Views: 0 Author: Site Editor Publish Time: 2025-11-05 Origin: Site
Fiberglass fabrics are one of the most widely used reinforcements in the composite materials industry. They provide high tensile strength, dimensional stability, and excellent resistance to heat and corrosion, making them essential in marine, automotive, aerospace, and construction applications.
Within the broad category of fiberglass reinforcements, woven and knitted fiberglass fabrics stand out as two of the most common forms. While both are made from continuous fiberglass filaments, their structures, production techniques, and performance characteristics differ significantly.
Understanding these differences helps engineers, manufacturers, and product designers select the right fabric for their composite process—ensuring optimal strength, formability, and cost efficiency.
Fiberglass fabrics are classified based on how the glass fibers are arranged and bonded together. The most common types include:
Woven fabrics: Created by interlacing yarns at 90° angles (warp and weft).
Knitted fabrics: Produced by looping yarns, allowing more flexibility.
Non-woven mats: Consist of randomly oriented fibers bonded with resin or stitching.
Rovings and chopped strands: Continuous or short glass fibers used as primary reinforcements.
The way the fibers are arranged determines how the fabric behaves during processing—its strength, drapability, and resin absorption all depend on its internal structure.
Woven fiberglass fabrics are made by interlacing warp (longitudinal) and weft (transverse) yarns using traditional weaving techniques. Common weave patterns include:
Tight and balanced, offering good stability and uniform thickness.
Allows better drapability and smoother surface finish.
Provides high strength in one direction and an exceptionally smooth surface.
The interlaced fibers share load efficiently, giving excellent reinforcement in both directions.
The fixed intersections of yarns prevent distortion or stretching.
Ideal for precision composite parts requiring strict tolerances.
Smooth texture enables easy resin wet-out and minimal print-through.
Suitable for high-temperature or corrosive environments.
Knitted fiberglass fabrics are made using a warp knitting process, where multiple yarns are interlooped together instead of interlaced. The most common types are multiaxial knitted fabrics (e.g., biaxial, triaxial, or quadraxial), where layers of unidirectional fibers are stitched together.
The looped structure allows the fabric to stretch and conform to complex shapes with minimal wrinkling.
The open structure promotes faster resin flow, ideal for RTM (Resin Transfer Molding) and vacuum infusion.
The absence of crimped yarns reduces stress concentration points.
Offers good reinforcement while reducing overall laminate weight.
Cuts easily and stays stable during lay-up.
Feature | ||
Fiber arrangement | Interlaced at 90° (warp & weft) | Interlooped or stitched layers |
Strength | Very high, balanced in both directions | Moderate, depending on orientation |
Flexibility | Stiff, limited drapability | Highly flexible and formable |
Resin flow | Slower due to tight weave | Excellent due to open structure |
Dimensional stability | Excellent | Moderate |
Surface finish | Smooth and uniform | Slightly open texture |
Fatigue resistance | Moderate (due to yarn crimp) | High (no crimping) |
Ideal for | Flat panels, structural parts | Complex shapes, curved molds |
Summary:
Woven fiberglass provides precise geometry and superior strength, making it ideal for structural and load-bearing components. Knitted fiberglass, on the other hand, offers better formability and resin flow, making it the go-to choice for complex shapes or processes requiring high resin infusion rates.
Selecting between woven and knitted fiberglass ultimately depends on the specific application design, mechanical requirements, manufacturing process, and cost priorities. The right choice ensures optimal structural performance, processing efficiency, and product reliability.
Below are the key considerations to guide your decision:
The geometry and functional purpose of your composite part are the first factors to assess.
Flat, dimensionally critical structures — such as panels, decks, and bulkheads — benefit from woven fiberglass, which maintains precise thickness and uniform strength distribution.
Curved, contoured, or three-dimensional parts, like automotive interior shells or wind blade skins, are better suited to knitted fiberglass, thanks to its superior conformability and resistance to wrinkling during lay-up.
For impact-prone or dynamic parts, knitted fabrics offer better fatigue resistance and energy absorption.
Consider the load direction, stiffness needs, and durability of your final product:
Woven fiberglass delivers high biaxial strength and rigidity due to its orthogonal yarn arrangement, making it ideal for load-bearing or structural components.
Knitted fiberglass features non-crimped, multiaxial layers, allowing fibers to remain straight and fully aligned with the stress direction—resulting in better fatigue resistance and balanced performance under cyclic loads.
For precision parts that must retain shape and size under load, woven fabrics ensure minimal deformation.
For lightweight applications, knitted fabrics achieve a higher strength-to-weight ratio.
Each fabric interacts differently with resin systems and molding technologies:
Woven fabrics are preferred for hand lay-up, prepreg, and press molding processes. Their compact weave minimizes resin pooling and ensures consistent laminate thickness.
Knitted fabrics, with their open, permeable structure, excel in vacuum infusion, RTM (Resin Transfer Molding), and pultrusion, where fast resin flow and complete wet-out are critical to process speed and laminate quality.
For complex or multi-curvature molds, knitted fabrics reduce lay-up time and risk of bridging, leading to smoother, defect-free parts.
If your application demands a cosmetically smooth surface—such as visible automotive panels or exterior architectural laminates—woven fiberglass provides superior flatness and minimal print-through after curing.
Knitted fiberglass, while offering excellent strength and drapability, may require an additional surface veil or gelcoat layer for achieving high-gloss finishes.
Material Cost: Woven fiberglass is generally more economical per square meter.
Labor and Process Efficiency: Knitted fiberglass, though sometimes higher in material cost, can significantly reduce labor time during lay-up and improve resin infusion efficiency, lowering the total manufacturing cost.
Waste Reduction: Knitted fabrics conform easily to molds, reducing trimming waste and rework.
In high-volume production, the total cost difference may favor knitted fabrics due to faster cycle times and fewer defects.
Both woven and knitted fiberglass fabrics play vital roles in modern composite manufacturing. Woven fiberglass stands out for its strength, dimensional accuracy, and smooth finish—ideal for structural, high-precision applications. Knitted fiberglass, on the other hand, provides exceptional drapability, ease of handling, and resin flow efficiency, making it perfect for intricate, curved, or lightweight parts.
Choosing between them depends on your specific performance requirements, fabrication method, and final product design. By understanding these differences, manufacturers can ensure optimal performance, cost-effectiveness, and long-term durability in every composite application.
