Resin transfer molding automation

Vacuum-assisted resin transfer molding (VARTM) is a process to form and shape FRP composites. Fibers are layered on a solid mold base and covered by a vacuum bag. By generating a vacuum, the vacuum bag is compacted owing to the action of atmospheric pressure, and, therefore, air bubbles are ehminated. Porous fabrics absorb excess resin and the entire material is cured to obtain better mechanical properties. This processing technology is suitable to a certain level of automation and ensures a good geometrical control and a smooth surface. 

The resin transfer molding forming technique is particularly interesting for the opportunity of automation it offers and, therefore, large-scale production. Moreover, very large members can be thus molded. 

Devillard, M., Hsiao, K.-T. and Advani, S. G. (2005), Flow sensing and control strategies to address race-tracking disturbances in resin transfer molding. Part II Automation and vafidation . Composites Part A Applied Science ondManitfacturing, 36(11), 1581-1589. 

An early move toward automation and mass production was the invention of preform machines that sprayed chopped-glass strands onto a three-dimensional air screen that approximated the shape to he molded. The preformed glass mat was placed in a matched metal die in a compression molding press and liquid resin was added to form the product. Today, resin transfer molding (RTM) and resin injection molding (RIM) preform die-molding processes are used to mass-produce small and mid-size parts with two finished sides, notably automobile bodies, truck cabs, and even small boat shells. 

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