Profilometry for Powder Coating Finish Measurement

Table of Contents

Introduction
Importance of Profilometry Inspection for R&D and Quality Control
Measurement Objective
Results
Conclusion

Introduction

Powder coating is known for its long-lasting properties. This coating is applied electrostatically as a dry, free-flowing powder and then cured under heat. This results in a hard and long-lasting layer/coating that is often used on aerospace and automotive parts and metal household appliances. Historically, powder coatings have been visually inspected. The accepted or intended finish of a powder coating will differ considerably from application and will rely on the dry powder particle size in the μm range.

Importance of Profilometry Inspection for R&D and Quality Control

Due to unreliability of visual inspection and large variation possible, the surface finish of powder coatings should undergo profilometery inspection for quality control. It is important to understand these surface features so as to achieve the best selection surface finish and control measures. Ensuring the quality control of such parameters will largely depend on quantifiable, reliable and reproducible inspection. The Nanovea 3D Non-Contact Profilometers employ chromatic confocal technology with unparalleled capability to measure powder coatings. These profilometers succeed, where other techniques fail to provide reliable data due to surface variation, probe contact, absorption, reflectivity or angle.

Measurement Objective

In this application, the surface finish of four different powder coated samples are measured and compared using the Nanovea ST400 Profilometer. From the coating profile, a number of surface parameters will be automatically measured. Here, focus is given to Surface Roughness, Surface Area and Peak to Valley for comparative evaluation.

Measurement Objective

Results

Sample 1

3D View of Sample 1

3D View of Sample 1

Height Parameters of Sample 1

ISO 25178
Height Parameters
Sa 27.927 µm
Sq 41.306 µm
Ssk 2.1221
Sku 8.7157
Sp 257.93 µm
Sv 153.39 µm
Sz 411.31 µm
Other 3D Parameters
Miscellaneous
Sdar 173.34 mm2
Spar 60.000 mm2

Falsie Color View of Sample 1

False Color View of Sample 1

Sample 2

3D View of Sample 2

3D View of Sample 2

Height Parameters of Sample 2

ISO 25178
Height Parameters
Sa 17.371 µm
Sq 21.427 µm
Ssk -0.066279
Sku 2.7247
Sp 75.953 µm
Sv 68.661 µm
Sz 144.61 µm
Other 3D Parameters
Miscellaneous
Sdar 91.964 mm2
Spar 60.000 mm2

False Color View of Sample 2

False Color View of Sample 2

Sample 3

3D View of Sample 3

3D View of Sample 3

Height Parameters of Sample 3

ISO 25178
Height Parameters
Sa 11.443 µm
Sq 13.992 µm
Ssk -0.020995
Sku 2.5702
Sp 45.409 µm
Sv 45.322 µm
Sz 90.731 µm
Other 3D Parameters
Miscellaneous
Sdar 62.521 mm2
Spar 60.000 mm2

False Color View of Sample 3

False Color View of Sample 3

Sample 4

3D View of Sample 4

3D View of Sample 4

Height Parameters of Sample 4

ISO 25178
Height Parameters
Sa 22.149 µm
Sq 27.725 µm
Ssk -0.59415
Sku 3.1891
Sp 55.517 µm
Sv 108.14 µm
Sz 163.66 µm
Other 3D Parameters
Miscellaneous
Sdar 61.035 mm2
Spar 60.000 mm2

False Color View of Sample 4

False Color View of Sample 4

Conclusion

This article has demonstrated how the surface finish of the powder coated samples can be precisely characterized using the Nanovea ST400 3D Profilometer. (*Note, many other measurements could have also been made besides those shown here). By observing the three highlighted parameters such as Surface Area, Surface Roughness, and Peak to Valley, the variations between the quality and finish of the four samples can be easily measured which otherwise may not be apparent by visual inspection. Armed with this information, powder coatings can be analyzed for research and development or quality control procedures.

For a more detailed view, a 2D cross section can be quickly selected to analyze special areas of interest, at nanometer range. With integrated Microscope module or AFM, special areas of interest could have been further examined. The speeds of Nanovea 3D Profilometers range from 20 mm/s to 1 m/s for research or laboratory to the needs of hi-speed inspection. These profilometers can be constructed with custom size, scanning capabilities, speeds, Class 1 Clean Room compliance, with Indexing Conveyor and for online or Inline integration.

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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