Profilometry for Rotational Measurement

Table of Contents

Introduction
Importance of Rotation Stage for Part Inspection
Measurement Objective
Results and Discussion
Conclusion

Introduction

Accurate surface topography, step height measurement and roughness are provided by high resolution profilometry. This technique detects minute surface features which may not be detected by the naked eye.

The Nanovea 3D Non-Contact Profilometer is different from other techniques such as touch probes, and it measures the surface features without coming into contact with the sample. The profilometer analysis software allows a wide range of studies that are relevant to the unique surfaces.

Importance of Rotation Stage for Part Inspection

Surface texture and roughness of the mechanical parts is important to its end use. Traditional surface profilometry often scan the surface of the sample from only one direction. To measure detailed surface feature from various angles, a precise 360° surface inspection of parts with a cylindrical shape is required. This 360° 3D inspection assures the narrowest tolerances in quality control of manufacturing processes. In addition, during the service time, cracks, dents and surface roughening occur all over the cylindrical part surface as a result of wear. If surface inspection is done on one face of the sample, significant information concealed on the backside may be missed.

Measurement Objective

In this analysis, the 360° surface profile of a brass hose fitting was used as a representative sample and measured using the Nanovea ST400 Profilometer equipped with a rotation stage. Here, it is shown that the Nanovea profilometer fitted with a rotation stage is a suitable tool for defining the surface features of a cylindrical-shape sample.

Non-contact optical pen scanning on the sample.

Figure 1. Non-contact optical pen scanning on the sample.

Results and Discussion

Figure 2 shows the 3D view and false color view of the surface profile of the hose fitting sample, offering users a tool to easily visualize the surface features of the cylindrical sample at various angles.

(a) False color view and (b) 3D View of the scanned surface.

Figure 2. (a) False color view and (b) 3D View of the scanned surface.

Line profile is then extracted along the longitudinal direction to reveal a cross-sectional view of the hose fitting contour in Figure 3. The peaks of the surface shape have a fairly uniform size. By setting up a tolerance limit value, the analysis software can automatically establish the quality of the hose fitting, thereby enabling users to make an accurate and fast fail/pass decision on the part.

2D profile contour analysis of the hose fitting sample.

Figure 3. 2D profile contour analysis of the hose fitting sample.

The uniformity and roughness of the part surface play a major role in ensuring its functionality and quality. The local surface morphology of the sample at a high magnification is shown in Figure 4. The texture direction as well as the surface roughness values are measured and summarized in Table 1. During the sample manufacture, directional machine marks were created. A dent is identified on the surface of the sample as a local defect.

Local surface finish of the hose fitting sample at a higher magnification.

Figure 4. Local surface finish of the hose fitting sample at a higher magnification.

(a) Roughness:

ISO 25178
Height Parameters
Sq 9.05 µm Root-mean-square height
Ssk -0.514 Skewness
Sku 3.69 Kurtosis
Sp 38.2 µm Maximum peak height
Sv 58.5 µm Maximum pit height
Sz 96.7 µm Maximum height
Sa 7.34 µm Arithmetic mean height

(b) Texture direction:

Surface roughness and texture direction.

Figure 5. Surface roughness and texture direction.

Conclusion

In this application, a ST400 Nanovea 3D Non-Contact Profilometer was used to comprehensively analyze the 3D surface features. It was shown that the Nanovea 3D Non-Contact Profilometer, fitted with a rotation sample stage, can accurately define the 360° 3D surface morphology of samples with a cylindrical shape. The precise and detailed 360° surface scan serves as a perfect tool for part inspection and quality control. The data shown here denotes only a part of the calculations available in the analysis software. The Nanovea Profilometers are designed to measure almost any surface in a variety of fields such as Aerospace, Automotive, Biomedical, Machining, Metallurgy, Semiconductor, etc.

Nanovea

This information has been sourced, reviewed and adapted from materials provided by Nanovea.

For more information on this source, please visit Nanovea.

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