The fast development in the fields of integrated circuits, photovoltaics, the automobile industry, advanced manufacturing, and astronomy have led to the importance and necessity of quickly and accurately obtaining three-dimensional (3D) shape data of specular surfaces for quality control and function evaluation. Owing to the advantages of a large dynamic range, non-contact operation, full-field and fast acquisition, high accuracy, and automatic data processing, phase-measuring deflectometry (PMD, also called fringe reflection profilometry) has been widely studied and applied in many fields. Phase information coded in the reflected fringe patterns relates to the local slope and height of the measured specular objects. The 3D shape is obtained by integrating the local gradient data or directly calculating the depth data from the phase information. We present a review of the relevant techniques regarding classical PMD. The improved PMD technique is then used to measure specular objects having discontinuous and/or isolated surfaces. Some influential factors on the measured results are presented. The challenges and future research directions are discussed to further advance PMD techniques. Finally, the application fields of PMD are briefly introduced.

The recently developed direct phase measuring deflectometry (DPMD) method can directly measure the three-dimensional (3D) shape of specular objects with discontinuous surfaces, but requires a calibrated distance between a reference plane and liquid crystal display screen. Because the plane and screen are different distances from the imaging device, they cannot be clearly captured given the limited depth of field (DOF) of the lens. Therefore, existing machine vision-based methods cannot be used to effectively calibrate a DPMD system. In this paper, a new distance calibration method that uses a mirror with a hollow ring matrix pattern and a mobile stage is presented. The direction of the mobile stage in the camera coordinate system is determined by the mirror’s pattern at several positions in the camera’s DOF so that the reference position outside of the DOF can be calculated. The screen’s position can also be calibrated by displaying patterns at a known scale. Therefore, the required distance is accurately obtained in the camera coordinate system. Evaluation results show that the maximum value of the absolute error is less than 0.031 mm. The experimental results on an artificial stepped mirror and a reflected diamond distribution surface demonstrate the accuracy and practicality of the proposed method.

Owing to its unique combination of properties, γ -TiAl alloy demonstrates remarkable advantages in high-temperature lightweight structural applications, establishing itself as a new critical material. However, the degradation mechanisms of material surface integrity at atomic-scale precision remain insufficiently investigated within existing machining systems. Based on molecular dynamics methodology, this research systematically investigates the influence of varying grinding parameters (depth and speed) on burr formation of γ -TiAl alloy during nanogrinding processes. The analysis elucidates the underlying correlations through multiple aspects: surface deformation, grinding force fluctuations, dislocation defects, and stress distribution. Simulation results demonstrate that employing higher grinding speeds in conjunction with reduced grinding depths enhances surface finish quality and minimizes material accumulation. However, due to complex dislocation dynamics, the evolution of exit burrs exhibits a non-monotonic behavior. A comprehensive analysis of surface deformation, forces, and defects indicates that, within the studied parameter range, a grinding speed of 400 m s ⁻¹ combined with a shallow grinding depth of 1 nm represents a favorable processing configuration. This work comprehensively reveals the formation mechanisms of surface burrs during nanogrinding of γ -TiAl alloys, establishing this mechanism as a fundamental basis in precision manufacturing applications of the alloy.

As a critical strategic material for extreme environment applications, the surface integrity of single-crystal tungsten directly dictates the performance and reliability of functional devices. However, the damage evolution mechanisms of single-crystal tungsten during nanopolishing manufacturing processes have yet to be systematically explored. In this study, molecular dynamics simulations of nanopolishing were established to specifically investigate the mechanical properties, crystal defect evolution, and subsurface damage mechanisms under various initial surface roughness conditions at the nanoscale. The results reveal that surface roughness texture, acting as a key geometric constraint for material removal mechanisms, exerts a significant influence on atomic migration, cutting load fluctuations, and the distribution of subsurface stress fields. Meanwhile, the internal energy dissipation and dislocation density within the system exhibit trends of dynamic growth and non-linear oscillation. Furthermore, variations in the structural complexity of the surface texture lead to distinct shifts in the temperature rise patterns within the processing zone. This research elucidates the nanopolishing mechanisms induced by surface morphology from an atomic perspective, providing essential theoretical criteria and technical guidance for achieving high-efficiency and low-damage ultra-precision manufacturing of single-crystal tungsten.