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The present study discusses the conventional stretch flanging process which is employed to create flanges using the specimens of different widths of (25, 30 and 40 mm). Finite element simulations are performed and the various quality characteristics such as strain path, thickness distribution and geometrical accuracy are analysed. The bend centre region has shown thickening effect, whereas thinning is observed at the free edge of the flange region. For the larger flange width the maximum thinning rate (MTR) of 11.36% is observed for the case of 650 °C + AC condition followed by 10.33, 9.36 and 8.97% for RT, 920 °C + AC and 930 °C + FC conditions. Also, a maximum absolute error between the FE simulated thickness and experimental one is found to be less than 2.50% for all the conditions. The springback is more pronounced at the bottom of the flange for all the flanges and the average springback is found to be highest for 650 °C + AC and is least for the specimen flanged at RT condition. [ABSTRACT FROM AUTHOR]

The process of spinning and machining for heavy plates has the problems of a large amount of machining, large springback, and easy cracking. Aiming to address these issues, we proposed a deep drawing forming method for a plate with differential thickness to manufacture an integral ellipsoid component with a thin zone in the middle and a thick zone in the periphery. The plate with a differential thickness was initially produced through machining, followed by the execution of deep drawing deformation. During the deformation process of plates with differential thickness, the thin zone is prone to rupture defects. Therefore, a hydroforming method utilizing an elastic auxiliary plate was adopted to solve this problem. Through mechanical analysis and deep drawing experiments, the influences of hydraulic pressure and elastic auxiliary plate on the distributions of thickness and strain were studied, and the influence of friction on hydroforming was analyzed. The results indicate that increasing the hydraulic pressure and setting elastic auxiliary plates can increase the interfacial friction, reduce the thickness thinning rate, and improve the thickness distribution and deformation uniformity within the thin zone. When the hydraulic pressure is 5.2 MPa and the thickness of the elastic plate is 5 mm, the maximum thickness thinning rate of the ellipsoid shell is 8.8%, which is 34% lower than that of the ellipsoid shell obtained via conventional deep drawing. [ABSTRACT FROM AUTHOR]

Environmental pollution by plastic waste has become a serious problem, and there is increasing demand to reduce the weight of PET bottles. To fabricate reduced weight PET bottles, research on the PET blow molding process is essential. In this study, experiments and computer simulations were performed on the stretch blow molding process used to fabricate carbonated soft drink PET bottles. The computer simulations were performed under the same conditions as the experiment using isothermal and non-isothermal models to analyze the blowing phenomena, thickness and temperature distributions, stretch ratio, and the stretching path of PET bottles. Experimental and simulation results were compared, confirming that the stretch blow molding simulation was useful for designing and fabricating improved PET bottles through the stretch blow molding process. [ABSTRACT FROM AUTHOR]

The application trend of integrated lightweight aluminum alloy components is becoming increasingly common with the demand for energy conservation, emission reduction, and automotive safety. The aluminum alloy variable cross-section components manufactured by the hydro-pressing method can achieve both lightweight and weight reduction goals, as well as overall integration, effectively improving product performance, and is one of the important lightweight structures. However, the hydro-pressing of double-cavity profile components still faces problems such as billet shape, sealing, pressure coordination, rib plate deformation control, and corner filling. Therefore, the hydro-pressing method for AA6063 aluminum alloy double-cavity variable cross-section components is studied in this paper. Numerical simulation and experiment were carried out to investigate the formability of AA6063 double-cavity profiles, such as the effects of process parameters on corner filling, height and width dimensions, rib plate flatness, and wall thickness distribution. The results indicate that the radius of the corner increases with the increase of supporting pressure, and the increasing trend of the upper corner radius is more pronounced than that of the lower corner radius. Additionally, the deviation of component height dimension decreases, but the deviation of width dimension increases with the increase of clamping force. The flatness of the rib plate in the characteristic cross-section of the double-cavity profile deteriorates, and there is a significant thinning in the straight and corner area of the "C" shape area, while there is a thickening in the corner of the characteristic area with increasing supporting pressure. Finally, the applicability of the AA6063 double-cavity profile forming rules to other material types was discussed through numerical simulation. [ABSTRACT FROM AUTHOR]

This article deals with the thermoforming process, in which the plastic sheet is heated to a suitable temperature and stretched through a single-sided mould. This paper focuses on the study of thickness distribution along the final part through numerical simulation with T-SIM software and optical characterization of the practical process. PC LEXAN™ 8A13E films, with different initial thickness, were moulded by two types of moulding (positive and negative). It was intended to evaluate, characterize and correlate the effect of the process on the optical properties of the films. The findings of the study suggest that films formed with a negative mould exhibit more pronounced thickness variations compared to those formed with a positive mould, resulting in lower final thicknesses. Additionally, thicker films exhibit higher thickness variations after thermoforming, as supported by the experimental data. Regarding the optical characterization of the films, transmittance and reflectance tests were performed. In the case of transmittance, a significant increase in this property is observed after thermoforming, while a decrease in the reflectance values was observed. This paper is then focused on the study through numerical simulation and optical characterization of the thermoformed films, elucidating the dynamics inherent in the thermoforming process with transparent polycarbonate films, providing valuable insights for optimization and application across various industrial sectors. [ABSTRACT FROM AUTHOR]

Organic thin layers are highlighted as crucial components of flexible and printed electronic products due to their ability to provide mechanical flexibility in various applications, such as flexible displays and wearable electronics. The thickness and uniformity of these layers are crucial factors that influence surface planarization, mechanical stress relief, and the enhancement of optical performance. Therefore, accurate measurement of their thickness distribution is essential. In this study, the two-dimensional thickness distributions of spin-coated and inkjet-printed organic microlayers on glass substrates were measured using a light extinction image method. Using a 300 nm wavelength light source and a camera, images with an area of 4872 × 3640 μm2 and an XY resolution of 3.5 μm were obtained through single measurements. The precision of the measured thickness could be enhanced to several nanometers through pixel binning and image overlaying. Using this light extinction measurement system, we measured and analyzed the thickness distribution of the center and edge of the spin-coated and inkjet-printed organic layers with thicknesses of several micrometers. [ABSTRACT FROM AUTHOR]

This study proposes a model for the measurement of microscale liquid film thickness distribution using fluorescence signals. The interfacial conditions between the tool and the workpiece in mechanical machining are important for understanding these phenomena and mechanisms. In this study, indentation tests with transparent tools were used to observe interfaces; however, it was challenging to obtain the signal from a thin fluorescent liquid film on smooth and steeply inclined surfaces. Therefore, fluorescence-based measurement, such as laser-induced fluorescence, was employed. To measure the absolute thickness of the thin fluorescent film, calibration of the measurement system is necessary. Therefore, a theoretical model was proposed considering the multiple reflections of excitation light and fluorescence at the inclined surface between the indenter and workpiece. By measuring the profile of the surface topography of the indented workpiece and comparing the results with those measured by a surface profiler, the validity of the proposed calibration method and the performance of this measurement system were demonstrated. The measured surface profiles, including scratches of 2–4 µm, were in good agreement, demonstrating the validity of the proposed method. Highlights: Development of a model for measurement of liquid film thickness distribution at a steep, smooth indentation interface. Confirmation of the linearity between the fluorescence intensity and thickness, excitation intensity, and coefficient characterized by reflectance. Consistency of the measured film thickness distribution with the workpiece surface profile. [ABSTRACT FROM AUTHOR]

Predicting the results of multi-stage deep drawing in determining the thickness distribution and thinning of the workpiece are measures that will help reduce production costs by saving materials and production time. Machine Learning (ML) technique is a promising method for predicting the thickness distribution (TD) of drawn copper metal. Macro and micro products are currently used in sensitive electronic and structural applications. In this study, ML defines the relationship between the scaled thickness and the respective number of stages governed by the scaling law. It includes the development of Artificial Neural Network (ANN) tools based on machine learning to model the relationship between thickness by scaling law and stages based on multi-stage deep-drawn cups. TD is a measure of consistency. The TD is measured from the initial blank of 1500 mm long, 750 mm wide, and 6 mm thick Cu strip, reduced by 50% in nine successive steps until a final thickness of 0.1875 mm. Two ANN models used for TD prediction are Bayesian regularization (BR) and Levenberg-Marquardt (LM) algorithms. A trained machine learning model can successfully predict and verify the unseen data of 1.5 and 0.38 mm TD. ANN is used to predict the Finite Element Analysis (FEA) results and confirm them through the experimental results. The developed model can predict the TD of the multi-stage cup with the die design parameters. The difference between the TD predicted value and the measured value is based on the simulation results of multi-stage cups using the finite element method. When the predicted and measured TD, the difference in cup drawing depth is 0.5%–2.0%. The results show that the LM model is suitable for predicting the TD of formed copper cups following the scaling law. [ABSTRACT FROM AUTHOR]

This experimental study probes the dynamic behaviour of a 3 mm ABS sheet during positive mould vacuum-assisted thermoforming. In this process, the sheet undergoes large and fast deformations caused by the applied vacuum and mechanical stretching by the mould. The objective is to elucidate the complexities of these large, rapid, and non-isothermal deformations. The non-isothermal conditions are caused by the radiative heating of the sheet, convective heat loss to the surrounding air, and conductive heat transfer from the sheet to the mould. By utilizing stereo digital image correlation (DIC) in tandem with thermal imaging, the present study accurately maps the occurring displacement, strain, and strain rate field in relation to real-time temperature variation in the material. The study progresses to observe the ABS material from the moment it contacts the mould until it conforms to a positive 250 mm diameter semi-sphere cast aluminum mould. The DIC methods are validated by comparing thickness values derived from DIC's principal strain directions to ultrasonic thickness gauge readings. This knowledge not only broadens the understanding of the thermo-mechanical behaviour of the material but also aids in optimizing process parameters for improved thickness uniformity in thermoformed products. [ABSTRACT FROM AUTHOR]

To solve the common issue of transverse thickness variation in finished strip steel during the sevenstand hot continuous rolling process, the deformation of rolls in the rolling process of beam Steel 700L and the genetic characteristics of plate thickness distribution were analysed by finite element simulation. Using actual process parameters from the production of beam Steel 700L, a dynamic rolling finite element model was established. The equivalent stress field between the working rolls and strip steel in each stand and the exit thickness distribution of beam Steel 700L were investigated. Results show that the equivalent stress indicates a gradual increase despite a decreasing reduction rate during rolling. Deviations in thickness between the centre and edges of the strip steel at the exit of each stand become apparent from the second stand onwards, demonstrating a hereditary phenomenon during the rolling process. A comparison of measured and simulated thickness reveals errors within 5 %, validating the accuracy of the simulation. The obtained findings provide a foundational understanding for addressing thickness defects in subsequent beam Steel 700L production. [ABSTRACT FROM AUTHOR]

Liquid impact forming (LIF) is a new composite forming technology based on tube hydroforming (THF) technology, which changes the volume of die cavity through impact load and rapidly generates internal pressure to realize tube forming. It does not need external pressure supply source, and it is low cost and high efficiency. In order to study the forming characteristics of the natural bulging area of thin-walled metal tube under different model side lengths and different closing velocities, the change of the cavity volume of thin-walled metal tube under impact hydraulic bulging was first analyzed theoretically, and a mathematical model of internal pressure was established. Then the effects of different loading parameters on the internal pressure, bulging height and wall thickness distribution in the natural bulging area of thin-walled metal tube were studied. Finally, through the comparison of finite element simulation analysis and experiment, it was found that the deviation between the experimental results and the numerical simulation was within 6%, which verified the accuracy and reliability of LIF. It also provides a certain theoretical research and application basis for the development of LIF of metal thin-walled tube. Tube hydroforming technology based on structural lightweight and integration is now widely used in the production of parts and components in aviation, automobile, household appliances and other industries. The technology takes the tube as the blank, bulges the tube into the desired shape under the combined action of liquid pressure and axial load. But it must rely on the high pressure hydraulic power source and the corresponding control system, which has the disadvantages of high manufacturing cost and low forming efficiency. Liquid impact forming is a new tube forming technology developed on the basis of stamping and hydraulic bulging. By changing the volume of tube cavity by impact load, the liquid pressure can be rapidly increased. This process does not require a high-pressure hydraulic power source, has high forming efficiency, and one-time forming, which has great research value. This technology has many applications in aerospace and mechanical engineering, such as automotive subframes and rear axles, etc. And the technique can also be applied to pipeline engineering, especially metal shaped tubes such as tees and special-shaped tubes, etc. [ABSTRACT FROM AUTHOR]

The development of rapid prototyping methods has been very drastic in recent years. One of these methods, with a nature similar to sheet-forming processes, is the incremental forming method. In the last two decades, this technique has attracted much attention in industrial applications. The incremental forming process has been able to play a major role in advancing industrial projects in the production of low-volume prototypes. This process is a suitable alternative to conventional forming processes in the single production of conical geometries because of the low cost of machinery, equipment, and tools. In this paper, the two-point incremental forming of conical parts by three multi-point matrix designs, including single, double, and three-step cylinders, were investigated. For this purpose, the feed rate (400-1000 mm/min) and the penetration step of the tool (0.5-1.1 mm) were investigated in three levels to form the aluminum sheets with a thickness of 0.5 mm. In the following, the effect of the input parameters on the limiting height of the formed specimens, thickness distribution, surface roughness, and geometric accuracy of longitudinal cut specimens was assessed. According to the results, using the multi-point matrixes, despite increasing the final geometric accuracy, friction was reduced compared to the conical matrix. Using a two-step matrix, deeper pieces were formed by increasing the formability of the sheet, in which the average height was improved by an average of 12%. However, no significant change was observed in the roughness of the samples formed by all three types of matrixes. Therefore, the design of the proposed matrix had almost no tangible effect on the final surface roughness output. From the view of geometric accuracy, the matrix design with three steps created the highest geometric accuracy, as well as the least deviation relative to the planned path.

The process of spinning and machining for heavy plates has the problems of a large amount of machining, large springback, and easy cracking. Aiming to address these issues, we proposed a deep drawing forming method for a plate with differential thickness to manufacture an integral ellipsoid component with a thin zone in the middle and a thick zone in the periphery. The plate with a differential thickness was initially produced through machining, followed by the execution of deep drawing deformation. During the deformation process of plates with differential thickness, the thin zone is prone to rupture defects. Therefore, a hydroforming method utilizing an elastic auxiliary plate was adopted to solve this problem. Through mechanical analysis and deep drawing experiments, the influences of hydraulic pressure and elastic auxiliary plate on the distributions of thickness and strain were studied, and the influence of friction on hydroforming was analyzed. The results indicate that increasing the hydraulic pressure and setting elastic auxiliary plates can increase the interfacial friction, reduce the thickness thinning rate, and improve the thickness distribution and deformation uniformity within the thin zone. When the hydraulic pressure is 5.2 MPa and the thickness of the elastic plate is 5 mm, the maximum thickness thinning rate of the ellipsoid shell is 8.8%, which is 34% lower than that of the ellipsoid shell obtained via conventional deep drawing.

Uneven thickness distribution was the main reason for affecting product performance and forming quality when single-point incremental forming the thin-walled parts with complex shapes. Hydraulic supporting was introduced into the single-point incremental forming process, and a hydraulically supported single-point incremental forming process was proposed, uniform distribution of thickness was promoted by adding flexible support to the overhanging sheets. Conical parts with different wall angles were formed by single-point incremental forming of All060 sheets under the auxiliary supports of hydrostatic and variable pressure, the effects of hydrostatic parameters and variable pressure schemes on the thickness distribution and the critical angle of thickness uniformity were quantitatively analyzed through numerical simulations and experimental studies. The results show that the favorable hydrostatic pressure range is as 0 ~ 0.18 MPa for the critical angles of uniform thickness distribution, and the most favorable hydrostatic pressure value is as 0.17 MPa. Compared with unsupported single-point incremental forming, the hydraulically-supported single-point incremental forming process may increase the critical angle of thickness uniformity by 7°, which effectively improves the uniformity of thickness distribution and forming performance of the sheets. [ABSTRACT FROM AUTHOR]

Copyright of Electroplating & Finishing is the property of Electroplating & Finishing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The incremental forming technology has enormous potential in manufacturing sheet parts. However, non-un8iform thickness distribution is a common technical existing issue in forming thin-walled parts using this technology. The use of hydraulic supports has been a realistic, promising solution to this issue. Based on hydraulically-supported incremental forming technology, a variety of strategies were proposed in this article for hydrostatic and variable pressure supports respectively. For each supporting strategy, the thickness distribution and materials flow laws in various forming regions were explored. Experimental and simulation results indicate that when the hydraulic pressure is less than 1.8 bar, the thickness distribution of the hydrostatic-supports is significantly better than that of conventional incremental forming, and the thickness distribution of the variable-pressure supports may be better than that of the hydrostatic-support. The hydraulically-supported incremental forming technology has an potential of enhancing enhance the thickness distribution performance and forming performance of thin-walled parts. [ABSTRACT FROM AUTHOR]

Producing conical parts from sheet metal is a highly intricate process that poses significant challenges in the manufacturing industry. To investigate the ductility of an AL-1050 conical part with 12 indentations, the present study employed both experimental and numerical methods, utilizing hydroforming deep drawing with radial pressure (HDDRP). Specifically, the study analyzed the effects of the pressure path, wherein the punch moves towards the die, on the punch force and the distribution of thickness. The study findings indicated an inverse relationship between pressure and cup thickness, with higher pressure resulting in reduced thickness, and the force-displacement curve revealed that the punch force initially increased and then decreased due to an increase in the deformation resistance of the sheet. Additionally, it was observed that when the angle of the conical section was less than 35°, workpiece rupture occurred. To optimize the process parameters, a genetic algorithm–based approach was implemented. The process parameters were fine-tuned by genetic algorithm–based optimization to achieve an optimal outcome. [ABSTRACT FROM AUTHOR]

Single point incremental forming is a flexible sheet forming process that does not require a dedicated punch and die for making products for various applications. However, forming parts at steep wall angles, closer to 90°, using this process poses difficulties due to excessive thinning. The motivation behind this study is to overcome the challenges associated with forming parts at steep wall angles using the single point incremental forming process. Controlling the thickness distribution is a significant challenge that needs to be addressed. Excessive thinning leads to disqualification of design criteria, thereby restricting the process' industrial applicability. In the present work, an improved clamping mechanism along with a multi-stage forming approach is employed to address the issue of excessive thinning. Two strategies were evolved; in strategy 1, an improved clamping mechanism was developed for single stage single point incremental forming, while strategy 2 consists of the improved clamping strategy along with a multi-stage forming approach for a single point incremental forming process. The improved clamping was based on the deep drawing process' blank holding type clamping mechanism in both these strategies. The study aimed to compare the formed components' forming depth and thickness distribution using the two strategies. The result revealed that strategy 2 was more effective, resulting in better thickness distribution in the formed component. The thickness distribution improvement resulted from metal flow from the flange region, owing to the improved clamping strategy, during the single and multi-stage forming at steep wall angles. [ABSTRACT FROM AUTHOR]

Copyright of Journal of South China University of Technology (Natural Science Edition) is the property of South China University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this present work, the AA7075 was selected as matrix material and boron carbide (B4C) particles as reinforced material with several weight percentage of B4C particles (2, 4 and 6) and were prepared by two step stir casting technique to distribute the reinforced particles uniformly in the composite. It is one of the method to increase ductility of the composite is superplastic deformation, to exhibit very large elongation without failure. The basic requirement of fine structure superplasticity is the average grain size of the specimen is less than 10 µm; to achieve this fine grain size through the thermomechanical treatment process includes furnace cooling from the solution treatment to the overaging, warm rolling, recrystallization and aging treatment. The superplastic forming and cavitation behavior of the prepared composite under biaxial stress were investigated under constant forming pressure and temperature of 0.2 MPa and 550 °C, respectively. The formability and cavitation effect of composites were entirely different from the normal superplastic alloys. The yield strength and ultimate tensile strength have reduced drastically after addition of 4% B4C particles the main reason was agglomeration of the ceramic particles. In the superplastic forming process the sample B exhibits very high formability of dome height at 16.5 mm compared to the samples A and C. It is due to the uniform distribution of the particles without agglomeration on the grains as well as along the grain boundaries. [ABSTRACT FROM AUTHOR]

Incremental forming (IF) is one of the sheet metals forming technique where is a sheet formed into a final workpiece using a series of small incremental sheet deformations. In Incremental sheet metal forming process, one of the important steps is to produce the forming part with acceptable performance such as product accurate and uniform thickness distribution with a homogenous grain distribution that consider as the main challenge of incremental sheet metal forming process. This work is carried out to find the best method to control the product performance of the final parts using a new method of applying a primary stretching forming process with a hemispherical forming tool followed by single point forming SPIF. Different primary forming depth (10, 20, 30 and 40 mm) were applied to find their effect on the forming behavior of the final product and compare them to the single point forming product without using a primary forming process. The experimental results showed the improvement in microstructure by applying SPIF process after primary stretching, with grain size of 36 μm at 40 mm forming depth as compared to 52 μm when using pure SPIF, a twining effects presence in both cases. A high improvement with a minimum dimension deviation of (6%) with respect to the forming process in single point incremental forming process without a primary forming process that result forming deviation equal to (11.6%) with respect to the desired design. The thickness distribution of the final product also improved by applying the primary stretching forming process before the SPIF process reaches to (6.9%, 9.1%, 14.9% and 21.5%) at forming depth (10, 20, 30 and 40) mm, respectively. [ABSTRACT FROM AUTHOR]

In this present work, the coefficient of friction (COF) at the interface of punch and ultra-thin sheet materials of AA1050, C101 and SS304 grades was evaluated under dry and lubricated conditions using a sub-sized stretch forming test setup and tribometer. The finite element (FE) models of the stretch forming process and stamping of serpentine shaped micro-channels were developed incorporating the experimentally evaluated COF and the anisotropic properties of all the three materials. It was found that the deformation load during the stretch forming process was influenced by the COF; however, the ratio of interface contact pressure to strength coefficient of the material at the inflection point was found to be negligible. The strain path during the stretch forming process shifted close to equi-biaxial deformation mode with more uniform strain distribution and delayed localized necking under the application of Teflon tape and lubricating oil. Moreover, the successful stamping of micro-channels on these ultra-thin sheets was demonstrated under both dry and lubricated conditions, and the effect of lubrication on the formability of the channel was presented in terms of peak load, maximum thinning and thickness distribution along the channel wall. [ABSTRACT FROM AUTHOR]

Parabolic blending (PB) is one of the important topics in applied mathematics and computer graphics. The use of generalized parabolic blending (GPB) for different scenarios adds flexibility to the polynomial. Overhauser (OVR) elements is a special case in GPB (r=0.5, s=0.5). GPB can also be used in estimation. In this study, data obtained from thickness distribution of a 3mm thick high impact polystyrene product after thermoforming using a mold was used for data estimation. For this purpose, software has been developed. The software development steps and formula usages are explained. Using the developed software, polynomials for GPB and default PB (OVR) were created. The data set was compared with the y values produced by the polynomials for certain x values. At the end of the research, it was determined that the results obtained from the GPB were 0.1728 percent more accurate than the data obtained from the PB for the default values.

Single-point incremental forming (SPIF) is a kind of incremental sheet forming that is significantly novel. This method involves the utilization of a computer numerical control (CNC) machine to control the path of a forming tool, which is produced by a computer-aided manufacturing program (CAM), as it stretches a metallic sheet to achieve a desired shape. Low patch output and customized parts are good candidates for this kind of technique. The aim of the present investigation is first to study the effect of Aluminum alloy 6061 strength on the thickness distribution and thinning ratio in SPIF and then select the optimal strength to ensure uniform thickness and minimize the thinning. In order to achieve this, two different strengths of Al 6061 sheets have been employed: One used in its original form and the other heat treated to change its strength. Specimens have been prepared using the SPIF procedure for a truncated cone with dimensions of 120 mm diameter and 40 mm depth; the forming slope is 50°, and Solid work program was used to create the tool path. The thickness reduction along the wall portions was analyzed employing the finite element method using Abaqus software, and the numerical results were experimentally confirmed, where the deviation ratio between simulation and experiment was 3% for sample 1 and 5% for sample 2. The findings manifested that the specimens exhibited a consistent distribution of thickness, and the maximum thinning ratio decreased from 30% to 28.5% as the yield strength decreased from 278 MPa to 68.7 MPa, respectively. [ABSTRACT FROM AUTHOR]

When lightweighting studies are examined, thermoplastic matrix composites come to the fore as they have a high specific strength, are recyclable, and can be formed by thermoforming. Some obscurity needs to be overcome for the rapid forming of three-dimensional parts from laminated thermoplastic composites. In this study, deep drawing experiments were carried out to investigate the forming capabilities of continuous glass fiber reinforced polypropylene composite laminates. The parameters of drawing depth, laminate temperature, holding pressure, and punch speed were examined at each three different levels. The effects of these parameters were evaluated on the earing defect and the thickness distribution. It was concluded that the laminate temperature affected both deformations the most. It was determined that all parameters caused a change in flange diameter, but the amount of earing increased with the increase of drawing depth. It was established that inhomogeneous thickness distributions occurred in the part and the highest thickening took place in the curve region. [ABSTRACT FROM AUTHOR]

The Thorndike et al. (1975, https://doi.org/10.1029/jc080i033p04501) theory of the ice thickness distribution, g(h), treats the dynamic and thermodynamic aggregate properties of the ice pack in a novel and physically self‐consistent manner. Therefore, it has provided the conceptual basis of the treatment of sea‐ice thickness categories in climate models. The approach, however, is not mathematically closed due to the treatment of mechanical deformation using the redistribution function ψ, the authors noting "The present theory suffers from a burdensome and arbitrary redistribution function ψ." Toppaladoddi and Wettlaufer (2015, https://doi.org/10.1103/physrevlett.115.148501) showed how ψ can be written in terms of g(h), thereby solving the mathematical closure problem and writing the theory in terms of a Fokker‐Planck equation, which they solved analytically to quantitatively reproduce the observed winter g(h). Here, we extend this approach to include open water by formulating a new boundary condition for their Fokker‐Planck equation, which is then coupled to the observationally consistent sea‐ice growth model of Semtner (1976, https://doi.org/10.1175/1520-0485(1976)006<0379:amfttg>2.0.co;2) to study the seasonal evolution of g(h). We find that as the ice thins, g(h) transitions from a single‐ to a double‐peaked distribution, which is in agreement with observations. To understand the cause of this transition, we construct a simpler description of the system using the equivalent Langevin equation formulation and solve the resulting stochastic ordinary differential equation numerically. Finally, we solve the Fokker‐Planck equation for g(h) under different climatological conditions to study the evolution of the open‐water fraction. Plain Language Summary: A quantitative understanding of the evolution of the thickness distribution of sea ice is necessary to accurately predict changes in the Arctic ice cover. In the original formulation of the governing equation for the thickness distribution by Thorndike et al., the treatment of the redistribution term—which represents the mechanical deformation of ice by rafting and ridging—is referred to as "arbitrary" and "burdensome." Using an analogy with Brownian motion, we have recast the redistribution term, closed the original theory and incorporated the process of open water formation to produce seasonal predictions of the thickness distribution. Using our theory we show that a second peak in the thickness distribution emerges in summer, which is consistent with observations. Furthermore, we explore how the greenhouse gas and oceanic heat flux forcings impact the open‐water fraction and mean thickness, and the relative sensitivities to these forcings. Key Points: A new theory that accounts for the formation of open‐water in the Arctic during spring and summer has been developedA second peak in the thickness distribution is observed to emerge in summer, in agreement with observationsThe ice cover becomes indistinguishable from open water when the ocean heat flux is 60 Wm−2 [ABSTRACT FROM AUTHOR]

This experimental study probes the dynamic behaviour of a 3 mm ABS sheet during positive mould vacuum-assisted thermoforming. In this process, the sheet undergoes large and fast deformations caused by the applied vacuum and mechanical stretching by the mould. The objective is to elucidate the complexities of these large, rapid, and non-isothermal deformations. The non-isothermal conditions are caused by the radiative heating of the sheet, convective heat loss to the surrounding air, and conductive heat transfer from the sheet to the mould. By utilizing stereo digital image correlation (DIC) in tandem with thermal imaging, the present study accurately maps the occurring displacement, strain, and strain rate field in relation to real-time temperature variation in the material. The study progresses to observe the ABS material from the moment it contacts the mould until it conforms to a positive 250 mm diameter semi-sphere cast aluminum mould. The DIC methods are validated by comparing thickness values derived from DIC’s principal strain directions to ultrasonic thickness gauge readings. This knowledge not only broadens the understanding of the thermo-mechanical behaviour of the material but also aids in optimizing process parameters for improved thickness uniformity in thermoformed products.

Thermoplastic composite sheets have great potential for use in industrial applications owing to their fast-forming properties in the mold. One of the important matters of forming is the tendency of the part to recover elastically after it comes out of the mold. This behavior affects the dimensional accuracy of the final part. In this study, V-bending experiments were carried out to understand the spring-back phenomenon of continuous glass fiber-reinforced polyamide- 6 composite sheets. Unidirectional and cross-ply composite sheets were used in the experiments and bending angle, die radius, pressure, and dwell-time were investigated systematically. After bending, the spring-back angles of the parts were measured and the effects of the inspected parameters were compared. Also, variations in part thickness caused by springback were evaluated. Finally, the deformations in the specimens resulting from the residual stress were visualized with a scanning electron microscope. When the results were compared, it was determined that the bending conditions where the spring-back defect could be minimized were 6 mm radius, 90° angle, 120 s dwell-time, and 3 MPa pressure. Under these situations and in sheets bent 90°, the amount of spring-back was determined as 22° for unidirectional composites and 15° for cross-ply composites. [ABSTRACT FROM AUTHOR]

Thermoplastic composite sheets have great potential for use in industrial applications owing to their fast-forming properties in the mold. One of the important matters of forming is the tendency of the part to recover elastically after it comes out of the mold. This behavior affects the dimensional accuracy of the final part. In this study, V-bending experiments were carried out to understand the spring-back phenomenon of continuous glass fiber-reinforced polyamide-6 composite sheets. Unidirectional and cross-ply composite sheets were used in the experiments and bending angle, die radius, pressure, and dwell-time were investigated systematically. After bending, the spring-back angles of the parts were measured and the effects of the inspected parameters were compared. Also, variations in part thickness caused by spring-back were evaluated. Finally, the deformations in the specimens resulting from the residual stress were visualized with a scanning electron microscope. When the results were compared, it was determined that the bending conditions where the spring-back defect could be minimized were 6 mm radius, 90° angle, 120 s dwell-time, and 3 MPa pressure. Under these situations and in sheets bent 90°, the amount of spring-back was determined as 22° for unidirectional composites and 15° for cross-ply composites. [ABSTRACT FROM AUTHOR]

Uniform wall thickness plays an essential role in avoiding forming failure in incremental sheet forming. However, it is challenging to promote the uniform distribution of wall thickness in single-pass forming of high wall angle and complex three-dimensional thin-walled parts using flexible dieless incremental sheet forming technology. In this article, based on the hydraulic support single-point incremental sheet forming technology, the finite element software is used to simulate and analyze the influence of different support pressure on the wall thickness distribution and the uniform critical angle of single-pass incremental sheet forming truncated pyramid parts. The results show that the hydraulic support can effectively improve the thickness uniformity and critical forming angle. In addition, a single-point increment experiment system of hydraulic support is designed, and the uniform critical angle of wall thickness corresponding to different support pressure is obtained. The experimental results are consistent with the finite element simulation results. Therefore, this article provides guidance for manufacturing high wall angles and complex parts with uniform wall thickness in single-pass incremental sheet forming. [ABSTRACT FROM AUTHOR]

There is an increasingly challenging need for the production of agile manufacturing methods that can easily be adapted to the relentless launch of new products in the market. A single point incremental sheet forming (SPIF) is a novel approach for rapid prototyping and small-batch sheet metal part manufacture. A small-sized tool deforms the clamped blank incrementally through a prescribed tool path, despite being low-cost consuming compared to traditional forming techniques. The incremental forming method is not commonly employed due to excessive surface roughness, uneven sheet thickness distribution, and springback. The investigation has been made to commercialize this technology on the shop floor through rapid prototyping and new product development. An attempt was made to evaluate the influence of process parameters like dummy sheet thickness, the number of cut-out blanks, and wall angle on the final sheet thickness, forming forces, and springback by applying the finite element method. It has been observed that the wall angle is found to be the most effective parameter affecting the final sheet thickness, forming force, and springback in SPIF, followed by dummy sheet thickness and the number of cut-out blanks. In the current investigations, initially, a FE analysis was performed to examine the influence of new process parameters on SPIF performance using a well-designed statistical tool. Later, ANOVA was employed to study the effect of all the individual effects on process performance. In order to reach a generalized conclusion, the study has to be made on a variety of materials (polymer, composite, and metal) and shapes to evaluate the exact effect of parameters on the SPIF process performance in real-time applications. [ABSTRACT FROM AUTHOR]

Warm deep drawing of polypropylene, a semi‐crystalline thermoplastic polymer, is studied using finite element analysis. In this process, a circular polypropylene blank is preheated to a temperature much below its melting temperature and deep drawn into the shape of a flat‐bottom cylindrical cup using a punch‐die combination, both initially at 25°C. The material model used for the analysis considers the effects of varying temperature and strain rate during the deep drawing process on the depth of draw. The effects of blank holder force, initial blank temperature, blank diameter, and die and punch corner radii on the depth of draw are determined. Thickness, temperature, and strain variations in the drawn cups, punch forces, and failure modes are also determined. [ABSTRACT FROM AUTHOR]

Aerospace, automobile and biomedical sector focuses on innovative rapid manufacturing processes, which can enable product customization, reduction in cost and manufacturing lead time. Aerospace, automobile and biomedical industries mostly use magnesium AZ31 and aluminium 6061 alloy materials for manufacturing of products because of their lower elastic modulus, excellent corrosion and fatigue resistance. The conventional sheet metal forming processes often require additional tools like punch and die and would not be economically viable to produce the customized structure for applications. An emerging forming technique known as warm incremental sheet forming process is evolved, which is capable of forming intricate, asymmetrical components at elevated temperature with localized deformation method. The characteristics of warm incremental sheet forming process suggest the need for the investigation of magnesium AZ31 and aluminium 6061 alloy materials for wide application of the process. Experimental investigation on the influence of process parameters on warm incremental sheet metal forming of magnesium AZ31 and aluminium 6061 alloy materials using electric heating technique was studied. Experimental results revealed that magnesium AZ31 and aluminium 6061 alloy sheet metal component formed with incremental depth of 0.1 mm, wall angle of 50° and temperature of 300°C showed maximum formability and thickness reduction with minimum geometrical deviation. [ABSTRACT FROM AUTHOR]

In the present work, the effect of different forming strategies on material flow in incremental forming of hemi-spherical dome shaped components is investigated. During single stage forming strategy the part has failed at 10 mm depth from the entrance of hemi-spherical dome due to steep wall angle. To overcome this problem, the sheet is deformed by adopting two different multistage forming strategies. Both these strategies have four stages with different intermediate shapes. In the first strategy, the intermediate shapes are modelled as cones with different heights and wall angles. In the second strategy, the intermediate shapes are modelled as domes with different radius of curvature and height. Even though the sheet is formed successfully in both multistage forming strategies, it is found that the intermediate shapes have significant effect on forming limits, geometric accuracy and manufacturing time. The accuracy of dome formed using first strategy is found to be deviating from the desired shape due to formation of stepped features, which has overcome by implementation of second strategy. In addition, a new theoretical model is proposed to predict the thickness of the sheet during the multi-stage forming based on the volume consistency approach. The FE simulations are also performed to study the forming behaviour in both single stage and multi-stage forming. Various quality parameters found from FE simulations such as thickness distribution, forming forces and geometrical accuracy are in agreement with the experimental results.

Current study researches the impact of material and forming factors on punch force and sheet thickness in sheet forming of Aluminum 6061 composites. The particular properties of aluminum make it the most excellent candidate to replace the heavier materials in the vehicles which act as reaction to the mass drop interest inside the car area. As of now, the high-heat treatable composites Al 6000 series alloys are applied to broad applications. The forming tests were directed depending upon L27 orthogonal array (OA) planned by taking into account about temperature, die speed, sheet thickness and type of lubricant as input for process parameters. Multi target improvement was done to decide the individual significance of every reaction through Taguchi based Grey Relational Analysis (GRA) along with Principal Component Analysis. The procedure provide the ideal parameter condition for example sheet thickness of 2mm, die and blank temperature of 300oC, die speed of 0.4 mm/s, with Boric Acid lubrication that results in 25.96% decrease in Punch power and thinning improved by 50.74%. ANOVA is valuable to make out the significance and furthermore the result of each cycle factors on response parameters. Though, considerably all the parameters play important role, the die and blank temperature affects 80.11% of the reaction parameters as that of forming factors whereas die speed turned to be the slightest significant factor. Confirmation test was performed for approving the best blend. [ABSTRACT FROM AUTHOR]

In this study, hot stamping tests on continuous glass fiber (GF)-reinforced thermoplastic (PP) composites were conducted under different process parameters using a self-designed hemispherical hot stamping die with a heating system. The effects of parameters such as preheating temperature, stamping depth, and stamping speed on the formability of the fabricated parts were analyzed using optical microscopy and scanning electron microscopy (SEM). The test results show that the suitable stamping depth should be less than 15 mm, the stamping speed should be less than 150 mm/min, and the preheating temperature should be about 200 °C. From the edge of the formed parts to their pole area, a thin-thick-thin characteristic in thickness was observed. Under the same preheating temperature, the influence of stamping depth on the thickness variation of the formed parts was more significant than the stamping speed. The primary defects of the formed parts were cracking, wrinkling, delamination, and fiber exposure. Resin poverty often occurred in the defect area of the formed parts and increased with stamping depth and stamping speed. [ABSTRACT FROM AUTHOR]

Renal glomeruli have traditionally been studied by micrometer-scale optical microscopy to interrogate overall physiology or molecular distributions and by nanoscale electron microscopy to interrogate the ultrastructure of thin sections. While these approaches are powerful, they have been limited in their ability to obtain detailed views of the glomeruli as holistic 3D functional units. To fill this knowledge gap, we have developed a novel pipeline for imaging, reconstructing, and analyzing whole mouse glomeruli at 100 nm resolution using super-resolution fluorescence microscopy. This pipeline integrates both manual and machine learning approaches to annotate and analyze glomerular structures. Using this method, we created 18 detailed glomerulus models, from a range of healthy, aged, and model diseased mice, that outline all major structures and cell types. These models have been made publicly accessible in an online repository, providing a valuable resource for further studies. Our results also uncovered a diverse set of novel phenotypes including nuclear enlargement in all glomerular cell types in aging and disease, as well as an aging-related pattern of regional thickening of the Bowman's capsule basement membrane near the tubular-glomerular junction.

The thickness detection of quantum well has always been the research focus, especially for InxGa1-xAs-based indium-rich cluster (IRC) structure, which has a thickness fluctuation of normal and indium-deficient InGaAs layers caused by IRC effect. In this paper, a simple and effective detection method for the special IRC structure is proposed by point-to-point acquisition. The photoluminescence (PL) spectra emitted from different InxGa1-xAs positions are measured by moving the metal mask with a 0.2-mm-diameter light hole. By establishing the relationship between InxGa1-xAs thickness and spectral intensity, the thickness fluctuation of normal In0.17Ga0.83As and indium-deficient In0.12Ga0.88As layers is determined by comparing the intensity of dual peaks. The dual peaks are typical feature of this IRC structure, which is caused by the migration of indium atoms. The significance of this experimental results is that it not only can detect the thickness distribution of InxGa1-xAs materials with different x values, but also determine the critical thickness of indium atom migration in the growth of highly strained quantum well.

In this study, the plastic deformation of a metallic bipolar plate with a serpentine flow field was investigated during the stamping process. The strain path and thickness distribution in 304 stainless steel bipolar plates with a thickness of 0.1 mm were determined. To achieve this purpose, the process was simulated by the ABAQUS commercial finite element code, and the validity of the results was evaluated by experimental tests under simple and lubricated conditions. According to the results, the flow of material has a significant effect on the thickness distribution of the central and lateral channels, and the thickness reduction percentage of the central channel in the longitudinal, diagonal, and transverse directions is higher than the lateral one. The maximum thickness reduction in the central channels is observed in the longitudinal direction, while the diagonal direction is considered as a critical direction for lateral channels. Due to the existence of the equibiaxial tension strain path in the diagonal direction, significant thickness reduction is observed in both the side and the rib zone of the channels. However, using lubricant led to a decrease in the thickness reduction percentage by improving the flow of material into the die cavity. Moreover, under lubricated conditions, the critical area is transferred from the side area of the channel in the longitudinal direction to the rib area in the diagonal direction

The superplastic forming process has been used extensively in aerospace applications for its advantages in manufacture of complicated components. But it has been limited to the long production cycle and the non-uniform thickness distribution of the final formed part. The two-stage SPF process in opposite directions for 5083 aluminum alloy door frames was investigated. A finite element model in PAMSTAMP was used to simulate the forming process. Analyzed the effect of pre-forming die parameters on the minimum thickness of the final formed part by the Response Surface Methodology and optimized the pre-forming die parameters. Moreover, the influence of different rated pressure on the forming quality and forming time of the door frames under the same strain rate were investigated to determine the ideal pressure profile. The result was that the minimum thickness meets the requirements (thinning not exceeding 40%) while reducing the production cycle. Finally, the two-stage superplastic forming experiment in opposite directions was conducted to verify the accuracy of the numerical simulation and produce the door frames with high quality.

To overcome the problem of welding distortion on conventional multiple segment structures, and the problem of requiring large-scale forming equipment and severe thinning occurs in high-pressure hydroforming process, a novel less-loading hydroforming process is proposed for manufacturing large-size hollow components in this paper. The geometrical relationship of the tube blank during less-loading hydroforming process is firstly discussed. Then, experiment and numerical simulation are conducted to investigate the forming behavior of a large-size tubular component of aluminum alloy 5A06 with rectangular cross-section. It is found that the needed internal pressure, die closing force, and axial force for the less-loading hydroforming are significantly reduced, which are about 1/22, 1/8 and 1/28 of those required in high-pressure hydroforming, respectively. During the less-loading hydroforming process, the tube blank is firstly deformed by bending to fill the die corners, and then deformed by circumferential compression. Moreover, the compression deformation characteristics make the thickness increase. However, a too large circumferential compression and/or an insufficient supporting pressure will cause a wrinkle defect. These results provide insights for less-loading and approaching uniform manufacturing of large-size hollow components.

Orthodontic aligners undergo deformation during installation, producing an unexpected component of elastic restoring force that causes unintended changes in the dentition. The aim of this study was to investigate the relationship between strain and elastic recovery of the aligner. We distinguished the contributions to aligner deformation due to molding and installation by measuring the thickness distribution of an aligner after molding using micro-CT and tracking changes in grid patterns drawn on the sheet used to fabricate the aligner. The aligner was installed on a device that simulated canine movement. Although canine strain was quite strong around the cusp, and in premolar, it was observed mainly in their centers. Furthermore, after molding, thickness distribution of the aligner was found. But, it is no clear relationship between the thickness distribution and the strain distribution. Our method of analysis can help improve aligner design and establish molding method to deliver optimal orthodontic treatment. [ABSTRACT FROM AUTHOR]

In the present work, novel serpentine-shaped micro-channels were successfully fabricated in ultra-thin sheets of AA1050, C101, and SS304 materials using the sheet hydroforming (SHF) process. In-house fabrication methods, namely punch-less SHF and die-less SHF processes were designed and developed on a 20-t press to manufacture these channels. The finite element (FE) modeling of both processes was developed for the prediction of the deformation behavior of these sheets. The elasto-plastic FE models incorporated the elastic properties, Barlat 89 anisotropic yield model, and Hollomon hardening law for all the three sheets, and their corresponding forming limit diagrams (FLDs) were implemented as damage criteria. It was observed that the maximum pressure was 28 MPa and 32 MPa for the punch-less and die-less SHF process, respectively. The manufacturability of the hydroformed channels was examined through channel depth, aspect ratio, and thickness distribution. The average channel depth and aspect ratio were found to be higher in the case of the die-less SHF compared to punch-less SHF. The failure occurred in the AA1050 channel under plane strain deformation mode near the die corner region and punch corner region for punch-less and die-less SHF processes, respectively, indicated by a sudden dip in the thickness distribution profile. Moreover, the surface quality of the formed channels was investigated through surface roughness value, and this was further correlated with effective plastic strain incurred in the deformation process. It was observed that the surface roughness of the deformed channels fabricated by the punch-less SHF process was lower than those formed through the die-less SHF process in the present study. [ABSTRACT FROM AUTHOR]

• A good prediction model of the average liquid film thickness on the simulant was established, and the relative error is within 10 %. • The PDF curves corresponding to the instantaneous liquid film thickness distribution on the simulants exhibit multimodality. • The liquid film thickness distributions on the simulants have multi-frequency characteristics. • The ash slag simulants with a size larger than the distribution slit will cause the liquid film to be biased or unevenly distributed, which should be avoided in actual operation. To explore the influence of ash slag adhering to the scrubbing-cooling tube on the turbulent falling film flow, three hemispheres with different radii (R = 2 mm, 4 mm, and 6 mm) were used to simulate the slag. Ultrasonic Doppler Velocimetry was used to investigate the liquid film's thickness distribution and fluctuation characteristics under Reynolds number of liquid film Re f ≈8.75 × 103 ––2.63 × 104. The liquid film thickness distribution at low Reynolds numbers exhibits an isosceles triangle when subjected to R = 4 mm and 6 mm hemispheres. At high Reynolds numbers, the average thickness of the liquid film is smaller downstream of the three simulants. The simulants can enhance the liquid film's perturbations. A mathematical model has been established to predict the mean liquid film thickness on hemispherical simulants, and the relative difference is within 10 %. The probability density distribution curves of the instantaneous liquid film thickness on the simulant exhibit multimodality. [ABSTRACT FROM AUTHOR]