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Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

The New Hotness

  • MPCNC: Power Supply Brick Mount

    A laptop-style power brick supplies 24 V for the MPCNC’s stepper motors, but I didn’t want it wandering around on the Basement Laboratory floor and getting in trouble, so a pair of brackets seemed in order:

    Power Supply Brick Mount - trial fit
    Power Supply Brick Mount – trial fit

    They build flat on their backs to avoid support material:

    Power Supply Brick Mount - Slic3r
    Power Supply Brick Mount – Slic3r

    The nicely rounded corners produce a very thin line of plastic on the first layer, so the model now has thicker base plates to improve the situation. A set of mouse ears would keep the tips pasted to the glass.

    The OpenSCAD source code as a GitHub Gist:

    // Power Supply Brick brackets
    // Ed Nisley KE4ZNU 2018-02-26
    Layout = "Show";
    //– Extrusion parameters
    ThreadThick = 0.25;
    ThreadWidth = 0.4;
    HoleWindage = 0.3; // enlarge hole dia by this amount
    function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);
    Protrusion = 0.1; // make holes look good and joints intersect properly
    //– Useful sizes
    inch = 25.4;
    Tap10_32 = 0.159 * inch;
    Clear10_32 = 0.190 * inch;
    Head10_32 = 0.373 * inch;
    Head10_32Thick = 0.110 * inch;
    Nut10_32Dia = 0.433 * inch;
    Nut10_32Thick = 0.130 * inch;
    ID = 0;
    OD = 1;
    LENGTH = 2;
    //– Bracket Dimensions
    Brick = [170.0,66.0,40.0]; // overall size, add details in module
    Socket = [30.0,24.0]; // IEC power socket
    Cable = [6.0,15.0]; // DC output cable ID=wire OD=strain relief
    WallThick = 3.0; // default wall thickness
    BaseThick = 4.0;
    Screw = [5.1,10.0,3.0]; // screw size, more-or-less 10-32, OD & LENGTH for head
    NumSides = 3*4;
    //———————-
    // Useful routines
    module PolyCyl(Dia,Height,ForceSides=0) { // based on nophead's polyholes
    Sides = (ForceSides != 0) ? ForceSides : (ceil(Dia) + 2);
    FixDia = Dia / cos(180/Sides);
    cylinder(r=(FixDia + HoleWindage)/2,
    h=Height,
    $fn=Sides);
    }
    //———————-
    // Models
    module BrickMount(End="Both") {
    difference() {
    union() {
    hull() // main block
    for (i=[-1,1], j=[-1,1], k=[0,1])
    translate([i*(Brick.x/2 + WallThick – WallThick),
    j*(Brick.y/2 + WallThick – WallThick),
    k*(Brick.z + WallThick – WallThick)])
    sphere(r=WallThick,$fn=NumSides);
    hull() // screw flanges
    for (i=[-1,1], j=[-1,1])
    translate([i*(Brick.x/2 + WallThick – BaseThick),
    j*(Brick.y/2 + WallThick + 2*Screw[OD] – BaseThick),
    0])
    sphere(r=BaseThick,$fn=NumSides);
    }
    for (i=[-1,1], j=[-1,1]) // remove screw holes
    translate([i*(Brick.x/2 + WallThick – Screw[OD]),
    j*(Brick.y/2 + WallThick + Screw[OD]),
    -Protrusion])
    rotate(180/6)
    PolyCyl(Screw[ID],2*WallThick,6);
    translate([0,0,Brick.z/2]) // remove center part to leave ends
    cube([(Brick.x + 2*WallThick – 4*Screw[OD]),2*Brick.y,2*Brick.z],center=true);
    if (End == "Socket")
    translate([Brick.x/2,0,Brick.z/2]) // remove cable end to leave socket
    cube([(Brick.x + 2*WallThick – 4*Screw[OD]),2*Brick.y,2*Brick.z],center=true);
    if (End == "Cable")
    translate([-Brick.x/2,0,Brick.z/2]) // remove socket end to leave cable
    cube([(Brick.x + 2*WallThick – 4*Screw[OD]),2*Brick.y,2*Brick.z],center=true);
    translate([0,0,Brick.z/2 – Protrusion/2]) // remove power supply brick from interior
    cube(Brick + [0,0,Protrusion],center=true);
    translate([0,0,-Brick.z]) // remove below XY plane
    cube(2*Brick,center=true);
    translate([0,0,Brick.z/2]) // remove AC socket
    rotate([0,-90,0])
    rotate(90)
    linear_extrude(height=Brick.x,convexity=2)
    square(Socket,center=true);
    translate([0,0,Brick.z/2]) // remove DC cable
    rotate([0,90,0])
    rotate(180/8)
    PolyCyl(Cable[OD],Brick.x,8);
    translate([Brick.x/2,0,Brick.z/4 – Protrusion/2]) // … and wire slot
    cube([Brick.x,Cable[ID],Brick.z/2 + Protrusion],center=true);
    }
    }
    //———————-
    // Build it
    if (Layout == "Show")
    BrickMount("Both");
    if (Layout == "Build") {
    translate([5,0,Brick.x/2 + WallThick])
    rotate([0,90,0])
    BrickMount("Cable");
    translate([-5,0,Brick.x/2 + WallThick])
    rotate([0,-90,0])
    BrickMount("Socket");
    }