profilometer

A profilometer is a measuring instrument used to characterize the micro- and macro-scale topography of a surface by tracing its height profile. Profilometers generate data describing surface roughness, texture, and form, typically as a height map or profile across a line or over an area.

Profilometers are broadly categorized into contact and non-contact instruments. Contact profilometers, or stylus profilometers, use a sharp stylus mounted on a cantilever to trace the surface as the specimen or stylus is moved in the x-y plane. The vertical displacement is converted into an electrical signal to produce a height profile. Non-contact profilometers use optical methods such as confocal microscopy, interferometry, or laser scanning to map height without physical contact.

Measurements yield roughness parameters such as Ra, Rq, and Rz for line profiles; areal measurements use parameters in ISO 25178. Optional features include measurement of waviness, form, and peak-to-valley heights. Modern instruments often provide 3D areal maps with high lateral resolution.

Profilometers are used in a range of industries to assess surface finish, wear, and texture, and to ensure conformity to specifications. Standards include ISO 4287 and ISO 11562 for roughness, and ISO 25178 for areal surface parameters. Limitations include potential stylus-induced surface damage and tip wear in contact profilometers, and optical sensitivity to surface reflectivity, translucency, or color.