3D Surface Roughness and Wear Measurement, Analysis and Inspection

Average Roughness

Are you relying on average roughness (Ra) to control your surfaces? We made this short animation using data from Digital Metrology Solutions, Inc. to show that very different surfaces can all have the same Ra value...and that Ra alone can't tell you which one you've manufactured!

If you rely on average roughness (Ra) to control your surfaces, check out this short animation. It shows that very different surfaces can all have the same Ra value…and Ra alone can’t tell you which one you’ve manufactured! If you want to know more about where to go “beyond Ra,” check out our Surface Roughness, … Read more

What are the 3D optical profiler measurement modes?

surface roughness measurement, optical profiler measurement modes, psi, vsi, vxi, usi

In the early days of 3D optical profiling, we needed to know an “alphabet soup” of measurement modes in order to operate the systems. Smooth surface? That’s one mode. Rougher surface? That requires another. A combination of both? We might not be able to measure it at all! Today’s systems are smarter. Measurement modes that … Read more

Which feature size scales matter for coating adhesion?

When it comes to coatings, the amount of surface area matters. We know that increasing the surface area can improve adhesion, and that “roughing up” a surface increases surface area. But is all “roughness” equal when it comes to making coatings stick? Surface area Surface area impacts how well a coating will adhere, how well … Read more

Noise May be Hiding in the Waviness

Abrasive wear can greatly impact the performance of engines and machinery. This kind of wear can be caused by excessive roughness on either of the contacting surfaces. However, just looking at roughness may not give you the complete story. When we define roughness, we typically exclude longer spatial wavelength structures that may also advance wear. … Read more

Resources

Michigan metrology has been gathering and sharing information on surface roughness, texture, and tribology for almost thirty years.

Why do some bearings look shiny with wear?

Surface texture - a bearing surface may look shiny as it wears because the peak material with short spatial wavelengths has been removed during the run-in period. Michigan Metrology

We tend to think of “new” surfaces as shiny and smooth, and “worn” surfaces as rough, dull, or uneven. But for a bearing surface, the opposite is often true: the initial, manufactured surface, with its carefully controlled texture, may become smooth and shiny over time…and that may not be good news at all. The way … Read more

A plant with self-cleaning leaves?

A lotus leaf is Superhydrophobic due to both the surface energy of its waxy coating and the spatial wavelengths of its surface texture

A lot of effort goes into creating materials that can resist sticking, repel water, or keep oils off of cell phone screens. But some plants are able to accomplish tasks like these naturally. In this post we look at one amazing example…but first, a crash course in surface energy and surface wetting. Surface energy and … Read more

When is “non-contact measurement” important?

non-contact optical 3d measurement of aircraft engine, 4d inspec surface gauge, courtesy 4D Technology and BP Aero

For surface roughness measurement, it would seem like “non-contact” methods would always be preferable. After all, being able to measure a surface with no possibility of contact damage would always be appealing…right? As usual, the actual answer is a little more complex. When non-contact is preferable Non-contact measurements are typically made using optical methods such … Read more