Warp and weft knitting, although so similar when their loop construction is viewed from its face side, are quite different in their mechanical behavior and properties.

In this article are introduced the forming causes of normal weft loop and weft loop caused by the interlaced filament ends and the measures to prevent them.

According to the characteristics of warp knit fabrics, open and close loop models as well as fall-plate and weft insertion models of multi-bar that accords with actual loops were set up.