Fabric GSM-Wise Required Yarn Count

In the textile industry, selecting the correct yarn count for a desired fabric GSM (grams per square meter) is crucial to achieve the desired weight, texture, and performance. Yarn count and GSM are interrelated and influence the quality of the finished fabric. This article explores how to determine the required yarn count based on fabric GSM.

 

What is GSM in Fabrics?

GSM, or grams per square meter, is a measure of fabric weight. It indicates how much one square meter of fabric weighs and is used to categorize fabrics as:

• Lightweight: Below 150 GSM (e.g., t-shirts, summer wear).
• Medium-weight: 150–350 GSM (e.g., hoodies, shirts).
• Heavyweight: Above 350 GSM (e.g., towels, jackets).

 

What is Yarn Count?

Yarn count refers to the thickness or fineness of yarn and is expressed in systems such as:

• Ne (English Count): Higher numbers mean finer yarn (e.g., 40 Ne is finer than 20 Ne).
• Nm (Metric Count): Similar to Ne but measured differently.
• Tex/Denier: Used for synthetic yarns. Lower numbers mean finer yarn.

 

Factors Affecting GSM and Yarn Count

1. Fabric Type: Knit or woven fabric influences the GSM and yarn count relationship.
2. Fabric Construction: Parameters like loop length (for knits) and ends/picks per inch (for woven fabrics) affect GSM.
3. Fiber Type: Cotton, polyester, or blends impact the yarn count selection.
4. Finishing Processes: Enzyme wash, brushing, or compacting can alter fabric GSM.

 

How to Determine Yarn Count for Desired GSM?

The required yarn count for a specific GSM can be calculated using empirical formulas or charts based on fabric construction.

General Formula for Knitted Fabrics

For single jersey:
GSM = (Loop Length × Yarn Count × Stitch Density × 0.092)

Where:

• Loop Length is in centimeters.
• Yarn Count is in Ne.
• Stitch Density = WPI (Wales per Inch) × CPI (Courses per Inch).

General Formula for Woven Fabrics

GSM = (Warp Yarn Weight + Weft Yarn Weight) × (Ends per Inch × Picks per Inch) ÷ 25.4

 

Examples of GSM and Corresponding Yarn Counts

1. Single Jersey Knit Fabric:
• 120 GSM: 30–32 Ne
• 160 GSM: 24–26 Ne
• 180 GSM: 20–22 Ne
2. Fleece Fabric:
• 200 GSM: 20 Ne (Finer yarn in the surface layer, coarser in the base layer).
• 280 GSM: 16 Ne
3. Woven Fabrics:
• 120 GSM (Poplin): 40–50 Ne warp and weft yarn.
• 180 GSM (Twill): 30–40 Ne warp and weft yarn.

 

Practical Approach to Yarn Count Selection

1. Step 1: Understand Fabric Requirements
   Identify the GSM, texture, and application (e.g., t-shirts, denim, upholstery).
2. Step 2: Choose Yarn Fiber
   Select cotton, polyester, or blended yarns based on performance needs.
3. Step 3: Use GSM-Yarn Count Charts or Software
   Many factories and design systems have pre-set charts or CAD software for precise GSM to yarn count matching.
4. Step 4: Conduct Lab Testing
   Create small fabric samples to verify the correlation between yarn count and GSM.

 

Key Considerations

• Tolerance Levels: Always include a tolerance range (±5 GSM) to account for variations during production.
• Impact of Finishing: Finishing processes like compacting can alter the GSM, so adjust yarn count accordingly.
• Blends: For blends (e.g., 60% cotton, 40% polyester), adjust yarn counts based on fiber proportion and spinning properties.

 

Conclusion

Determining the correct yarn count for a specific fabric GSM is a critical skill in textile manufacturing. By understanding the relationship between yarn count, fabric type, and construction, textile professionals can ensure their fabrics meet desired standards for weight, durability, and comfort.

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