Why Surface Roughness is Shifting from Ra to Sa
As optical manufacturing and precision engineering continue to advance, traditional 2D surface roughness metrics like Ra are no longer sufficient for fully characterizing complex surfaces. This article explores why manufacturers and standards bodies are increasingly adopting Sa, a 3D areal roughness parameter that provides a more comprehensive representation of surface texture. Learn the key differences between Ra and Sa, the benefits of areal surface measurement, and what this shift means for quality control, metrology, and modern manufacturing applications.