FDM Speaker Experiment

thingiverse

Maker's Log, 20190525: Got sidetracked by various household printing jobs and a nasty extruder driver blowout on my Melzi board that required a full rebuild of my RAMPS/Marlin setup. The subsequent build process took longer than anticipated, and I'm still unsure if I can match the initial diaphragm test print's quality. My Tronxy-built i3 clone is currently holding me back from tackling this project, but I'll return with updates as progress unfolds. Update 4: After crunching some numbers, I realized that to achieve around 8 ohms impedance, I need approximately 600+ turns of wire. Calculations suggest about 672 turns for an 8-ohm resistance load, considering the impedance and inter-turn capacitance will contribute to the overall resistance. Most speakers have a DC resistance roughly three-quarters of their rated impedance, bringing the number of turns down to around 488. The winding should fit comfortably on the voice coil; now I just need to wait for the tiny neo magnet and winding core to arrive. Update 3: Here are the last two images featuring the diaphragm I'll be using in test model 1. I've ordered a small 6x1.5mm magnet and plan to pick up some copper wire from Jaycar this weekend. Update 2: PLA+ is the chosen material for later diaphragm pics, but I need to make a design modification. Giving it a lip should help overcome potential warping, and I've reduced the layer height from 0.6 to 0.5 for three layers (plywood works best with odd numbers, right?) – I'll share that pic in the morning. Update: Flexible PLA isn't the correct material... see the attached picture. I came across a printed speaker driver online and decided to give it a shot myself, so here's the initial kernel of this idea. This is still a work in progress... I'll post prints as I make progress; for now, I'm stuck waiting for the necessary components to arrive. 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); } } }