Vacuum Bag or CCBM

Also known as film bagging, this method is a closed mold process where the primary mold is similar to the mold used in open molding and  compression on the B-side surface is accomplished through the use of a flexible sheet or re-usable bag. This process yields increased laminate compression, a higher glass-to-resin ratio, and excellent strength-to-weight characteristics when compared to open molding.

In vacuum bagging, the fiber reinforcements are placed in the mold dry, vacuum is then applied to compact the reinforcement and eliminate air. Resin is also drawn through the reinforcement by the vacuum.

Very large parts can be made by vacuum bagging by utilising very low viscosity resin and an appropriate resin distribution medium and multiple ports. This resin infusion process results in very low void content and excellent mechanical properties due to the relatively high glass content.

The vacuum bag process can use reusable silicone bags, or disposable film bagging materials depending on the size of part, number of parts required and the relative value of each part. The handling of a large silicone bag can be cumbersome and impractical for very large parts, whereas the cost of the consumables may make film bagging impractical for commodity priced products.

The reusable vacuum bagging process is suited to low-medium volume part production in the 200 to 500 parts per year range. All vacuum bagging allows for the application of gel coat finishes for desired part finish and is considered to be environmentally friendly because the resin in the bulk laminate cures in a closed mold, minimizing the release of VOC’s.