Hi guys! I arrived in Chicago after a long trip to go to MRRF! I haven't gotten the time yet to respond to your questions and suggestions, but I soon will. Maybe meet you there!
Aw, man. I couldn't make it this year. 😢 I hope I get the opportunity at a future MRRF. Have a good time there! Awesome work on this - I can't wait to see what comes of it.
You don’t have the squish of SLA and you are not doing small cross section free form print so To counter balance the tiny surface tension effect. Start by printing the inside wall and apply a Z shift at each layer. That should do the trick and allow you to use low viscosity resin which would be the easiest to prevent leaks
Awesome experiments. Great note on safety for the lasers, but you missed a very important warning with this type of work. Photopolymer resins give off heat when curing. If you have some on your hands (even with gloves) it can burn you if it starts curing - if too much uv light hits the spot. Be careful, even a smudge can burn you to blistering level.
Thin the mix. Add a tiny spray head of resin, like spray painting, the laser cures the "paint". Attach a standard 3d print head to your rig. Precise controlled color depths for 3d prints. This way its lack of layering is a benefit. Easy to scale up to full color printing. You could also combine it with a 3d scanner and make an automated 3d coloring device for existing 3d prints.
@@properprinting Why are you curing the resin right near the print head. Put a shade system so that what you are actually printing doesn't get cured until it moves outside of the print area. Also the fibre optics. make a loop, and sand it. The light will come out the sides instead of the end.
This was the toughest video I've made so far. I badly underestimated FDM printing with resin, but I'm happy with the result. The pump on itself already enables some interesting possibilities for the extruder series! If you've got suggestions on how to FDM print resin, than let us know in the comments!
What about turning off the laser on travel moves? If you are controlling it with the fan output, you can just wrap all G0 moves in M107 - M106. Then even if it leaks resin it will stay liquid. Also in DIW adding a filler to change the rheology is very common (eg SiO2 or TiO2). PS is the pump design uploaded somewhere? Kinda want to try it out
@@daliasprints9798 Yep, although that depends on the firmware you're running. I know for sure you can do it with duet, but I haven't had to do it with others. Also you might want retract to lower pressure in the needle, though that quickly result in air bubbles. The M106-107 is just a regex substitution
Interesting idea, love it! On a topic of predictable flow I would suggest trying a system with a reservoir residing above the printer(maybe on a shelf) such that it can introduce a manageable pressure in the tube. Pump may add the resin to the reservoir at a predictable pace and reservoir will act a a buffer to have enough resin to keep needed pressure. Then the two challenges still left: a) stop the flow and b) control the flow intensity. To be able to stop the flow I would add a small solenoid to close the resin output right at the print head; just before the nozzle. And to be able to control the flow I would try to have a prolonged/rectangular shaped reservoir, such that when rotated/tilted the height of the resin change and pressure change with it. Idea with tilting resin reservoir will require a motor of some kind. This whole idea is very dependent on ether ton of experiment or a mode to predict its physical behavior. Anyway, good luck with the project!
The pulsation can be solved by using 2 tubes. Both tubes run on the same set of rollers but the outside housing has a phase shift for both tubes. This way the pulse of 1 tube falls in the dead period of the other. Watson Marlow (Dutch peristaltic pump manufacturer) has a few model doing this running in the lab here.
Thanks for the info! As it looks for now it seems not to be pulsating too much with this design. One tube makes it easier to work with, so I hope I can stick to it.
you need gel instead of liquid, liquids will move on you before curing and it retracts unpredictably. I would like to see some trace testing to tune every parameters, you can't use standard fdm parameters. You need to cover a wide spectrum of values because you're into unknown territory. We don't know if the fluctuation in extrusion is causing real issues. When the first layer is nice, then test to stack them and succeed to have consistent height. I would try pointing the laser on the nozzle and use high speed printing to avoid clogging. Considering each layer will cure more previously laid ones, the power of the laser needs to be tuned to barely solidify the resin with one pass, this will reduce clogging. We can check if the layers need to be thinner than the nozzle diameter and if prefers over or under extrusion. if the resulting parts are tacky, it's not an issue you can cure them after.
When people are amazed by engineers they think it’s just because of how smart they are. In reality it’s often the dedication and patience that makes them uniquely capable.
16:48 - So the resin itself is acting as a light pipe, allowing the reflected UV light to travel up the nozzle and prematurely cure the material. I didn't see that coming.
So kinda "upstream contamination" but with light. Maybe printing with dark / black resin could prevent it? Or maybe just adding some coal powder / dark pigment to existing resin could do the trick?
@@puerlatinophilus3037 the resin itself needs this light pipe type of process (penatrating) in order for any curing past the surface level of the print regardless of the method used to print. I think what we are seeing here is actually seeing. How we know an object is somewhere generally relies on light waves reflecting from its surface or the absence of that. This is no different. The laser light is reflecting from the surfaces and penatrating the nozel. Either controlling the light or shielding the actual nozzle or both is what will be needed. But I guess if it was that easy, they would be mass produced and on the market by now. So what do I know.
Edison would have been proud of you as this is a perfect example of his theory of repetitive experiments where creative failure leads to progressive knowledge accumulation. Good Work.
One note on the optical fibers, they can actually fail to reflect the light along the fiber if the bend radius is to small, maybe that was also a reason why the first design failed
Whilst we can see “some light” at the end of the fibres, some materials have much lower transmission at UV wavelengths. For example Germicidal 250nm fluorescent tubes have to be made with quartz as glass filters a lot of the energy at this wavelength. I suspect end polishing of the fibres also has an impact.
In this case it was because of the fucked up surface. One cannot cut fibre optic cable with a kitchen knife and expect it to transmit light perfectly. The cables must be cut with a special tool that makes sure the surfice is perpendicular and doesn't have defects. You also need to align very well the start of the fibre to the laser beam making sure it also is parallel to the beam. If the laser is coming at an angle, there will be huge reflections at the beginning. I liked his idea don't get me wrong, but it is pretty clear he didn't research how fibre optics cables work
Maybe more like an ink jet and pulsing the laser… But bravo again. Every issue I wanted to make a suggestion and each time you made the same conclusion. Love it
Have you tried/considered a non translucent resin? I think ideally something dark like black. I think the issue is that the resin refracts some of the laser internally, and funnels it up the nozzle opening like an optic fibre. Perhaps a less translucent resin would prevent this. It would be a lot slower but you could also try doing dropwise extrusion (and retract to break the physical connection between the resin in nozzle and the print, possibly mitigating the optic fibre like effect)? or print a layer then cure it?
I was thinking along that line as well, when you watch Joel's video the resin used is an opaque white. A different resin should do the trick, hope it gets resolved it would be an awesome addition to the tool box.
Absolutely love your videos! The thing I love most is watching you work through issues and roadblocks. Not only have I learned a ton from watching your videos, but you've inspired me to be more experimental. Some of my experiments work out, some don't, but the most important thing is I learn from each and every one.
I have made some projects similiar to yours, i like finding someone with similiar problems and stuff (but you are way better i'd say) i can't find anyone like you you are severely underrated
I like this guy. I just found this video and he seems to not pretend to know what he's doing but at the same time knows how to make things work. Very fun to watch.
I work with lab instruments that use peri-pumps. They have a lot of advantages, such as easily adjusting flow and volume by changing the ID of the pump tubing. You can eliminate the pulsing by using the flexibility of the tubing between the pump and nozzle as a pressure receiver. If the flow from the pump is slightly higher than the nozzle size can handle, the tubing between the pump and nozzle will pressurise and expand slightly , acting like bellows to absorb the pressure pulses. Also, having more rollers reduces the volume of the tubing between rollers and therefore the volume that is pumped with each revolution. Most commercial peri-pumps use only 2 or 3 rollers.
I used to use peristaltic pumps. I also recall them only having about 3 rollers and they definitely delivered continuous flow to lab instruments. I remember calibrating the flow and we used special tubing in the actual pump section with coloured tags on each end which indicated the flow range based on ID, these tags locked in place to stop tube movement and put the tube in the pump under slight tension.. helps with pulsing and stops tube feed. Main issue with a peristaltic is over time it damages the tube changing the flow or even wearing through completely. So another reason for the short section in the pump as you just replace that small length each time. Overall I think he should take a quick look at lab grade peristaltic pumps as they solved all these issues decades ago.
@@RocketMagnetUK I agree . There are many different designs. I have even seen hospital infusion pumps that used many flat plates operated by a helical cam to pinch the tubing in a continuous wave. A company like Watson Marlowe would be able to give him all the information he needs
Hi really nice project. I have worked in a lab for uv curable resins but I have no experience with 3d resis. There are basically two kinds of catalyst for this typ of stuff. Radical and Kationic catalysts. The radical ones have the advantage that they stop working when Light is emited which is super important for high res., while the Kationic once continue after the UV is gone but they are way slower. So you actually could use a really thick resin with a cationic catalyst. It would allow the resin to cure after it has left the nozzle. But you would need rather thick layers and would have low resolution, but you actually might be able to get super fast printing speeds. If you do not care about colours curcumin is actually a pretty good kationic catalyst. Greetings from Germany
You tried the idea that I have been thinking of for about a year, great job! I would use multiple UV LED's in a circle pointing at just below the nozzle. The point is you don't need to fully cure the model during printing, so you won't need that much power delivered by a UV laser. The model can be fully cured later in a UV chamber, we just want this to get the proper model shape in the first place.
I totally had a similar heat related issue when playing with the plastic optical fibers on a project. Even got glue would partially melt the fibers, and be responsible for blocking the proper light transmission. I felt your pain my friend.
Really nice, maybe instead of trying to cure full cure the resin while printing you can add a UV lamp and after every layer the nozzle go to a light protected place, turn on the Light for a couple of second and then continue printing
It won't stay it place this way. The resin is still a liquid that would flow down while you are printing one layer. You need to constantly cure resin that was just extruded.
@@Karavusk it depends on the layer thickness, the surface tension of the resin and the nozzle diameter, you can add something to the resin so it get thicker, like baby powder, the video you quote use a thicker resin more like a gel
Great video! I would use an air pump inside the bottle, and a valve on the nozzle instead of a pump, like the system used in the m3 max to top up the tank. Also i would try to print at very low temperature to have a viscous resin, much more like the gel in noel's video. That would allow to increase distance of the laser light from the nozzle and prevent clogging. Just my 2 cents here.
@Arpad Toth you just need to build enough pressure. Anycubic use the very same method to automatically top up the vat in the m3 plus and max printers: a sealed cap on the resin bottle and a small air pump that just pumps air into the bottle which then sends out resin to the vat.
@Arpad Toth just need to have enough pressure, people who have a well for their domestic water supply the water is pumped into a tank with an air bladder which then pushes into the house. Our old house had that and it kept a steady 60PSI. In theory a hybrid system would work to eliminate the issues of pulsing, a pressurized tank and the pump constantly pushes resin into this tank while an pressurized air pocket moves the water along. Just like how the well pump pushes water into the storage tank but the air bladder pushes it up into the home.
Indeed, it seems like you can take some notes from that machine in Joel's video. Opaque white gel resin is what they use. Less UV reflection with opaque white. Gel because surface tension is unlikely to hold. Perhaps if a single laser is not pointed at the tip of the needle but instead - a couple mm BEHIND the line of resin as it's being printed. That would only work if printing in that single direction, though. Hmm.
Sugesstion, paint the printning surface mate black, and use black resin to prevent ligth leaks, use a weaker lazer or dim it out, you tecnically can shine a weak lazer directly to the center, but, weaker so it doesnt solidify instantly, more like a flash ligth, that wen the center of the lazer gets away from the printnted point a second ago its solid enough to hold it self up, untill the next layer goes over
You are the most Swedish person I have ever seen. You are the literal stereotype of a Swede. I have a Swedish friend and he agrees. So I can’t be wrong. 😁
I think your on the right track using a standard Nozzle shape, the V angles down towards the tip so no matter which direction the nozzle goes any oozing will flow back to the tip. With normal fdm the plastic is always soft and will be wiped off when the direction changes and gets 'run over' in the part when the nozzle returns thus it doesn't accumulate but with resin it needs to get cleared asap. the standard nozzle looked the best if you can sort the leaks.....hope this is some help, Andrew. love watching you work ....it's FUN
Whether you get this working or not, this project and several other videos on your channel are truly inspirational! I don't have anywhere near your level of design skills or engineering knowledge, hell, I don't even own a 3D printer but I can't wait to see what you come up with next! Goed bezig kerel! 👍
Wow, what a cool video and idea! I've seen some great suggestions in the comment section about pulsing the lasers. I am not an engineer by any means, but perhaps a "simpler" first attempt would be to extrude the resin with the laser off, then run the same path (without extruding the resin) with the laser on to cure the resin. The higher viscosity resin would probably be more ideal, since it better resists flowing away from the previously deposited layer. Yes, you are running the same print moves twice which will greatly increase the "print time", but I don't know that speed is necessary concern at this stage. Just an idea (maybe others had it in the comments too). I am looking forward to your next video!
Amazing, as always! Have your sponsor make you a custom resin that is more cohesive like silicone sealant texture or toothpaste so there is no surface tension trying to form drops. I believe that is why your nozzle ends up scraping. The trick will be to balance thickness vs 'pumpability'
I watched the same RU-vid video and thought the process would be the end all in 3D printing. I have two suggestions. Lose the laser. Go with what we know already works, UV leds. Cheaper and easier to work with. you'll still need some way the shield people from the light. Second use a tank to store the resin and air pressure to pump it. You can control the pressure very precisely and electronic valve to turn the flow on and off. Good luck and I'd love to see you make this work.
I just love your perseverance and patience! With your ingenuity, you will get this done I am certain. What a process! But, what a great idea!! Keep going ...
Try adding an additive to the resin to turn it into a gel, add some viscosity to it so it acts more like melted filament vs water. Surface tension causing too many issues
I had this idea a long time ago back when there was a kickstarter for a UV resin pen. I forgot about it entirely and I'm glad you have taken the time to work on this.
I would experiment with led exposure time for resin cure. With this I would set up a led timer circuit with the pump module so put sensors on the position of the pump to give you timing so it can interrupt the led and pulse it as a strobe effect. I believe the resin is illuminating on itself so a timed led pulse strobe would most likely help. Remember translucent liquid acts as a magnifying glass for light. This will take mulitple sessions to get the timing correct.
One quick solution to try should be to get some kind of matte dark black coating or cover on the build plate, which should greatly reduce the curing issues, as the black material should absorb most of the laser light. Maybe use a bottle of Black 3.0 to paint a build plate and place under some kind of transparent matte non-stick sheet? You may still have issues with the light reflecting off the printed material, but should otherwise greatly cut down on the reflections.
It is more or less the functionality of a Multijet (3D Systems) / Polyjet (Stratasys) Printer. Works exactly the same way. But rly good progress and achievement. GL with it.
Inkjet printing has had similar flow issues with nozzles, one of the ones that worked well there was with a piezoelectric crystal for a drop on demand printhead. This was used to control droplet size and speed of droplet ejection from a reservoir. Very exciting to see this, looking forward to more updates.
Commenting before finishing the video, I just had to say that the water printing part had me genuinely laughing, thank you for this great video and all your efforts.
Nice vid! Just a few observations; if the glue has same index of refraction as the fiber optic they might disrupt light flow. Also, just snipping the ends of fibers is not a good idea. Pros actually use special tools to grind the fibers completely flat under a microscope. The ends are the most important part of the fiber in many respects. So 1. fit fibers 2. cut all fibers at once in the laser end and grind them down to a flat surface together 3. grind each strand flat separately in the other end 4. fixate with something non transparent like rtv 5. profit
Try to print the thick resin without the lasers. Then when finished with the layer (via laver change g code) switch a UV Lamp (via Relais) on to cure the whole layer.... The only thing that will be important is to protect your nozzle at the curing process...
I have not watched this to the end yet but 1st thing I thought of for a pump is a 2 bladder pump. Resin in 1 and pump air into the other, as it fills with air it pushes the resin out.
i suspect the liquid resin itself acting like an optical fiber inside the nozzle, uv light hitting the cured part is getting by a process called "frustrated total internal reflection" bounced around inside the cured part, and up into the nozzle, curing the resin prematurely in and around the tip. your printed part is in this case also acting as fiber optic, where the liquid is touching the part when its getting "extruded", a uv light bridge occurs, releasing these internal reflections from inside the part into the nozzle. you are an absolute mad man even attempting this. we need more of this lunacy
tremendous challenge, that effort was titanic, a lot of desperation, but science is like that, success and error, greetings from Mexico, I am attentive to your videos.
Hi Adam, I tested this solution last year and my best results were on my old coreXY by reversing my bed plate and axles. print upwards, the resin holds better to the plate and the prints are clean!
when you use resin printers to make things like your... laser funnel thing, I was really surprised to see that you only printed one at a time. You can print multiple at once with no cost to the print speed, giving you multiples incase something breaks or if there are small printing defects you can sort of choose from a batch. A lot of what you do is way over my head, hoping this small thing I saw can help improve your QoL during these epic experiments.
@@simonquvang6073 I don't personally find that to be critical issue, especially not when trying to develop new hardware. I'm saying that as a person with absolutely no income. Obviously when you are evaluating resin printers or printing in general it should probably matter, but uh, for this guy and for this use, I'm gonna label it a non issue/
Once upon a time, there was a roller pump (application) that suffered from poor impulse control. But as luck would have it, that problem was solved back in the early 1970s. The application was pumping blood in heart-lung machines, but the impulses caused by the action of the roller(s) would put a "squeeze" on the red blood cells, causing them to burst. You need an entirely different solution (no pun intended) to your fluid transport problem.
Incredible first iteration! I'm glad your persistence payed off. If your enthusiasm towards this project still outweighs your frustration and you're planning on a redesign, I have one possibly good suggestion: Higher pressure resin through a much smaller nozzle. If you get the pressure high enough you can form a small jet of liquid that will still be diposited even if the nozzle lifts off the surface. As a side benefit, this will increase the flow velocity giving less time for the resin to cure in the tip of nozzle (also the smaller opening will let in less UV). If you like the idea then I'd look into using a scroll pump for consistant high pressure flow. The elasticity of the peristaltic pump tube would be an issue at these pressures, especially when you want to turn it on and off quickly. Perhaps pneumatic tubing would be a good choice.
Time ago I was thinking about a resin 3d printer based on rotating uv laser beam and plastic fiber to optically pass to a linear printer head. Like old matrix printers😬. I know resolution will be poor but is an interesting aproach .. As said.. only an idea.. . Great efford and inspiring videos..👌🏻
so this is essentially the way stratasys polyjet printers work, except they use many more nozzles in what i can only describe as a vernier grid array. also in order overcome the overhang issue, support material is printed around the part preventing loss of shape or drooping. if you can add another head to do the gel support, you will have much better success.
Love it, I understand you pain always have more material on hand as the first time you don't succeed try, try, try, and then try once again thank you for showing your struggles 😊
Wow, that is very cool!! You made amazing progress and thank you for showing all the issues you ran into. I am not sure if this is possible. If there was a way to thicken the resin that it is more like a gel, so the laser(s)/fiber optics do not have to be aimed at the nozzle. The resin just needs to hold its shape long enough for the to laser pass over it.
@@CalebKraftmakes the company that makes the resin extrusion printer has two ways of cleaning the nozzle so buildup is definitely an issue for this type of 3d printer
Printing is looking great, very confident you will get this right. If you wish to steady the flow from your pump fit an accumulator. They are used to even the pulses created from a pump system easy install.
The first printer that I had any experience with used resin and "wax" to print almost like a standard ink printer. It would lay down the wax and cure it to form the support/retention wall, then it would lay down resin and cure it. Cleaning the prints required a pressure washer and lots of scrubbing.
Loved this video. The biggest issue is the reflecting light really. Have you tried putting down a layer first with high viscosity resin, and then curing it? Or maybe a ballpoint pen mechanism could work to block the resin inside the extruder, you would risk locking up the ball though.
I believe one source of error comes from the resin. You need to modify it so it gets a higher viscosity. Transform it into a paste which can keep it's shape for a while. Then you can just extrude it, it should stick to the surface like molten plastic. Another bonus is that all the FDM parameters and tricks will work that way. Things like "line width" for example.
I love the idea for the pump design. I'm designing a powder binding 3d printer, the pump and the printhead is basically what I'm looking for to improve the design. Thanks
your enemy is chemistry not mechanics ;) The MSLA resins are having a very high content of photocatalyst - try resin for instance used on a Formlabs printer, they cure totally different from a spatial perspective. The MSLA resin you use disperse the laser and react to it much stronger than the SLA resins. It will be a function of viscosity and time / distance from the print head you cure. The current resin is most likely 'wicking' the laser laser under the nozzle, despite your attempts of 'shading' it, the resin is way too sensitive to the laser. You could try to reduce the sensitivity and viscosity, by passing it through a peltier cooler prior the nozzle, sort of turn the heat block into a ice block. That will change chemistry and viscosity, allowing you to cure further from the head.
Mix some talc with ur resin, make it creamier. Then offset the lazers away from the nozzel so that it prints a cream/jel and the laser cures it only after the nozzel moves a bit
Ah I now see how you used the syringe pump. My thought was actually to use a very large syringe, 200ml for example, and to have the syringe pump sit next to the printer and still use a flexible line to feed the print head. You can get super precise pumping rates and easily track the accuracy of the pumping and still add zero weight to the head. Obviously you've done way more work in this area than me though!
Hey man.... greetings from Brazil. Long time no talk!!! I told you your channel would bem twice as mine in no time didn't I? Congrats your videos are awesome as always!!! The Karmeliet in the end is just the cherry on top!!! Best Beer ever!!!
Fun project! Maybe gelifying the resin? Either through slight cure or adding clear gel monomers of some sort? Adding a thick black Nozzle with a flat bottom that curves up to absorb refracting light. Change the resin color to dark grey solid or other dark solid to make it easy to test. I was able to manually "print" using a 3d UV pen so I always wondered why not with a machine? Sometimes maybe the key is to start super slow with thinner layers. You can try a flexible tip inside the nozzle tube like a brush for more control and lineance with bumps? Anyhow, Good luck!
Thanks for your suggestions! I received resin with separate additives to control the curing rate, making it matt black and turning it into a paste. I'm going to get this to work!
am working on same approach since 2 years, and I got some results out of it, first you need to use 2 pumps and a pressure regulator, the needle is fine but it should be modified a little, the tubes you used to transfer the resin should start at 3mm and end at 1mm at the extruder ( this will give more pressure ), also normal gcode wont be a great help that also needs to be modified (Flow rate)
I have see Massivit machines operste first hand. Everything has to be perfect or the whole system doesnt work. Your idea is much more controllable. Sweet video. Your dedication is much appreciated. If you can create a bead of uncured resin behind the nozzle as the nozzle moves then theoretically the resin won't cure inside the nozzle.
I would've solved the peristaltic pump issue differently by having several tubes in parallel a collector / buffer, this will make the flow pretty stable with minimal maintenance requirement (the tube will wear quicker the way you solved it), it is even more precise since it doesn't have to move a lot...
I genuinely don't understand why you don't have more subscribers Also, the fact that you could see the light coming from the sides of the fiber probably means you weren't getting proper total internal reflection
Amazing man! You should definitely keep working on this! Maybe try with pulsing the lasers? More like when laser engraving something grayscale. But that could be quite tricky on the gcode side. Great work!
Excellent Work! Have you considered printing a bracket to support lenses that would focus the lasers or even one laser to a smaller area? I expect that a lense from reversed binoculars would focus the laser on a smaller area there would be less bleeding of light from the fresh resin and less clogging at the extruding nossel. Another idea is to bind 9 arms to the extruder that curve out and away from the extruder-pointing perpendicular to the printing surface-with a bearing at the end of each arm and a lipped ring around the bearings with a small motor to rotate the ring some distance either direction depending on how much power is applied with a laser module attatched to the outer edge of the ring pointing beside the extruder nossel so that the extruder nossel is just out of range of the laser regardless of the position of the laser rotation where the laser can be rotated 360° clockwise or counterclockwise to stay behind the extruder and cure as the unit moves depending on how much conductor is leading to the motor and how much of an issue it is when the conductor wraps around the extruder-easily managed by something as simple as rubber bands that keep the motor conductor out of the work area. The size of the motor can be significant and even heavy provided that it's not too heavy to move and that the Armature/Axle/Moving Piece of the motor can reach the ring.
To reduce the pulsing further you could do something similar to a capacitor in electronics..Use a flexible/expandable piece in the line that is slightly bigger than the line. Once the expandable portion fills up it will collapse when flow slows down, if sized correctly it will allow continuous flow...kinda the same way a capacitor stores voltage (electrical pressure) and releases the voltage when the voltage on the line decreases. The trick would be finding the right material that is flexible enough....I wonder if a small balloon would work?
The easiest solution would be the next size tubing. :-) But, I like your design and would suggest 3 roller chambers with offset rollers to increase the volume without increasing the pulse rate. In addition, a small accumulator could absorb the pulses giving a smoother flow.
Try coating the print bed in either Vanta Black or Black 3.0 to try and prevent the reflection of the laser back into the nozzle. I hope that helps cause I would love to see this work.
Higher pressure smaller nozzle with some sort of thickening agent in the fluid so it sprays out like a plaster or putty, the higher pressuure should cause some adhesion and consistency in volume. The amount of light shouldnt be an issue with the brass nozzles but im not sure if even .1mm would be small enough. You're definitely on the right track keeping light out of the tube but I also think with a higher pressure spray/squirt you can have a larger distance from the print also stopping the clog.
