Causes and Solutions for Fabric Underweight

------Main Causes  of Fabric Underweight

1) Grey Fabric

1. The actual yarn count is higher than required, with finer yarn leading to low weight.

2. Low warp and weft density makes the fabric structure loose.

3. Excessive tension during weaving stretches the grey fabric and reduces its weight.  

2) Pre-treatment

1. Over-intensive desizing, scouring, bleaching or mercerization removes excessive size, lint and fiber.

2. Excessive cross stretching thins the fabric and lowers the unit weight.  

3) Dyeing Process

1. Continuous high tension stretches the fabric lengthwise.

2. Low adhesion of dyes and auxiliaries, especially for light colors.

3. Excessive washing causes further weight loss.  

4) Finishing & Setting (Key Factor)

1. Over-stretching on stenter widens the fabric and makes it thinner.

2. Low overfeed rate results in flat fabric with poor bulkiness.

3. Over-drying leads to excessive moisture loss and low test value.

4. Insufficient dosage of weighting agent and softener.

5) Operation & Testing

1. Unauthorized adjustment of process parameters on site.

2. Non-standard testing environment and improper sampling cause inaccurate data.  

------ Solutions  

1) Control Grey Fabric Inspect yarn count, density and original weight before production. Calibrate loom tension and keep consistent raw materials.  

2) Standardize Pre-treatment Follow standard process parameters to avoid over-processing. Control stretching range properly.  

3) Optimize Dyeing Process Reduce running tension and control washing times. Add qualified filling agents when necessary.  

4) Adjust Finishing Process

1. Set fabric width strictly in accordance with order requirements.

2. Increase overfeed rate appropriately to improve fabric bulkiness.

3. Adjust drying parameters to keep reasonable moisture content.

4. Apply weighting agent and softener as formulated.  

5) Standardize Management & Testing Lock process parameters and conduct first article inspection. Balance fabric under constant temperature and humidity before testing, and take samples at multiple positions.  

6) Remedial Measures for Finished Products

1. Slight underweight: Re-do weighting finishing or adjust stenter parameters.

2. Large deviation: Sort fabrics separately for less demanding products or small cut pieces.

3. Seriously unqualified products shall be downgraded.