1. Flatness inspection
Place a steel flat ruler with a straightness tolerance of 0.1mm on the two diagonal lines of the inspected surface naturally, and measure the gap between the ruler surface and the board surface with a feeler gauge or vernier caliper.
2. Angle inspection
It is measured with a 90 degree steel square with an internal angle perpendicularity tolerance of 0.13mm and an internal angle side length of 500mmx400mm.
3. Appearance quality inspection
With pattern and color tone, put the qualified board and the tested board flat on the ground, standing at a distance of 1.5m from the board for visual inspection.
