Liquid Composite Molding control methodologies using Vacuum Induced Preform Relaxation

A major limitation with Vacuum Infusion Processes (VIPs) is the inability to dynamically control the resin flow during infusion. A new method called Vacuum Induced Preform Relaxation (VIPR) has demonstrated that one can influence the permeability of the reinforcing fabric during infusion and hence be able to manipulate the resin flow. The VIPR process uses an external vacuum chamber that seals against the flexible molding surface of a VIP mold and applies a secondary vacuum to locally reduce the compaction pressure on the fibers which increases the permeability of that region steering resin flow to that region. In this paper flow control methodologies are introduced with VIPR for online flow correction. The VIPR process is coupled with an automated gantry system and control methodologies to exercise flow control during infusion. The capability of the automated flow control is demonstrated with two online flow control methodologies.