New Thermoform Mold

The mold for the thermoform part of the yoyo needed to be redesigned because webbing occurred between the protrusions of the pinwheel piece (as seen below).

                Webbing occurred despite many variations in the thermoforming parameters, so it was concluded that a new mold needed to be machined. The new mold was a draw-down mold as opposed to a draping mold. Changing the thermoforming method eliminated all of the webbing in the thermoform part, but jeopardized some of the sharpness of the geometry. The two molds can be seen below (the original mold on the left and the new mold on the right).

 

                When the mold was changed to a draw-down mold, the dimensions of the trapezoids in the mold were increased back to dimensions of the full size part because the size of the pockets was the maximum size of the final part. Shrinkage in the part after forming created clearance for the thermoform part to fit through an injected molded part to be stacked on top of it.

The part was molded in both white and clear 0.03” thick plastic to compare materials. Parameters were optimized so the sharpness of the geometry was not lost due to the change in thermoform method.

The new thermoformed part next to the old thermoformed part.