How to measure the waviness and folding of tempered glass edges?

Measurement of edge waviness:

Place the tempered glass upright on a glass frame, with the lower surface of the glass in contact with the roller facing outward. Use a 300mm knife edge ruler to align one end of the ruler perpendicular to the glass front (or back) and close to the glass. Use a feeler gauge to measure the gap between the glass and the knife edge ruler, and the maximum value is the waviness of the glass edge.

Measurement of folded edges:

Place the tempered glass with its upper surface facing upwards and horizontally on a platform, with the front (or rear) edge of the glass suspended 50-100mm. Use a 300mm knife edge ruler to measure the gap between the knife edge ruler and the front (or rear) edge of the glass, which is perpendicular to the direction of the glass front (or rear) edge. One end of the knife edge ruler should be flush with the glass front (or rear) edge and close to the glass. Measure the gap between the knife edge ruler and the front (or rear) edge, which is the folded edge value of the glass. Folding usually occurs within a range of 20mm from the front or back edge of the glass.