Vacuum Infusion

Vacuum infusion, or resin infusion, has a unique set-up within the vacuum bag. As noted, layers of fabric are secured without the presence of resin. Once infusion begins, resin enters the laminate at a given point and requires flow media to deliver it across the surface of the laminate.

Flow media is placed between the reinforcement and the bag or between layers of reinforcement. In fact, in some cases, flow media becomes part of your laminate. At FibreGlast.com, we carry flow media in a variety of formats:

• EnkaFusion^® Nylon Flow Media offers the fastest flow rates in the category. It features randomly oriented nylon filaments.
• Green HDPE and Red LDPE are both nylon mesh fabrics that deliver a more controlled resin flow.
• Divinymat is a DIAB Divinycell H foam designed to be both a flow media and a sandwich core. The sheet of foam is scored and bound with a light scrim backing.
• Lantor Soric^® is the most conformable of flow media in our selection. It's available in both 2 mm (about 0.08 in) and 3 mm (about 0.12 in) thicknesses.
• EnkaFusion^® Filter Jacket is a nylon mat encased within a nonwoven sock. It can be used for longer or wider applications, and is never meant to be part of the finished composite.

All of the flow media at FibreGlast.com are compatible with all the resins on our website, including epoxy, vinyl ester, and polyester.

The vacuum infusion process, also known as resin infusion, is a method used in composite manufacturing to efficiently and uniformly impregnate dry fibers with resin. It involves the following steps:

1. Preparing the Mold: A mold or tooling is prepared to the desired shape of the final composite part. The mold surface is typically prepared by applying a mold release agent to facilitate easy removal of the cured part.
2. Dry Fiber Layup: Layers of dry reinforcement fibers, such as fiberglass or carbon fiber, are carefully arranged in the mold. The fibers can be in the form of fabric, mat, or unidirectional tapes. The fiber layup is designed to achieve the desired strength, stiffness, and orientation of the composite part.
3. Placement of Resin Distribution Media: A resin distribution media, often in the form of a flow medium or infusion mesh, is placed on top of the dry fiber layup. This material helps evenly distribute the resin throughout the laminate during the infusion process.
4. Vacuum Bagging: A vacuum bag is placed over the mold and sealed tightly, creating an airtight environment. The vacuum bag is typically made of flexible film material that can conform to the shape of the mold and part.
5. Vacuum Application: A vacuum pump is connected to the vacuum bag, and the air is evacuated from the bag. The vacuum pressure creates a pressure differential between the mold and the atmosphere, which helps to compact the dry fiber and prepare the mold for resin infusion.
6. Resin Infusion: Once the vacuum is established, resin is introduced into the mold. There are different methods for resin infusion, but a common approach is to use a feed line or inlet tube to introduce the resin at one end of the mold. The resin is drawn through the mold under vacuum, saturating the dry fibers and displacing the air.
7. Resin Cure: After the resin has fully infused with the fibers, the composite part is left to cure. The curing process may involve heat, which is often applied using heating blankets or an oven, depending on the resin system being used. The curing time and temperature are determined by temperature and the resin used.
8. Demolding and Finishing: Once the resin has cured and the part has achieved the desired strength, the vacuum bag and excess materials are removed. The composite part is carefully demolded from the mold and undergoes any necessary trimming, sanding, or post-processing to achieve the final desired shape and surface finish.

The vacuum infusion process is commonly used in the production of large and complex composite parts where a high fiber-to-resin ratio, uniform resin distribution, and reduced void content are desired. It offers several advantages, including improved fiber consolidation, reduced resin waste, and the ability to produce lightweight and high-performance composite structures. However, it requires careful process control, proper material selection, and adherence to specific curing protocols to achieve optimal results.

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