Selecting the correct carbon fiber yarn requires a deep understanding of tensile strength, modulus, and filament count (K-value). For most commercial applications, 3K, 6K, and 12K are the industry standards. You must prioritize high-strength (T-series) for aerospace or sporting goods, while high-modulus (M-series) is essential for rigidity-critical components. Always verify the sizing agent compatibility with your specific resin system (epoxy, polyester, or vinyl ester) to ensure optimal interfacial bonding.