How to avoid the lines exist on the elastic band?

Why some lines occur among the elastic tape and webbing?
The woven elastic band when it is used for long boots, it would be visible and damage the value of the brand, if there were some line on it
so how to avoid this kind of problem?
Firstly, that problem probably comes from the thread when the dyeing factory sends us unstable color. It is not easy to discover before it is created to the textile product .because the color is exactly similar. So we have to pick up the stable yarn factory to establish long term cooperation.
Second, the lines may happen during the process of making the textile, when the roller is too sharp and not smooth enough it will leave some lines or marks on the products;
Third, the line occurs. Maybe the yarns get the non-uniform stress of the beam, which will make some threads loose so the textile will appear lines.
Finally, during the production, the inspectors have to keep the all yarn running if there is a thread that has snapped, but our people ignored it, then it will leave the lines on the textile.
Our product is not just a webbing but a band to connect with you, we are your textile expert in offering you excellent product to meet your standard and suit your market.