3D Surface Roughness and Wear Measurement, Analysis and Inspection

Welcome to the Surface Roughness Analysis Blog

Why do brakes squeak? When will a gasket leak? What caused the haziness in my painted finish?

Surface texture and function are tightly linked. Understanding the relationship between texture and function, and sharing that information with engineers and quality professionals, is what Michigan Metrology is all about. 

The articles in this blog explore the concepts of surface texture analysis and measurement. We show how you can apply these concepts to solve problems related to leaks, squeaks, appearance, wear, noise, fit, friction, vibration, adhesion, and many other functions.

Looking for more information on specific surface texture parameters? Visit our Surface Texture Parameters Glossary for an introduction to dozens of 3D surface roughness analysis parameters.

And, if you want to learn much more about surface texture consider attending our online and in-person classes for an immersive introduction to the many concepts in surface analysis.

Average Roughness—in surface texture measurement, it's one of the most frequently specified surface roughness parameters. In this video we look at how average roughness (Ra, or Sa) is calculated for 2D (profile) and 3D (areal) measurements. We look at what Ra can — and can't — tell us about a surface. And, we discuss the differences between Ra and Sa, and some similar parameters that you may encounter in surface texture analysis software.

How Do We Define Average Roughness?

October 17, 2023

Average Roughness—in surface texture measurement, it’s one of the most frequently specified surface roughness parameters. In this video we look at how average roughness (Ra, or Sa) is calculated. We

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Honing Plates (Sharpening Stones)

September 26, 2023

Hone plates, or sharpening stones, are used to produce a fine edge on knives, scissors, and other tools. A kit of stones provides progressively finer grit sizes and spacings to

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How Do We Define “Roughness?”

September 13, 2023

“Roughness” can mean a lot of things, but in surface texture analysis, it has a very specific meaning. In this short video we look at how 2D and 3D surface

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Noise May be Hiding in the Waviness

September 5, 2023

Download this article as a PDF Abrasive wear can greatly impact the performance of engines and machinery. This kind of wear can be caused by excessive roughness on either of

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We know that measuring surface roughness is important for performance, quality, and durability. But how

How “Rough” is Roughness?

August 21, 2023

We know that measuring surface roughness is important for performance, quality, and durability. But how “rough” are the typical “average roughness” values that we see on prints and specifications? In

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Friction and surface roughness, Real Area of Contact and Apparent Area of Contact, how the difference affects frictional force, Leonardo Da Vinci, Michigan Metrology

Friction and the Real Area of Contact

July 25, 2023

If I need to push a long, heavy block, it seems like it should be easier if I stand the block up rather than laying it flat on its face…and

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Dashboard surface, highly engineered surface texture with both fine surface roughness to scatter light and larger roughness to hide wear

Dashboard surface texture

July 7, 2023

When you’re thinking about the most engineered surfaces in a car, you may think of cylinder bores, clutches, brakes, etc. But we’d like to put one more item on your

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Cavitation erosion

June 22, 2023

Cavitation is the formation of air bubbles in a fluid as it goes from high pressure to low pressure. The dissolved gas can grow into bubbles—and under certain conditions those

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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

Why do some bearings look shiny with wear?

April 25, 2023

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

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surface texture filtering animation - Michigan Metrology

Visualizing “filtering” — an animation

April 18, 2023

Surface texture can be described as a spectrum of spatial wavelengths. “Filtering” is the process to isolate the wavelengths that matter for our application. But what does that really look

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

A plant with self-cleaning leaves?

March 29, 2023

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

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Surface roughness of paint - surface texture is a spectrum of spatial wavelengths, and by examining different ranges within that spectrum we can spot differences that we might miss if we only track the overall average roughness

Paint finish and spatial wavelengths

March 14, 2023

Two lots of steel pass inspection for surface roughness. Yet, when we paint a panel from each lot, one looks great, and the other…does not. How can it be, when

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