3D printed waveguides

[300Z]

Your metal vs softy shootout was one of my all time favorite projects and I for one was disappointed when you seemed to take a few year long hiatus from posting - you, Mark K, J Kim, and Zaph are among my favorite posters - all the best seem to get discouraged or otherwise unable to continue participating for one reason or another. I do also value J.B.s contributions of course...

x2. I miss the work done by these guys and will be forever grateful for all the work they provided to the community.
Thank you Brandon.

[augerpro]

Thanks 300Z! I have more "experiments" coming. This waveguide project alone will be pretty huge by the time I'm done. BTW I have the CNC'd guides on the way and the phase shields at the printer. Measurements should be starting soon.

Off topic, anyone with a solid measurement setup has come to find that the typical microphone holder causes diffraction, so many have come up with ways to attach the mic to the stand with PVC pipe or something similar. Anything to make it pointy and sleek. So I worked up a low diffraction microphone mount. The mic slides in the tapered end and the cord comes out the slot. Other end is threaded for a standard microphone stand. Super clean. When it's done at the printer and I confirm fitment I'll make the .stl file available to anyone that wants it. Here's a pic:

[deschu]

Note: threads can be difficult to 3D print as their tolerances are much tighter than many other things. I highly recommend tricks like bonding in a metal nut to a hex recess to provide such a thread.

The printers can all generate the threaded forms, it's just that dialing in the right settings for a specific printer and filament can be difficult. Pro-level machines and large threads like these, however, generally not a problem.

[augerpro]

It's with an industrial producer (I guess) using SLA resin @ 25 micron. Fingers crossed.

[deschu]

Depending on the resin, just watch out for cracking and it'll be fine. You can always carefully chase the threads with a tap if necessary. (SLA generally has much better tolerances than FDM, but most consumer/low end 3D printers are FDM).

[DanP]

It's with an industrial producer (I guess) using SLA resin @ 25 micron. Fingers crossed.

If you're getting this made from the standard (i.e. inexpensive) SLA resin, you won't be able to use this for yourself for very long. These resins are very brittle and are intended for fit testing and visual examination. There are some more durable resins that you could actually use as a finished part, but these are much more expensive. Either way, you should get your fitting complete to see if the file is good.

Glad to see you're keeping this moving Brandon.

Dan

[augerpro]

The resin is "Fun To Do Industrial Blend Resin" no idea of the properties. Another option was Fabb something or other, I think they make a machine also, had a material called Tough Resin".

[augerpro]

So the phase shields and mic mount have arrived. Looks like really good quality, though I haven't checked with a caliper yet. If anyone wants to print the mic mount here is the file: https://www.dropbox.com/s/eijmpzwauz...reads.stl?dl=0

This was a 25 micron print in resin at leaderprototyping.com

[tmhutson]

Someone must sell these! I don't have access to a printer. :(
Awesome job!

[ani_101]

Someone must sell these! I don't have access to a printer. :(
Awesome job!

Please read post #203. You can send the file to leaderprototyping.com and have them print and send it to you. You can search for any other online 3D print service and use them - Brandon has provided the STL file.

[ernperkins]

Any idea of the cost? I did something very similar with PVC pipe, but this looks much more professional.

[tmhutson]

You can send the file to leaderprototyping.com and have them print and send it to you.

I forgot about that option. For some odd reason my brain thinks it's expensive. I have heard of people making things that are not expensive. So I should get off my butt and make one.

I may toy with the idea of making one with pvc. I had heard of the idea some time ago but hadn't tried it.

[augerpro]

It *can* be expensive depending on the printing method and material used. I went the most expensive route with SLA resin at a small micron. The main thing is that the quality is high enough for the threads in the end to be functional. I don't know what resolution that would take. I'm sure 50 micron is fine. Not sure about 100. But there are a lot of cheaper options if 100 micron, and say ABS or PLA material works ok. BTW 3Dhubs.com can provide pricing to many printing outfits, that's how I found these guys.

[augerpro]

So the waveguides from Tim have arrived and the phase shields are in place. Looking good so far. To reiterate these are all 5" waveguides. Depth is varied for one pair. For the other pair the horn wall is made either tangent or non-tangent at the mouth. The tangent mouth ones have constant flare radius of 2.xx" (can't remember exactly), and the non-tangent mouth ones have a set radius of 4", so much shallower curvature. I have to make a flat baffle mount so the results can be compared to that, hoping to get a friend's 3D printer working this week to make that.

[augerpro]

Measurements start tomorrow! Finally! I stumbled across a new source for waveguides and hope to be able to tear through some iterations as fast as possible. Finish quality is excellent, although not smooth, similar to 100-200 grit sandpaper. Some sort of laser-sintered nylon process I've never heard of. Anyway, I had the four designs that Tim supplied me in CNC'ed wood above printed on this new process. So some comparisons between the manufacturing method should be helpful.

Right now all the designs are 5" diameter mouth, with two variables to play with: depth (1" vs 3/4") and whether the mouth is tangent to the baffle or not. Depending what the results are I'm going to play with wall radius more, and with and without phase shield. Once I find "best practices" at 5" I'll design some 8" waveguides and see if those hold. If so, I can easily extrapolate in between and just print a couple samples to verify the prediction, instead of doing a bunch of variations at every size.