Multi-source errors, as critical obstacles limiting the accuracy retention and machining performance of machine tools, hold fundamental and strategic significance for achieving high-precision, high-efficiency, and high-reliability machining in modern manufacturing systems. However, these errors typically exhibit complex characteristics such as strong coupling, time-variance, and nonlinearity, which challenge traditional methods of error identification, modeling, and compensation in terms of adaptability, real-time capability, and integration. Therefore, it is imperative to establish a systematic and intelligent multi-source error control framework. Firstly, this work systematically reviews typical error sources and their evolution mechanisms, evaluates multi-scale detection technologies including laser interferometry, double ball-bar systems, multi-sensor fusion, and vision-based systems, and constructs an intelligent error identification and evaluation framework. Next, it reviews classical modeling methods such as homogeneous transformation matrices, screw theory, thermal equilibrium models, finite element analysis, and modal analysis, compares physical modeling, data-driven, and hybrid modeling strategies, and develops an integrated multi-source error modeling architecture centered on digital twin technology and artificial intelligence. Furthermore, key technologies, including geometric error mapping and real-time compensation, online thermal error prediction and active temperature control, dynamic error suppression, and adaptive control, are summarized. A multi-level integrated error compensation architecture is proposed by combining physical models, data models, and cyber-physical synchronization. This architecture encompasses core processes such as error traceability and decoupling, dynamic prediction, real-time compensation, and closed-loop optimization, emphasizing engineering implementation mechanisms based on cyber-physical collaboration, multi-physics coupling, and multi-scale fusion, thereby effectively enhancing accuracy stability and control robustness under complex operating conditions. Finally, frontier challenges such as constructing high-fidelity coupled models from heterogeneous multi-source data, edge–cloud collaborative control, and cross-platform interoperability are discussed. The application prospects of multi-source error evaluation are also envisioned, providing theoretical foundations and technical support for the precise management and optimization of the entire lifecycle accuracy of machine tools.

The drying process is one of the most essential steps in the initial processing of Chinese medicinal materials. Current natural drying (such as sun and shade drying) approaches have been widely used to improve the quality of medicinal materials, due to their simplicity and low cost. However, the natural environmental conditions can dominate the quality of dried medicinal materials, resulting in low drying efficiency. It is still lacking in the strengthened research of controllable drying. In this study, a critical review was given on the research status of drying technology and equipment for Chinese medicine materials. Firstly, a systematic investigation was performed on the moisture migration, diffusion and removal of Chinese medicinal materials during drying, as well as the changes in color, appearance, microstructure, and physical and chemical properties. The moisture removal rate and drying quality depended mainly on the water content, volume, and tissue structure of Chinese medicinal materials in the conditions of drying, such as temperature, relative humidity and wind speed. Secondly, the drying mechanisms, equipment structure and working principle were performed on various drying, including hot air, heat pump, infrared, microwave, vacuum and high voltage electric field drying. The performances of drying equipment were analyzed, such as uneven drying, high-energy consumption and low efficiency. The structure of the drying chamber was optimized to improve the airflow distribution using heating with multiple heat sources. Chinese medicine materials remained in a dynamic state during drying, in order to improve drying uniformity. At the same time, the drying performances were also evaluated on various drying technologies under different conditions. Some parameters were then considered, including drying temperature, slice thickness, and vacuum degree. The drying temperature generally improved the drying rate while shortening the drying time. Much higher temperature led to reduce the sensory quality and efficacy of medicinal materials. Pretreatment, staged variable temperature and humidity, and intermittent drying were also discussed to obtain comprehensive drying quality, efficiency and cost, and application scopes. Among them, the hot-air drying equipment was suitable for the large-scale drying of cheap Chinese medicinal materials, due to its simple, low cost and large scale, but with the low drying efficiency and quality, as well as the high energy consumption. Vacuum drying was suitable for small batch drying of Chinese medicinal materials, which were easy to oxidize and brown with high added value. The low temperature and oxygen environments were used to improve the drying quality of Chinese medicinal materials, but with the low drying efficiency, the high investment and the operation cost of equipment. Moreover, the drying mechanisms were analyzed for the microwave-vacuum, microwave-hot air, and far infrared-heat pump drying in the coupling or series combination modes. The research progress on the development of combined drying equipment was summarized to compare the combined and single drying, in order to explore the limitations of combined drying equipment and processes. Finally, the research directions were predicted from the evaluation standards, the drying-related models, and the drying equipment of Chinese medicinal materials. This finding can provide the theoretical basis and technical support for the research and innovation of drying technology and equipment for Chinese medicinal materials.

Magnetic lubricants are emerging as advanced lubricants with controlled flowability and enhanced lubrication and heat transfer capabilities, showing potential for use in extreme conditions such as aerospace. Although their excellent properties have been preliminarily confirmed, the mechanisms by which these properties influence performance—including fluid dynamics, electromagnetism, and chemistry—require systematic investigation. This paper addresses this gap by systematically reviewing the preparation, physicochemical properties, and potential applications of magnetic lubricants. First, the formulations of magnetic lubricants, including the base fluid and stabilizing additives, are thoroughly examined, considering various magnetic materials and preparation methods to elucidate the mechanisms influencing dispersion stability and magnetic response. Next, the physical properties, such as saturation magnetization, viscosity, and flowability, are analyzed through theoretical and experimental studies, and constitutive models for the fluid dynamics of magnetic lubricants are summarized. Furthermore, the advanced tribological and thermal properties, as well as the physical behavior under magnetic fields, are discussed, highlighting the superior antifriction, antiwear, cooling, and controlled flowability performance compared to traditional lubricants. Finally, current applications and potential fields, such as bearings, machining, and heat exchangers, are reviewed. This paper provides a valuable reference for both theoretical studies and engineering applications of magnetic lubricants.

In the precision cutting of difficult-to-process metals, surface thermal damage to a workpiece is a significant technical challenge. Although clean minimum quantity lubrication (MQL) technology, which replaces traditional pouring cooling, is used, inadequate heat dissipation remains an issue. Cryogenic air MQL (CAMQL), an eco-friendly technology, can enhance the heat transfer performance of the lubricating film in the cutting zone, offering excellent cooling and lubrication effects. However, the influence of jet and temperature parameters on the average particle size and distribution characteristics of atomized droplets is not well understood. This study first analyzes the evolution of lubricant physical properties and establishes a quantitative mapping relationship between cryogenic air temperature and physical parameters of lubricant. Next, the unstable fluctuation in the annular liquid film at the two-phase flow nozzle exit is observed and analyzed. A thickness model of annular liquid film is developed, revealing the effect of airflow field on the annular liquid film. Finally, a model for the average particle size of atomized droplets under CAMQL is established. Numerical analysis and validation experiments under different working conditions show that the measured values align with the theoretical values. Under an air pressure of 0.4 MPa and an air flow temperature of −50 °C, the droplet particle size is 133.5 μm, with an error of 8.2%. The effect of air pressure on particle size is greater than that of air flow temperature. Additionally, the distribution spans of droplet size under different conditions are analyzed, and the results demonstrated that low temperatures help shorten the interval between particle sizes and improve the relative uniformity of particle size distribution. This research provides a theoretical basis for the application of CAMQL technology in the cutting process.

The use of Minimum Quantity Lubrication (MQL) with bio-lubricants has been extensively studied in aerospace sustainable manufacturing. Enhanced MQL technologies have been proposed to reduce tool wear and improve workpiece surface integrity by increasing lubricant activity. However, the relationship between enhancement behavior, physicochemical properties of bio-lubricants, and processability remains unclear, presenting challenges for MQL technologies, particularly with difficult-to-machine materials. To address this gap, this paper provides an in-depth mechanism analysis and a comprehensive quantitative evaluation of the machinability of enhanced MQL technologies, considering chemistry, molecular dynamics, fluid dynamics, tribology, and heat transfer. Firstly, the cooling and lubrication enhancement mechanisms of nano-lubricants were systematically summarized, focusing on molecular structure, physical properties, and preparation processes. Secondly, the atomization enhancement mechanism of Electrostatic Minimum Quantity Lubrication (EMQL) was analyzed, revealing a 49% reduction in PM2.5 concentration during the atomization process compared to conventional MQL. Thirdly, the transport and infiltration enhancement mechanisms of bio-lubricants in cutting and grinding zones were summarized, incorporating electromagnetic fields and ultrasound-assisted processes. Finally, for cutting and grinding applications involving difficult-to-machine materials in aerospace, the optimized machinability of enhanced MQL technologies was concluded, showing a 50.1% increase in lubricant heat transfer coefficient and a 31.6% decrease in grinding temperature compared to standard MQL. This paper aims to help scientists understand the effective mechanisms, formulate process specifications, and identify future development trends in this technology.

The machining surface integrity of aero-engine turbine disc slots has a significant impact on their fatigue life and service performance, and achieving efficiency and high-precision machining is still a great challenge. The high machining requirements of future aeroengine turbine disc slots will be difficult to satisfy using the broaching method. In addition, existing methods of slot machining face difficulties in ensuring surface integrity. This study explored a cup shaped electroplated Cubic Boron Nitride (CBN) abrasive wheel for profile grinding the turbine disc slots of FGH96 powder metallurgy superalloy. The matrix structure of the cup shaped abrasive wheel was designed and verified. A profile grinding experiment was conducted for fir-tree slots on a five-axis machining center. The accuracy and the surface integrity were analyzed. Results show that the key dimension detection results of the slots were within the allowable tolerance range. Meanwhile, an average surface roughness Ra of 0.55 μm was achieved, the residual stress was compressive, the plastic deformation layer thickness was less than 5 μm, and the hardening layer thickness was less than 20 μm. The research findings provide a new approach to machining the slots of aviation engine turbine discs and guidance for the high-quality processing of complex components.

Grinding is a crucial process in machining workpieces because it plays a vital role in achieving the desired precision and surface quality. However, a significant technical challenge in grinding is the potential increase in temperature due to high specific energy, which can lead to surface thermal damage. Therefore, ensuring control over the surface integrity of workpieces during grinding becomes a critical concern. This necessitates the development of temperature field models that consider various parameters, such as workpiece materials, grinding wheels, grinding parameters, cooling methods, and media, to guide industrial production. This study thoroughly analyzes and summarizes grinding temperature field models. First, the theory of the grinding temperature field is investigated, classifying it into traditional models based on a continuous belt heat source and those based on a discrete heat source, depending on whether the heat source is uniform and continuous. Through this examination, a more accurate grinding temperature model that closely aligns with practical grinding conditions is derived. Subsequently, various grinding thermal models are summarized, including models for the heat source distribution, energy distribution proportional coefficient, and convective heat transfer coefficient. Through comprehensive research, the most widely recognized, utilized, and accurate model for each category is identified. The application of these grinding thermal models is reviewed, shedding light on the governing laws that dictate the influence of the heat source distribution, heat distribution, and convective heat transfer in the grinding arc zone on the grinding temperature field. Finally, considering the current issues in the field of grinding temperature, potential future research directions are proposed. The aim of this study is to provide theoretical guidance and technical support for predicting workpiece temperature and improving surface integrity.

Minimum quantity lubrication (MQL) is a relatively efficient and clean alternative to flooding workpiece machining. Electrostatic atomization has the merits of small droplet diameter, high uniformity of droplet size, and strong coating, hence its superiority to pneumatic atomization. However, as the current research hotspot, the influence of jet parameters and electrical parameters on the average diameter of droplets is not clear. First, by observing the shape of the liquid film at the nozzle outlet, the influence law of air pressure and voltage on liquid film thickness (h) and transverse and longitudinal fluctuations are determined. Then, the mathematical model of charged droplet volume average diameter (VAD) is constructed based on three dimensions of the liquid film, namely its thickness, transverse wavelength (λ_h), and longitudinal wavelength (λ_z). The model results under different working conditions are obtained by numerical simulation. Comparisons of the model results with the experimental VAD of the droplet confirm the error of the mathematical model to be less than 10%. The droplet diameter distribution span value Rosin–Rammler distribution span (R.S) and percentage concentrations of PM10 (particle size of less than 10 μm)/PM2.5 (particle size of less than 2.5 μm) under different working conditions are further analyzed. The results show that electrostatic atomization not only reduces the diameter distribution span of atomized droplets but also significantly inhibits the formation of PM10 and PM2.5 fine-suspension droplets. When the air pressure is 0.3 MPa, and the voltage is 40 kV, the percentage concentrations of PM10 and PM2.5 can be reduced by 80.72% and 92.05%, respectively, compared with that under the pure pneumatic atomization condition at 0.3 MPa.

The passivation process of a tool is a necessary step in the manufacturing process, which could improve tool life and machining efficiency by removing microscopic defects of in tool surface (such as burrs and micro cracks) after grinding or polishing. The abrasive water jet passivation (AWJP) is one of the most commonly used processes for carbide, ceramic and steel materials tools. Nevertheless, the complex action law from passivation to machining performance is indistinct, which makes passivation parameters rely on empirical summaries. To fill this gap, this paper concentrates on the detailed review of AWJP and comprehensive assessment between machining performance and AWJP parameters. Firstly, the mechanism of AWJP is analyzed, and the influence law of jet parameters on the tool nose radius is investigated. Secondly, the effect of tool nose radius on the force in turning and milling are summarized and analyzed. The jet pressure, abrasive concentration and jet time are positively correlated with the tool nose radius. Additionally, then the tool nose radius is positively and negatively correlated with cutting force and tool wear, respectively. Finally, future directions regarding the different parameters in AWJP and the machine tool for tool passivation are proposed: to reveal the complex nonlinear relationships between the parameters in AWJP. Develop economical, practical and efficient tool passivation machine tools to improve passivation efficiency and passivation accuracy and apply them to domestic tool passivation technology.

Metal cutting fluids (MCFs) under flood conditions do not meet the urgent needs of reducing carbon emission. Biolubricant-based minimum quantity lubrication (MQL) is an effective alternative to flood lubrication. However, pneumatic atomization MQL has poor atomization properties, which is detrimental to occupational health. Therefore, electrostatic atomization MQL requires preliminary exploratory studies. However, systematic reviews are lacking in terms of capturing the current research status and development direction of this technology. This study aims to provide a comprehensive review and critical assessment of the existing understanding of electrostatic atomization MQL. This research can be used by scientists to gain insights into the action mechanism, theoretical basis, machining performance, and development direction of this technology. First, the critical equipment, eco-friendly atomization media (biolubricants), and empowering mechanisms of electrostatic atomization MQL are presented. Second, the advanced lubrication and heat transfer mechanisms of biolubricants are revealed by quantitatively comparing MQL with MCF-based wet machining. Third, the distinctive wetting and infiltration mechanisms of electrostatic atomization MQL, combined with its unique empowering mechanism and atomization method, are compared with those of pneumatic atomization MQL. Previous experiments have shown that electrostatic atomization MQL can reduce tool wear by 42.4% in metal cutting and improve the machined surface R_a by 47% compared with pneumatic atomization MQL. Finally, future development directions, including the improvement of the coordination parameters and equipment integration aspects, are proposed.