Specifications for surface texture frequently focus on surface “roughness”—the finer structures in the texture—often to the exclusion of the “waviness”—the larger structure of the texture. Unfortunately, problems related to sealing, vibration, noise, wear, etc., are regularly caused by issues hidden in the waviness domain, which cannot be captured by common roughness specifications.
The distinction between roughness and waviness helps us understand the makeup of a surface’s texture and how that texture will affect the surface’s performance.