Closed Molding Processes

Closed mold processes such as Light Resin Transfer Molding (LRTM), Reusable Bag Molding (RSBM) and Vacuum Infusion Process (VIP) are used to produce precision parts at lower costs for a variety of applications. Compared to open mold processes, closed mold technologies offer such advantages as:

Open Mold Process
  • Reduced waste and emissions
  • Cleaner, healthier environment
  • Lower material/disposal costs
  • Greater consistency and repeatability
  • Reduced cycle times
  • Higher productivity and lower labor costs.

The Closed Mold Alliance works with three key processes: Light Resin Transfer Molding (LRTM), Reusable Bag Molding, and Vacuum Infusion Process (VIP). 

 Reusable Bag Molding

Reusable Bag Molding is often described as a hybrid process that borrows desirable features from both LRTM and VIP; most manufacturers use one of two methods: Closed Cavity Bag Molding (CCBM) or Silicone Bag Molding (SBM).


 Vacuum Infusion Process

Vacuum Infusion Process (VIP) distinguishes itself by being the only process that utilizes only atmospheric pressure to push the resin into the mold cavity, which can be a one-sided mold with bagging film being utilized for the “B” side, a two-sided mold, or even a soft “envelope” bag.


 Light RTM

Light Resin Transfer Molding, or Light RTM, is a process by which composite products are manufactured using a closed mold system, which consists of an “A” side mold (base mold) and a semi-rigid “B” side mold (counter mold) that are sealed together using vacuum pressure.