Relation Between Fabric GSM and Yarn Count

The relationship between fabric GSM (grams per square meter) and yarn count is a fundamental concept in the textile industry. It directly impacts the fabric's weight, texture, strength, and overall quality. Understanding this relationship is crucial for textile designers, merchandisers, and manufacturers to produce fabrics that meet the desired specifications.

 

What is Fabric GSM?

Fabric GSM refers to the weight of one square meter of fabric, expressed in grams. It is a critical parameter used to classify fabrics:

• Lightweight Fabrics: Less than 150 GSM (e.g., summer t-shirts, scarves).
• Medium-Weight Fabrics: 150–350 GSM (e.g., shirts, hoodies).
• Heavyweight Fabrics: Above 350 GSM (e.g., denim, winter jackets).

 

What is Yarn Count?

Yarn count indicates the thickness or fineness of yarn and is expressed using various systems:

• Ne (English Count): Higher values mean finer yarn (e.g., 40 Ne is finer than 20 Ne).
• Nm (Metric Count): Higher values also indicate finer yarn but use a different calculation.
• Tex/Denier: Lower values mean finer yarn.

 

The Core Relationship Between GSM and Yarn Count

The GSM of a fabric is heavily influenced by its yarn count, as well as other factors like fabric construction and density. Generally:

• Finer Yarn (Higher Count): Produces lighter fabrics with lower GSM.
• Coarser Yarn (Lower Count): Produces heavier fabrics with higher GSM.

For example:

• A 40 Ne yarn in single jersey knit fabric results in a lightweight fabric (~120 GSM).
• A 20 Ne yarn in the same fabric type results in a medium to heavy fabric (~180–200 GSM).

 

Other Factors Impacting the Relationship

1. Fabric Construction:
• Knitted Fabrics: The loop length and stitch density significantly affect GSM.
• Woven Fabrics: Ends per inch (EPI) and picks per inch (PPI) influence GSM.
2. Fiber Type:
   Different fibers (e.g., cotton, polyester, viscose) with the same yarn count can produce fabrics with varying GSM due to differences in fiber density and texture.
3. Finishing Processes:
   Processes like compacting, brushing, or washing can increase or decrease GSM by altering the fabric’s structure.

 

Empirical Relationship Between GSM and Yarn Count

For knit fabrics, the relationship can be approximated using this formula:

GSM ≈ (Loop Length × Yarn Count × Stitch Density × Constant)

For woven fabrics, the formula is:

GSM = (Warp Weight + Weft Weight) × (EPI × PPI) ÷ Constant

 

Practical Examples

1. Single Jersey Knit Fabric:
• 120 GSM: 30–40 Ne yarn count.
• 160 GSM: 24–26 Ne yarn count.
• 200 GSM: 20–22 Ne yarn count.
2. Woven Poplin Fabric:
• 120 GSM: 40 Ne warp and weft yarn.
• 200 GSM: 30 Ne warp and weft yarn.
3. Denim Fabric:
• 12–14 oz/sq. yd (407–475 GSM): 7–12 Ne yarn count.

 

Key Observations

1. Higher Yarn Count ≠ Higher GSM: A finer yarn count (e.g., 40 Ne) typically reduces GSM because less fiber material is present in a given fabric area.
2. Fabric Density Plays a Role: Higher EPI/PPI (woven) or tighter stitches (knit) increase GSM even when using finer yarn.
3. Blended Fabrics: In blended fabrics, the proportion of each fiber type (e.g., cotton-polyester) influences GSM and the choice of yarn count.

 

Why Understanding This Relationship is Important

1. Design Precision: Ensures the fabric meets functional and aesthetic requirements.
2. Cost Efficiency: Helps optimize yarn and material usage for desired GSM.
3. Customer Satisfaction: Produces fabrics that align with buyer specifications.

 

Conclusion

The relationship between fabric GSM and yarn count is dynamic, depending on fabric type, construction, and fiber. By carefully analyzing this relationship, textile professionals can create high-quality fabrics tailored to specific uses.

For more textile tips and insights, visit Learn Easy Textile.