Cost Factors Affecting Productivity

Fabrication of slender elastic shells by the coating of curved surfaces

“…Solidification upon cooling ceases the flow and results in a solid shell of nearly constant thickness 1 . Beyond chocolatiers, the polymer industry abounds with needs to fabricate thin shell structures, and a plethora of manufacturing processes have been developed for this purpose, including: injection 2 , rotational 1 and blow molding 3 , as well as dip coating 4 . Common to all of the above techniques are limitations in the thickness of the shells (e.g., ∼0.5 mm for injection molding) and its uniformity (typically ∼20% for rotational molding 5 ), as well as a striking lack of predictive theoretical models due to the multi-physics complexity of the processes.…”

“…Rotational molding, for example, involves coating the inner surface of a hollow mold with a polymer melt, which is then rotated biaxially while applying a decreasing heating profile until a solid shell is formed 1 . As another example, injection molding, is geared for mass-production manufacturing and requires costly precision-machined molds that are inflexible to variations in the geometry of the part 2 . In these processes, the optimization of the control parameters is largely tuned empirically, with compromises on versatility, predictability and reproducibility 5 .…”