Analysis and minimization of void formation during resin transfer molding process

• Published in: Composites science and technology Vol. 66; no. 16; pp. 3281 - 3289
• Main Authors: Lee, Doh Hoon, Lee, Woo Il, Kang, Moon Koo
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.12.2006; Elsevier
• Subjects: Applied sciences; Exact sciences and technology; Forms of application and semi-finished materials; Laminates; Molding process; Polymer industry, paints, wood; Resin transfer; Technology of polymers; Void formation; Void formation; Resin transfer; Molding process; Transport properties; Laminate; Process control; Fiber reinforced material; Optical sensor; Polymer; Void fraction; Experimental study; Transfer molding; Processing parameter; Mold filling; Formation mechanism
• ISSN: 0266-3538; 1879-1050
• DOI: 10.1016/j.compscitech.2005.07.008

In the resin transfer molding process, residual air in the pores of fiber preform results in dry spots and microvoids in the finished product. The dry spots are usually formed due to irregular permeability of fiber mat and improper injection locations. The microvoids result from non-uniform microarchitecture of the fiber preform, and they are transported through the gap between fiber tows during infiltration of the resin. In this study, a real-time simulation/control method was proposed to actively control the formation and the transport of air voids during the mold filling. The flow equations were solved in real time to predict the change of the flow front shape. The flow front was detected by optical sensors and the control actions were taken based on the sensor signals. Through this automated simulation/control scheme, a real-time control of resin flow could effectively avoid the dry spots and minimize the formation of microvoids by modulating the injection pressure.