Sheet Thickness Research Articles

Optimization of Rubber Sheet Rolling Machine Parameters using a Taguchi-based TOPSIS Linear Programming Model

The Multi-Response Optimization (MRO) problem is a critical aspect of the engineering design, particularly in improving process efficiency and product quality. This study focuses on optimizing the parameters for a rubber sheet rolling machine, a vital component of Thailand's natural rubber industry. The objective is to enhance its operational efficiency and product consistency by addressing key criteria, such as production time and rubber sheet thickness. A novel approach integrating the Taguchi method and the Technique for Order Preference by Similarity to Ideal Solution Linear Programming (TOPSIS-LP) model is proposed. The Taguchi method systematically designs experiments, while the Preference by Similarity to Ideal Solution (TOPSIS) model consolidates multiple performance indicators into a single optimal solution. Optimal roller gaps of 4.5 mm, 3.0 mm, 2.0 mm, and 0.1 mm for the first, second, third, and fourth roller pairs, were, respectively, identified. The results demonstrated a reduction in rubber sheet thickness to 2.06 mm (5.94% improvement) and production time to 9.71 seconds per sheet (1.33% improvement) compared to the original settings. The qualitative analysis confirmed the robustness and reliability of the optimized parameters, achieving consistent results across various evaluation methods. This study presents a significant advancement in the MRO problem, offering a robust framework applicable to similar challenges in industrial settings. The findings provide a foundation for future automation and optimization efforts, driving sustainable improvements in the manufacturing efficiency and product quality.

Exploring the impact of sheet thickness scaling on Nanosheet FET gate electrostatics using k.p based simulations

This work explores the impact of sheet thickness scaling on gate electrostatics of NsFETs using k.p simulation. It is shown that thin channel NsFETs exhibit higher threshold voltage irrespective of the substrate orientation and channel material. However, the influence of geometrical confinement varies among different substrate orientations and channel materials due to variations in carrier quantization mass. It is also shown that thin channel NsFETs deliver higher inversion charges at equivalent gate over-drive voltages, thereby offering enhanced gate electrostatics. However, the advantage of gate electrostatics in thin channel NsFETs is limited by quantum capacitance. Optimizing the sub-band structure through strategic selection of substrate orientations and channel materials is essential to regulate quantum capacitance and to fully exploit the benefits of sheet thickness scaling in NsFETs.

Influence of asymmetric rolling paths on the microstructure, texture, mechanical behavior, and electrical conductivity of electrolytic tough-pitch copper

In this work, the influence of asymmetric rolling paths on the microstructure, texture, mechanical behavior, and electrical conductivity of electrolytic tough-pitch copper was studied. Four different asymmetric rolling paths including unidirectional (UD), rolling (RD), transverse (TD), and normal (ND) with a thickness reduction of 90% were applied. Based on simulation results, the uniformity of strain distribution in the UD path was less than the other paths, the RD and ND paths had a better distribution of strain along the thickness, and the TD path exhibited the best strain distribution. Because of this, the TD, ND, and RD samples revealed a better distribution of copper oxide particles compared to the UD sample. The homogeneity of texture through the sheet thickness for the RD, TD, and ND paths was more than that for the UD path due to the uniform strain distribution. Unlike the other samples, the UD sample exhibited {001}〈110〉 Rotated Cube and {001}〈100〉 Cube orientations in the areas close to the surface due to the formation of severe accumulated strain. The maximum yield strength (405.5 MPa) and tensile strength (419.0 MPa) belonged to the RD sample. The TD sample showed a lower strain hardening rate as a result of easier cross-slip. The highest electrical conductivity (85.2 %IACS) belonged to the TD sample due to its lower dislocation density. The presence of θ-fiber and γ-fiber improved the electron conductivity of copper.

Influence of thread pitch on material flow and mechanical properties of stationary shoulder friction stir lap welded dissimilar joint

To investigate the influence of varying pitch values on the flow behavior of materials and the mechanical attributes of stationary shoulder friction stir lap welded (SSFSLW) joints. In this paper, three kinds of tools with different pitches are designed, and the lap joint of a 6061-T6 aluminum alloy plate and an AlSi10MnMg alloy plate was realized by stationary shoulder friction stir welding. Different computational fluid dynamics (CFD) models of friction stir lap welding were founded and the connection between the pitch and material flow behavior was investigated. The increased pitch pin boosts the velocity of material in the shear layer, expands flow area of aluminum alloy material, and promotes materials flow upward along the orientation of pin thread. The pin with a 1 mm pitch results in a joint that featuring the shortest hook extension distance, the largest effective sheet thickness (EST), and the largest effective lap width (ELW). The fracture locations of shear testing are all on the base material of AlSi10MnMg alloy. Numerous dimples could be seen at the fracture appearance, and the type of fracture is ductile fracture.

Investigation on multiple bending using laser forming of mild steel plate and its bend angle prediction

In manufacturing industries like shipbuilding, automotive, microelectronics, and aerospace, laser forming is a potential new technology. Laser forming is an intricate thermo-mechanical process in which the process mechanisms are determined by the temperature profile across the sheet thickness, which is influenced by laser power, scan speed, number of passes, laser beam diameter, and workpiece geometry. During the process, the material deforms because of compressive stress generated in the underneath region due to the thermal expansion of the irradiated region. This study focuses on the multiple bending and the effect of different process parameters on the laser bending of the sheet. Experiments were performed on 4 mm and 8 mm thick sheets of mild steel sheet of grade IS 2062 E250 using a 2-kW fiber laser with various influencing parameters such as power, scan speed, and laser spot diameter. Hardness and grain size measurements of laser-formed surfaces at different combinations of influencing parameters were performed and the features formed due to laser irradiation were analyzed. An artificial neural network (ANN) model is proposed to predict the bend angle value.

Detachable Top Electrode-Organic Photodetector for Repeated Nondestructive Evaluation of Device Performance and Surface Analysis of the Active Layer.

Organic photodetectors (OPDs) are key devices for monitoring vital signs, such as heart rate and blood oxygen level. For realizing the long-term measurement of biosignals, stable operation is essential. To improve the stability of OPDs, it is important to analyze each layer to understand the degradation mechanism. We developed detachable top electrode (DTE)-OPDs to enable both surface analysis of the active layer and device characterization to be performed nondestructively and repeatedly within a single device. The substrate of the top electrode is a 2 μm thick elastomer sheet reinforced with polyurethane nanofibers. The DTE-OPDs showed a Dsh* of 1.4 × 1012 Jones by attaching the top electrodes to the bottom stack without external pressure. The DTE-OPDs showed no degradation after 1000 attaching/detaching cycles of the top electrodes. Using the DTE-OPDs, we successfully observed the relationship between dark current increase and oxidization of the active layer.

Investigation into high-speed impact response of composite sandwich structures

Sandwich structures composed of top and bottom face sheets and an inner core are commonly used for energy-absorbing applications, mainly because of their superior stiffness-to-weight ratio and crashworthiness. Despite extensive studies on the ballistic behavior of monolithic and composite materials, limited research has focused on hybrid sandwich structures combining lightweight and ductile materials like thermoplastic polyurethane (TPU) with high-strength aluminum. This study aimed to numerically establish the ballistic limit velocities and the penetrating and perforation resistances of composite sandwich structures to address this gap. The sandwich panels were manufactured from thermoplastic polyurethane (TPU) and aluminum (Al) 2024-T351 as core and face sheets/skins, respectively. The panels were subjected to an impact to investigate the effects of various thicknesses of their face skins and core on high-speed impact resistance. From the results obtained, it was evident that the numerical models simulated experiments with high accuracy. The impact and damage resistances of the composite sandwich structures increased with the thicknesses of their core and face sheets. The resistance of the structure increased by 19% by increasing the thickness of face sheets from 1.2 to 2.0 mm. Similarly, the resistance of the composites can be increased by 44% by increasing the core thickness from 20 to 50 mm. Therefore, it can be established that the impact resistance of the composite sandwich structures depended on the thicknesses of their core and skins. The investigated performances of the different composite sandwich structures should guide their choice for various industrial applications.

Influence of Heat Treatment on Properties and Microstructure of EN AW-6082 Aluminium Alloy Drawpieces After Single-Point Incremental Sheet Forming

An EN AW-6082 aluminium alloy is one of the 6000 series aluminium alloys with the highest strength properties. Due to its favourable strength-to-density ratio, it is used, among others, in the automotive and aviation applications. It is also characterised by good formability, especially in the annealed condition. This article presents the results of investigations on the possibility of forming a 2 mm thick EN AW-6082 alloy sheet using the incremental sheet-forming process depending on the material condition (O, W, T4, T6). The microstructure of the material after heat treatment and the mechanical properties of the workpiece material in as-received state, as well as after forming, were examined. Additionally, for selected cases, additional heat treatment of the drawpieces was performed to improve their mechanical strength. The values of the limit-forming angle were determined for the materials tested. The values of this angle varied from 69° for the annealed sheet to 61° for the material in the T6 condition. The highest yield stress (YS) and ultimate tensile strength (UTS) were found for sheets (YS = 305 MPs and UTS = 324 MPa) and the artificially aged drawpieces (YS = 333 MPa and UTS = 390 MPa). Additional ageing after incremental sheet forming resulted in an increase in strength properties compared to drawpieces without additional heat treatment only in the case of drawpieces made of sheet metal after the solutionising and in T4 condition.

Fabrication of three-layered aluminium-copper laminated composites using friction stir additive manufacturing

Abstract The current study employed the friction stir additive manufacturing (FSAM) method to fabricate three-layered laminated composite by utilizing 3 mm thick sheets of AA6061-T6 alloy (top and bottom layers) and pure Cu (middle layer). The feasibility of FSAM in producing high-performance Al/Cu/Al laminated composites was evaluated by analyzing the influence of tool rotational speed on the microstructure and mechanical properties. The composites were fabricated at rotational speeds of 900 rpm, 1200 rpm, and 1500 rpm; maintaining a traverse speed of 90 mm min−1 throughout the experiments. Changes in the weld morphology, macrostructure, microstructure, and intermetallic formation were noted and analyzed. The findings indicated that achieving macro defect-free joints is possible with a rotational speed of 1200 rpm. Detailed examinations via electron dispersive spectrum and x-ray diffraction revealed the presence of AlCu, Al2Cu and Al2Cu3 intermetallic compounds within the nugget zone. Significantly varied microhardness levels ranging from 59.4 to 143.7 HV0.1 were observed, corresponding to distinct microstructural features within the processed zone. The Al/Cu laminated composite exhibited an excellent combination of strength and ductility; a UTS of 214.6 MPa and an elongation of 23.4%. The findings showcase that utilizing FSAM presents an exceptional opportunity to fabricate novel Al/Cu multilayered composites with distinctive mechanical properties.

Increasing the Wear Resistance of Stamping Tools for Coordinate Punching of Sheet Steel Using CrAlSiN and DLC:Si Coatings

The punching of holes or recesses on computer numerical control coordinate presses occurs in sheets at high speeds (up to 1200 strokes/min) with an accuracy of ~0.05 mm. One of the most effective approaches to the wear rate reduction of stamping tools is the use of solid lubricants, such as wear-resistant coatings, where the bulk properties of the tool are combined with high microhardness and lubricating ability to eliminate waste disposal and remove oil contaminants from liquid lubricants. This work describes the efficiency of complex CrAlSiN/DLC:Si coatings deposited using a hybrid unit combining physical vapor deposition and plasma-assisted chemical vapor deposition technologies to increase the wear resistance of a punch tool made of X165CrMoV12 die steel during coordinate punching of 4.0 mm thick 41Cr4 carbon structural steel sheets. The antifriction layer of DLC:Si allows for minimizing the wear under thermal exposure of 200 °C. The wear criterion of the lateral surface was 250 μm. The tribological tests allow us to consider the CrAlSiN/DLC:Si coatings as effective in increasing the wear resistance of stamping tools (21,000 strokes for the uncoated tool and 48,000 strokes for the coated one) when solving a wide range of technological problems in sheet stamping of structural steels.

Investigation of the Effect of the Shape of Cutting Knives Limiting Burr in High-Strength Multiphase Steel Sheets.

In this study, numerical modeling and experimental tests of the sheet metal cutting process were carried out in order to determine the shape of the cutting knives for a roller shear, ensuring the minimization of burr on the cut edge. A rolling mill was used for the tests, enabling the replication of the cutting process in a roller shear (demonstrating the possibility of using cutting rollers). The cutting edges of the sheets were examined using light microscopy and then compared with the results of numerical simulations to determine the cutting quality. The tests were performed for multiphase Complex Phase (CP) grade steel. The initial thicknesses of sheets were equal to 1 and 2 mm. Based on the results of theoretical research, four shapes of cutting rollers were designed, of which two shapes were selected for experimental tests. The analysis of the test results shows that the lowest burr values were obtained for straight and beveled rollers. Analyzing the size of burr obtained in experimental tests, it can be concluded that for each of the two variants of the roller shape, a reduction in burr was achieved. Greater reductions in burr were achieved for shaped (cut) rolls.

Investigation of the Effects of Wafer-Baking Plates on Thermal Distribution, Wafer Thickness, and Wafer Color Distribution

Wafer-baking ovens are machines that bake liquid batter by heating the interconnected cast plates in a gas oven. The plates in contact with the wafer batter are generally made of the cast material. Although there are many studies on the contents in the recipes of wafer products and the effects of the additives included in the recipes on the quality of the wafer sheet, there are few studies on the effects of the material type of the wafer-baking plate on the baking process. In this study, the thermal distribution of two baking plates made of different materials (GG-25 gray cast iron and GJV-350 vermicular cast iron), their effects on the thickness of the wafer sheet, and their effects on the color distribution of the wafer sheet were investigated at different baking rates. The experiments were conducted in an industrial wafer-baking oven at two different production rates. As a result, it was observed that the GJV-350 vermicular casting plate provides a more homogeneous heat distribution, more stable wafer sheet thickness, and more homogeneous color distribution of the wafer sheet at a maximum production rate.

A study based on biochar as a reinforcing agent of irradiated waste thermoplastic composite for polymer engineering and electromagnetic shielding applications

A study based on biochar as a reinforcing agent of irradiated waste thermoplastic composite for polymer engineering and electromagnetic shielding applications

Investigation on the Thermal Decomposition Behavior of Molybdenum Trioxide Precursor.

The ultrafine MoO3 powders were prepared by the combination of centrifugal spray drying and calcination in this work. The thermal decomposition behavior of the spherical precursor was studied. The phase constituents, morphologies, particle size, and specific surface areas of MoO3 powders were characterized at different temperatures. It is found that the decomposition of the precursor is subjected to five stages, and forms different intermediate products, including (NH4)8Mo10O34, (NH4)2Mo3O10, (NH4)2Mo4O13, h-MoO3, and the final product α-MoO3. Moreover, the decomposition rate equation is established based on the thermal decomposition kinetic parameters of the precursor. With an increase in decomposition temperature, the morphology changes from unclear boundary particles to dispersed flake particles, and the flaky particles exhibit larger sizes, higher crystallinity, and better dispersion, which can be attributed to the mass transfer of gaseous MoO3 products. Additionally, the MoO3 particle size decreases progressively, and the specific surface area increases and then decreases. At 500 °C, it can achieve ultrafine flaky MoO3 powder with the size of thick sheets, with a thickness of about 300 nm and a length of about 1-3 μm. This research can offer an innovative strategy for preparing ultrafine MoO3 powder.

Structure failure and strength evaluation of honeycomb-based sandwich composites under variable hydro-thermal-mechanical load

The high-strength and lightweight sandwich structures have broad application prospect in aerospace, wind turbine generator, traffic and civil engineering. The sandwich structures usually service with severe environment and complicated mechanical load, structure failure and strength prediction are crucial issues. Under time-varying and optional position hydro-thermal–mechanical loading, this paper systematically analyzes strength failure, buckling and delamination of a sandwich beam with carbon fiber-reinforced polymer face sheet and aluminum honeycomb core. Effects of elastic boundary conditions, hydrothermal stress, configuration of honeycomb cell and thickness of face sheet on failure pattern and critical failure loading are evaluated. The theoretical deformation model is verified by performing a bending experiment of cantilever beam. For the honeycomb core with small re-entrant angle and shot horizontal cell wall, the sandwich cantilever beam occurs strength failure of face sheet and delamination is happened in simply supported beam. With increase of re-entrant angle and cell wall length, buckling of horizontal cell wall becomes the primary failure pattern of sandwich beam. With thickness increase of face sheet, the failure pattern switches from face sheet’s strength failure to delamination. The critical load for delamination decreases to a volley value and then increases with thickness of face sheet.

Domain Wall Structure Model through the Thickness of Fe-Si Sheet Studied by X ray Topography

Domain Wall Structure Model through the Thickness of Fe-Si Sheet Studied by X ray Topography

Statistical Study of the Solar Wind Current Sheet Properties: Defining Instrument Requirements for the Seven Sisters Mission Concept

AbstractThe present study performs a procedure of estimating the current sheet (CS) thickness in the solar wind. Motivated by the science requirements for a multi‐spacecraft solar wind mission called the Seven Sisters, this research aims to address the required temporal resolution of the magnetometer in order to entirely encompass the observations of thin CSs. Additionally, this procedure can contribute to addressing the unresolved turbulence heating problem in the solar wind. We have statistically provided the solar wind CS thickness estimated, with full instrumental resolution of 128 Hz, from the Flux Gate magnetometer (FGM) data of the Magnetospheric Multiscale (MMS) mission. Out of 183 cases of solar wind CS crossings, the thicknesses varied from 0.1 to 3 Mm with a maximum of 32.97 s, minimum of 0.16 s and average of 3.08 s crossing time. Of these, 73.22% of the CSs can be identified by using 1‐Hz measurement cadence, while 12.5 Hz data can fully identify all of the CSs. Therefore, it can be concluded that the 1‐Hz sampling rate is sufficient for the survey mode, while the sampling frequency of 12.5 Hz as the burst mode is capable of achieving even the strictest scientific objectives. Our statistical results also report a population below 100 km or , which should be further examined.

Numerical investigation of the influence of pulse frequency on the weld pool size in pulsed current TIG welding

This study simulates the pulsed current tungsten inert gas (TIG) welding process to investigate the transient development of the weld pool in a 4 mm thick aluminum sheet, focusing on the effects of pulse frequency on the weld pool size. Two pulsed currents, 230 and 180 A, with a 30% background current, were examined. The 230 A current achieved full, while the 180 A resulted in partial penetration. Five pulse frequencies (1, 4, 10, 20, and 50 Hz) were analyzed. A numerical model was developed to compute heat and current fluxes on the workpiece surface. The arc profile shifted from a bell shape in high-frequency cycles to a conical shape in low-frequency cycles. The heat and current fluxes served as inputs to another model that simulated weld pool behavior for both direct and pulsed current TIG welding. The results showed that weld pool size decreased in pulsed current TIG welding. At 230 A, full penetration changed to partial penetration under pulsed current. At 1 Hz, sufficient time was available for solidification during the low-cycle period, but at 50 Hz, the weld pool remained liquid. As pulse frequency increased from 1 to 50 Hz, the weld pool depth decreased significantly, with a reduction from 2.4 to 0.9 mm at 230 A and from 1.1 to 0.34 mm at 180 A. Convection in the weld pool was influenced by temperature and was strongest at higher temperatures. The decrease in weld pool size was most pronounced between 1 and 10 Hz, stabilizing between 20 and 50 Hz. Validation against experimental macrographs demonstrated good agreement with the simulations.

Slurry Synthesis and Thin-Film Fabrication Toward Production of Li₂O-B₂O₃-Al₂O₃-Based Multilayer Oxide Solid-State Batteries for Internet of Things Applications.

Developing thin-film sheets made of oxide-based solid electrolytes is essential for fabricating surface-mounted ultracompact multilayer oxide solid-state batteries. To this end, solid-electrolyte slurry must be optimized for excellent dispersibility. Although oxide-based solid electrolytes for multilayer structures require sintering, high processing temperatures cause problems such as Li-ion volatilization and reactions with graphite anodes. Thus, low-temperature sinterable oxide-based solid-electrolyte materials should be devised. We successfully developed the conditions for producing thin films from 21 μm thick solid-electrolyte sheets of Li2O-B2O3-Al2O3, one of the most promising candidates for multilayer solid-state batteries. A comprehensive analysis of the fabricated thin films included X-ray diffraction (XRD) to confirm their amorphous structure, scanning electron microscopy (SEM) for particle morphology, and contact angle measurements to verify surface hydrophilicity. Evaluation of a 32-layer bulk sample of solid-electrolyte sheets revealed an ionic conductivity of 2.33 × 10-7 S/cm and charge transfer resistance of 100.1 kΩ at a sintering temperature of 430 °C. Based on these results, cathode and anode active materials will be applied to develop high-energy-density multilayer ceramic batteries with hundreds of layers in future work.

Enhancing metallurgical and mechanical properties of friction stir lap welding of aluminum alloys by microstructure reconstruction

Friction stir processing (FSP) is successfully employed to alleviate their hook defects of friction stir lap welding (FSLW) of aluminum alloys. The mechanical properties and microstructural characteristics are compared and analyzed between the FSLW&FSP joint fabricated by FSLW and FSP and the FSLW joint. The microstructural analysis shows that the hook defect zone at the advancing side of the FSLW joint is changed into the overlap zone (OZ) of the FSLW&FSP joint due to microstructure reconstruction caused by performing the FSP. The heterogeneous and coarse grains at the hook defect zone of the FSLW joint are transformed into refined and equiaxed grains at the OZ of the FSLW&FSP joint as a result of dynamic recrystallization. The results of tensile tests show that tensile strength and fracture toughness of the FSLW&FSP joint are 85.7% and 220% higher compared to those of the FSLW joint, respectively. The cross sections of broken lap joints reveal that their failure location is shifted from the hook defect at AS of the FSLW joint to the thermo-mechanically affected zone of the FSP zone of FSLW&FSP joint. The combined action of effective sheet thickness increasement, microstructure uniformity, grain refinement, and local stress concentration reduction act as the strengthening mechanism of the lap joint of aluminum alloys.