Rz, or the Rz value, is a measurement used in surface roughness analysis. It represents the average vertical distance between the highest peak and the lowest valley within a specified sampling length on a surface. This value helps engineers and manufacturers assess the quality and functionality of materials and components. In manufacturing, a lower Rz value indicates a smoother surface, which can be crucial for applications requiring precise fits or reduced friction. Conversely, a higher Rz value may be acceptable for surfaces that need better adhesion or increased wear resistance, depending on the intended use of the product.