Standard Cut Length Gravimetric Methods for Line Flax Linear Density Testing
Standard cut length gravimetric testing uses strict pretensioning, razor sectioning, and moisture regain corrections to establish spinnable tex accurately.
Decitex Determination
Linear Density
The measurement of mass per unit length of flax yarn or fibre provides the fundamental basis for grading yarn fineness. Decitex determination involves measuring a specific length of yarn and weighing it under controlled atmospheric conditions to calculate the decitex value. This metric defines the yarn count, indicating how many grams a ten-thousand-meter length of the yarn weighs.
Moisture Correction
Linen is highly hygroscopic, and its moisture content directly affects its weight and measured fineness. To ensure accuracy, the decitex determination must be performed on specimens that have been brought to moisture equilibrium in a standard testing atmosphere. Alternatively, the yarn is oven-dried to find its bone-dry mass, and the commercial moisture regain is added to compute the standard decitex.
This correction ensures that yarn traded across different regions meets the contract specifications regardless of the ambient humidity during transport.
Spinning Control
Maintaining consistent yarn fineness is critical for preventing weaving defects and ensuring uniform fabric density. Spinning mills monitor the decitex during the drafting and spinning processes to detect anomalies in the sliver feed or spindle speed. Consistent measurements help to prevent thin spots that could break during weaving or thick spots that spoil the fabric appearance.