1. Detailed explanation of carbon fiber vacuum forming process
Core concept: A composite material forming process that utilizes vacuum negative pressure as the sole or primary pressing force
Seal the carbon fiber reinforced material (dry cloth+resin, or prepreg) stacked on the mold with a vacuum bag
Vacuuming creates an environment below atmospheric pressure (usually ≥ -0.08 MPa), utilizing atmospheric pressure (approximately 0.1 MPa)
Uniformly compact and lay the layer, while combining heating (oven, blanket, or ambient temperature) to make the resin flow, infiltrate the fibers, and cure
2. Characteristics of Vacuum Forming Process
The investment in equipment (vacuum pump, oven) is much lower than that of hot press cans
The cost of molds (often wooden molds, composite molds) is significantly lower than that of high-pressure high-precision metal molds used for hot press cans
Single source of pressure: relying solely on atmospheric pressure (about 0.1 MPa) as compaction pressure, with limited pressure
Relatively uniform pressure: Atmospheric pressure acts on the vacuum bag from all directions, providing better uniform compaction effect (better than contact molding)
Excellent exhaust capability: Continuous vacuum effectively removes air, moisture, and volatile substances, reducing porosity (not as effective as hot press cans)
3. Carbon fiber vacuum forming process
Material Preparation – Lay up – Sealing – Demolding and Post treatment
4. Advantages and disadvantages of carbon fiber vacuum forming process
advantage
Simple equipment and low site requirements: vacuum pumps and ovens (or hot blankets) can meet most of the needs
Excellent adaptability to complex shapes: extremely strong adaptability to curved surfaces, grooves, and large-sized structures
Good surface quality (mold surface): The mold surface can achieve a high degree of smoothness
Effective reduction of porosity: continuous vacuum exhaust, significantly better than open mold contact molding
Relatively easy to operate and learn: the technical threshold is lower than that of the hot press tank
Inconvénients
Mechanical properties are limited: the maximum compaction pressure is only 0.1 MPa, resulting in low fiber volume content (50-55%), high porosity (1-3%+), and significantly lower mechanical properties (especially interlayer strength and compressive strength) compared to hot press products
Resin flow control challenge (wet method): prone to uneven infiltration (poor/rich resin), resin flow, and other issues that affect performance and appearance consistency
Curing temperature and time limitations: limited by oven size, power, or resin system
Reliability of vacuum bag system: There is always a risk of seal failure, which may result in batch scrap
Relatively low production efficiency: layer laying (especially wet methods), packaging time, and curing time may be longer
Double sided quality difference: The vacuum bag surface (non stick surface) is usually rougher and requires additional processing
Volatile matter treatment (wet method): Some resins (such as polyester/vinyl ester) may produce irritating odors or small amounts of VOCs during the curing process
5. Application fields of carbon fiber vacuum forming process; Future Development Trends
Application field
Automobiles: body coverings (hood, spoiler), interior parts, non load bearing structural components, prototype car parts
Ships and oceans: hull, deck components, hatch covers, deflectors, kayaks, paddles
Wind power generation: small and medium-sized wind turbine blades, nacelle covers, fairings
Sports and leisure: bicycle frame (entry-level/mid-range), helmet, surfboard, snowboard, fishing rod, rowing boat (some non main load-bearing components)
Industrial equipment: machine protective covers, panels, brackets, pipelines, tank liners, fixtures and jigs
Architecture and Art: Architectural Decorative Panels, Sculptures, Models, Exhibits
Consumer electronics: drone body (consumer grade), audio enclosure, high-end electronic device enclosure
Aerospace (secondary load-bearing components/interior): fairings, interior panels, ducts, secondary brackets
Future Development Trends
Prepreg optimization: Develop high-performance, low viscosity, and high flowability prepreg (VO Vacuum Only) specifically optimized for vacuum bag processes
Efficiency and Automation
Automated laying application: exploring the application of automatic cutting machines and simple laying equipment in vacuum forming, especially suitable for flat or single curvature components
Rapid curing resin system: Shorten curing cycle and improve production efficiency
Modular/Integrated Equipment: Developing Compact and Easy to Operate Vacuum Heating Integrated Systems
Dry fiber infusion replaces wet method: improves infiltration uniformity and reduces VOCs emissions (although strictly speaking this is a RTM variant, it is often combined with vacuum)
Application expansion: Continuously replacing traditional materials and more expensive processes in the fields of small batch customization and large-scale non main load-bearing structures
Summary
Its core lies in using atmospheric pressure (about 0.1 MPa) to uniformly compact and lay layers through a vacuum negative pressure system, combined with heating (oven/hot blanket/room temperature) to complete resin curing and fiber infiltration