2, Aperture, hole spacing problem. The smaller the hole is, the denser the pitch is, the worse the flatness is. The punching process of the punching needle and the stainless steel rod when the 420 stainless steel rod is pressed is equivalent to annealing the stainless steel rod, so the stainless steel rod is not well leveled.

　　3, Leaving the edge of the board. The bigger the margin, the worse the flatness is. The opening ratio is larger, the aperture is larger, and the four sides are whiter. It is not easy to level, but we have leveling equipment, and we will level the 420 stainless steel rod as much as possible. Convenient for customers.