FDM Speaker Experiment

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Maker's Log, 20190525: I haven't got back to this because of a number of other more general, household printing jobs and lately, I had to rebuild my printer because of an extruder driver blowout on my Melzi board. The subsequent RAMPS/Marlin rebuild is taken longer than anticipated and I'm not sure I could even come close to the build quality of the initial diaphragm test print. So, while I seriously want to finish this project, my Tronxy built i3 clone is standing in the way of too many projects at the moment. More news as it comes to hand. Update 4: worked out that, to get around 8 ohms impedance, I need about 600+ turns of wire. (672 turns for 8 ohms resistance, but the impedance and inter-turn capacitance will account for some of the 8 ohms load.) Most speakers have a DC resistance typically around 3/4 of their rated impedance, bringing the number of turns theoretically down to 488. The winding will fit on the voice coil easily enough. Just got to wait for the tiny neo magnet and winding core to arrive. Update 3: last 2 images are the diaphragm I’ll be building test model 1 with. I’ve ordered a tiny 6x1.5mm magnet and plan to pick up some copper wire from Jaycar this weekend. Update 2: PLA+ is the go (later two diaphragm pics),but I need to make a design mod. Giving it a lip to overcome potential warping and I’ve reduced the layer height from 0.6 to 0.5, for three layers (plywood is odd numbers, right?) that pic in the morning Update: Flexible PLA is not the right material... see pic. I've seen a printed speaker driver on here and wanted to have a crack at making one myself, so here is the very beginning of the kernel of the idea. Totally a work in progress... I'll be back with prints, as I get time to make them. Diaphragm first, of course because, if I can't make that work, there's no point proceeding. Have a crack yourself, meanwhile. The details... it reverses the magnet/coil placement. A tiny neodymium magnet is glued to the diaphragm and motion is energised by the voice coil on the housing. This *should* make for a much lighter moving mass. We'll see. There may also need to be some tweaking of the iron core position inside the voice coil, optimising field strength between the core and the neodymium magnet. First build will tell me if I've designed something workable or not. ` ///////////////////////////////////////////////////////////// //////////// - 3D PRINTED EXPERIMENTAL SPEAKER - //////////// ////// CC 4.0 Atribution, non-commercial, share-alike. ////// //////////// "Crunchysteve" (Steve) Jay. //////////// ///////////////////////////////////////////////////////////// // Assembly Instructions // 1. Print housing and diaphragm as per instructions // in comments next to each. // 2. Supaglue steel core in cavity at centre of housing. // 3. Wind copper coil tightly onto formwork at the // rear of the housing. // 4. Very carefully Supaglue neodymium magnet into the // center cavity of the diaphram. // 5. Very (!!!) carefully glue diaphragm to housing as shown. // // Energise the coil from your iPod headphone jack! :-) ///////////////////////////////////////////////////////////// housing(); // print at 0.1mm layer height at 60mm/s diaphragm(); // print at 0.06mm layer height, 2 layers (PLAflex?) // print very slowly! steel_core(); // copper_winding(); // many turns of fine copper wire // (To be calculated, aim for 8 Ohms.) magnet(); // 6mmx1mm neodymium magnet $fn=120; module housing(){ color("SlateGray") difference(){ union(){ cylinder(d=82,h=4); translate([0,0,-8]) cylinder(d=8,h=8); } translate([0,0,3.5]) cylinder(d=80.2,h=1); translate([0,0,1]) cylinder(d=77,h=5); translate([0,0,-6]) cylinder(d=6.2,h=8); } translate([0,0,-8]) cylinder(d=20,h=1); } module copper_winding(){ translate([0,0,-7]) color("Orange") difference(){ cylinder(d=19,h=7); translate([0,0,-0.5]) cylinder(d=8,h=9); } } module steel_core(){ translate([0,0,-6]) color("Silver"){ cylinder(d1=5,d2=6,h=1); translate([0,0,1]) cylinder(d=6,h=6); translate([0,0,7]) cylinder(d1=6,d2=5,h=1); } } module magnet(){ translate([0,0,3.87]) color("Silver") minkowski(){ cylinder(d=5.5,h=0.5); sphere(0.25); } } module diaphragm(){ translate([0,0,3.5]) color("White",0.5){ cylinder(d=80,h=0.12); difference(){ cylinder(d=7.4,h=1); translate([0,0,0.12]) cylinder(d=6.2,h=1.5); } } } `

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