Finite Element Analysis of Solidifying Processes in Rapid Freeze Prototyping

Abstract

Rapid Freeze Prototyping (RFP) can generate three-dimensional ice patterns from CAD models by depositing and solidifying water droplets layer by layer. One important issue of the RFP process is how to fabricate the ice pattern to desired accuracy in an acceptable short time. The waiting time between two successive layers is a critical factor. A waiting time that is too short will lead to unacceptable part accuracy, while a waiting time that is too long will lead to an excessive build time. Finite Element Analysis is employed in the study, as described in the present paper, to predict the solidification time of a newly deposited water layer and to develop a better understanding of heat transfer during the RFP process. ANSYS is utilized to develop software for the prediction of solidification time. Effect of various process parameters on the solidification time of an ice column and a vertical ice wall is investigated. These parameters include environment temperature, heat convection coefficient, initial water droplet temperature, layer thickness, and waiting time between two successive layers.