Advanced nozzle design
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@hebigt said in Advanced nozzle design:
@mrdui I'm curious about this too. I wonder if the longer orifice creates significantly more pressure loss due to friction compared to a standard V6.
I would say that's highly likely (although not necessary just due to friction). Based on my own exploits into multi-input hot ends, something like a Diamond which has about 2mm final orifice length needs an immense amount of pressure advance compensation but has very little tendency to ooze and requires only a little retraction length on top of the PA compensation. But my own design which uses "standard" M6 threaded nozzles and thus a much shorter final orifice length, requires hardly any pressure advance compensation but has a much higher tendency to ooze and requires much higher retraction length values. The nozzle diameter, filament and temperature in both cases being the same.
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@darth-scoob I made the same observation. I assume this is a sort of "ironing" effect due to the larger flat at the end of the nozzle. I definitely think the larger taper causes heat dissipation issues and plan to get the taper to the standard geometry as soon as possible. As for the toolchanger, I like it a lot. There are many things I would/have changed about it, but that's the beauty of open source 3d printing products.
@mrdui That will be one of the final tests I perform. High speed printing is lowest on the list of what I'm interested in here, but obviously want to know how it compares. Who knows, I may be surprised. Assuming I see reduced throughput, I've considered adding features like this:
https://procdn.blob.core.windows.net/pages/nozzles-caddie-wrench.pdfI am unsure how patents would affect similar features on a 3d printing nozzle as I simply haven't gotten that far.
Overall, I assume there is more pressure loss in the ADV nozzle vs. V6. Whether it significant or can't be compensated via software, I am unsure at this time. I am also hopeful the improved geometry and reduction in sharp angles help to mitigate such an issue. Plastic really dislikes sharp angles.
Just for posterity, the primary areas I'm looking to improve are a) overall consistency in extrudate, b) improved surface finish, and c) reduced drool/stringing. On C, PLA is the material I am least interested in, but as it is the defacto 3d printing standard I decided to start with it. The nozzle is being developed with higher temp/viscosity and engineering grade polymers in mind. I'm very optimistic about doing Nylon test prints.
EDIT: One other thought, and correct me if I'm off base -- I assume standard nozzles have such a short orifice length due to machining limitations. After all, that's a very small tool and deflection would become an issue if making it much longer. I highly doubt the current "standard" orifice lengths are necessarily optimized.
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@plasticfactory said in Advanced nozzle design:
......................... EDIT: One other thought, and correct me if I'm off base -- I assume standard nozzles have such a short orifice length due to machining limitations. After all, that's a very small tool and deflection would become an issue if making it much longer. I highly doubt the current "standard" orifice lengths are necessarily optimized.
That's a thought that has also occurred to me. I would guess there ought to be an optimum orifice length to diameter ratio. Or if not, then at least some trade-offs to be made between long vs short, or pros and cons to put it another way. The only data point I have is the very unusual Diamond mixing hot end which, for an 0.4mm nozzle diameter, has a 3mm long section at 0.4mm for each individual input, then they combined into a further 2mm long section which is the nozzle proper. I know that this design needs an immense amount of PA compensation but oozes very little, especially when the volume of molten plastic in the melt chamber is taken into account.
Here is a picture of the beast
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I'm not sure if anyone is still interested in updates on this, but a lot of testing has taken place, as well as numerous design revisions. All inspections were performed with a new Keyence LM. All brands used in testing were "high end" or otherwise among the most popular in the community (I'm not sure how I feel about including specific names compared to measurements taken). Key updates:
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We have dialed in our machining process to hold a +/-0.001mm tolerance. The EDM machined nozzle is objectively higher precision than anything I can find on the market. The latest .80 nozzle measures at 0.801mm. The +/-0.001mm is consistent and achievable regardless of major ID nominal size (IE, a .40mm nozzle will come out to ~.401mm). Nothing I measured across all popular brands came close.
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The machining process is very conducive to getting roundness right. The EDM machined nozzle is objectively rounder than everything I tested (across 6 nozzle brands). The EDM machined nozzles hold a roundness of 0.010mm, with the typical roundness across all tested brands being ~0.019mm.
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The machining process results in a surface finish more consistent than anything else we dissected. This is typical for EDM machining vs. traditional cutting. Because we have some control over how matte or gloss the finish is, and the subjective nature of the effect this has on parts, I won't share much more until I have good pictures.
Overall, I'm very pleased with how things are turning out, though I was hoping for improvements in other areas, too. I think there is value in knowing you're .40 nozzle is as close to .40 as possible, for obvious slicing benefits and repeatability when swapping nozzles. The most precise nozzles I inspected were e3d's, averaging 0.394mm, with most brands measuring ~0.38mm, and the worst (and among the most expensive!) as low as 0.36mm. It definitely seems to me knowing your exact orifice size is just as valuable as knowing your exact filament diameter.
Where I go from here... Unsure. Are there any tests users would like to see performed? Specific prints? If this is allowed, I'd even love to get feedback on overall perception -- assuming things were priced similarly, what would make current options more appealing than this?
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Thanks for the update!
Have you considered adding additional surface area, in the larger diameter section, to improve heat transfer to the filament?
The Bondtech CHT nozzles are improving max flow rate, with their 3 converging hole approach. With the EDM, I think you could do better and have essentially an internal spline shape.
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@CCS86 Actually, yes! I was inspired by this IMM product:
https://procdn.blob.core.windows.net/pages/nozzles-caddie-wrench.pdf... but was frustrated to see someone did exactly this with the Bozzle (https://www.fabreeko.com/products/bozzle-0-5mm-full-tungsten-carbide-nozzle-by-rentable-socks).
I am confident it could be done with even better geometry/finish (I have cross sectioned and tested the Bozzle along with the other popular nozzle brands), but higher flow has been toward the bottom of my list. I will definitely consider focusing on that next as it seems the community is very driven by faster/higher flow these days.
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@plasticfactory said in Advanced nozzle design:
@CCS86 Actually, yes! I was inspired by this IMM product:
https://procdn.blob.core.windows.net/pages/nozzles-caddie-wrench.pdf... but was frustrated to see someone did exactly this with the Bozzle (https://www.fabreeko.com/products/bozzle-0-5mm-full-tungsten-carbide-nozzle-by-rentable-socks).
I am confident it could be done with even better geometry/finish (I have cross sectioned and tested the Bozzle along with the other popular nozzle brands), but higher flow has been toward the bottom of my list. I will definitely consider focusing on that next as it seems the community is very driven by faster/higher flow these days.
So they did!
I can definitely see room for improvement in surface area of the Bozzle.
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@plasticfactory I would be interested in seeing if there are any differences in the consistency of the extrudate size compared to a standard nozzle I would also be interested to see if the improvements made to the nozzle since the previous tests had any effect on the surface finish of parts, or line consistency.
