In this article, I wanted to go beyond the simple go/no go measurements that most air gaging is used for. Air gaging is a highly effective and efficient way for measuring these simple diameter requirements. It is also extremely repeatable on tight tolerances, but for this article, I wanted to focus on using air gaging to measure form requirements such as roundness, flatness, perpendicularity/squareness, taper, straightness, matching, and others. 

Our Introduction to Surface Roughness Measurement guidebook is an excellent initiation to noncontact surface roughness measurement. It offers practical information on various topics to help make roughness measurement easy and efficient.

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.

Surface finish affects how a part will fit, reflect light, transmit heat, wear, distribute lubrication, accept coatings and more. The right finish should ultimately be determined by the part’s function and the engineering requirements of the application.

The Keyence IM-7030T is the newest addition to the IM Series. The new drop-indicator, light probe, 8 x12 in. FOV, and programmable ring light help make this the most capable measurement unit to date. 

The L.S. Starrett Co., a leading global manufacturer of precision measuring tools and gages, metrology systems and more, will be demonstrating at IMTS a wide range of its latest solutions from Automated Vision Technology.

When explaining surface finish measurement, it can be helpful to start with the classic metaphor of a desert, as often described by gage maker Taylor Hobson. Imagine grains of sand as roughness, the ripples of sand as waviness, and then the undulating dunes as the surface profile.

Aloisi completed her PhD program in mechanical engineering from the University of Padova, Italy.

Beginning some 30 years ago, portable surface finish gages—some small enough to fit in a shirt pocket—brought a new level of part control to the manufacturing floor.

The Hommel-Etamic Toposcan is a system used for measuring the surface of cylinder bores larger then 60mm in dia.