| Operation Steps：
1. Prepare the glass lid and hammer.
2. Put Transparent Tape on the glass lid surface, in case of hurting people during testing
3. To knock on the 1/6 position of the lid edge (No near to the steam hole) till the whole lid broken.
4. Count the particle number within 50*50mm square. Particles no less than 80 pieces and each one no more than 2g are qualified.