy pro! A better fanduct would be great. The one on my prusa is melting all the time. I print a lot of ABS at 260/100.
Re: Playing with the air nozzle design
I'm interested in this thread, because Tom's recent E3D tour video contained which reminded me of something in a Forest Mims book I read when I was a kid: https://books.google.com/books?id=-sE7JVywygQC&pg=PA188&lpg=PA188&dq=forrest+mims+hot+wire+anemometer&source=bl&ots=pm0Gqj6Twg&sig=TOjM_tLk2Pdn0HD2t8a31_brvb0&hl=en&sa=X&ved=2ahUKEwiwnYGFyt7eAhWmFzQIHW3QBcMQ6AEwB3oECAkQAQ#v=onepage&q=forrest%20mims%20hot%20wire%20anemometer&f=false
It seems like it might not be too hard to rig this kind of thing up cheaply and map out airflow at a few different part cooling fan speeds. Is it possible to force the hotend's cooling fan on and off manually with gcode, or would it be best to just achieve that by setting the hotend heater to a fairly high temperature vs off?
Re: Playing with the air nozzle design
That looks really cool and promising.
A model that I still have only failed to get printed nicely on the mk3 cause cooling sucks: mooncity 2.0. The overhangs especially in the front are always coming out ugly.
Maybe that would be a nice model for comparing performance!
Also the bottom Part of the sorceress is finicky about cooling
Re: Playing with the air nozzle design
I am grateful for suggestions for test prints, or you may want to test the nozzle when I have a suitable model ready.
Right now, I simulate a model I designed and make small detail adjustments between each simulation.
The problem right now is to try to direct the side streams to the correct center point
The goal is to have a good simulation before printing the new nozzle.
Bear MK3 with Bondtech extruder
Re: Playing with the air nozzle design
I am looking forward to the product of your research!
Re: Playing with the air nozzle design
This is very interesting work. I am struggling to print https://www.thingiverse.com/thing:678170 on my Mk3. Needs excellent cooling and I just can't make it with the standard cooling, so if you have a model that I can try, I'd love to test it!
Re: Playing with the air nozzle design
It's still a prototype, but if you want to try it, please let me know the resault.
You must use the attached nozzle support, no support material needed when printing parts.
Bear MK3 with Bondtech extruder
Re: Playing with the air nozzle design
I do not claim that Prusa Nozzle R3 is a bad air nozzle, but I think the air flow should be more concentrated to the tip of the nozzle.
The pictures show a clear difference in how the air is distributed between the different air nozzles.
Feel free to come up with comments and ideas about how a nozzle should look.
Attached ZIP file contains STL files for testing.
Rotate the details in Slic3r 90 degrees (X-axis). I unfortunately wrote them on the wrong work plan.
No need for support material. Nozzle ABS, nozzle support PETG, 0.20 or 0.15 mm.
Replaced the file with Rev. 2
Bear MK3 with Bondtech extruder
Re: Playing with the air nozzle design
I just printed the prototype fanduckt and tested the airflow with my vaporizer. Looks pretty good. The parts also fit very well to the print head of the MK3. My first Benchi (in my case not the boring boat) is printing right now and I will upload some more pictures as soon as it's done.
In any case, the air stream seems to arrive where it should be. The model is also better to print than the original. My respect for that.
Very good work so far!
Re: Playing with the air nozzle design
Love this "human-bio-testing-machine" 😆 😎
Thomas
Re: Playing with the air nozzle design
Mike, that was a really good test video of the nozzle and it seems to spread the air as it was supposed to be. Unfortunately, I can not test myself because I do not smoke 🙂
Did you do a comparative test with Prusa R3 too?
The file RHD_MK3_Nozzle.zip in my last post is a bit updated and the nozzle support against the extruder is slightly better.
And you had many interesting videos like the one with the vacuum pot. Do you use it to recondition moisture filaments?
Bear MK3 with Bondtech extruder