Material Metric
The numerical factor used to quantify the proportion of wasted fibers at the borders of a textile web during carding or nonwoven bonding determines the yield efficiency of the line. The edge loss coefficient calculates how much wide fabric must be trimmed to obtain a uniform density across the roll. It is expressed as a ratio of border waste to total throughput, providing a clear indication of width-wise uniformity during the initial web lay-down process.
Process Calculation
Trimmed borders are weighed and compared against the nominal weight of the usable center portion of the web. This edge loss coefficient increases when the airflow or mechanical guide plates at the sides of the machine are misaligned. It helps production managers adjust the deckle width on nonwoven lines.
Web Uniformity
Nonwoven webs often have thinner edges due to lateral fiber migration during the web-forming stage. Monitoring the edge loss coefficient ensures that the trimmed margin is kept to the minimum required to achieve the target area weight. This maintains high material utilization during production.
Cost Evaluation
Raw material costs in nonwoven manufacturing constitute the largest portion of total operating expenses. Minimizing the edge loss coefficient directly increases the profitability of the mill. This calculation is a routine part of shift performance audits.
