A new methodology for race-tracking detection and criticality in resin transfer molding process using pressure sensors

Abstract

In this study, a simplified cost effective simulation-based methodology is proposed to assist manufacturing engineers in the design and development phase of the resin transfer molding process. Race-tracking is unavoidable in the resin transfer molding and can lead to entrapment of air pockets, which results in parts being discarded as scrap. A purely numerical methodology is presented to distinguish between the critical and non-critical race-tracking scenarios, that will guide the design and production engineers plan an efficient and effective manufacturing strategy. The detection methodology is based on computing the pressure evolution with time during the injection process. The novelty relies on the superimposition of the computed pressure gradient maps that reveals unsuspected common features in the numerous race-tracking cases investigated in the various geometries of increasing complexity considered. The pressure sensors are meant to detect and evaluate different race-tracking scenarios and their level of criticality. The minimum number and locations of pressure sensors arise directly from the highest pressure gradient zones for simple geometries. Sensors placement guidelines are introduced for a simple rectangular shape, then this information is used to qualitatively apply the guidelines to parts of more complex shapes. A general rule that all parts, no matter how complex, can be considered as a combination of simpler ones is presented. Furthermore, a new failure criterion is proposed based on the flow patterns that highlights the likely flow patterns to entrap voids.