3D printed waveguides

[TN Allen]

There would still be support. The plastic filament can sag until it has cooled and hardened. This was a problem printing in the MakerBot a few tears ago.

It also helps maintain tighter tolerances. I haven't tried a multi-part print with parts inside of parts yet, or a print with very small intricate sections, but the support material would also be necessary in these, unless the latter were flat and thin, partially to provide clearance, partially for stability.

After printed, some parts require a long heated bath to disolve the support material. One of the sample files is of a detailed dinosaur skull complete with teerh, this would require considerable internal support while printing.

This printer will print quite high as well, I don't recall the Z dimension, but well over 12". It runs quite hot, so the plastic doesn't become stable until removed and cooled.

I considered turning the model over to print, but any dangling ends of hot filament, and the tendency to sag argued against this. As it is, I should have gone with a higher density print, the finish would have been better.

I suppose at some point 3D printing will build "wood" models by placing molecules rather than plastic filament, until then, I prefer the CNC mill, or turning guides.

[TN Allen]

Double post. A strange overloaded bandwidth and recption problem, not unusual in this part of Maine during tourist season.

[TN Allen]

Tripple post.

[bwaslo]

Timely that i just ran into this thread. I've been playing with 3D printed waveguides, particularly "Synergy Horn" types. I've printed these, but of all things have gotten held up by the wood cabinet part -- thew my back out so it will be a little while before I can sling plywood around on a table saw to do the cabinets (and then, the crossovers) for these. 19" wide, 1" compression driver, two 4" midranges, two 6" woofers.

[TN Allen]

That's an impressive printing project!

Sorry you're slowed down with back problems, hopefully you can work again soon and complere your project.

Could you elaborate on the printer you're using, design process, and the time and material required to print, and problems?

[jhollander]

Timely that i just ran into this thread. I've been playing with 3D printed waveguides, particularly "Synergy Horn" types. I've printed these, but of all things have gotten held up by the wood cabinet part -- thew my back out so it will be a little while before I can sling plywood around on a table saw to do the cabinets (and then, the crossovers) for these. 19" wide, 1" compression driver, two 4" midranges, two 6" woofers.

Nice Bill, what are the mids?

[bwaslo]

Thanks for the encouragement guys. The mids are the celestion 4" sealed-back mids (can't remember the model number at the moment).

The printer is a Folgertech FT-5 (mucho modified, as those tend to be). Design is via Fusion360 and only newbie skill (so far). Uses about 2/3 of a kg roll of PLA for each half -- it's printed in half pieces, which get bolted together and epoxied. I've done some optimization on the midrange response. Tweete response came out good (it's basically a big SEOS). Woofer response should be the same as on a baffle as the horn isn't large enough to do much down low. But the woofers are spaced away from each other, which pulls the overall directivity down to the 400Hz range (with some fancy crossover work yet to be done on this horn, but I did it on a SEOS15 in a design called "SmallSyns" over at Diyaudio,com).

There are some tweeter and midrange measurements posted over at DIYAudio for the new horn (no directivity plots, yet, though -- can't do that till I get cabinets and a working back again!)

[augerpro]

Just got back from July 4th vacation so nothing new to report. Tim I'll look into your email when I get a chance. BTW I've found a good cooling fan at the print point helps avoid using support material. It helps to use a slicer like Simplify3D that has separate settings for just bridging.

[TN Allen]

Brandon,

I think this printer was designed and built for accuracy and finish, that's why the support structure is extensive. I suspect heat is carefully controlled to produce parts that are dimensionally stable, it could probably print a working assembly of moving parts within parts with adequate stable clearances, all in one printing. I plan to try this.

The printer is a Dimension 1200es, roughly the size of a medium size refrigerator. I plan to heat my lunch in it during the winter, using some of the excess heat it generates. Perhaps someday, I'll be able to "print" my lunch, and have it ready in a few hours, and at a pleasant temperature.

[augerpro]

Tim Biscuits are people!!

[TN Allen]

Printing lunch is already a possibility:

https://www.digitaltrends.com/cool-tech/3d-food-printers-how-they-could-change-what-you-eat/

[emilime75]

After testing a bunch of guides made by DanP, I found the circular profile provided the smoothest response for both on and off axis. And they worked great with the faceplate of the RS28 (and Usher and SEAS 27TBFC) left in place.

One other thing to consider is the opening angle. If it's less than 90 degrees at the mouth the high frequency response seems to suffer.

Over the past few years I've used the RS28 and 9950 in various combinations of drivers, always with a guide similar to that described by Pete, ~8" diameter X 2-2.25" deep, but without the face plate. The sound is robust and clear, very satisfying. I'll need to try the driver with the face plate in place.

It might be beneficial to do a set of guides for the RS28 to test various configurations, for example with and without the face plate, and with and without the surround occluded. Perhaps in doing this we can methodically provide a repeatable baseline data set with a well known tweeter. New guide contours could then be produced to test new ideas and expand the baseline data. Perhaps there is a better tweeter for this, the RS 28 seems popular though and has a fairly broad response range.

I find these 2 posts really interesting. Thought I read, on several occasions, how round guides aren't good which made me not do anything with the 8" Dayton round guides I bought. Is there something inherently wrong with the Dayton round guides? I don't see them used much at all. Maybe the large CTC spacing using them?

And, what about the SEOS-8? Seems like the obvious choice for the RS28/9950/other similar drivers. Cheap, well made, easy mounting of flanged drivers, width that matches an 8" woofer which is most likely what they would be mated with. I've been meaning to build something similar to Pete's RS28A/8BG51 bookshelf, but with the 9950 and active.

Sorry if all this has been talked about or goes off topic. Haven't read all 15 pages of this thread.

[Pete Schumacher]

Round guides are fine with tweeters that allow a low XO point. That makes CtC distance less important.

[augerpro]

Looks like some posts disappeared from this thread, I'm looking for the ones that had suggestions for a photo upload site that doesn't charge to link, like photobucket just decided to charge $40 / month for :/

[300Z]

I just use my Onedrive to post pictures when I need it.