This is a (3,2) ribbon torus knot designed by Cathy Wang and edited by Dave Pfaff and myself for my Math 341 Introduction to Topology class in Fall 2014.
You may need to rescale this object by a factor of 10 in Makerware since it is sized in cm not mm. You may also need to move the knot onto the platform, I think it is just above it. The knot is about 10cm x 11cm x 5cm in size. This knot was first printed on a Projet-260 3D Systems printer.
The entire model was designed in Cinema4D. The knot was created using the Formula tool with parametrization x=(2+cos(2t))cos(3t), y=(2+cos(2t))sin(3t), z=-sin(2t) from t=-pi to t=pi. The trianglulated surface was created by first adding in a small rectangle, then using the SweepNurbs (without caps). The width and height of the rectangle was adjusted so the band is not a constant size through the knot. The overlapping edges and small gaps were also fixed. Finally, the knot was colored with a beautiful rainbow-gradient. (The color doesn't show in the .stl file.)