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3D printed waveguides

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  • Sounds very interesting. What are the tolerances for parts produced using the process, especially if heat treated. Do you know if similar machines can produce metal parts? Sent from my LG-V495 using Tapatalk

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    • Our typical accuracy is about +/- 0.15mm per 100mm. Heat treating does not affect this tolerance unless geometry induced stresses cause the part to move as plastic will do.

      There are many laser sintering machines capable of metal processing. We had an M270 for a while and ran Titanium in it, but the business model was not a good fit for us. We also tried an EBM (Electron Beam Melting) machine that was VERY cool. It used a 4kW electron beam instead of a 200W laser to melt the metal powder. It was crazy fast compared to other metal machines, but not refined enough to create a good market for itself. We got rid of that one too. At the end of the day, most products being developed can get by with a functional glass-filled nylon prototype, so that's what we have focused on. There are a few guys on here who have seen the parts. They're no joke and unfortunately it has left me a little jaded when it comes to all the makerbot type parts coming out. It was supposed to be a revolution, but besides the novelty and a few niche applications, there's just not that much you can do with a makerbot part that you couldn't have already made in a different, better, or cheaper way.

      Dan
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      • Dan,

        Thank you for the information, I plan to contact the manufacturer. This may be a good addition to the machine shop where I teach.
        Regarding MakerBot and similar machines. I agree, that there are better ways to make parts similar to those 3D printed. The promise of 3D printing has excited many people but the results are not nearly as exciting. After printing several objects using a MakerBot one of the school student groups lent me over Christmas break a few years ago, I realized its practical uses are limited. The time required for printing, and quality of the printed object could not compare to the same object milled on the Haas CNC machine. Comparing the cost of the machines, the Haas cost 100K 12 years ago, the M-Bot cost 2K, the M-Bot isn't a bad option for prototyping some objects where material, tolerance and finish aren't important.

        Printed waveguides may be useful if a person hasn't other options, especially if the results are improved over time, and the time and cost required for printing is significantly reduced. I think it's a good idea to follow thru with the ideas in this thread as a way to explore the potential for printed WGs.

        There are potential significant educational advantages to 3D printing, although, I suspect these may not be used as often or as advantageously as possible. Students learning CAD could benefit from seeing the design process thru to producing a part. Too few students I encounter have much experience going from an abstract concept(sketch) to a real object. Sadly, that also seems to be the case for many of the engineers I encounter.

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        • Originally posted by augerpro View Post
          Bummer results...
          UPS >$200
          Red Rocks printing >$200
          lowest vendor on 3yourmind (including i.materialise.com) $117
          ITEAD Studio $80
          That is disheartening.

          "Not a Speaker Designer - Not even on the Internet"
          “Pride is your greatest enemy, humility is your greatest friend.”
          "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

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          • Originally posted by augerpro View Post
            Well the library won't work. They had to print at a lower resolution and it still took 4 hours. They adjust resolution to keep it under 2 hours if possible. The quality is not very good. I'm looking to get estimates from some online places.
            Brandon,
            Could you post a few photos? They may be informative, and I'd like to compare the guide I have to it. I can post more detailed photos too.

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            • I agree with your points above. The 2 large frame machines we have cost almost $1M each with all the ancillaries, but we do have a smaller machine that builds even better parts (smaller laser diameter and thinner building layers) that sells for around $250k. The downside to this machine is that it has a max part size of 8" x 10" x 12". The material is quite expensive too, especially in the large machine where very little can be recycled.

              Dan
              _____________________________
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              • Originally posted by DanP View Post
                I agree with your points above. The 2 large frame machines we have cost almost $1M each with all the ancillaries, but we do have a smaller machine that builds even better parts (smaller laser diameter and thinner building layers) that sells for around $250k. The downside to this machine is that it has a max part size of 8" x 10" x 12". The material is quite expensive too, especially in the large machine where very little can be recycled.

                Dan
                Dan,

                250K may be an obstacle, perhaps there are other machines adequate for instruction.

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                • Originally posted by TN Allen View Post

                  Brandon,
                  Could you post a few photos? They may be informative, and I'd like to compare the guide I have to it. I can post more detailed photos too.

                  Here you go. Fusion 360 can generate CAM files for a CNC. So I think both possibilities (3D and CNC machining) can be explored in unison, both for the prototyping and final designs for users? I think something like the phase shield can really only work on with 3D printing, but they are so small that would be acceptable I would think.
                  Attached Files
                  ~Brandon

                  Soma Sonus
                  DriverVault

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                  • That is a bit rough, but not much more so than what I printed at higher resolution. I looked at the final guide and remembered that I added a piece of Corian to the throat and milled it to improve the throat. This also provided a better mounting flange.

                    Perhaps it makes sense to mill a series of MDF guides to continue with the idea of testing. These might be done in increments of 1/2" and 3/4" MDF with a Formica layer on the back to provide a hard surface at the throat. This makes it easier to sand and maintain the throat contour.

                    Looking ahead, if the guides are round, they can be turned fairly quickly using a jig on a lathe. If oval, then a more elaborate jig would need to be made, or they could be milled using a CNC router. The jig might be the better less expensive choice.

                    Another sensible possibility is to wait for Dave Pellegene to start making guides again.

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                    • Originally posted by Face
                      https://i.materialise.com/ Pricing appears to be better than the other companies I've researched. As far as quality goes, I can let you know in a week or so. Staples offers the service online and in some stores, but was much more expensive.
                      Received the sample the other day. Item looks smoother than others pictured here, but could still use a hand sanding. The only issue, I can't use the sample for my application, I need to learn how to use software to edit the sample.
                      "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche

                      http://www.diy-ny.com/

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                      • Just curious, what sample did you use? I may be able to modify the geometry, or provide a different sample file. Sent from my LG-V495 using Tapatalk

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                        • Originally posted by TN Allen View Post
                          Just curious, what sample did you use? I may be able to modify the geometry, or provide a different sample file. Sent from my LG-V495 using Tapatalk
                          An adapter place to allow me to use Vifa XT tweeters in a waveguide. PM me your email address and I can send the file and additional information over, thank you.
                          "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche

                          http://www.diy-ny.com/

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                          • PM sent.

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                            • Before I send off the first prototypes to Dan, I'd like to see if anyone has any suggestions or criticisms. I have 3 designs for the SB26. All are 5" mouths. One is 1" and the flare is tangent to the baffle. The next is identical except 3/4" deep. The third is 1" deep like the first but the flare is not tangent at the mouth. The flare radius is 4" versus roughly 2.2" for the other two. So a good start there I think. Does anyone see an issue with the phase shield? it is .47" diameter like both the SB26 and RS28A. It's radius is 1.5", had to guess here as that seemed about the radius a typical 1" dome would have just visualizing it in my head. It is attached to the horn with a small 1/16" bar, and sits just a hair over 1/16" from the dome.

                              ~Brandon

                              Soma Sonus
                              DriverVault

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                              • Looks good Brandon. The only changes I would make are to add some mounting features, like recessed screw holes or something, just because it's easier to do in CAD than after the fact. And I would add at least 1 more bar connecting the phase shield, 2 or 3 would be even better. It will be very fragile as you have it drawn.

                                Dan
                                _____________________________
                                Tall Boys
                                NRNP Computer Sub
                                The Boxers
                                The Hurricanes
                                The Baronettes
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