Vacuum Bag Composite Curing Technology: A Comprehensive Overview
As industries using advanced technologies continue to grow, so does the need for high-strength, lightweight materials. Manufacturers of products used in space exploration, high-efficiency vehicles, aircraft manufacturing, and wind power constantly pursue opportunities to reduce weight without sacrificing strength and durability. Composite materials are among the best candidates for this light-weighting trend. Composites were once primarily used in the aerospace industry but are increasingly used in more industries looking to reduce product weight.
What is vacuum bag curing?
One of the most common methods of manufacturing composite materials is vacuum bagging, which uses atmospheric pressure to hold the composite material tightly in a mold and heat to cure the material. Vacuum bag composite curing begins with placing a fabric prepreg made of carbon or other fiber into a mold and manually forcing epoxy resin into the weave with a roller or other tools. Multiple prepreg mats are then layered onto the first, with the epoxy embedded into and between each layer. A plastic bag is placed over the mold and connected to a vacuum system to draw the air out, which forces the bag tightly onto the impregnated material, to shape the material to the mold. The mold is then heated and cured in an industrial oven while the vacuum is maintained.
The Vacuum Bag Curing Process
- Preparing the mold: The mold is cleaned and prepared for the layup.
- Laying up the prepreg: The prepreg mats are cut to size and layered in the mold.
- Applying the resin: The resin is applied to the prepreg mats to saturate the fibers.
- Bagging the laminate: The saturated mats (laminate) is covered with a vacuum bag and sealed onto the mold.
- Generating a vacuum: A vacuum pump removes air from the bag through holes in the mold, applying pressure to the laminate and compacting it against the mold.
- Curing the laminate: The mold and laminate are heated in an industrial oven according to the resin's curing specifications.
- Cooling down the laminate: After the heating process, the oven cools down slowly to prevent internal stresses in the cured part.
- Demolding: Once cool, the vacuum bag is removed, and the finished part is extracted from the mold.
- Trimming the part: The part is trimmed to its final size.
- Post curing: The part may require post curing, which is a second heating process, depending on the resin formulation
Benefits of Vacuum Bag Curing
- Superior Part Quality: High-quality parts with exceptional strength-to-weight ratios.
- Improved Surface Finish: Smooth, blemish-free surfaces that require minimal post-processing.
- Dimensional Accuracy: The vacuum pressure ensures close adherence to the mold, delivering precise and consistent part dimensions.
- Versatility: Works with a wide range of materials and mold shapes, making it a truly adaptable solution.
Where is Vacuum Bag Curing Used?
Products manufactured using vacuum bag composite curing are all around. From rockets and aircraft to cars and wind turbines, vacuum bag curing technology can be found in a multitude of applications across industries, such as:
- Aerospace: Aircraft components, structural elements, engine parts
- Marine: Boat hulls, rudders, sailboat masts
- Automotive: Car bodies, interior panels, engine covers
- Sports and Recreation: Skis, tennis rackets, surfboards
- Renewable Energy: Wind turbine blades, solar panel frames
- Construction: Building panels, structural beams, bridge components
Part 2: Key Features When Designing a Composite Curing Oven
When designing a composite curing oven for vacuum bagging applications it is important to consider specific features and options to prevent improper curing of parts. Learn more about the key design features to consider for your next vacuum bag composite curing oven in part 2 of this blog series!