3-D printing of a horn or a lawn dwarf

[Lee in Montreal]

Well. This thread may not last long after the initial enthusiasm. I have several friends who have 3D printers and they use them to build (not just prototype) automotive components, exposed to the outside weather (rain, dust, sun, heat). I suppose that now, the technolgy has evolved far enough that those 3D printers can output strong parts, thanks to an advance in powder/plastic technology. Gone are the days of just fragile prototypes. So, the idea is to produce a model of TAD horn and have it "printed" in one single piece, using the densiest material available. Part of the exercice will involve designing walls no thicker than half inch (12.7mm). SolidWork will most likely be the final model format as it can be read by most softares used in 3D printing. http://www.geocities.jp/arai401204/Horn/HornDesign/Horn10.jpg http://www.geocities.jp/arai401204/Horn/HornDesign/Horn11.jpg http://www.geocities.jp/arai401204/Horn/HornDesign/Horn12.jpg How far will this brain fart go? I don't know, but after CAD woodwork, then we get 3D printing. Isn't technology great? :D

[10 Watt Street]

Does your clone include the Helmholtz resonant trap that virtually all TAD horn clones disregard?

See the dark dot on the horn flare?
62593

[JeffW]

That doesn't look like a TH-4003, I think those are asymmetrical top vs bottom and don't have fins.

Like this

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=8647&stc=1&d=1119637852

[Lee in Montreal]

Thanks for the comments, guys. Interestingly, this thread is more about the process of "printing" a horn than the actual object being reproduced. Let's start all over again, and let's pretend I will be reproducing a dwarf to put on my lawn. At this point of the project, I don't even mind if the drawing is of an Iwata or a TAD, as long as the process works, I will be a happy camper :D But 10-watt street is right. Many wood or resin TH-4003 clones skip this device. How paramount is it? I dunno but I will be interested in knowing more. Also I am sure that most people will not be fooled by a plastic copy and thinking I am passing a clone as the real thing...

That being said, I am awaiting a reply from a friend who has a business and uses a couple of 3D printers.

PS - I think that the drawing presented might be of a TAD TH-4001. Those had no Helmoltz gismo and were symetrical.

http://livedoor.blogimg.jp/deep__green/imgs/d/c/dc01c3f3.JPG

http://i228.photobucket.com/albums/ee238/penndan_Audio/_MG_5993.jpg

[Lee in Montreal]

If somebody can 3D print and shoot a "printed" shotgun, then I suspect that I can find the proper quality of plastic to print a horn.

http://www.extremetech.com/extreme/133514-the-worlds-first-3d-printed-gun

http://www.extremetech.com/wp-content/uploads/2012/07/3d-printed-gun.jpg

[10 Watt Street]

Lee, I do think it is a good project and exercise.

[macaroonie]

Excellent Lee , here's a suggestion , scale it down to 25% and see how it comes out. If it's good , carry on .
Then start collecting the G codes for other ' favorite ' horns

BR Mac

[Lee in Montreal]

It is so easy to start from a Solid Works model and print a complex object, compared to machining or making molds. I think that the technology is going to evolve very quickly and change the face of small scale productions. Just like when Apple came out with the first Macintosh in around 1984 and it introduced what was known as "desktop publishing". Design, creation and production were changed forever.

[grumpy]

Why not "print" a much thinner "skin" and then backfill to the desired thickness with a dimensionally stable and somewhat inert material ... ? especially if the cost is related to the amount of printer material and time used... Just a thought (I've wondered similarly re H9800 type horns vs milling the entire thing)

...or print a hollow mold core to minimize printed material.

[Lee in Montreal]

Why not "print" a much thinner "skin" and then backfill to the desired thickness with a dimensionally stable and somewhat inert material ... ? especially if the cost is related to the amount of printer material and time used... Just a thought (I've wondered similarly re H9800 type horns vs milling the entire thing)
There are many ways to perform the job. Save on plastic and printer time, but spend more on finishing. Ideally, I would prefer to spend, say, $50 extra on printer time and material, than $200 on hand finishing. Also I think people may want to glue some thick tar sheets to make the horn more inert. Anyway, I am not set yet on the exact horn to prduce. One with no fins/dividers, or one with them. Ideally, it will be horn that covers 500Hz to a possible 17KHz with DSP correction. I'd like to stick to something I can use in a two-way system. Plans are easy to reproduce and bring into Solidworks format.

[grumpy]

Understood. Last time I checked (admittedly quite awhile ago), printing large/dense objects was a costly venture. It would be cool if I was just out of touch in that regard :)

[Mr. Widget]

Understood. Last time I checked (admittedly quite awhile ago), printing large/dense objects was a costly venture. It would be cool if I was just out of touch in that regard :)I haven't priced 3-D printing (rapid prototyping as we called it) in quite a few years... I have used quite a number of different technologies since the late '80s. Yes, this technology has been around that long. But in my experience growing or printing a large horn would be pretty expensive. Most of the materials I have experienced are not very stable and always have very obvious grow lines requiring filling and sanding if you want a nicely finished part.


Widget

[Mr. Widget]

Does your clone include the Helmholtz resonant trap that virtually all TAD horn clones disregard?

See the dark dot on the horn flare?I cloned an actual TH-4003. (See the rough prototype posted by JeffW above) When I first cast my clone I had the tuned resonator and my clone didn't measure as closely to the original as when I removed it. I thought this might be due to the mass differential between my clones and the original. I used a very dense material similar to JBL's sonoglass. It is extremely inert and is more than twice as dense as the maple ply used by TAD.


Widget

[honkytonkwillie]

UC Berkeley has a 3D printing vending machine. http://www.ibtimes.com/dreambox-worlds-first-3d-printing-vending-machine-hits-uc-berkeley-video-1288777 If these take off, I don't think 3D printing will reach the ubiquity of PCs anytime soon.

I can see myself needing to replace some 2344A horns in another decade when my little ones are teenagers. With luck, newly printed ones will be a lot cheaper than originals.

[Allanvh5150]

I have a few customers here in NZ with rapid prototyping machines. Some of the new print mediums yield a very smooth surface, certainly adequate for making a horn. But most of them are also rather expensive.

Allan.

[pos]

Lee, to what compression driver would you like to mate this horn?

The thin printed skin + damping material it appealing indeed.
This is what Rich did for his H9800 clone, using sikaflex (albeit no 3D printing there...).

[Lee in Montreal]

Lee, to what compression driver would you like to mate this horn?

The thin printed skin + damping material it appealing indeed.
This is what Rich did for his H9800 clone, using sikaflex (albeit no 3D printing there...).

I have some 2440, 2441 and 2445. Aluminum, titanium and Radian diaphragms. So, 2" throat.

BTW The drawings I linked in the first post are Yuchi's A290 from his own website. He also did an A290S and A290FL. And many others.

[pos]

Ok so maybe that would be a good idea to modify the title, as there is nothing related to the TH4003 here :D

Interested to know what you end up with though...

[JeffW]

Will your lawn dwarf have 1.5" or 2" throat?

[grumpy]

Not sure I like where this is going... :eek::rotfl:

[Lee in Montreal]

Will your lawn dwarf have 1.5" or 2" throat? I dunno, but lawn dwarves are known to have big mouth when you walk away...

http://i00.i.aliimg.com/wsphoto/v0/1851403468_3/Decorative-home-accessories-garden-courtyard-lawn-ornaments-Elf-Dwarf-furnishings-Cartoon-Snail.jpg

Back to topic

In order to reduce the cost of plastic and "printing" time, as well as shipping costs, why not "print" an hollow shell with, say 1.5mm (1/16") walls, and fill it with epoxy or any dense material when received? Fill it on the evening, allow the night for catalysing. Basically, the vanes would remain solid, but everything else would be hollow.

[grumpy]

as long as the whole process (printing/"drying"/filling/curing) allows for reasonable dimensional stability,
that sounds pretty much along the lines of what I was thinking (and saves building an external mold) :)

[Lee in Montreal]

My friend currently produces automotive headlamp buckets using ABS in his printer. So far, there will be limitation in size, but for the experimental purpose, I don't mind outputing a half sized unit. Just to see if it works, and test the process. For strength before fill up, the horn can have the cavities ribbed to hold the shell.

One 1kg (2.2lbs) roll of ABS filament seems to run $25.00/$30.00. So, making a hollow shell makes sense if it weight 1kg, costs $30.00 in material + printer time. Then fill with catalysed automotive bondo. Maybe rubber, but have no experience with liquid rubber.

[Mr. Widget]

In order to reduce the cost of plastic and "printing" time, as well as shipping costs, why not "print" an hollow shell with, say 1.5mm (1/16") walls, and fill it with epoxy or any dense material when received? Fill it on the evening, allow the night for catalysing. Basically, the vanes would remain solid, but everything else would be hollow.I'd suggest building in a network of internal supports so that the hollow horn (or gnome) doesn't distort when you back fill it with a casting resin. Also realize many casting resins have an exothermic reaction and may heat your plastic to a degree that it distorts.

All that said, I think with a bit of experimenting this could work.


Widget

[Lee in Montreal]

All that said, I think with a bit of experimenting this could work.

Experimenting is indeed the key word in this thread. BTW I've read good reviews on Yuichi's A290 and A290S (flat sides) as well as luke warm apreciations of the TH 4001. So, some A290S might reproduced. Sorry guys, no lawn dwarves :D

[dr_gallup]

I've had lots of rapid prototypes made for work and there are definite size/strength/resolution/speed/cost tradeoffs. The fused deposition material machines material costs the least, cheap stuff is about $20/lb. High end material can cost ten times that. Most of the inexpensive desktop printers are limited to a 6"x6"x6" build volume so a big horn is going to have to be made from a lot of little pieces and glued together. There are big build volume machines but they cost a lot. While I love the technology and it's going to keep getting cheaper and better, I think most of the predictions are way overblown.

[Lee in Montreal]

I've had lots of rapid prototypes made for work and there are definite size/strength/resolution/speed/cost tradeoffs. The fused deposition material machines material costs the least, cheap stuff is about $20/lb. High end material can cost ten times that. Most of the inexpensive desktop printers are limited to a 6"x6"x6" build volume so a big horn is going to have to be made from a lot of little pieces and glued together. There are big build volume machines but they cost a lot. While I love the technology and it's going to keep getting cheaper and better, I think most of the predictions are way overblown.

Yup. Seems correct. Size is the first limitation I can see. I will still proceed to make a CAD drawing of an A290S. Then maybe look for another production method, maybe involving 3 axis CNC, if 3D printing goes nowhere.

[srm51555]

Has anyone tried to print out a horn adapter such as a JBL 2328. When I built my 2397 Smith Horns (Big Thanks to Mr. Widget!!), I found the adapter was just as challenging to build as the whole horn. It is the first thing the sound wave travels through.

[Lee in Montreal]

There are plenty of those adapters available used. Priced from $20 to $200... You have to be there at the right time and at the right place. Very often, JBL 2350 horns are thrashed and their adapters along. ;-(

[tomee]

Hey Lee,
Nice project! I've been thinking similar thoughts lately as co-workers are using 3Dprinting for prototype work. The prototypes are very strong and rigid and need minimal sanding and smoothing. The process is not cheap - maybe $500 to $5000 per part depending on the time in the machine. It seems the material cost is not such a big deal as the time in the machine. There are many on-line companies that will return quotes if you send them the design files.
Do a half size prototype model and you have a 1" throat, and you use/test it with 2425 etc! Best of luck - I admire your initiative in getting out and doing this!!

[lowpoke]

For what it’s worth, I just had some adapters printed for my wood Yuichi 290 horns. I needed an adapter to transiiton smoothly from the Altec 288 mouth to the rectangular horn entry.
I got Shapeways to print me a pair of adapters. This cost about US$375.


My first design (shown below) was going to cost near $700. I then had to rework the model to reduce wall and flange thickness. It is not strong enough now to support the horn without some kind of assistance, but I’ll just need to incorporate a support in the design of my stands. The finished pieces though, are works of art. Very clean and accurate.