The wear and tear of the edge of net: the worst wear section is in the area of inserting which conbines the vacuum and not vacuum( it is in 10-15cm area distance with the edge of net)；the solution:

  (1) try to broaden the stagger width of vacuum chamber in turn

  (2) add the  Atmospheric water lubrication in the edge of vacuum chamber

  (3) add stiffener in the appropriate space

 (4) check if there are sharp edges or gap in the edge wiper plate and vacuum box, especially the weak which link the joint and ceramic panel.