A Methodology to Obtain a Desired Filling Pattern during Resin Transfer Molding

Abstract

In Resin Transfer Molding (RTM), dry spot formation and air entrapment during the filling stage often lead to defective parts and high scrap rate. These problems are usually caused by improper design of inlet conditions and vent locations that prevent the Last Point to Fill (LPF) location from coinciding with the preset vent location. Use of direct filling simulation as a design tool for the RTM process often involves trial-and-error procedures in order to find the appropriate inlet conditions and locations as well as exit vent locations. This design procedure becomes complex when adesign involving multiple inlet gates is being considered, especially in large parts. There may also be uncertainty as to whether the final design (obtained using trial-and-error simulation procedures) is indeed the optimum design. This paper presents a methodology to design the RTM process with a desired filling pattern free of dry spots and knitlines. Unlike the traditional filling simulation that predicts the filling pattern using prescribed inlet conditions and the specification of the preform permeability field, this methodology calculates the optimum inlet conditions based on the specification of the desired filling pattern and the prescription of preform permeability. The use of this algorithm greatly enhances

Gate elements at injection locations in numerical simulations of flow through porous media: applications to mold filling

“…This process is repeated until the complete mold is filled. This approach is relatively mature and widespread [15][16][17][18], fairly simple and quite robust, and its utilization stretches into the fields of optimization and control [19][20][21][22][23][24][25]. More importantly, if 'incremental' system matrix decomposition is used [26], the solution is very fast, as the set of system equations is solved only once for the complete filling cycle.…”

Permeability of Hybrid Reinforcements and Mechanical Properties of their Composites Molded by Resin Transfer Molding

“…R ESIN TRANSFER MOLDING (RTM) is a process that is increasingly used to manufacture fiber reinforced polymeric composites [1]. This type of liquid composite molding technique has been used to produce high-performance polymer composites, e.g., automotive and aerospace structural components [1,[2][3][4][5]. RTM has many advantages over other manufacturing processes, including lower labour cost, shorter cycle time, fabrication of large and complex structures with lower environmental impact, and production of parts with finished surfaces on both sides [2,5].…”

“…The RTM process involves the injection of a liquid resin into a closed mold cavity containing the fiber reinforcement and subsequent resin curing, producing a rigid composite part [1,4]. Dry spot formation and air entrapment during the filling stage are among the major problems that lead to defective RTM parts [4].…”

Modeling Flow in Compression Resin Transfer Molding for Manufacturing of Complex Lightweight High-Performance Automotive Parts

“…Originally, the models were used just to verify the pre-existing process designs. More recently, their application has been extended to address process optimization and control [14,[16][17][18][19].…”