Membrane-based infusion processing

A typical setup for a VARTM infusion process with membrane is illustrated in Fig. 10.11. Here, the layup includes the dry reinforcing fibers as a preform on the mold. A peel ply separates the high-permeability layer (i.e., distribution media) from the preform. The membrane is placed on the distribution media and sealed to the tooling surface. Often, an additional breather material is placed between the membrane and bag to facilitate fast volatile flow to the vent. 

The infusion behavior is identical to standard VARTM processes where the vents are placed at the last location of fill. The membrane layer enables any point of the fabric surface to be connected to the vacuum port thus reducing the need for an optimized placement of the venting system. Nevertheless, the post-infusion behavior can be significantly different compared to standard VARTM processing. No resin bleeding occurs as the vent is placed on the impermeable membrane surface. Hence, the pressure behavior and consequently the overall thickness gradient and fiber volume 

Membrane/areal vent Breather doth Bagging film 

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