Optimal Parameter Combination Research Articles

Experimental study on optimization of WC-Co surface quality by in-situ laser ultrasonic assisted turning

Abstract Tungsten carbide (WC-Co) materials have high strength and hardness, as well as excellent wear resistance, and these properties make the effective machining of WC-Co a technically demanding task. In the conventional machining process, the surface of hard-to-machine materials, such as WC-Co, is prone to severe brittle fracture, and the machining quality is difficult to ensure. In contrast, the in situ laser ultrasonic assisted turning (in situ LUAT) process has demonstrated efficacy in the machining of such materials. In this study, a systematic optimization analysis of the main influencing parameters in WC-Co in situ LUAT was carried out by response surface design of experiments, and the surface roughness value of the material after machining with the optimal parameter combination was reduced by 47.9%. The surface formation and damage characteristics of WC-Co under different processing modes were analyzed by one-factor comparative experiments, and the main forms of physical and thermal damage on the material surface were systematically analyzed. This study provides a promising machining method for ultra-precision turning of WC-Co materials.

Design and Experiment of a Dual-Disc Potato Pickup and Harvesting Device

To address the inefficiency and high cost of manual potato pickup in segmented harvesting, a dual-disc potato pickup and harvesting device was designed. The device utilizes counter-rotating dual discs to gather and preliminarily lift the potato–soil mixture, and combines it with an elevator chain to achieve potato–soil separation and transportation. Based on Hertz’s collision theory, the impact of disc rotational speed on potato damage was analyzed, establishing a maximum speed limit (≤62.56 r/min). Through kinematic analysis, the disc inclination angle (12–24°) and operational parameters were optimized. Through coupled EDEM-RecurDyn simulations and Box–Behnken experimental design, the optimal parameter combination was determined with the potato loss rate and potato damage rate as evaluation indices: disc rotational speed of 50 r/min, disc inclination angle of 16°, and machine forward speed of 0.6 m/s. Field validation tests revealed that the potato loss rate and potato damage rate were 1.53% and 2.45%, respectively, meeting the requirements of the DB64/T 1795-2021 standard. The research findings demonstrate that this device can efficiently replace manual potato picking, providing a reliable solution for the mechanized harvesting of potatoes.

Rapid assembly of highly ordered DNA origami lattices at mica surfaces

The surface-assisted assembly of DNA origami lattices is a potent method for creating molecular lithography masks. Lattice quality and assembly kinetics are controlled by various environmental parameters, including the employed surface, the assembly temperature, and the ionic composition of the buffer, with optimized parameter combinations resulting in highly ordered lattices that can span surface areas of several cm2. Established assembly protocols, however, employ assembly times ranging from hours to days. Here, the assembly of highly ordered hexagonal DNA origami lattices at mica surfaces is observed within few minutes using high-speed atomic force microscopy (HS-AFM). A moderate increase in the DNA origami concentration enables this rapid assembly. While forming a regular lattice takes 10 min at a DNA origami concentration of 4 nM, this time is shortened to about 2 min at a concentration of 6 nM. Increasing the DNA origami concentration any further does not result in shorter assembly times, presumably because DNA origami arrival at the mica surface is diffusion-limited. Over short length scales up to 1 µm, lattice order is independent of the DNA origami concentration. However, at larger length scales of a few microns, a DNA origami concentration of 10 nM yields slightly better order than lower and higher concentrations. Therefore, 10 nM can be considered the optimum concentration for the rapid assembly of highly ordered DNA origami lattices. These results thus represent an important step toward the industrial-scale application of DNA origami-based lithography masks.

Effect of Injection Molding Parameters on the Tensile Strength of Short-Carbon-Fiber-Reinforced Nylon 6

SCF/PA6 composites have gained extensive industrial applications due to their superior processability and moldability, with long-fiber pellet injection molding being the predominant manufacturing technique. However, systematic investigations into injection molding parameter optimization and its mechanistic impacts on tensile strength remain scarce. This study employed the Taguchi method to investigate the effects of four critical process parameters—injection pressure, melt temperature, mold temperature, and injection time—on the tensile strength of short-carbon-fiber-reinforced nylon 6 (SCF/PA6), while elucidating their underlying mechanisms. The optimal parameter combination within the experimental range was determined to be an injection pressure of 100 bar, a melt temperature of 280 °C, a mold temperature of 100 °C, and an injection time of 2 s. Under these optimized conditions, the tensile strength reached 184.33 MPa, representing an 8.05% enhancement over baseline values. Mechanistic analysis revealed that melt temperature and injection time (essentially reflecting injection velocity) primarily govern fiber orientation distribution. Notably, melt temperature additionally regulates molecular chain orientation in the amorphous matrix regions. Injection pressure predominantly influences process-induced defect formation and material densification. Mold temperature exhibits a negligible impact on tensile strength.

Optimization of DLP 3D printing parameters via the Taguchi method for improvement in dimensional and geometric accuracy

Purpose The quality of the final polymer part fabricated via digital light processing (DLP)-three-dimensional printing technology strongly depends on the process parameters selected. The purpose of this study is to optimize the process parameters (namely, layer thickness, cure depth and build orientation) that affect the dimensional and geometric accuracy of DLP-printed parts. Design/methodology/approach The experimental design of the Taguchi method was used to examine the effects of process parameters on the dimensional accuracy, such as length, width, height and diameter, and geometric accuracy, such as roundness and flatness of printed parts. Analysis of variance (ANOVA) and factor response tables were generated to determine the most significant parameters, and the optimal parameter combination was obtained via the CRITIC-TOPSIS method. Findings First, on the basis of the findings of the ANOVA and factor response table, layer thickness and build orientation were the most significant factors affecting accuracy, whereas cure depth was the least significant factor. Second, via the relative closeness values calculated using the CRITIC-TOPSIS method, the overall accuracy of the printed parts first increases and then decreases with increasing layer thickness and build orientation. Finally, the results of the confirmation test show that the optimized process parameters can improve the overall accuracy of DLP-printed parts. Originality/value This study focuses on both the dimensional and geometrical accuracy of DLP-printed parts and proposes the use of the CRITIC-TOPSIS method to optimize the process parameters to improve the quality of these parts. Unlike prior studies that rely on subjective weighting (e.g. grey relational analysis) or single-response optimization, the CRITIC-TOPSIS method eliminates subjectivity by deriving weights from data variability and intercriteria conflict and balances trade-offs between different accuracy metrics, thereby ensuring a comprehensive improvement in part quality.

Wellhead corrosion mechanism and optimization under alternating injection condition of liquid CO2 and fracturing fluid

Abstract With the continuous exploitation of conventional oil and gas resources, their recoverable reserves are decreasing day by day. Unconventional oil and gas resources have attracted much attention, and CO2 enhanced fracturing technology is gradually taking the lead. During the implementation of this technology, the electrochemical corrosion of CO2 on the inner wall of pipelines will have a significant impact on the exploitation efficiency and equipment service life. To elucidate the corrosion mechanism of wellhead components under alternating CO2 and fracturing fluid injection conditions, and to identify the key controlling factors influencing corrosion within actual engineering parameters while investigating their corrosion patterns, this study employs a finite element numerical simulation approach. The research takes into account the structural characteristics and spatial distribution of erosion pits formed in the pipeline following fracturing fluid injection, subsequently conducting a comprehensive analysis of the electrochemical corrosion processes during the CO2 injection phase. The results indicate that injection displacement, pressure, and temperature are the main factors influencing pipeline corrosion, with decreasing degrees of influence. Optimization analysis reveals that the optimal parameter combination is: injection displacement of 3 m3/min, injection pressure of 42 MPa, and injection temperature of −14°C. Under these conditions, the corrosion on the inner wall of the pipeline is minimized. Specifically, increasing the injection displacement significantly reduces corrosion, increasing the injection pressure makes corrosion more severe, while increasing the injection temperature slightly alleviates corrosion.

Parameter design and experiment of rotary plate pineapple fruit picker

Research on pineapple harvesting machinery remains in its early stages, and the design and development of such machinery play a crucial role in advancing mechanization and automation within the pineapple industry. This study designs the rotary plate pineapple fruit harvester’s cutting table structure based on the physical and mechanical properties of pineapple plants. The design process includes simulating manual harvesting techniques. Initially, a thorough analysis was performed to determine the structural parameters of the cutting table’s key components, including the plucking speed ratio, the height of the fruit-picking plate from the ground, and the forward speed of the harvester. A stress analysis of the stem during harvesting was then conducted based on the principle of large deflection. This analysis allowed for the examination of two conditions that occur during fruit picking: (1) the stress state when the fruit and stem are separated at the end of the stem connection, and (2) the stress state when the stem breaks at a point along its length, leading to separation. A simplified rigid-flexible coupling model of the cutting platform and pineapple plant was developed using simulation software, followed by a three-factor, five-level virtual response surface analysis. This analysis was conducted to determine the optimal parameter combinations that would ensure the effective force exerted by the picking plate on the pineapple exceeds the average separation force of 60.45 N, while minimizing the peak force. The optimal parameters included a pulling ratio of 1.8, a picking plate center height of 890 mm above the ground, and a forward speed of the harvester of 0.4 m/s. Subsequent field experiments were carried out to validate the effectiveness of the optimal picking plate parameters. The field experiments with the optimal parameter combination demonstrated that the pineapple fruit picking rate was 71.3%, and the damage rate was 14.8%. The study’s results provide valuable insights for future research on pineapple harvesting machinery.

Pick-Up and Breakage Characteristics of Non-Spherical Particles Using CFD-DEM Coupling

This study investigates the motion and fragmentation of non-spherical particles in pipeline pneumatic conveying, using gangue particles as the research object. The effects of airflow velocity and particle shape on the picking characteristics, as well as the influence of elbow angle, airflow velocity, particle size, and air pressure on particle crushing, were analyzed through a combination of Computational Fluid Dynamics and Discrete Element Method (CFD-DEM) coupled simulations and experiments. Orthogonal experiments were conducted to determine the optimal combination of parameters for minimizing particle breakage rates and pipeline pressure drops. The results show that the airflow velocity significantly affects the pick-up rate of particles, while particle shape also plays a key role, with higher sphericity resulting in lower pick-up rates. Among the factors influencing particle breakage, airflow velocity has the most pronounced effect, followed by elbow angle and particle size, whereas air pressure has a relatively minor impact. In terms of the pressure drop inside the pipeline, all factors—airflow velocity, elbow angle, particle size, and air pressure—exert considerable influence, with air pressure being the most critical factor. The optimal configuration for minimizing both particle breakage and pressure drop was determined to be an elbow angle of 150°, particle size ranging from 7 to 11 mm, airflow velocity of 20 m/s, and air pressure of 0.4 MPa.

Effects of process parameters on dynamic and static load capacity of EN AW-2024-T3 aluminum alloy joints prepared by friction stir welding

This study investigates the impact of friction-stir welding (FSW) process parameters on the mechanical performance and fracture behavior of EN AW-2024-T3 aluminum alloy joints. A series of static and dynamic mechanical tests were conducted on six welded samples, revealing that the joint strength and fracture characteristics are highly sensitive to FSW parameters, particularly tool rotational rate, pin length, and traverse speed. Sample III, which exhibited the optimal combination of parameters, achieved the highest static load capacity, reaching 98.5% of the raw material's strength. Dynamic testing further confirmed Sample III's superior performance, with the highest recorded load capacity and significant energy absorption, as evidenced by ductile fracture features and high surface roughness. In contrast, Sample V, characterized by an excessive pin length, showed the lowest static and dynamic strength, along with a brittle fracture mode. The surface topography and SEM analysis of fracture surfaces indicated that optimized FSW conditions promote a ductile fracture mode, enhancing joint toughness under dynamic loading. These findings underscore the critical role of process parameter optimization in improving the mechanical properties and fracture resistance of FSW aluminum joints, making them more suitable for applications subjected to static and dynamic loading.

Research on the Effect of Micro-Pit Parameters on Tool Wear in Turning GH4169

Tools with micro-textures have found wide application in cutting difficult machining materials. The cutting performance of tools is closely related to the arrangement, morphology, and size parameters of micro-textures. In this research, micro-pit tools were used in turning GH4169 in spray cooling. The effect of micro-pit parameters on tool wear was investigated through simulation and cutting experiments. In simulation, a model of cutting GH4169 in spray cooling was built to analyze the wear of micro-pit tools with different parameters, and the optimal combination of micro-pit parameters with excellent anti-wear performance was obtained: when the distance between the micro-pit and tool nose is 60 μm, the diameter of micro-pits is 70 μm, and the pit spacing is 100 μm. In the cutting experiment, micro-pit textures with different parameters were fabricated by femtosecond laser, and cutting experiments were conducted in spray cooling to analyze the wear on the rake face of micro-pit tools. Furthermore, Ansys Fluent was used to simulate the dynamic pressure of oil film on the surface of micro-pits, and the anti-wear mechanism of micro-textured tools was verified. This research provides technical reference for the design and development of micro-textured tools.

Parametric cushioning lattice insole based on finite element method and machine learning: A preliminary computational analysis.

Parametric cushioning lattice insole based on finite element method and machine learning: A preliminary computational analysis.

Influence Law of Surface Roughness Cut by Pre-mixed Abrasive Water Jet

Abstract Pre-mixed abrasive water jet machining is affected by multiple parameters, and the key influence on the machined surface roughness is not yet clear, resulting in low efficiency. The key influencing parameters were determined based on the dimensional analysis method, water jet operating pressure (P), feed rate (v), target distance (h), and nozzle outlet diameter (d), respectively. Full-factorial cutting experiment L81 (34) on Q235 carbon steel was conducted, with the significance relationship obtained based on the polar variance analysis and the optimal parameter combination determined. The experimental results showed that the machined surface roughness Ra 1) decreased and then increased with the increase in the P, 2) increased with the increase in v, 3) increased with the increase in h, and 4) decreased with the increase in the diameter of the d. Hence, this study provides valuable data and parameters to enhance the machining, improving cutting surface quality and process efficiency.

牧草粉碎机关键部件设计与仿真分析

In view of the problems of low efficiency, poor crushing quality and inapplicability to high water content forage, the cutter and crusher rotor of hammer type forage grinder was designed, the cutter and crusher process was analyzed theoretically, and the parameters of cutter and crusher rotor were determined. The modal analysis of the cutting and crushing rotor was carried out by ANSYS Workbench to verify the rationality of the rotor structure. The alfalfa with water content of 65% was taken as the processing object, and the quadratic orthogonal rotation combination test was carried out with the output speed of motor, sieve diameter and feeding amount as the test factors, and the productivity and silking rate as the evaluation indexes. Through the analysis of variance and target optimization of the test results by Design-Expert 12.0 software, the regression equation between the test factors and the evaluation index was obtained. With the goal of maximizing the productivity and silking rate at the same time, the output speed of the motor, the diameter of the sieve and the feeding amount were solved by multi-objective optimization, and the optimal parameter combination was determined as follows: The output speed of the motor is 443.77r/min, the diameter of the sieve is 14mm, and the feeding amount is 1.27kg/s. The verification test shows that the productivity is 5065.98kg/h, and the silk rates is 94.87%. The device has high crushing efficiency, good quality, and can crush high water content forage, which meets the design requirements of forage mill.

高效低损伤烟叶仿生采摘装置的设计与试验研究

To address the issues of high damage rate and low harvesting efficiency during the tobacco leaf picking process, this study analyzed the separation mechanics of tobacco stems and leaves. A low-damage bionic picking device was designed by imitating the manual method of harvesting tobacco leaves. Based on theoretical analysis of the device and its key components, the structure and parameters of the complete system were determined. The picking process was simulated using ADAMS software, focusing on the contact force between the rigid and flexible components at various picking rod speeds. This analysis yielded the optimal combination of structural and operational parameters. Field experiments were subsequently conducted, and a response surface mathematical model was established using Design-Expert software to evaluate the relationship between key factors and performance indicators. The optimal parameter combination was found to be: a picking rod speed of 0.8 m/s, a device inclination angle of 30°, a picking rod spacing of 90 mm, and a forward speed of 0.69 m/s. Under these conditions, the tobacco leaf damage rate was minimized, meeting the requirements for low-damage harvesting. Further experimental validation showed consistency with simulation results, confirming the model's reliability and demonstrating the practical feasibility of the device for tobacco field operations. This provides a valuable reference for the development of low-damage tobacco leaf harvesting equipment.

玉米播种和穴播施肥同步控制系统的设计与试验研究

To solve the problems of slow system response speed and poor uniformity of seeding and fertilizer application, this paper designs a control system for synchronized corn seeding and precision hole fertilization. A sliding mode control method with integral variable structure and disturbance observer composite (ISMDO-SMC) is proposed. Furthermore, a three-factor, five-level quadratic orthogonal rotation combination experiment was conducted to develop a mathematical model for parameter optimization using a multi-objective variable optimization method. Simulation results from four algorithms were compared, revealing a regulation time of 0.42 seconds, a recovery time to steady state of 0.13 seconds, and a descending rotational speed of 2.5 r/min, which demonstrates the strongest dynamic response and stability. Moreover, the optimal parameter combination was determined to be the forward speed of 2.8 km/h, the fertilizer discharge shaft speed of 42 r/min, and the fertilizer discharger opening of 5.5 mm, resulting in the fertilizer application error of 1.7 g and the seed-fertilizer spacing error of 2.2 mm. The results of this study provide a theoretical basis for achieving efficient and stable seeding and fertilization operations.

铡切揉碎组合式牧草粉碎机数值模拟与参数优化

The lack of effective visualization research methods for the crushing process of grass kneading has restricted the development of grass kneading machine to a certain extent. In this paper, the hay kneading process was numerically simulated by using the discrete element method, the stem movement rule, the mechanical characteristics of the stem particle group and the power consumption of the kneading were analyzed, and the motion and breaking mechanism of the grass in the hay kneading machine were defined. The effects of motor output speed and feed rate on the spinning rate and power consumption were studied. The regression equation between test factors and evaluation indexes was established. With the goal of maximizing the silk rates and minimizing the power consumption, the motor output speed and feeding amount are optimized and solved. The optimal parameter combination is determined as follows: when the output speed of the motor is 282.88r/min and the feeding amount is 1.86kg/s, the knead verification test shows that the silk rates is 92.88% and the power consumption is 3.68kJ. The research results provide a reference for realizing high efficiency and low power consumption of grass kneading and parameter optimization of kneading device.

丸粒化水稻种子物性参数测定与离散元仿真参数标定

The calibration of parameters for pelleted rice seeds (PR) is crucial for enhancing research on PR-related machinery and for executing high-speed precision hole sowing with unmanned aerial vehicles. This paper focuses on determining the fundamental physical and contact parameters of PR. A series of tests were conducted, including the Plackett-Burman test, the steepest ascent test, and the Box-Behnken test, using the stacking angle as the primary variable. These tests led to the identification of optimal combinations of simulation parameters. Specifically, the coefficients of rolling friction for the PR-PLA plate and PR-PR were measured at 0.137, while the coefficient of static friction for the PR-PLA plate was 0.336. This study provides a reference for calibrating simulation parameters of pelleted seeds and research on high-speed precision seeding.

玉米高速密植播种机气送式螺旋供种装置设计与优化

In order to improve the seed supply performance of seed-supplying link of high-speed dense planting seeder of maize, an air-assisted spiral seed-supply device was designed and optimized. The kinetic model of maize seeds in the migration zone was established. Based on computational fluid dynamics (CFD) simulation, the pressure and velocity distribution in the axial plane were explored when the blower pressure was 4.0, 4.5, 5.0, 5.5, 6.0 kPa, respectively. A two-factor, five-level central composite design (CCD) experiment was conducted using blower pressure and rotational speed of spiral shaft as test factors and seed supply rate, coefficient of variation of seed supply rate stability and seed breakage rate as seed supply performance indicators. Explored the impact trend of interaction terms of factors on seed supply performance indicators. Based on the multi-objective variable optimization method, the optimal working parameter combination of the air-assisted spiral seed-supply device was determined and verified by bench experiments. The results showed that the optimal combination of working parameters was the blower pressure of 6.0 kPa and the rotational speed of spiral shaft of 80 r/min. Under the verification test, the seed supply rate, the coefficient of variation of seed supply rate stability and the seed breakage rate were 2933.21 g/min, 1.87% and 1.69%, respectively, and the relative error was within 5.5% compared with the optimized results. This study can provide a reference for the optimal design of the seed-supply device of the high-speed dense planting seeder.

气吸式蒜苗单体的设计与实验

Based on the requirements for hybrid garlic seed sowing, the overall structure of an air-suction garlic seeding unit was designed, and its working principle was described. The adsorption pressure required for the seed metering device was determined to be -5 kPa. One hopper was selected for the bud reversing device, with an angle of 24.5°, and the perimeter of the insertion device measured 600 mm. The optimal combination of parameters for sowing involved a negative pressure of -5 kPa and a forward speed of 1 km/h at the third level. Under these conditions, the qualified rate of individual sowing reached 84.26%, while the missed sowing rate was 7.12%, meeting the agronomic requirements for garlic seed sowing. Field experiments validated the theoretical analysis and bench tests, providing a solid foundation for the future production and promotion of garlic sowing units.

制繁种水稻分段可调脱粒装置设计与试验

In response to the current challenges in the harvesting process of hybrid rice, where the threshing gap cannot adequately adapt to the varying threshing requirements, leading to high grain breakage rates, loss rates, and frequent clogging of the drum, a new threshing device for hybrid rice was designed by adjusting the gap of the concave screen. The concave screen was divided into a low-loss threshing section and a low-damage threshing section, with the addition of a hydraulic system to enable the adjustment of the threshing gap. A dynamic analysis of the rice at the spiral feeding inlet and within the threshing drum was conducted, determining that the adjustable range of the threshing gap is between 10 and 20 mm. A prototype of the low-loss threshing device for hybrid rice was built, and bench tests were performed with feed rate, drum speed, and threshing gap as influencing factors, while cleaning rate and breakage rate were used as response indicators in an orthogonal experiment to determine the optimal parameter combination. The optimal threshing performance was achieved at a threshing gap of 14.19 mm, a drum speed of 460.12 r/min, and a feed rate of 2.13 kg/s, resulting in a cleaning rate of 97.67% and a breakage rate of 0.295%. Subsequent verification tests under the optimal combination showed a cleaning rate of 96.2% and a breakage rate of 0.36%, meeting the harvesting standards for hybrid rice. This research provides theoretical support for the development of mechanized harvesting equipment for hybrid rice.