There are many researches in scheduling an optimal feedrate profile under various constraints by numerical calculation. A large number of discrete feedrate data points are obtained. They are inconvenient for the parametric interpolator. Therefore, these discrete feedrate data points need to be fitted by parameter curves. Different from the regular curve fitting, the inappropriate feedrate fitting method can generate larger acceleration and jerk that seriously affect the machining accuracy and stability, although the feedrate satisfies the error requirements. In order to generate a suitable feedrate profile, a segment feedrate profile fitting method using B-spline is proposed in this article. The discrete feedrate data points are segmented in the jerk discontinuous points. In each segment, the feedrate profile is fitted by the linear least squares method. These fitted feedrate profiles are combined to generate a unified feedrate profile. The unified fitted feedrate profile and the tool path trajectory are used in the controller to command the axis. In this article, the process of parametric interpolation is separated into the arc-length calculation process and the curve parameter calculation process. Using parallel computation, the two processes are calculated simultaneously in the controller, and the computational efficiency is improved. Both simulation and experiment are carried out to verify that the fitted feedrate profile satisfies the error requirements, and the novel interpolation can be applied to the controller appropriately.

Increasing the mixing efficiency of the fuel jet along the combustion chamber is a crucial step for the advancement of the current high-velocity vehicles. In this article, comprehensive computational investigations have been performed to disclose the role of an annular air jet on the fuel mixing of the single extruded nozzle located inside the combustion chamber. This study has tried to offer hydrodynamic insight about the jet flow feature when released from the extruded nozzle in supersonic cross flow. Computational fluid dynamic is used for the visualization of fuel jet interactions with air stream. Effects of nozzle height on the mechanism of fuel jets are extensively analyzed in this investigation. Our results show that the injection of the annular jet would increase the strength of the circulations, and consequently, fuel mixing improves inside the combustion chamber. Our findings display that fuel mixing increases about 100% by the injection of the annular air jet in the combustion chamber.

Components with super-smooth freeform surfaces are being applied more and more extensively in various fields. Among the valuable non-traditional finishing processes for generating super-smooth freeform surfaces that have been developed, the two-axis vibration assisted polishing process has attracted great attention from some scholars in recent years. However, in the existing two-axis vibration assisted polishing process, vibrational coupling occurs between the traverse and axial directions in the vibrating body and causes the actuating polishing tool to rotate, which limits the polishing effect. To solve the above-mentioned vibration coupling problem, herein we develop a novel two-dimensional ultrasonically actuated polishing process using two mutually perpendicular Lange in vibrators. Through theoretical analysis and experimental tests, the influences of the contact pressure, feed rate, and vibrational parameters on the material removal rate of the proposed polishing process were revealed. The experiments demonstrated that the polishing removal rate was greatly improved.

The magnetorheological jet polishing (MJP) technique, as a revolutionary flexible contact polishing approach, is exceptionally suitable for the smooth and ultra-smooth machining of functional surfaces with tiny or microstructures due to the following essential advantages. Machine tool accuracy is not required and there is nearly no tool wear in addition to high polishing efficiency, minimal surface damage, great surface shape adaptation, superior material removal process selectivity, and so on. This work examines the machining mechanism, the development of machining devices, and the optimization of the process parameters in MJP. This review also covers the MJP technique’s existing limitations and opportunities.

To analyze the effect of particle shape on deformational behavior in the cutting simulation process for metal matrix composites (MMCs), two 2D mesoscopic-based finite element (FE) models reinforced with randomly distributed circular and irregular polygonal particles were developed. Different material properties (metal matrix phase, particle reinforced phase) and the properties of the particle–matrix interface were comprehensively considered in the proposed FE model. Systematic cutting experiments were conducted to compare the differences between two modeling approaches with respect to particle fracture, chip formation, cutting force and surface integrity. The results show that the irregular polygonal particle model is closer to the microstructure of MMCs, and is better able to reflect the deformation behavior of particles. The simulation model with irregular polygonal particles is even able to capture more details of the impact caused by particles, reflecting variations in the cutting force in the actual cutting process. The initiation and propagation of microcracks is mainly determined on the basis of particle geometry and further affects chip formation. Both models are able to correctly reflect surface defects, but the irregular polygonal particle model provides a more comprehensive prediction for the subsurface damage of MMCs.