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AR Monthly Archives: February 2021
Tire Tread Depth & Rubber Surface Roughness Measurement | 3D Optical Profiler
TIRE TREAD DEPTH & RUBBER SURFACE ROUGHNESS MEASUREMENT using 3D Optical Profiler
Prepared by
ANDREA HERRMANN
While tire tread depth is commonly measured with handheld gauges for consumer safety, industrial R&D and tire manufacturers require more advanced methods. This application note demonstrates how a 3D optical profilometer provides precise tire tread depth measurement, contour mapping, and rubber surface roughness analysis for high-accuracy studies.
INTRODUCTION
Like all materials, rubber’s coefficient of friction is related in part to its surface roughness. In vehicle tires, both tread depth and surface roughness directly affect traction, braking, and wear performance. In this study, the rubber surface and tread’s roughness and dimensions are analyzed using 3D non-contact profilometry.
THE SAMPLE
IMPORTANCE OF 3D NON-CONTACT PROFILOMETRY FOR TIRE TREAD DEPTH MEASUREMENT
Unlike other techniques such as touch probes or interferometry, NANOVEA’s 3D Non-Contact Optical Profilers use axial chromatism to measure nearly any surface.
The Profiler system’s open staging allows for a wide variety of sample sizes and requires zero sample preparation. With a single scan, users can capture both overall tire tread depth and micro-level surface roughness, with zero influence from sample reflectivity or absorption. Plus, these profilers have the advanced ability to measure high surface angles without requiring software manipulation of results.
This versatility makes NANOVEA profilers ideal for both tire tread wear testing and advanced rubber material research.
MEASUREMENT OBJECTIVE
In this application, we showcase the NANOVEA ST400, a 3D Non-Contact Optical Profiler measuring tire tread depth, contour geometry, and rubber surface roughness. A sample surface area large enough to represent the entire tire surface was selected at random for this study. To quantify the rubber’s characteristics, we used the NANOVEA Ultra 3D analysis software to measure groove dimensions, tread depth, surface roughness, and developed vs. projected area.
NANOVEA ST400 Standard
Optical 3D Profilometer
ANALYSIS: TIRE TREAD
The 3D View and False Color View of the treads show the value of mapping 3D surface designs. This provides engineers with a straightforward tool to evaluate tread depth uniformity, groove design, and wear from multiple angles. The Advanced Contour Analysis and Step Height Analysis are both extremely powerful tools for measuring precise dimensions of sample shapes and design.
ADVANCED CONTOUR ANALYSIS
STEP HEIGHT ANALYSIS
ANALYSIS: RUBBER SURFACE
The rubber surface can be quantified in numerous ways using built-in software tools as shown in the following figures. It can be observed that the surface roughness is 2.688 μm, and the developed area vs. projected area is 9.410 mm² vs. 8.997 mm². These results demonstrate how rubber surface roughness affects traction and performance, enabling comparisons between different rubber formulations or varying levels of surface wear.
CONCLUSION
In this application, we have shown how the NANOVEA 3D Non-Contact Optical Profiler can precisely characterize tire tread depth, contour dimensions, and rubber surface roughness. The data shows a surface roughness of 2.69 µm and a developed area of 9.41 mm² with a projected area of 9 mm². Various dimensions and radii of the rubber treads were measured as well. This information can be used by tire manufacturers, automotive researchers, and materials engineers to compare tread designs, rubber formulations, or tires with varying degrees of wear. The data shown here represents only a portion of the calculations available in the Ultra 3D analysis software.
