It is necessary in factories to assess the severity of the surface defects of castings. as a slight surface defect will be taken as qualified when it brings no bad effect or it can be removed by the subsequent processing. In practical production. professional technicians visually inspect the surface defect severity according to their individual experience. https://www.alarecre.com/Virescent-Harmony-Galaxy-A14-5G-Clear-Case-p106336/