Manager Hao (pre oxygenation thread): 13831164999
Manager Shi (pre oxygenation wire): 17332928150
Manager Gu (Pre oxygenation Silk): 13833138900
Manager Zhao (woven fabric, pre impregnated fabric, prefabricated body): 15028196018
Manager Zhang (woven fabric, axial fabric): 13703314888
Manager Zhao (Composite Products): 13944687090
Address: 226 Shifu East Road, Gaocheng District, Shijiazhuang City, Hebei Province
The prepreg process is a mainstream method for manufacturing high-performance carbon fiber composites, widely used in aerospace, new energy vehicles, and high-end industrial equipment. Its core advantage lies in precise control of resin content and fiber orientation, which ensures the consistency and stability of the final product. Below are the key technical points of the process, structured for B2B technical content creation:
This stage directly affects the lamination effect and defect rate, and it is the first line of defense for product quality.
Strict thawing of prepreg: Follow the standard thawing procedure—thaw the vacuum-sealed prepreg at 20–25°C, RH <40% for 12–24 hours. Never use heating equipment to accelerate thawing; this will cause uneven resin softening and local premature curing. After thawing, use the prepreg within 8–16 hours to avoid moisture absorption.
Cutting and orientation control: Cut the prepreg according to the design requirements, and strictly ensure the fiber direction accuracy (tolerance ≤±1°). For parts with directional strength requirements (e.g., aircraft wing spars, automotive chassis beams), unidirectional prepreg must be laid in specified angles (common angles: 0°, 45°, 90°, -45°). Use positioning fixtures to prevent fiber displacement during cutting and transfer.
Cleanliness management: Operate in a dust-free workshop (class 1000 or higher) to avoid dust, oil stains, or other impurities adhering to the prepreg surface. Impurities will cause interlaminar bonding defects and reduce the composite’s mechanical properties.
Lamination is the process of stacking prepreg layers according to the design scheme, and its quality determines the interlaminar strength and dimensional accuracy of the composite.
Layer sequence design and execution: Formulate the layup sequence based on the part’s stress characteristics. For example, 0° layers bear the main tensile load, 45° layers improve shear resistance, and 90° layers enhance transverse strength. Strictly follow the sequence to stack layers—any disorder will lead to a sharp drop in the part’s performance.
Bubble removal during lamination: Use a hand roller or automatic laminator to roll each layer of prepreg from the center to the edges. This step removes trapped air between layers and ensures close contact between adjacent prepregs. For large or complex-shaped parts (e.g., wind turbine blade shells), use vacuum bagging for preliminary debubbling before formal curing.
Control of layup pressure and temperature: During manual or automatic lamination, maintain a constant ambient temperature (20–23°C) to avoid resin viscosity changes caused by temperature fluctuations. Avoid excessive pressure during rolling to prevent resin squeeze-out and fiber wrinkling.
This stage is where the prepreg is transformed into a solid composite part, and the control of temperature, pressure, and time is the core of the entire process.
Tooling and mold preparation: Use high-precision molds with smooth surfaces (surface roughness Ra ≤0.8 μm) to ensure the part’s appearance and dimensional accuracy. Apply a release agent evenly on the mold surface to facilitate demolding; for high-precision parts, use a release film to further improve the surface quality.
Temperature curve control (the most critical parameter): The curing temperature must follow a three-stage curve (heating → holding → cooling) to match the resin’s curing kinetics:
Heating stage: Heat at a slow rate (2–5°C/min) to the gelation temperature of the resin. Rapid heating will cause the resin to cure unevenly, leading to internal stress and microcracks.
Holding stage: Maintain the temperature at the resin’s curing temperature (e.g., 120–180°C for epoxy resin) for a specified time (2–4 hours). This ensures complete cross-linking of the resin molecular chains and maximizes the composite’s mechanical properties.
Cooling stage: Cool to room temperature at a rate of 1–3°C/min. Slow cooling reduces internal stress caused by thermal expansion and contraction, avoiding warping or cracking of the part.
Pressure matching and application timing: Pressure is applied when the resin reaches the minimum viscosity stage (after gelation starts but before full curing):
For autoclave curing: Apply pressure of 0.3–0.7 MPa to eliminate residual bubbles, promote resin flow, and ensure full fiber wetting.
For compression molding: Use higher pressure (1–5 MPa) for mass-produced parts (e.g., automotive carbon fiber panels) to improve production efficiency and part density.
For vacuum bag-only curing: Rely on atmospheric pressure difference (≈0.1 MPa) for low-stress, non-critical parts.
For high-performance composites, post-curing can further optimize the resin’s cross-linking degree and reduce residual stress.
Post-curing process: Place the demolded part in an oven, heat it to a temperature 10–20°C higher than the curing temperature, and hold it for 1–2 hours. This step enhances the composite’s heat resistance, tensile strength, and fatigue resistance.
Demolding and trimming: Demold the part after it cools to room temperature, and use CNC cutting or grinding tools to trim excess edges. Ensure the trimming process does not damage the part’s structural integrity.
Implement a two-level inspection system (in-process inspection + final inspection) to eliminate defective products:
In-process inspection: Check the prepreg’s tackiness before lamination; verify the layup sequence and fiber orientation during lamination; monitor the temperature and pressure curves in real time during curing.
Final inspection: Use non-destructive testing methods (ultrasonic testing, X-ray CT, infrared thermography) to detect internal defects (porosity, delamination, fiber misalignment); conduct mechanical property tests (tensile, shear, bending) on sample parts to verify whether they meet design standards.
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Ltd. All rights reserved.
Manager Hao (Pre-oxidized Fiber): 13831164999,hjh@hbtangu.com
Manager Shi (Pre-oxidized Fiber): 17332928150,sj@hbtangu.com
Manager Gu (Pre-oxidized Fiber): 13833138900
Manager Zhao (Woven Cloth, Prepreg Cloth, Preform): 15028196018,zb@hbtangu.com
Manager Zhang (Woven Cloth, Axial Cloth): 13703314888
Manager Zhao (Composite Products): 13944687090, zqy@hbtangu.com
Email: hbtg@hbtangu.com
Address: No. 226, East Shifu Road, Gaocheng District, Shijiazhuang City, Hebei Province
