Sustainable Machining for Difficult-to-cutting Materials

Experimental Study on Cold Plasma Jet (CPJ) Assisted Micro-Milling of 30CrMnSiNi2A

As a typical high-performance alloy, the excellent mechanical properties and stringent processing requirements of 30CrMnSiNi2A high-strength steel pose great challenges to high-quality and efficient processing. Currently, researchers have proposed methods such as improving cutting tool performance, minimal quantity lubrication (MQL), and applying external energy field to assist processing. However, due to the unregulated material properties, the further improvement of surface quality is limited, and there are problems of phase change and thermal damage in laser processing. Cold plasma jet (CPJ) is rich in active particles and has a low macroscopic temperature. It can effectively regulate material properties without causing serious surface damage. Therefore, a new 30CrMnSiNi2A machining approach adopting CPJ is proposed to improve the cutting process. The mechanism of its action on material properties and cutting process is revealed based on single-grain diamond scratching tests and micro-milling tests. The results show that CPJ can promote material fracture and improve material removal efficiency. The material removal efficiency R at 400 mN is increased from 0.433 before treatment to 0.895. Under the optimal processing parameters (feed speed V_f = 800 μm/s, spindle speed n = 40,000 rpm, and milling depth a_p = 5 μm), compared with dry micro-milling, the cutting forces F_z, F_x and F_y in CPJ-assisted micro-milling are reduced by 26.5%, 24.8% and 31.3%, respectively. The surface roughness Sa is reduced by 19.3%, and the phenomena of plastic flow and burr are suppressed. The CPJ-assisted machining process proposed in this paper can regulate the material properties to improve the cutting process without causing serious damage to the material, providing a new approach for achieving high-quality and efficient processing of 30CrMnSiNi2A.

A Review of Ultrasonic Vibration-Assisted Grinding for Advanced Materials

Ultrasonic vibration-assisted grinding (UVAG), which superimposes high-frequency, micro-amplitude ultrasonic vibration onto conventional grinding (CG), offers several advantages, including a high material removal rate, low grinding force, low surface roughness, and minimal damage. It also addresses issues such as abrasive tool clogging, thereby enhancing machining efficiency, reducing tool wear, and improving the surface quality of the workpiece. In recent years, the rapid development of advanced materials and improvements in UVAG systems have accelerated the progress of UVAG technology. However, UVAG still faces several challenges in practical applications. For example, the design and optimization of the ultrasonic vibration system to achieve high-precision, large-amplitude, and high-efficiency grinding remain key issues. Additionally, further theoretical and experimental studies are needed to better understand the material removal mechanism, the dynamics of grinding force, abrasive tool wear, and their effects on surface quality. This paper outlines the advantages of UVAG in machining advanced materials, reviews recent progress in UVAG research, and analyzes the current state of ultrasonic vibration systems and ultrasonic grinding characteristics. Finally, it summarizes the limitations of current research and suggests directions for future studies. As an emerging machining technology, UVAG faces challenges in many areas. In-depth exploration of the theoretical and experimental aspects of high-precision, large-amplitude, and high-efficiency ultrasonic vibration systems and UVAG is essential for advancing the development of this technology.

Biological Bone and Replacement Materials in Grinding: Force Model and Processing Capability

Grinding is widely used in orthopedic surgery to remove bone tissue material, but due to the complex and brittle structure of bone, it is prone to mechanical stresses that cause cracks and damage to the bone tissue. Furthermore, bone replacement materials typically have high hardness, strength, and brittleness, which lead to increased tool wear and damage, such as cracks and deformation during grinding. Therefore, ensuring the surface quality of bone and replacement materials during the grinding process has become a critical issue. This necessitates the development of grinding force models that consider various processing parameters, such as feed rate and cutting depth, to guide industrial production. However, currently, research on the grinding force prediction models for bone tissue and its replacement materials is relatively scarce, and there is a lack of corresponding grinding force model reviews for unified guidance. Based on this, this article focuses on bone grinding technology and, conducts a critical comparative analysis of the grinding force models for bone tissue and its replacement materials, and then summarizes the grinding force prediction models in the grinding process of bone tissue and bone replacement materials. First, according to the material types and material removal mechanisms, the materials are categorized into bone tissue, bio-inert ceramics, and bio-alloys, and the material removal process during grinding is analyzed. Subsequently, the grinding force prediction models for each material and the accuracy errors of each model are summarized. The paper also reviews the application of these grinding force prediction models, explaining how processing parameters such as feed rate and cutting depth influence grinding forces and their interrelationship. Finally, in light of the current issues in the grinding of bone tissue and replacement materials, potential future research directions are proposed, aiming to provide theoretical guidance and technical support for improving the grinding quality of bone tissue and its replacement materials.

Machining Characteristics of Graphene Oxide-Based Nanosuspensions in Abrasive Machining of Single-Crystal Si and SiC

Single-crystal silicon (Si) and silicon carbide (SiC) are core semiconductor materials in communication, lighting, power generation, and transportation. However, their high hardness and wear resistance combined with low fracture toughness have posed significant challenges for high-efficiency and low-damage machining. Aqueous suspensions containing nanoparticle additives have recently been developed for sustainable manufacturing due to their satisfactory tribological performance and environmentally friendly nature. In this work, nanoadditives, including two-dimensional (2D) graphene oxide (GO) nanosheets and zero-dimensional (0D) diamond nanoparticles, were ultrasonically dispersed in water to formulate different GO-based nanosuspensions for achieving high-efficiency and low-damage abrasive machining. The experimental results indicated that GO nanosuspension was a suitable coolant for grinding Si, generating a ground surface of 32 nm in R_a, owing to its great lubricity and excellent resistance against mechanical abrasion. Diamond-GO hybrid nanosuspension demonstrated a synergistic effect in abrasion, lubrication and oxidation, which was thus appropriate for polishing SiC single crystals, leading to approximate 60% and 30% improvements in removal and roughness respectively, in comparison to a commercially available diamond suspension.

Thermal Characterization Study of Double End Face Grinding Powder Metallurgy Stainless Steel 316L

Double end face grinding machining is a highly efficient surface grinding technique. And grinding temperature is an important factor affecting the surface quality of workpieces. However, it is difficult to monitor the surface temperature of the workpiece in real time because of the covered contact between the grinding wheel and the upper and lower surfaces of the workpiece during the machining process. This paper aims to conduct a mechanistic analysis and experimental investigation of the machining process to address this challenge. Initially, the paper conducts an analysis of the kinematic mechanism, modal analysis, and the grinding force mechanism specific to the double end face grinding process. Afterwards, the mechanisms leading to the generation of grinding heat and the associated heat transfer mechanisms are explored in depth. The paper then proceeds to solve the instantaneous temperature field during double end face grinding by the finite element method (FEM). Furthermore, the micro and macro profile heights of the machined workpiece surfaces are measured and analyzed. The results show that the machined workpiece surface shows a high center and low edge. This is due to the fact that the temperature at the edge of the workpiece is higher than the center during machining, resulting in more material removal. Through these investigations, the study is able to determine the optimal process parameters for the machining process. This in turn improves machining efficiency and product conformity. And these findings not only guide practical production processes but also provide a foundation for future theoretical research in this area.

Review on Vibration Control of Wafer Handling Robot

The wafer handling robot serves as the pivotal component of the wafer transfer system, wherein its operational speed and motion precision exert a direct influence on both the yield and productivity of wafer processing. With the semiconductor manufacturing process advancing towards nanoscale linewidths and heightened throughput, the time-varying stiffness characteristics of the flexible joints in wafer handling robots, along with the resultant end vibration issues, have emerged as critical challenges that constrain overall performance. A comprehensive understanding of the stiffness change mechanisms, coupled with enhancements in control methodologies, plays an indispensable role in the effective vibration control of wafer handling robots. To facilitate research in pertinent areas, this paper systematically reviews the cutting-edge methods for vibration suppression in variable stiffness flexible joint wafer handling robots, concentrating on the following core aspects: The impacts of diverse dynamic stiffness identification methodologies on the accuracy of stiffness identification are thoroughly examined; This paper also explores the potential of collaborative optimization strategies involving trajectory planning, control methodologies, and lightweight intelligent algorithms in enhancing real-time control. Furthermore, it evaluates the application scenarios and feasibility of passive vibration absorbers and semi-active adjustable dampers within the context of broadband vibration suppression technologies. In conclusion, this paper synthesizes and critically discusses the advantages and limitations inherent in various research findings, while also constructing a “model-control-vibration suppression” closed-loop optimization system aimed at facilitating ultra-precision vibration control of wafer handling robots under conditions of high dynamic operation. By elucidating the bottlenecks present in existing technologies alongside the trajectory for future interdisciplinary integration, this work provides theoretical support for the intelligent advancement of wafer handling robots and fosters the expedited and reliable development of wafer transfer systems.

A Shear Stress Model for Magnetorheological Fluid with High Volume Fraction

Shear stress prediction in high-concentration magnetorheological fluids (MRFs) faces limitations due to the oversimplified magnetic dipole interactions and neglect of multibody effects in classical single-chain models, particularly under conditions (30–40 vol.%) where stress prediction errors start escalating nonlinearly. To address this gap, based on the classic single-chain model, this study proposed a new revised calculation method that integrates three novel components: (1) a distance-weighted dipole interaction model incorporating material-specific correction factors, (2) dynamic chain reconstruction mechanisms accounting for magnetic aggregation under shear deformation, and (3) transverse field overlap parameters quantifying anisotropic field distributions. Validated against Lord Corp.’s MRF-132DG, the proposed approach reduces shear stress prediction root-mean-square error (RMSE) by 71.7% (from 27.40 kPa to 7.76 kPa). It rectifies the R-square metric from −0.9236 to 0.8457, outperforming existing models in high-concentration regimes. The work resolves the bottleneck of modeling chain-to-network transition behaviors through Monte Carlo simulations with energy barrier analysis, revealing how localized dipole rearrangement governs macroscopic rheological responses. The methodology’s adaptability to pre-saturation magnetization stages further enables systematic evaluation of multi-dipole interaction thresholds critical for high-performance MRF engineering applications.

Sustainable Machining for Difficult-to-Cutting Materials