Workpiece rotational grinding is widely used in the ultra-precision machining of hard and brittle semiconductor materials, including single-crystal silicon, silicon carbide, and gallium arsenide. Surface roughness and subsurface damage depth (SDD) are crucial indicators for evaluating the surface quality of these materials after grinding. Existing prediction models lack general applicability and do not accurately account for the complex material behavior under grinding conditions. This paper introduces novel models for predicting both surface roughness and SDD in hard and brittle semiconductor materials. The surface roughness model uniquely incorporates the material’s elastic recovery properties, revealing the significant impact of these properties on prediction accuracy. The SDD model is distinguished by its analysis of the interactions between abrasive grits and the workpiece, as well as the mechanisms governing stress-induced damage evolution. The surface roughness model and SDD model both establish a stable relationship with the grit depth of cut (GDC). Additionally, we have developed an analytical relationship between the GDC and grinding process parameters. This, in turn, enables the establishment of an analytical framework for predicting surface roughness and SDD based on grinding process parameters, which cannot be achieved by previous models. The models were validated through systematic experiments on three different semiconductor materials, demonstrating excellent agreement with experimental data, with prediction errors of 6.3% for surface roughness and 6.9% for SDD. Additionally, this study identifies variations in elastic recovery and material plasticity as critical factors influencing surface roughness and SDD across different materials. These findings significantly advance the accuracy of predictive models and broaden their applicability for grinding hard and brittle semiconductor materials.

A large number of countersunk holes need to be machined during the assembly of aerospace components. The widespread use of difficult-to-cut materials has brought new challenges to the hole-making technology. As a new hole-making technology of assembly, helical milling can be used to machine countersunk holes with special tools, and the machining quality can be improved by using the characteristics of helical milling principle. Firstly, the kinematics analysis of helical milling in machining countersunk holes was carried out. Next, finite element simulation was used to simulate the helical milling process of countersunk holes in titanium alloy materials. Then, the accuracy of the finite element simulation was verified through the cutting force and chip morphology in helical milling test. Finally, the established simulation model was used to analyze the influence of dimple depth and process parameters on the cutting force acting on the cutting tool.

Working performances of the components made out of 49Fe-49Co-2V alloy are closely related to the surface integrity of the drilled holes, which are influenced remarkably by the cooling conditions. The present study focuses on the surface integrity differences between wet and dry drilled 49Fe-49Co-2V alloy holes. The drilled hole surface roughness and topographies, metallurgical and mechanical properties, and the exit characterizations were obtained using optical microscopy (OM), scanning electron microscopy (SEM), electron backscatter diffraction microscopy (EBSD), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and Vickers hardness techniques, etc. The effects of cooling conditions on the surface integrity were concluded and the influence mechanisms were analyzed based on the force and temperature differences in drilling process with different cooling conditions. It is found that the surface roughness and the thickness of refined-grain region of the dry drilled holes are larger than those of wet drilled holes; work hardening induced by wet drilling is more serious than dry drilling; chippings occurred in the exits of the wet drilled holes due to the material brittleness, which could be avoided by dry drilling. The surface integrity differences of wet and dry drilled holes are closely related to the force and temperature differences in drilling process with different cooling conditions.

Fine finishing of tungsten alloy is required to improve the surface quality of molds and precision instruments. Nevertheless, it is difficult to obtain high-quality surfaces as a result of grain boundary steps attributed to differences in properties of two-phase microstructures. This paper presents a theoretical and experimental investigation on chemical mechanical polishing of W–Ni–Fe alloy. The mechanism of the boundary step generation is illustrated and a model of grain boundary step formation is proposed. The mechanism reveals the effects of mechanical and chemical actions in both surface roughness and material removal. The model was verified by the experiments and the results show that appropriately balancing the mechanical and chemical effects restrains the generation of boundary steps and leads to a fine surface quality with a high removal rate by citric acid-based slurry.

Diamond tools play a critical role in ultra-precision machining due to their excellent physical and mechanical material properties, such as that cutting edge can be sharpened to nanoscale accuracy. However, abrasive chemical reactions between diamond and non-diamond-machinable metal elements, including Fe, Cr, Ti, Ni, etc, can cause excessive tool wear in diamond cutting of such metals and most of their alloys. This paper reviews the latest achievements in the chemical wear and wear suppression methods for diamond tools in cutting of ferrous metals. The focus will be on the wear mechanism of diamond tools, and the typical wear reduction methods for diamond cutting of ferrous metals, including ultrasonic vibration cutting, cryogenic cutting, surface nitridation and plasma assisted cutting, etc. Relevant commercially available devices are introduced as well. Furthermore, future research trends in diamond tool wear suppression are discussed and examined.