3D topography and roughness measurement of the inner surface of semi-closed parts

Semi-enclosed parts have a wide range of applications in precision manufacturing, aerospace, and reverse design. Understanding and characterizing the 3D topography and roughness of the internal surfaces of semi-enclosed parts is critical to ensure part performance, assembly quality, sealing effectiveness, friction characteristics, vibration behavior, and wear durability. However, some semi-enclosed parts are small and have complex internal structures, and conventional measurement methods are not effective in accurately measuring the 3D topography and roughness of the internal surfaces of semi-enclosed parts. Therefore, we propose a microdevice-based interferometry system, which adds micrometer-scale devices such as microsteering devices to the interferometric structure, for measuring 3D topography and roughness of the inner surface of semi-closed parts. Experiments have demonstrated that our proposed measurement system has excellent measurement accuracy down to the nanometer level. By providing accurate surface 3D topography and roughness data, this technique opens up new possibilities for future engineering design and manufacturing and is expected to advance the development of advanced manufacturing technologies.