Product variability associated with continuous sheet-fed thermoforming operations

An extensive amount of published data exists with regard to the variation of part weight and other properties for products manufactured by injection molding and blow molding. Relatively little information is available with regard to thermoformed parts. Such data are of considerable practical and theoretical value in establishing realistic processing targets in commercial processing operations. Experimental data have been systematically collected over an extended period of time on drinking cups manufactured at two different facilities by means of a continuous sheet-fed thermoforming process. The cups are produced in a multi-cavity mold. The measured parameters included the weight of individual cups, stacking height, and the wall thickness of individual cups measured at four different locations from the edge to the base of the cup.