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In nanometric cutting, the dominant material removal mechanism can be greatly different with macroscopic cutting process. In this work, molecular dynamics (MD) simulation was carried out to investigate the cutting features of single-crystal silicon. The effect of the tool rake angle and the workpiece crystal orientation on the transition of the material removal mechanism was studied. Theoretical analysis and cutting experiments were conducted to verify the simulation results. The results indicate that with a decrease of the tool rake angle, the material removal mechanism could transform from shear to extrusion and finally no material would be removed. In this process, the position of the stagnation region increases rapidly when the dominant material removal mechanism becomes extrusion and would reache to the uncut surface when no material is removed. The shear to extrusion transition is greatly influenced by the tool rake angle and workpiece crystal orientation while the dominant factor that affect the transition from extrusion to no removal is the position of the stagnation region and frictional force on tool rake face. Furthermore, based on the simulation results and theoretical analysis, when the tool rake angle is decreased, the shear stress plays an important role in the formation of the subsurface damage.

The critical negative rake angle of negative rake angle tool is the critical criterion for the state of cutting and plowing in micro-cutting. It affects the flow characteristics of cutting material, the deformation state of chip, the quality of the machined surface, and the amount of tool wear. Meanwhile, a stagnant region often appears in front of the tool surface when a negative rake tool is used to cut the plastic metal material, which would increase the actual negative rake angle. Therefore, based on the stagnant characteristics and the infinite shear strain approach, this paper constructs a critical negative rake angle model, and the orthogonal cutting experiment and the finite element model are used to verify the correctness of the model. By analyzing the deviation of the effective critical negative rake angle (theoretical value) and critical negative rake angle (experimental value), it can be known that the theoretical value is 0.36–4.15% larger than the experimental value, which indicates that the model considering the existence of stagnant region is closer to the actual critical negative rake angle. In addition, the relationship between the stagnant region (the deviation) and the multi-cutting factors can provide experimental basis of angle for solving the effective critical negative rake angle when the critical negative rake angle is known.

The nano cutting process of Zr-based amorphous alloy was simulated by molecular dynamics simulation in this paper. Through the research on the changing rule of cutting force in nano cutting of Zr-based amorphous alloy, it is found that the cutting force increases continuously, and the cutting rate is large at the initial stage of nano cutting, which may be related to the shear deformation of the atomic clusters or atomic clusters in the shear transition zone. The effect of cutting tool rake angle on nano cutting process for Zr-based amorphous alloy was studied. The simulation results show that the cutting force decreases with the increase of the rake angle of the cutting tool, and the friction coefficient between the rake face and the chip also decreases slightly. With the increase of the rake angle of the cutting tool, the pushing effect of the tool on the Zr-based amorphous alloy chip and the overall bending of the chip are weakened, leading to the increase of the chip height. The number of high-temperature atoms in the Zr-based amorphous alloy workpiece also decreases with the increase of the tool rake angle, and the cutting temperature distribution on the workpiece diffuses to the interior of the workpiece with the tool fillet as the center.

Machining of bone tissue is a significant procedure in many surgical interventions. Due to the limited research on this topic, understanding the processes occurring during bone processing is crucial for designing tools that optimize the surgical process. This paper presents a model of machining cortical bone with a negative rake angle tool based on three cutting modes. The model was prepared based on experimental data from the orthogonal cutting of cortical bone tissue, numerical simulations, and theoretical models considering the presence of the stagnation zone. Special attention was given to the influence of bone anisotropy on chip formation, chip morphology, and the type and propagation of cracks depending on the orientation of osteons relative to the cutting edge. The analysis of crack morphology and chip structure revealed the mechanisms involved in the material’s destruction, which were incorporated into the prepared model. The experimental results confirm the consistency with the proposed model. Based on the prepared cutting model, it is possible to determine the threshold depths of cutting that allow for controlled processing of bone surfaces, predicting the milling machine and the type of formed chips. The model developed based on experimental data is the first for cortical bone tissue. This analysis holds significant theoretical and practical importance for developing innovative orthopedic tools and surgical methods.

The objective of this research is to simulate the cutting edge micro-geometry in machining stainless steel (SUS-316L). This paper based on finite element method (FEM) analyzes the cutting mechanism of different cutting edge symmetry geometries (K = 1) and asymmetry geometries (K = 0.5 and K = 2), studied plastic strain and residual stress, Mises stress and distribution of temperature, and also tool-chip contact length and the effective rake angle γeff. By drag finishing prepared three kinds of cutting edge roundness with symmetry (K = 1) and asymmetry (K = 0.5 and K = 2), which is cutting test for verifying the correctness of the model through chip geometry morphology. The simulation results suggest that waterfall tools (K = 0.5) can increase stress strain and peak cutting temperature compared with other cutting edge micro-geometry. At the same time, the trumpet tools (K = 2) also have a great influence on sub-surface and surface stress distribution. Therefore, the cutting edge segment on the flank face Sα has significant the metal cutting process.

High-precision tapered threads are widely used in hard-loaded mechanical joints, especially in the aggressive environment of the drilling of oil and gas wells. Therefore, they must be made of workable materials often difficult to machine. This requires the use of high-performance cutting tools, which means the application of non-zero geometric parameters: rake and edge inclination angles. This study is based on analytical geometry methodology and describes the theoretical function of the thread profile as convoluted surfaces dependent on the tool’s geometric angles. The experiments were conducted using a visual algorithm grounded on the obtained function and prove the practical use of the scientific result. They predict the required accuracy of thread made using a lathe tool with a rake angle of up to 12°.

The delamination produced during drilling CFRP will affect its structural strength seriously. Delamination is closely related to the thrust force during drilling, which is closely related to the tool, so it is particularly important to choose the tools with appropriate geometric structure. Many scholars used tools with different geometric structure to drill CFRP, and then conducted the drilling damage analyses and drilling mechanism researches. It finally came to a conclusion that a drill with a special structure had certain advantages compared with a common twist drill in the drilling process. A new type of plane rake–faced twist drill was used to drill the CFRP laminate with a thin-woven glass fiber surface layer. Experimental results showed that the plane rake–faced twist drill along cutting edge had a constant reference rake angle value, which caused the plane rake–faced twist drill generated smaller thrust force and less drilling damage than the common twist drill. As the reference rake angle of the plane rake–faced twist drill increased, the thrust force and drilling damage decreased. It was revealed the inhibition of the thin-woven glass fiber surface layer on the drilling damage at entrance and exit. Finally, it was proposed that when the plane rake–faced twist drill was used to drill CFRP laminate with a thin-woven glass fiber surface, 46° reference rake angle should be selected.

SiCp/Al composites are widely used in many important engineering applications due to their excellent material properties. High-volume fraction SiCp/Al composites are recognised as a typical difficult-to-machining material with significant brittleness, and negative rake angles are more suitable for cutting brittle materials. Ultrasonic elliptical vibration cutting (UEVC) has proven to be a specialised machining method that can improve the machinability of difficult-to-machining materials. Elucidating the influence of the negative rake angle on the dynamic properties of composites during UEVC is therefore particularly important. In this paper, the direction of the combined cutting force is considered separately for negative rake angle tools, as well as UEVC's unique transient cutting thickness, variable cutting angle, transient shear angle and characteristic of friction reversal, a UEVC cutting force model based on negative tool rake angle has been developed. And the deviation of the main cutting force between the experimental value and the theoretical value is less than 15% by systematic turning experiments, which verifies the accuracy of the model. Finally, the influence of different machining parameters on the cutting force is determined using the established model. The results show its effect on the cutting force is more significant when the cutting speed is less than 200 mm/s, other things being equal. In addition, the cutting force tends to decrease significantly as the depth of cut from 5 μm to 20 μm increases. However, the cutting force fluctuated less when the feed was increased. This work provides the benchmark for negative rake angle cutting of SiCp/Al.

Fast tool servo and slow slide servo-based diamond turning are very important and widely used machining methods for freeform surfaces. In diamond turning of freeform surfaces, the research on tool path generation and machined surface topography prediction is generally for diamond turning processes using zero rake angle tools. But diamond turning with non-zero rake angle tools is also of great importance, for which very little research has been done on tool path planning and surface topography modeling. Therefore, based on coordinate transformations, this paper develops a new tool path generation method and discusses the tool geometry parameter selection for diamond turning utilizing non-zero rake angle tools. In addition, a new surface topography prediction model based on the actual position and orientation of the tool cutting edge is constructed for the machined surface. The machining experiments of a typical freeform surface are conducted based on the calculated tool paths and necessary critical tool geometry parameters. The measured results validate the developed tool path generation and tool geometry selection methods, and the constructed surface topography model.

Sticking friction is a significant factor which influences the tribological behavior at the chip-tool interface and cutting force. This study proposed a simplified cutting force prediction model based on friction angle calculation. Sticking friction has been incorporated to predict the friction behavior. The working rake angle has been determined as a function of tool rake angle, feed rate, and cutting speed. The normal and shear stresses developed on the chip segment have been estimated based on the sticking friction and material yield stress. Based on the stresses developed, the friction angle has been determined. Further the shear angle has been calculated using Lee-Shaffer model. Eventually, the cutting force and thrust force have been determined considering orthogonal machining process. The proposed model was able to predict the cutting force with an average of 4.27 % error and improved the prediction accuracy by approximately 7 times as compared to the conventional model.