In situfringe projector development for thermal coating deposition

Nicholas D Trail,Eustace L Dereniak,Michael W Kudenov

doi:10.1117/1.oe.53.7.074105

Nicholas D Trail, Eustace L Dereniak + Show 1 more

Open Access

https://doi.org/10.1117/1.oe.53.7.074105

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Abstract

Thermal barrier coatings (TBCs) and plasma spray coatings, in general, require fine control over the deposited thickness to achieve a reliable coating performance. Currently, the plasma spray industry quantifies thickness by sampling the part before and after TBC deposition. Approximate thickness is inferred from previous runs; however, process variability can cause errors in these approximations that result in wasted time and resources that can ultimately lead to nonreliant coatings. To this end, we present an in situ optical fringe projector technology that enables coating thickness measurements across a two-dimensional surface. The sensor is capable of achieving micron scale resolution in the harsh environment of a thermal spray booth. Furthermore, unlike the existing approaches, this technique is extendable to parts with complex geometries. The underlying background of the fringe projection method, including a differential measurement technique, is presented. Current results on production equipment and cylindrical parts are also discussed, showing good correlation and agreement with physical measurements captured in an industrial setting.

Highlights

Thermal barrier coatings (TBCs) are a key technology enabler in many industrial applications, such as spanning aerospace, automotive, and energy
Leveraging the sensitivity of optical interferometric methods while ruggedizing it for use in the harsh environment of thermal spray production, we demonstrate a fringe projection sensor that enables real-time per-pass thickness measurements
The fringe projection sensor was mounted to a tripod that was positioned perpendicular to the plasma stream [Fig. 8(b)], while the camera was triggered by an optical pickup and reflective tape to measure a repeatable area

Summary

Introduction

Thermal barrier coatings (TBCs) are a key technology enabler in many industrial applications, such as spanning aerospace, automotive, and energy. Leveraging the sensitivity of optical interferometric methods while ruggedizing it for use in the harsh environment of thermal spray production, we demonstrate a fringe projection sensor that enables real-time per-pass thickness measurements. Kudenov, and Dereniak: In situ fringe projector development for thermal coating deposition allows for the direct measurement of the coating layer’s thickness, independent of material properties, and thermal expansion

Background

In Situ Testing Results

Processed Results and Analysis

Conclusion