The working principle and scope of application of the cross-cut knife
The grid knife, also known as the white grid knife, is used to evenly draw a grid of a certain size. The degree of adhesion of the coating film to the substrate is evaluated by evaluating the integrity of the coating film in the grid. 'express. It is mainly used for the determination of cross-hatch adhesion of organic coatings, not only for laboratories, but also for construction sites under various conditions.
rating
ISO class: 0
ASTM grade: 5B
The edges of the cut are perfectly smooth and there is no peeling of the lattice edges.
ISO class: 1
ASTM grade: 4B
There are small flakes at the intersection of the cuts, and the actual damage in the cross-cut area does not exceed 5%.
ISO class: 2
ASTM grade: 3B
The edges and/or intersections of the incisions are spalled by more than 5% but less than 15% of their area.
ISO class: 3
ASTM grade: 2B
Partial peeling or full flakes along the edge of the cut, and/or part of the grid is peeled off in full flakes. More than 15% but less than 35% of the area was peeled off.
ISO class: 4
ASTM grade: 1B
Large pieces of peeling off at the edge of the cut / or partial or complete peeling off of some squares, the area of which is greater than 35% but not more than 65% of the crossed area.
ISO class: 5
ASTM grade: 0B is above the previous grade.
