International Journal of Precision Engineering and Manufacturing最新文献

The phenomenon of pressure shock is experienced in the operation of hydraulic transformers. A valve plate featuring a triangular groove buffer structure is designed in this paper to mitigate this phenomenon. The differential equation of oil pressure in the plunger cavity with buffer structure is established and transformed into the pressure increment equation of the plunger cavity, thereby obtaining the relation curves between the size of the buffer structure and the pressure change of the plunger cavity, as well as the influence law of the buffer structure on the pressure change of the plunger cavity. The optimal size of the triangular groove buffer structure for each distribution window is determined. The fluid model with the above buffer structure is subjected to a transient simulation using ANSYS, and the pressure distribution cloud diagram of the plunger is obtained. The simulation results show that the cushioning structure can effectively realize the pressure buffering effect.

Precision stages have been extensively researched and developed due to their broad range of applications across various fields. Magnetic levitation stages, in particular, control a floating top plate with six degrees of freedom without mechanical coupling. Consequently, the in-position stability performance of magnetic levitation stages is crucial, as it determines the overall stage performance and regulates manufacturing efficiency. Traditionally, efforts to enhance stability have primarily focused on improving the performance of sensors and actuators. This study introduces a novel approach that significantly improves in-position stability by adding specially designed reinforcement components. These components either convert an open frame structure to a closed one or increase the structural stiffness of the stage. Through modal analysis using the Finite Element Method (FEM), the modal shape across the stage was assessed and structurally weak parts were identified. The addition of reinforcement components resulted in a marked improvement in in-position stability, with the root-mean-square displacement values decreasing by 60.5% and 50.0% along the x and y axes, respectively. Moreover, these improvements were predictable through the use of FEM. Given its simplicity and cost-effectiveness, this method is proposed as a promising new strategy to enhance the performance of precision stages.

Artificial Intelligence (AI) technology is leading the fourth industrial revolution, particularly as a key element in high-performance computing, complex data analysis, and real-time decision support systems. For the advancement and efficient implementation of these AI technologies, high-performance semiconductor chip manufacturing requires the essential technology of hybrid bonding processes. Hybrid bonding minimizes the physical distance between chips, enabling high-speed data transmission and low power consumption, thereby maximizing AI chip performance. Additionally, this process facilitates chip miniaturization, reduces manufacturing complexity, and supports economical production, thus expanding the application range of AI technologies across various industries. By enabling the integration of multi-functional chips, hybrid bonding significantly improves AI applications in fields such as automotive, healthcare, and telecommunications, contributing to the advancement of the fourth industrial revolution. In this paper, Wafer-to-Wafer (W2W) hybrid bonding system is developed to solve precision degradation issues occurring during the room-temperature hybrid bonding process. Performance evaluation and experiments conducted on the bonding system, fabricated based on optimal design, confirmed high-precision bonding performance at room temperature through precise position control to be compensate position error of wafer bonding.

This study explores the growth of bacteria on zirconia and alumina, two ceramics commonly used in biomaterials, using a laser to prepare these surfaces for bacterial cultivation. We focused on how adjusting the laser fluence can change the size of ceramic particles on these surfaces, which in turn affects bacteria’s ability to grow. By measuring contact angle and roughness, their correlation with bacterial growth was confirmed. We found that higher laser power strengthens the natural properties of zirconia and alumina that affect bacteria growth. This result is significant for biomaterials and microbial engineering because it means we can enhance how well bacteria grow on these surfaces by simply using a laser parameter. This capability opens up new possibilities in designing surfaces that interact with microbes in specific ways, such as creating antimicrobial coatings or improving biomaterials for medical uses.

Deep drawing is the process of drawing sheet metal blank into a desired shape. A blank holder is used to prevent wrinkling in the product, especially with thin sheets. The implementation of this process requires the use of double action press, and when the blank-holder is eliminated, single action press can be used, thus saving energy. In the current study, a new arrangement of punch and die was adopted to produce a square cup of brass from thin sheet in a single stroke of reverse deep drawing without blank-holder. Square cup produced by pushing blank with a hollow square punch through a square outer die which has inner square die. The geometric shape of the blank and its dimensions can affect the determination of the wrinkling as well as the drawing load and the distribution of strain and thickness, in addition reducing the metal removed as a waste in the trimming process of product. To study the effect of this parameter numerically and experimentally, three shapes were employed, square, square with fillet at its corners, and circular blank. The results show that the square blank gave a successful square cup of 30 mm rib, and 20 mm height has 4 mm radius without wrinkling. The maximum load and thickness distribution were almost similar for all blanks and an apparent change appeared in the thickness of the base. The maximum strain value decreases in the square blank. The speed of the punch can affect the determination of the drawing load, so three punch speeds (3, 6 and 9 mm/min) were experimentally employed to investigate their effect on load. The results revealed that the speed of 6 mm/min was the best. Errors between numerical and experimental results don’t exceed 10%.

This research was performed to study the effect of surface roughness on the fatigue limit in martensitic stainless steel (STS 410). After heat treatment of STS 410 steel, mechanical property tests and rotary bending fatigue tests were performed by varying the surface roughness conditions of A-polishing, A-grinding, and A-#60 of STS 410 steel, respectively. The fatigue fracture surface was observed and analyzed using SEM and EDS. The fatigue limit of STS 410 steel decreased by 0.98% from 509 to 504 MPa when the surface roughness increased about 3 times from 0.226 to 0.664 μm. However, when it increased about 9 times from 0.226 to 2.053 μm, it showed a significant decrease of 7.66% from 509 to 470 MPa. The ratio of fatigue limit to tensile strength (fatigue ratio) of STS 410 steel decreased from 54.9 to 50.5% as the surface roughness increased from 0.226 to 2.053 μm. Beach marks, a typical shape of a fatigue fracture surface, were observed on the fracture surface near the start point of fatigue failure, and brittle (Fe, Cr, Mn, Si) based non-metallic inclusions that promote crack propagation and reduce fatigue limit existed.

The tooth fracture failure modes in the spur gear tooth root are mainly influenced by the magnitude and positions of bending fatigue load along the gear face width. Numerous studies in the literature used 3D finite element (FE) models to analyze crack propagation, but they did not take into account the effect of the load distribution ratio (LDR) throughout the gear face width, either in a moving load model or a uniform load model. In this study, an effort is made to investigate the impact of LDR and Load Sharing Ratio (LSR) in the modeling of moving loads for various loading positions and measure the actual crack propagation behavior of a spur gear with a root fracture using the 3D FE technique. Further, the influences of FE spur gear models on the variation of Actual Load Distribution with the effect of LSR, Stress Intensity Factors (SIFs), and crack propagation paths are also studied. A 3D FE crack propagation modeling procedure is validated with the experimental results of the SAEJ1619 fatigue test procedure. The experimental investigation using standard SAEJ1619 fatigue test procedure shows that the symmetric crack propagation failure at the crack front of the spur gear tooth was observed for a given uniform bending fatigue load. The results show that the mode I SIFs (K_I) and mode II SIFs (K_II) are dominant at the crack opening displacement for the positions of moving load between the Highest Point of Single Tooth Contact (HPSTC) and Highest Point of Tooth Contact (HPTC) lines. But, the K_II is highly influenced by K_I for further crack growth when the load is moved to the HPSTC line than the HPTC line. This study provides the guidelines to predict the actual crack propagation path failure behavior for various positions of moving load for various gear drive systems with root crack.

This study proposes the step-wise procedures involved in the development and fabrication of indigenous multi-resin 3D printer using vat photopolymerization process. The demand for simultaneous (i.e. single step) fabrication of multi-material intricate designs is exponentially increasing in the customization industries. The step-wise procedure involves the utilization of conceptual design approach to evaluate various sub-functions and their available solutions. Upon successfully identifying the sub-functions, their solutions, and the inter-dependency involved, three different types of multi-resin 3D printers are being be designed. Among the three proposed multi-resin 3D printer designs, the most optimized one is selected through the Verein Deutscher Ingenieure (VDI) 2225 guidelines. During the feasibility analysis as per the VDI 2225 guidelines, equal importance is given to the technical and economic aspects. Upon selection, the 3D printer is indigenously constructed using the locally available components and equipment. Moreover, the Taguchi method of level-3 is used to evaluate the best printing parameters for two different resins namely: DK-W (Dark-Water washable) and LT-W Light-Water washable). Furthermore, post-curing shrinkage analysis is carried out to examine the dimensional discrepancies. The excellent performance of the proposed printer was demonstrated by satisfactory printing of complex geometrical parts: Mobius ring and a ball inside a cage with acceptable accuracies.

This study optimized the laser welding process parameters of steel/Al by combining the Support Vector Machine model optimized by the Coati Optimization Algorithm (COA-SVM) with the Multi-Objective Cuckoo Search algorithm (MOCS), and the FeCoNiCrTi high-entropy alloy (HEA) powder was used as a filler metal to connect 5052 aluminum alloy with DP780 dual phase steel by laser welding. Using optical microscope and scanning electron microscope equipped with energy-dispersive spectroscopy to analyze the changes in joint structure and fracture morphology before and after adding HEA. The results showed that the optimized weld width decreased by 28.06% and the weld depth increased by 29.76%. The addition of HEA suppressed the Fe–Al mutual diffusion and significantly reduced the intermetallic compounds (IMCs) layer thickness. Some HEA elements participated in the reaction between Fe/Al, forming new phases such as Al₅FeNi, which increases ductility compared to the original phase. The maximum tensile force measured can reach 815 N. Compared with the absence of HEA, the maximum tensile force of the joint increased by 35.2%, and the fracture mode changed from brittle fracture to semi-brittle fracture.

Nickel-based superalloy such as Inconel 718 has worldwide applications in the manufacturing of aircraft components and defence industries due to superior properties at elevated temperatures. The importance of this material in high-temperature applications due to its excellent thermo-physical properties is subject to extensive area of interest. The machining of nickel-based superalloy is a challenging task due to generation of high heat in grinding zone which impels the study of improvement of surface quality in the present study. The main aim of the present study is to find the optimum process parameters corresponding to minimum R_a value using different optimization techniques so that the production cost of components and time consumption can be minimized. In the present experimental study, investigation has been carried out on Inconel 718 through a CNC surface grinding machine. Due to the complexity involved in tough-to-machine material, the study focuses on the improvement of surface roughness using down grinding process by the optimization of three influential parameters such as wheel speed, depth of cut and table speed. Response surface methodology based central composite rotatable design is used in this study to illustrate the surface roughness value (R_a) which is greatly influenced by wheel speed followed by depth of cut and table speed. For the optimization of machining parameters, RSM coupled with genetic algorithm (GA) and particle swarm optimization (PSO) is used to reduce the time consumption in the selection of machining parameters and desirous output response in grinding. The R_a value corresponding to GA is found to be 0.2735 µm while 0.2586 µm using PSO technique. The best optimal process parameters corresponding to minimum R_a value using PSO technique are depth of cut = 5 µm, wheel speed = 628 m/min, and table speed = 3588 mm/min. Comparatively, PSO provided better results in terms of minimum surface roughness than GA. The validation of experimental results is done with a statistical model that has shown a fine level of corroboration among them.