Modelling of dimensional accuracy in precision investment casting using Buckingham’s Pi approach

Abstract

Precision investment casting (PIC) simulation software is being increasingly used to predict product quality. Input parameters; include factors such as mould temperature, melting temperature, casting material, number and location of feeding points, diameter and length of inflow channels, angle of channel with respect to the main sprue axis. The previous studies highlights that simulation results cannot help the engineer for workpiece other than the one simulated. In this paper a Buckingham Pi model (based upon Taguchi macro-model) for dimensional accuracy (Δd) is presented aiming at such generalisation. To achieve this, a number of experimental runs were conducted for a number of parts, with varying runner geometry and casting conditions. The parameters characterising part geometry have been chosen to be volume-to-area (V/A) ratio. The other input parameters are: slurry layer’s combination (LC) and molten metal pouring temperature. This study will provide main effects of these variables on Δd and will shed light on the Δd mechanism in PIC.