Greetings, I am new here and would like to show you my 3D printed flute. For hole placement, it uses a machine-intelligence particle-swarm optimization with fit-formulae from C.J.Nederveen’s Acoustical Aspects of Woodwind Instruments. Right now, I am at what I consider version “1.0” of my flute. It sounds good to me and blows in tune when I play - but I am also an amateur player and hope to get some critical feedback on my flutes so I can improve. 
Pretty cool! I like DIY flutes. I make them myself from aluminium tube. Fairly easy to do and sounds great. What’s the stopper position on yours? Is it a cylindrical bore? How thick is the wall? What’s the inner diameter? What material did you use?
Thanks! I think it is pretty cool myself. The “stopper” position on mine is 17.0mm, but there isn’t really a stopper - the head joint is one solid piece. The head joint is a tapered bore, a so-called “parabolic” taper like on a Boehm head joint (as precisely identical as I could actually). The body is cylindrical. The bore diameter is 19.0mm, the wall thickness 3.5mm. The material is PLA - polylactic acid. It has about the same density as grenadilla wood and is made from plant starch (captured greenhouse gasses - nearly carbon-neutral).
Totally fantastic, and well done.
How are we going to give critical feedback - we’d need some samples to play, would we not?
A brilliant effort.
One thing about flutes, Irish or Silver Boehm flutes, is that the wall/tube material makes a big difference to the sound. For wooden flutes the very dense woods such as Blackwood or Mopane are superb, and the lighter materials like Boxwood and Maple are also great. For silver flutes, sterling silver is much, much better than cheap nickel silver, and flutists are prepared to spend a lot of money on expensive silver or gold flutes (despite the fact that many texts in acoustics say it does not make a jot of difference - and yet the differences are huge).
For synthetic flutes people have success with Delrin which is heavy and dense, as well as other polymer resins that are also dense.
So my question is what material are you using for the print? Ordinary ABS plastic would be fine for a test run but I can’t imagine you would get a decent sound from it. I know you can get a huge range of different 3D printing materials nowadays, a ling way from the early days of 3D printed ABS pink chess pieces.
Cool! Is that a cylindrical bore design or conical bore? As a 3D printed flute, I would assume you can make any bore taper and wall thickness you want, right?
I’m more a fan of traditional wood flutes as an aesthetic choice, but I’m fascinated by how much could be learned by the ease of making experimental changes in bore shape, wall thickness, tone holes, hole undercutting and all the rest with this technology. The flute maker community might learn things that could also be eventually adopted for wood flute making.
Thanks for answering my questions. That seems like pretty standard measurements. The wall thickness should be good for a nice embouchure. From the pics I have only one suggestion for an “improvement”. You could try to make the hole spacing for the lower hand more even by experimenting with the hole size. Is the embouchure just a straight hole or at an angle? Are any of the holes undercut?
Very cool! Looking forward to hearing it.
My neighbor 3d printed a whistle for me, from plans on the internet, as an experiment. i wasn’t very impressed with the results. it played, but the finish was sort of rough and the sections did not want to stay together well. I assume those were artifacts of the resolution of the printer he used. Was the printer you used capable of high resolution printing?
Yeah, at the “riser” the embouchure wall is 4.3mm and is at a 7 degree angle (all around). No undercutting yet. Since the body of the flute is determined my the machine-intelligence algorithm I would need to quantify the effect of an undercut to incorporate the design, but I haven’t done that yet (but it is on the list)
My printer is capable of accuracy down to 0.0125mm - but I target around 0.01mm and most probably get accuracy to around 0.05mm. I was stuck on getting the parts to fit together with an air-tight seal for a while, but then figured out I could use O-rings in the design, and now it seals wonderfully and stays together nicely while still being easy to disassemble.
Cylindrical bore body, tapered headjoint. Yeah I can and do specify the taper/wall thickness as I want. On the headjoint it is changing diameter by 0.1-0.3mm for every 10mm or so roughly (based on lab measurements of some headjoints). Neat thing about the algorithm I wrote, is that if I change something - like bore diameter or wall thickness - the system will automatically adjust all the tone-holes to keep them in tune (I actually didn’t place the holes, my machine intelligence algorithm did)
Don’t I know it. I love my maple Moeck Rottenbergh recorder and my silver headjoint. I was skeptical at first, trusting the science (as I do), but empirically, one can hear the difference in tone color. I have Native American flutes in various woods (like walnut and cedar) and the difference is clear to me.
I am currently working with PLA, which is just shy of Blackwood density (1.24g/cm3 vs 1.25g-1.27g for Blackwood)
I didn’t even know that was a “thing”.
It could be turned into fuel. The technology exists but might need a couple more years till the price would be the same as standard gasoline/diesel/etc.
I hope that isn’t an indictment of starlight’s flute! Usually we reserve such talk for flute-like objects from a certain country. 
Interesting. How well does the tuning correspond to predictions? Nederveen’s thesis is dated… older than you, I’d guess. There are newer models for toneholes and flute excitation.
I am using the revised edition which was updated in 1998 (the original was 1969). There are newer methods, like FEM and transfer matrix, but this seemed like a well-documented approach that would run fast enough for me to embed it in a statistical optimization algorithm to judge the merits of arbitrary hole arrangements. With this approach, I can “judge” about 200,000 virtual flute models per minute. However, if you are able to recommend some other research for download or purchase I would be interested in investigating. For Nederveen, his first-order approximation wasn’t enough, and I had to be sure to add his corrections for closed holes and end-flange which some authors seem to omit when they cover his work. Once I included corrections for those, it came into tune quite nice it seems. There are still things I would like to be able to characterize mathematically, for example, the effects of undercutting tone holes.
Very kool!
WIDesigner, https://github.com/edwardkort/WWIDesigner/wiki, uses transfer matrix models of the bore, toneholes, and excitation mechanism to perform rapid impedance calculations. Algorithm sources are listed here: https://github.com/edwardkort/WWIDesigner/wiki/Bibliography. The tonehole model in particular comes from the work of Antoine Lefebvre. He used FEM models to analyze air flow in toneholes and distilled the results to a transfer matrix model.
For your purposes, optimizing tonehole size and position, I’d suggest that a heavy-duty global optimizer is overkill. For that task, WIDesigner gets good results with Michael Powell’s local optimizer BOBYQA, Bounded Optimization BY Quadratic Approximation. A global optimizer doesn’t earn its keep until you start optimizing bore profiles as well.
I looked into 3D printing my Folk Flute model this winter, using the commonly available plastics. I shelved this project when I found out that these aren’t archival and that one should go to some of the more difficult plastics such as the Nylons or ABS that require better machines. My 3D printer (JGAurora A5S) which I set up but have yet to even test. I researched it while recovering from knee replacement surgery this winter. Then I had to jump right in to a pile of accumulated flute orders followed by the Coronavirus and getting us all in good shape to handle that (this included finishing a long bathroom remodel project) and I am finally going to catch up with my last year’s leftover orders and this winter’s queue and have a fairly open summer. I am scheduling all new orders for the fall, except for my popular folk flutes which I spend about 1 week per month on.
I will be using this printer to help prototype an alto flute with an unusual bore.
Am curious what printer you used, as well as the filament. Also, how long did it take? These would be good things to know.
As far as the acoustical parameters, there is much that can be done. Contact me privately if you want to discuss these. I am glad someone is pursuing this approach!
Casey