Hi Marcel,
I'd like to suggest keeping the lip on the base:
The petal in the attached image hasn't yet been glued in place....
Thanks!
I'd like to suggest keeping the lip on the base:
- It makes accurate/well aligned assembly of the petals a breeze; and
- Increases the surface area and therefore strength of the glue bond.
The petal in the attached image hasn't yet been glued in place....
Thanks!
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This UV triggered glue is tough and enables leisurely assembly time.
You control when it sets up by application of UV...
Bondic Liquid Plastic Welding
You control when it sets up by application of UV...
Bondic Liquid Plastic Welding
You still need the profile template to assemble the petals - I added it to the ZIP file: https://at-horns.eu/ext/ST260-petals.zip
I guess this depends on the precision of the print (+layer height, etc.) but I found both of your mentioned points to be actually worse with the lip. That's why I decided to remove it. Maybe I will leave only a small raised rim along the inner edge, I'll try that on the second set.
I guess this depends on the precision of the print (+layer height, etc.) but I found both of your mentioned points to be actually worse with the lip. That's why I decided to remove it. Maybe I will leave only a small raised rim along the inner edge, I'll try that on the second set.
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Where's the Like button!Free hand gluing is not recommendedActually, the picture looks worse than it really is. Even like this it would be usable with a bit of filler and dremel sanding. So I believe that with a simple alignment jig as mabat showed above it would be really easy to build a large horn like this.
FYI, the base + 10 (hollow) petals for one CE360 weights 340 g in total (PLA). This is ~ 7€, given a common filament price around 20€/kg. You can print a pair of these waveguides from one spool of filament with a reserve. A nice finish won't be cheap though, depending on one's demands.
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I've made a half size test piece of the ST260 that I've modified to print in two sections without supports. The idea being to create an alignment ring and to get minimal warping. The bed of my printer was just too small to print the top ring in one go so I will have to cut it in half or quarters to make bigger guides.
For some reason the estimated time for printing was way out, with gyroid infill the top piece took 11 hours to print The Base took 8 instead of an estimated 4 and 5 hours.
The principle seems to work and there is just a slight difference at the split on the inside surface. I like the two large flat glue surfaces with an easy alignment.
The gyroid infill was used as it it supposed to work well for filling with a resin
Stronger 3d Print With Polyester Infill : 3 Steps - Instructables
Edit: Just noticed when looking at the reduced size image that when the z seam is aligned on both parts the grain patterns of the two pieces match up as well.
For some reason the estimated time for printing was way out, with gyroid infill the top piece took 11 hours to print
The Base took 8 instead of an estimated 4 and 5 hours. The principle seems to work and there is just a slight difference at the split on the inside surface. I like the two large flat glue surfaces with an easy alignment.
The gyroid infill was used as it it supposed to work well for filling with a resin
Stronger 3d Print With Polyester Infill : 3 Steps - Instructables
Edit: Just noticed when looking at the reduced size image that when the z seam is aligned on both parts the grain patterns of the two pieces match up as well.
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My initial thought is that I'd be worried about significant diffraction, unless you could cross so low that the waveguide would appear invisible.
Kind of like prosound coaxials with attached horn flares. 1khz seems to be the upper limit in typical 12-15" coaxials where the horn covers most of the cone.
I think a 1.4" exit driver would be the best compromise in this arrangement. They certainly performed well in those plots posted awhile back.
I think a 1.4" exit driver would be the best compromise in this arrangement. They certainly performed well in those plots posted awhile back.
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^^^ The xo should be one wavelength, diameter of the horn, or lower so that the horn would become acoustically transparent to the sound emanating from behind without too much diffraction? steep xo slopes, yeah. If it is 26cm diameter waveguide, 1.3kHz, seems reasonable for 1" driver, might cross even lower? But you would want to align the directivity for drivers and the horn so some simulations required to see if there is setting that works well.
edit. fluid has everything already simulated
edit. fluid has everything already simulated