SLAM

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Tweeter part

Something like this then:

An externally hosted image should be here but it was not working when we last tested it.


Membrane is not so deep and moved closer to the front pole piece.

An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.


Yes, definitely stronger flux.

I hope I can mount it :magnet::magnet::magnet::eek:.
 
Finally got my 3D-printer, Prusa i3 Mk3, a couple of days before christmas:

An externally hosted image should be here but it was not working when we last tested it.



It took 1 hour and 53 minutes to print 2 cm of one side of SLAM!.
So the building rate is 0,5 cm an hour.
ABS filament at 0,2 mm height and 20 % fill.

I guess it will take a couple of iterations before I am satisfied with design.
One huge advantage with this building practice is that a smooth front can be made with any diffractional edges.

An externally hosted image should be here but it was not working when we last tested it.


But this is not the case yet.
 
Some iterations later:

IMG_1800.jpg


Front:

IMG_1802.jpg


Back, with room for the back pole pieces that will be mounted after the membrane:

IMG_1801.jpg


As you can see prototype is armed, the magnets will be glued to the side parts in the series specimens.
And the plastics will be black; it was a little easier to evaluate the prototypes using white.
A rim has been added for the membrane holder. Usable gap is now 60 mm.
 
Designed the tweeter membrane:

MWSnap022%202018-01-24,%2022_46_14.jpg


60 mm high and 290 mm wide will with 36 pockets yield a 48x48 mm finished membrane.

The first successful cut:

IMG_1831.jpg


6.0 Ohm, a little bit more than the calculated 4.3 Ohm. But the return feeds, the horisontal parts, were not included in that calculation.

The motors are growing centimeter by centimeter:

IMG_1832.jpg


Weight is now a mere 12 kg, 50 cm high.
Only 30 cm to go!

The 3D printer is working 8 hours a day:

IMG_1834.jpg



Next step is to design a folding tool in nylon.
I have tested nylon and it seems to withstand 170 degrees Celsisus, at least for 20 minutes.
 
It didn't turn out well with the nylon plates:

IMG_1843.jpg


But I found out that the kitchen oven "ovel shoot" when it comes to the temperature. It was actually over 240 degrees.

So I decided to build an oven out of two of these and some electronics:

MWSnap016%202018-02-15,%2020_12_53.jpg


IMG_1851.jpg


IMG_1852.jpg


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Then I tried poly carbonate at 160 degrees, but that was to hot as well:

IMG_1870.jpg


Another type of jigg:

IMG_1872.jpg


and a lower temperature, 140 degrees, did the trick:

IMG_1873.jpg
 
To fold the whole membrane in the new jigg went well as did baking it.

But the printer wasn't happy about it when I tried to make prototypes of the membrane holder:

Front:

MWSnap020%202018-03-18,%2011_45_33.jpg


Back:

MWSnap019%202018-03-18,%2011_22_50.jpg


As the holder was to be made in a softer material called TPU with a shore of 95A, didn't the extrusion gear manage to feed the extruder.
So I needed to re-build the printer. Luckily, there's a forum for that as well..

Anyway, after a week or so I managed to get a suitable membrane holder:

Front:

IMG_1885.jpg


Back:

IMG_1879.jpg


So in with the membrane and prepare for gluing:

IMG_1884.jpg
 
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