The length of the steel heald is related to the height of the shed. Larger openings require longer healds, smaller openings use shorter healds. The length is calculated by this formula: L=2.7xHxa, where "L" is the length of the heald, "H" is the drop height, and "a" is the eye length.

Heddle density refers to the number of healds per 1cm distance from the heald when the fabric is ready for weaving. If the heald density is too high, the friction between the heald and the warp will increase.

Insufficient density will increase the number of heald frames, resulting in a large difference in tension between the front and rear heald frames. At the same time, increasing the space for the heald to move on the rod will accelerate the wear of the heald ring.