Reverse Engineering and Dimensional Deviation Analysis of an Automotive Thermostat Housing using Structured Light 3D Scanning

Reverse Engineering (RE) is widely used in the industry when the original design data is unavailable to fabricate existing parts. This work presents the RE and dimensional deviation analysis of the cast thermostat housing of a Tata Zest car using the aid of the Structured Light (SL) 3D scanning. This is to come up with a digital model of the housing and analyze its geometric conformity with the CAD reference data through systematic deviation analysis. A high-resolution SL optical scanner was employed in the process of training the complicated outer shape and present inner features at a sub-millimetric accuracy. The data, in the form of point clouds, were subsequently processed in Geomagic Control X using best-fit alignment and Iterative Closest Point (ICP) registration options to match the scan with the CAD model. The dimensional deviations were quantified using statistical values and graphical tools such as 3D colour maps and 2D sectional comparisons. They determined that around 74.5 percent of the points of the scanned surface fall within a band of ±2.5 mm in the tolerance, and the overall Root Mean Square (RMS) error between the scan and CAD geometry is 0.4085 mm, a good overall fit. The increased outliers were largely confined to the fillets and the interior cavities, whereby the reflective surfaces and scanner inspectability placed a restriction upon the quality of the data. The results emphasize the accuracy of SL scanning when it comes to obtaining detailed geometries and validate its possibility of application in component inspection, design validation, and the development of digital twins in the car industry. This work substantiates the use of 3D scanning-based RE as a powerful metrology tool in precision manufacturing, quality assurance, and the management of the lifecycle of complex engine parts.