Air Conditioner CAM Replacement

Tue 25 August 2020 by Dr. Dirk Colbry

Picture with Part number

Our house has a 2-zone heating and air conditioning system. Today is the third time in the same number of years that one of the automated damper has broken. The problem seems to be the CAM that triggers the limit switches inside the motor is made of a flimsy plastic and easily breaks (see following pictures).

Original CAMs with a broken piece in the corner

Picture of the broken CAMs

I decided to build 3D print a stronger CAM. Instead of trying to replace with two adjustable CAMS my design includes one, thicker CAM which I modeled in OPENSCAD using the following code:

  difference() {
      union() {
          translate([0,12.5,0]) cube([3, 10, 4], center=true);
          translate([2,9.5,0]) rotate([0,0,45]) cube([3, 5, 4], center=true);
          translate([-2,9.5,0]) rotate([0,0,-45]) cube([3, 5, 4], center=true);

          rotate ([0,0,90]) union() {
              translate([0,12.5,0]) cube([3, 10, 4], center=true);
              translate([2,9.5,0]) rotate([0,0,45]) cube([3, 5, 4], center=true);
              translate([-2,9.5,0]) rotate([0,0,-45]) cube([3, 5, 4], center=true);
          }
          difference() {
              scale([0.1, 0.1, 1]) cylinder(h = 4, r = 100, center=true);
              scale([0.1, 0.1, 1]) cylinder(h = 5, r = 35, center=true);

          };
      }
      for (a =[15:65]) {
          rotate([0,0,-a]) translate([0,7.5,0]) scale([0.1, 0.1, 1]) cylinder(h = 5, r = 10, center=true);
      }
  }

Here is a picture of the final CAM design:

Rendered New Part

Link to the generated STL File

And here is the CAM put back into the moter housing:

New CAM in place

I have included the files in case someone else has the same problem. The part number for the entire uint is "DURO DYNE C 005096". Let me know if you find this helpful.


Comments