To start, we designed the mold to be compatible with resin transfer molding and to meet the customers geometric requirements.

Using automation to drive down labor costs, we use our 20′ cutting table to accurately cut fabric following the unique ply kit pattern for processing repeatability.

First, a thick chopped strand fiberglass mat is cut in both large and small patterns, followed by a thinner lay of fiberglass QUISO, a quasi-isotropic braided fiberglass fabric. We used the copped strand fiberglass mat, which measured 0.060″ thick, to minimize layup labor.

Layup begins on the male surface of the mold, starting with the chopped strand fiberglass mat, followed by a layer of the QISO fabric. The positioning of match tooling inserts ensures vertical flange walls with minimal draft angels are achieved. This layup process continues on all the mold’s surfaces.

For the outside edge, a layer of chopped fiber glass is sued followed by an internal layer of balsa wood. This helps to significantly lower the weight of the part, saving about 15lbs. Then the outer layer of chopped strand fiberglass mat is placed on top.

After layup is complete, the mold is closed in multiple steps.

The mold is then bolted closed and is plumbed for infusion. The mold as multiple outlets to allow us to control the resin flow of the outlets and make sure no region of the part lacks proper resin infusion. The mold is placed into the oven, infused with resin, and the cure cycle begins.

After cure, the mold is removed from the oven, the inlet tubes are removed, and the mold is opened in steps. First the match tooling removed, releasing the trapped parts of the composite and then the outer tooling s removed. The requirements for minimal draft required the design of a complex mold that worked as expected.

We then trim the vertical flanges using the machined tooling scribe lines and the part is finished and ready for painting.

The composite enclosure door was able to meet all geometric surface and stiffness requirements at only 32lb, less than 40% of the original weight of the metal enclosure door.

Hawthorn Composites utilizes dry fiber, resin infusion, and novel manufacturing methods to make complex geometry composites parts that are equal in performance and quality to baseline manufacturing methods at significantly lower cost.

Get more details about this case study by clicking here.