Carbon fiber materials demonstrate exceptional performance across many fields. Compared to traditional metal or plastic products, carbon fiber products exhibit superior lightweight properties. However, those familiar with carbon fiber manufacturing know that carbon fiber products require integration with matrix materials during production. This combination can lead to delamination after fabrication. This article explores the causes of delamination in carbon fiber products.
Carbon Fiber Product Manufacturing Process
To understand delamination, it is essential to review the manufacturing process. Most carbon fiber products are made using carbon fiber prepregs (pre-impregnated composite materials) to ensure production efficiency.
Take carbon fiber plates as an example:
Cut prepreg sheets to match the plate dimensions.
Layer the prepreg sheets onto a mold.
Seal the mold and cure it in forming equipment.
Demold the cured plate and perform machining.
The layered nature of this process inherently creates weak interfacial bonds. Despite resin melting and curing under high temperatures, residual interlaminar stresses remain. These stresses, combined with machining forces, often trigger delamination.
Causes of Delamination
1. Layered Structure
Carbon fiber products are built through sequential layering and curing. This creates anisotropic internal structures (direction-dependent properties) and material discreteness. Under microscopic examination, voids or weak resin-fiber interfaces become apparent.
2. Manual Layering Defects
Manual layering often introduces gaps between prepreg sheets. During machining, cutting forces exacerbate these gaps, leading to layer separation. Larger voids further increase delamination risks.
3. Process Control Issues
Inadequate pressure or temperature during curing weakens resin-fiber bonding, creating latent delamination risks.
4. Stress Concentration
Carbon fiber composites exhibit anisotropic stress responses. Machining forces perpendicular to fiber layers generate internal stresses. When these stresses exceed the resin-fiber bond strength, delamination occurs and propagates under sustained loads.
Conclusion
Delamination in carbon fiber products stems from their layered manufacturing process, manual handling defects, process inconsistencies, and anisotropic stress behavior. Addressing these issues requires optimized layering techniques, precise process controls, and advanced machining strategies to minimize interlaminar weaknesses.
