Vacuum Assisted Resin Transfer Molding

1. Preparing the preform:

The mold surface is cleaned and a release agent is sprayed onto the surface. Then, fabric layers are cur in desired dimensions and placed in the mold cavity.

In order to prevent sticking of the fibers to the vacuum bag, peel ply is placed on the fiber.

While manufacturing large structures, a removable layer of the flow-enhancement medium called flow mesh is used to provide resin propagating faster in the fibers. As an alternative to the flow mesh, an embedded core layer is used for flow-enhancement. Instead of placing on top of the fabric preform like flow mesh; core can be placed in the fabric preform, and it becomes an internal part of the manufactured composite material. In our experiments, for flow enhancement medium, a core will be used.

To direct the resin flow, an omega tube or spiral tube can be used.

Infusion braid and spiral tubes are placed near the vacuum connectors to have a uniformly distributed air ventilation.

2. Closing the mold:

After preparing the preform, a vacuum bag is placed to create a vacuum ambient in the mold cavity. The vacuum bag is bonded to the mold by using a sealant tape.

3. Vacuuming and final processing:

Resin is driven through the empty channels between the fibers of fabric preform by using a vacuum pump. After resin fills the entire mold cavity and eventually exits from the ventilation, we still apply to vacuum to keep the vacuum bag compacted. After curing, the vacuum bag is taken off and the manufactured part is taken out.