IR sheet heating in roll fed thermoforming: Part 1 - Solving direct and inverse heating problems

Abstract

Computational methods for modelling the heating stage in thermoforming of roll fed plastic sheet (direct problem) and for setting the temperatures of the heater bank to produce a prescribed sheet temperature (inverse problem) are presented, discussed, and experimentally validated. The algorithm computes the relevant local shape factors, and takes into account the effects of sag and of the surrounding air. The importance of same boundary conditions, such as air temperature, is discussed and quantitatively estimated.