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In this paper, the characteristics of special stamping process requirements and the shortcomings of existing application technology are studied. Through repeated motion simulation analysis and size optimization calculation, a kind of inertia-controlled molding press is proposed to make up for this technical vacancy. This paper first describes the working principle and structure scheme of the main transmission mechanism of the inertia-controlled molding press. With the help of Adams-View x64 2013, the main transmission mechanism is simulated and analyzed from the aspects of kinematics and dynamics, and a physical prototype is made to test the key reliability indexes of the main transmission mechanism. According to the test data, the static strength, stiffness, vibration characteristics, and dynamic characteristics of the 200 t inertia-controlled molding press are evaluated, which provides a reference for the design of this kind of machine tool. [ABSTRACT FROM AUTHOR]

Detection of scrap floating for a stamping die with 0.8 mm-thick A1050 aluminum sheets was conducted with multiple retrofit accelerometers attached to the outside of the stamping die-set. The accelerometers were attached to three locations on the side of the stripper plate and one location on the side of the punch plate of a 3-ϕ30 hole blanking die using a magnet-based jig. Anomaly detection technique using the Mahalanobis–Taguchi system was conducted with the gravity analysis of the waveform of the accelerometers' signal. A total of 106 experiments without foreign objects (i.e., a scrap) were conducted to collect instances of the signal profile for the normal samples. In addition, 24 error samples with a foreign object were fabricated for anomaly detection tests. Only one of the four locations achieved 100% accuracy in detection using only one sensor. In detection using only one sensor, only one of the four locations achieved 100% accuracy. We attempted to improve the accuracy by increasing the amount of learning. However, the accuracy did not improve by increasing the amount of training except for the one sensor mentioned above. This result implies that machine learning, in which features are predefined by the user, cannot compensate for the disadvantage of sensor location by the amount of training. Then, combinations of the sensors were examined. Learning with all features of all 4 sensors (i.e., with 12 features) resulted in a still imperfect separation between normal and error samples. However, even if a single sensor causes false positives, it was possible to combine the influential features of multiple sensors, that were chosen by SN ratio analysis, to detect all anomalies without false positives. In future work, we would like to consider the detection of anomalies with multi-discipline features and combine anomaly detection systems with design and quality control systems. [ABSTRACT FROM AUTHOR]

A positioning grid is a key clamping structure for fixing the transverse and axial positions of fuel assemblies in nuclear reactors, and it is generally prepared by the transverse stamping of a Zr-4 sheet. However, the texture formed in the processing process of Zr-4 sheets can affect formability, resulting in cracking in the stamping process. Therefore, the relationship between the formability of Zr-4 sheets and the normal Kearns factor (Fn) of basal texture was studied in this paper. The results showed that the Zr-4 sheet with an Fn equaling 0.720, prepared by an isobaric reduction rolling process, would crack in the stamping process. To avoid the cracking during stamping, the formability improvement of Zr-4 sheets based on texture optimization was discussed. By using the finite element model (FEM) and a visco plastic self-consistent (VPSC) model coupled simulation, the relationship between the initial textures and formabilities of Zr-4 sheet is established. It is found that the hardening exponents (n) decreased with increasing Fns in VPSC simulations. Meanwhile, as the Fn increases, cracks are prone to occur at the bottom corner of the stamped sheet in finite element simulation. Given the results from FEM and VPSC simulations, it is proposed that the Fn should be controlled to be less than 0.7 for preventing cracks in the sheet during stamping. Additionally, a new rolling process named non-isobaric reduction rolling was designed in which the Fn of the Zr-4 sheet is successfully reduced to 0.690. The stamping results indicate that the sheet is free of cracks under an Fn of 0.690. Therefore, texture optimization with the proposed rolling process can improve the formability of Zr-4 sheets, which effectively solves the cracking problem of Zr-4 sheets. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Nanchang University (Engineering & Technology) is the property of Nanchang University 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 article analyses the results of virtual experiments and studies of existing kinematic schemes of metal flow, in particular, normal and radial schemes. Based on the "equi-theory", the EQUI software package, which can serve as an effective tool for simulating the pattern of metal flow along the billet during metal pressure treatment, has been developed. The software allows performing express analysis and prediction of shape changes in flat billets and simulating spatial diagrams of contact stresses. [ABSTRACT FROM AUTHOR]

Air Circuit Breakers are used for circuit protection from the faulty current that might damage the subsystems of the circuits like motors, transformers, transmission systems, etc. The cost optimization of the component used in the mechanism unit of Air Circuit Breaker (ACB). This can be achieved by replacing the existing material AISI 9260 to equivalent proposed material AISI 4140. This material exhibits the better mechanical properties in all aspects, along with low process cost involved during manufacturing of the components. This paper presents comparative dealing with the properties like hardening & tempering, hardenability, weldability, stamping-ability, endurance limit, and modification factors of the existing material AISI 9260 to proposed material AISI 4140. The proposed steel AISI 4140 is suitable for ACB mechanism parts which exhibits the same reliability and better mechanical properties than presently used AISI 9260 steel. The proposed AISI 4140 steel reduces the cost of the component by elimination and replacing the partial or fully heat treatment cost and wire electric discharge machining (WEDM) cost respectively. Because the component manufactured with AISI 4140 steel shows the desired mechanical properties only in hot rolled conditions with additional localized hardening, wherever the rolling surface is present. The elimination and replacement of heat treatment and WEDM process cost involved in present AISI 9260 steel components, can be achieved by partial induction hardening and stamping process employed on proposed AISI4140 steel respectively. There are three conditions that is, when fully elimination of heat treatment saves 27% of the total process cost, when partial elimination of heat treatment cost saves 25.5% of the total process cost, and when replacing the WEDM to stamping saves 22% of the total component cost. The proposed material and process also maintain the same reliability for the rated 20,000 operations. [ABSTRACT FROM AUTHOR]

Stamping is a very important manufacturing process. To optimize the process parameters, a hybrid surrogate model based on the back-propagation neural network and sparse auto-encoder is proposed and compared with classical surrogate models to verify its reliability. Furthermore, the hybrid improved particle swarm optimization–genetic algorithm, based on chaos theory, is proposed and compared with other algorithms. A double-C part is used as an engineering example to verify the proposed method. The Latin hypercube sampling method is used for sampling and the response value is obtained by AutoForm simulation software. On this basis, the hybrid surrogate model is used to establish the mapping relationship between the forming quality of the double-C part and the stamping process parameters. The optimal stamping process parameters are obtained through the improved hybrid algorithm. The results demonstrate that the wrinkling of the optimized double-C part is significantly reduced and the forming quality is improved. [ABSTRACT FROM AUTHOR]

The transfer mechanism of a toner pattern printed on a soft film using a laser printer to a metal surface in compression was investigated by experiment and computer simulations. The toner pattern can be transferred successfully to the workpiece surface under the conditions that the entire soft film continues to be squeezed out smoothly from the workpiece edge until the transfer process is completed. The results indicate that the average tool pressure needed for the complete transfer of the toner pattern to the workpiece surface can be predicted by the average compression pressure calculated with slab method [ABSTRACT FROM AUTHOR]

The object of research in the paper is the technology of manufacturing segments of the rotor rim of large hydrogenerators-motors. The subject of study is the design and geometrical state of the rotor rim during the operation of hydraulic units. The goal is to make a three-dimensional mechanical calculation of the rotor segment for the further determination of the most optimal technology for the rotor rim manufacturing. The following tasks are set: to study the peculiarities of the manufacturing technology of the rotor rim segments; to perform an analytical calculation and a three-dimensional calculation with the determination of the average values of stresses and deformations in the rotor segment. The used methods are: finite element method of mathematical modeling of the thermal stress state of nodes. The following results were obtained: a description of the two main manufacturing technologies of the rotor rim segments, namely the stamping method and the laser cutting method, was provided. The advantages and disadvantages of each technological process were analyzed, and it was determined that the laser cutting method should be used in the production of powerful small-scale hydrogenerators. Three-dimensional models of the rotor segment were developed and a three-dimensional mechanical calculation of this model was performed, as a result of which the value of the displacement of the rotor of the hydrogenerator at the nominal frequency of rotation, as well as the average values of the stresses in the spoke and the rim of the rotor, were obtained. Based on the results of calculations, it was established that significant tolerances in the manufacture of rotor segments can lead to changes in the shape of the rotor during its further operation, the appearance of additional vibrations and further affect the performance of the hydraulic unit. The scientific novelty consists in a combined approach to the estimation of the average values of stresses and deformation of the rotor rim, taking into account the technology of its manufacture, which includes elements of analytical mechanical calculation and calculation in a three-dimensional setting.

The article is devoted to identifying the origins and regional features of the technology of high-relief coinage in the Kazan-Tatar jewelry tradition. The main source was the electronic database of Tatar jewelry from museum collections, collected within the framework of the academic project “Jewelry of the Turkic peoples of Eurasia: general and special” (Russian Foundation for Basic Research 2013–2014, No. 13-06-97056). The research was based on a systematic technical and stylistic analysis of traditional jewelry and a detailed synchronous-diachronic examination of Bulgar-Golden Horde and Tatar products with three-dimensional images. Reconstruction of technological techniques related to this type of artistic metal processing made it possible to identify specific features of the formation of decor. The manual method of obtaining a unique relief using punches with a figured striker predominated. The decorations are characterized by the following: two or three-level bas-relief, the absence of a “locking” profile, the principle of “compositing” that underlies the conventionally interpreted floral and plant motifs, geometric orderliness, subject to the laws of the central-radial composition. The completed form of the decoration corresponds to the typical features of “notch chasing”, which is a marker of the Tatar craft tradition: smooth relief and “grain” background. An integrated approach allowed us to conclude that the origins of the existing artistic and figurative system can be traced in artifacts of the Bulgarian and Golden Horde silver of the 11th–14th centuries, made by embossing, stamping, and punching on a matrix. The formation of technological features was influenced by the traditions of high-relief coinage, which received regional development among Kazan silversmiths in the 17th–18th centuries. The specifics of Tatar relief coinage as a whole were formed in the context of Islamic art.

Aimed at the poor accuracy in traditional deep drawing of aerospace aluminum alloy hemispherical shells, and by introducing metal spinning, a stamping-spinning hybrid process strategy for aluminum alloy hemispherical shells is proposed, which can achieve the forming processing of the formed component with a high thickness uniformity and high shape accuracy. The finite element simulation model of the hybrid process of the aluminum alloy hemispherical shell is developed, which realizes the simulation. In addition, the variation law of the wall thickness and shape fitting of the hemispherical shells formed by the hybrid process are analyzed. The simulation results show that the uniformity of wall thickness of the hemispherical shells formed by 50% stamping + 50% spinning is significantly improved. The shape accuracy of the component can be obviously improved by changing the stress state of the forming component by power spinning. Meanwhile, the hybrid process is verified by using an aluminum alloy hemispherical shell with a diameter of 1 m in processing test, which improves the thickness uniformity and the shape accuracy of the hemispherical shell.

We investigate a folding problem that inquires whether a polygon P can be folded, without overlap or gaps, onto a polyhedron Q for given P and Q. An efficient algorithm for this problem when Q is a box was recently developed. We extend this idea to a class of convex polyhedra, which includes the five regular polyhedra, known as Platonic solids. Our algorithms use a common technique, which we call stamping. When we apply this technique, we use two special vertices shared by both P and Q (that is, there exist two vertices of P that are also vertices of Q). All convex polyhedra and their developments have such vertices, except a special class of tetrahedra, the tetramonohedra. We develop two algorithms for the problem as follows. For a given Q, when Q is not a tetramonohedron, we use the first algorithm which solves the folding problem for a certain class of convex polyhedra. On the other hand, if Q is a tetramonohedron, we use the second algorithm to handle this special case. Combining these algorithms, we can conclude that the folding problem can be solved in pseudo-polynomial time when Q is a polyhedron in a certain class of convex polyhedra that includes regular polyhedra. [ABSTRACT FROM AUTHOR]

Precision metal stamping is an industrial process that uses machines equipped with dies to transform flat sheet metal, either in blank or coil form, into various custom shapes. In addition to stamping, these metal presses can also perform a wide range of processes such as stamping, tooling, notching, bending, punching, flanging, coining and more. Precision metal stamping is widely used for the production of a wide range of products. It can be performed as a single-step operation where each stroke of the metal press produces the desired shape on the plate or in a series of steps. The increasing demand for precision metal parts in various industries from medical to automotive and aerospace has pushed precision metal stamping to the forefront of today's manufacturing. This is because it provides a high degree of design flexibility for defining and implementing tiny features with tight tolerances and unique configurations. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Shanghai Jiao Tong University (1006-2467) is the property of Journal of Shanghai Jiao Tong University 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.)

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department 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.)

A positioning grid is a key clamping structure for fixing the transverse and axial positions of fuel assemblies in nuclear reactors, and it is generally prepared by the transverse stamping of a Zr-4 sheet. However, the texture formed in the processing process of Zr-4 sheets can affect formability, resulting in cracking in the stamping process. Therefore, the relationship between the formability of Zr-4 sheets and the normal Kearns factor (Fn) of basal texture was studied in this paper. The results showed that the Zr-4 sheet with an Fn equaling 0.720, prepared by an isobaric reduction rolling process, would crack in the stamping process. To avoid the cracking during stamping, the formability improvement of Zr-4 sheets based on texture optimization was discussed. By using the finite element model (FEM) and a visco plastic self-consistent (VPSC) model coupled simulation, the relationship between the initial textures and formabilities of Zr-4 sheet is established. It is found that the hardening exponents (n) decreased with increasing Fns in VPSC simulations. Meanwhile, as the Fn increases, cracks are prone to occur at the bottom corner of the stamped sheet in finite element simulation. Given the results from FEM and VPSC simulations, it is proposed that the Fn should be controlled to be less than 0.7 for preventing cracks in the sheet during stamping. Additionally, a new rolling process named non-isobaric reduction rolling was designed in which the Fn of the Zr-4 sheet is successfully reduced to 0.690. The stamping results indicate that the sheet is free of cracks under an Fn of 0.690. Therefore, texture optimization with the proposed rolling process can improve the formability of Zr-4 sheets, which effectively solves the cracking problem of Zr-4 sheets.

The strain compensation method for measuring in-plane forming limit curves (FLCs) using 2D digital image correlation developed previously [A method of measuring in-plane forming limit curves using 2D Digital Image Correlation, SAE Int. J. Mater. Manf., 2023] was modified and extended to more versatile and popular out-of-plane FLCs. The current study introduces a straightforward strain compensation technique for measuring Nakazima testing based out-of-plane FLCs utilizing an affordable single-camera (2D) DIC system. In this study, forming tests are performed on two automotive-grade sheet metal alloys: DP980 steel and a 6xxx series aluminum alloy using the Nakazima test method. The experiments are conducted on a customized setup that allows for simultaneous optical strain measurements using both a stereo DIC and a 2D DIC system. The FLCs are obtained by applying a temporal FLC computation approach to the two measurement sets. The results show that 2D DIC FLC points match those obtained by stereo DIC for both the materials after applying the proposed strain correction method.

This paper presents a new solution for shaping the rivet progression of a beverage end. The classic method uses three operations to press the cylindrical rivet using 0.208 mm and 0.203 mm thick sheets. The increasing demand for aluminium alloys is prompting measures to make more efficient use of this raw material. One possible solution is to produce packaging from ever thinner sheets. This requires the design of new tooling and the preparation of an appropriate technological process. A method has been developed to stamp a hexagonal-shaped rivet from 0.200 mm thick sheet metal, increasing the number of stamping operations to four. The proposed method was verified through a numerical analysis using the PAM STAMP 2022.0 software package. It was found that for appropriately shaped tools, sheet thicknesses of the stamped component could be achieved that were not less than those for the currently used technology, thus eliminating any possible break in the material structure. Suitable tools and experimental stamping tests were carried out for the developed process. In the simulations, the material Al5182_iso_Xmm was adopted from the programme database, while the experiments were performed on a laboratory press using AW-5182-H48 sheets with a thickness of 0.200 mm. The purpose of the study was to determine the validity for the proposed method of forming the rivet of the beverage end. [ABSTRACT FROM AUTHOR]

This article investigates the impact of temperature regimes, corresponding to various climatic zones, on the manufacturing process and operation of beverage can ends made of aluminum alloy AA5182. The production process of aluminum beverage can ends involves multiple steps, including melting, rolling, and stamping, where different temperatures can influence both the production process and the properties of the final product. Furthermore, the mechanical behavior of the final product is affected by the aging process of alloy AA5182, which progresses at varying rates depending on the temperature conditions during storage. The objective of this study is to simulate the production process under various climatic conditions using the finite element method (FEM) and experimentally investigate the dependence of the strength of alloy AA5182 can ends on storage time and temperature. The findings of the study reveal that, under temperature conditions corresponding to warmer climates, the punching force can be reduced by approximately 15% compared to production in colder climates. Additionally, the strength of the finished can exhibits a decrease of about 10% during a month of storage in a warm climate, while no significant decrease was observed in colder climates. These results hold practical significance for the beverage production industry, as the manufacturing and operation of beverage cans are localized in diverse climatic zones. [ABSTRACT FROM AUTHOR]

Process parameters have a great impact on product quality in stamping. In the paper, in order to improve the formability of 7A09 aluminum alloy in stamping, the influence of different heat treatment schemes on the properties of 7A09 aluminum alloy is analyzed, and a pretreatment process suitable for 7A09 aluminum alloy stamping is formulated. At the same time, to optimize pretreated 7A09 aluminum alloy stamping parameters, an improved BP neural network and multi-objective particle swarm algorithm are proposed. Relevant tensile and bulging experiments of different shapes are carried out for the pretreated 7A09 aluminum alloy material. The Hockett-Sherby constitutive equation is established. Take a double-C part as an example, the stamping process is simulated by a finite element model, and the stamping process of the double-C part is optimized by means of the improved BP neural network and multi-objective particle swarm algorithm. The results show that the proposed methods can effectively improve the quality of the formed part. [ABSTRACT FROM AUTHOR]

The requirements for green and sustainable manufacturing mean that stamping lubricants must be continuously re-evaluated and re-designed. In this investigation, the tribological performance of four base oils with different chemical structures (paraffinic and naphthenic) and viscosities (2 and 20 cSt), as well as water, was evaluated for the stamping of steel sheets and compared with a non-lubricated contact. Most lubricants reduce the coefficient of friction and maintain a similar wear coefficient for steel sheets as in dry contacts. Low-viscosity (LV) naphthenic oil performs very like both high-viscosity (HV) oils. A surprising exception is the LV paraffinic oil, with several-times-higher friction and wear compared to dry contact. This is due to the excellent wetting-spreading and very low cohesion forces that enable oil to escape from extremely thin-film contacts because the viscosity is so low, leading to lubricant starvation. In contrast, HV oils provide a sufficiently thick lubricating film, while strong cohesive forces help in the film's strength, lessening wear, and reducing friction. In thin-film lubrication with LV oils, such as when stamping, it is thus extremely important that the lubricant's wetting behaviour and viscosity are sufficient to provide enough film in the contact and prevent starvation, thus ensuring lower friction, less wear, and a longer lifetime of the contact. [ABSTRACT FROM AUTHOR]

Copyright of Automobile Technology & Material is the property of Automobile Technology & Material 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.)

As for the peeling of zinc coating appearing during stamping of automotive zinc-coated outer plate, the adhesion, micromorphology, microhardness, and adhesion of zinc coating on three kinds of automotive zinc-coated outer plates from different manufacturers, which differed greatly in peeling degree during stamping. The results showed that the uniformity, microhardness, and friction coefficient of zinc coating had great impact on peeling of it during stamping under the premise that the zinc coating had good adhesion to the substrate. [ABSTRACT FROM AUTHOR]

Lightweight design using high‐strength aluminum alloys has gained importance due to the continuing need for weight reduction and increasing crash safety requirements in the automotive industry. There are various manufacturing processes available for processing high‐strength aluminum alloys. Herein, the production of high‐strength aluminum parts by roll forming and stamping based on the example of an AA7075‐T6 hat profile is compared. Roll forming represents a continuous manufacturing process, while stamping is a discontinuous process. Different process routes (T6, W‐Temper and O) for roll forming as well as for stamping (T6, W‐Temper, O and hot forming) are in focus of the investigation. Fundamental differences of the forming processes and the tempering condition are observed and criteria for the choice of the manufacturing process and process route are presented. The temperature‐supported process routes improve the poor cold formability of AA7075 alloy and thus enhance the process window. Potential is offered for both manufacturing processes by applying tailored properties achieved through targeted quenching. [ABSTRACT FROM AUTHOR]

Non-uniform plastic deformation can easily generate large residual stress in components, resulting in greater springback and warping. Electromagnetic forming (EMF) is a high-speed forming method that can reduce springback of parts. In this study, the warping deformation height after quasi-static sheet metal stamping was found to be 12.2 mm, due to large radial compressive and tensile stresses on both the inside and outside of the sheet fillet. When a radial magnetic force was applied at sheet edge, warping deformation was eliminated. The effects of blank holder gap and discharge voltage on sheet warpage were analyzed both experimentally and through numerical simulation. After coil discharging, radial stress on inner and outer surfaces of the sheet fillet significantly decreased. When the discharge voltage was 4.5 kV and the blank holder gap was 0.5 mm, the warping deformation height was reduced to 0.8 mm and the sheet surface was smooth. Therefore, electromagnetic forming is an efficient, high precision method that eliminates warping of parts. [ABSTRACT FROM AUTHOR]

Stamping is the regarded as the best among manufacturing method of metallic bipolar plates considering its less production time and higher mass production capability. The present research studied the manufacturing of metallic bipolar plates with a parallel serpentine flow field made of a 304 stainless steel plate of 0.1 mm thickness via stamping. The wrinkling is a defect created in stamping these plates. It prevents the correct assembly of the plates and, hence, reduces the efficiency of the assembly. Accordingly, this paper first investigates the effects of using rubber blank holders on wrinkling reduction around the bipolar plates. Then, the influence of the geometric parameters of the rubber blank holder, such as the thickness, width, hardness, and compression percentage, are studied by the response surface methodology. Finally, the most appropriate path for the assembly of the plates in terms of wrinkling is selected. According to the results, a rubber blank holder reduces the wrinkles around the bipolar plate. Among the studied parameters, the compression percentage and hardness of the blank holder contributed most to the reduction in the wrinkling around these plates for better assembly. Furthermore, wrinkling decreases with an increase in the compression percentage, hardness, width, and thickness of the rubber blank holder throughout the selected paths at 3 mm and 6 mm distances. Among the distances selected on the plate edges, a distance of 6 mm from the edges is the best path for assembling the plates. [Display omitted] • The wrinkling of the MBP margin formed by the stamping process is simulated. • The rubber blank holder effect on the wrinkling of the MBP margin is investigated. • The blank holder geometric parameters effect are investigated on the wrinkling. • The appropriate paths are selected for the MBPs welding and assembling process. [ABSTRACT FROM AUTHOR]

The study of gold jewellery can provide important answers about the diffusion of goldsmith technologies and cultural beliefs in Mediterranean World. This work comprises gold ornaments recovered from archaeological contexts dated to the 1st millennium BC in southern Portugal, with special emphasis to two exceptional plaques portraying the Mesopotamian iconography of the “tree of life”, in addition to two rings, the so-called nezems, whose prototype also derived from Orientalising contexts. The set of gold items is completed with a fragment of an ornament such as a pendant or earring. The jewellery was characterised by p-EDXRF, SEM–EDS and optical microscopy to identify the production techniques and composition, while the reflectance transformation imaging technique was used to enhance the study of iconographic motifs. Some manufacturing processes were identified, namely the decoration with stamping on the “tree of life” plaques, a technique similar to strip-drawing on the nezems and the brazing with Au–Ag–(Cu) solder on the small fragment. Overall, the set showed gold alloys with highly variable silver contents (11–39 wt%), but rather constant copper amounts (1.8–2.5 wt%). The composition of individual items helped to establish associations, such as the use of an identical alloy for the pair of plaques. Moreover, the two nezems were made with gold of different purity probably due to economic reasons. Finally, the gold alloy compositions were compared with others from different collections in Iberian Peninsula and Eastern Mediterranean region, providing clues about the gold alloys used by ancient goldsmith workshops. [ABSTRACT FROM AUTHOR]

Abstract The requirements for green and sustainable manufacturing mean that stamping lubricants must be continuously re-evaluated and re-designed. In this investigation, the tribological performance of four base oils with different chemical structures (paraffinic and naphthenic) and viscosities (2 and 20 cSt), as well as water, was evaluated for the stamping of steel sheets and compared with a non-lubricated contact. Most lubricants reduce the coefficient of friction and maintain a similar wear coefficient for steel sheets as in dry contacts. Low-viscosity (LV) naphthenic oil performs very like both high-viscosity (HV) oils. A surprising exception is the LV paraffinic oil, with several-times-higher friction and wear compared to dry contact. This is due to the excellent wetting-spreading and very low cohesion forces that enable oil to escape from extremely thin-film contacts because the viscosity is so low, leading to lubricant starvation. In contrast, HV oils provide a sufficiently thick lubricating film, while strong cohesive forces help in the film’s strength, lessening wear, and reducing friction. In thin-film lubrication with LV oils, such as when stamping, it is thus extremely important that the lubricant’s wetting behaviour and viscosity are sufficient to provide enough film in the contact and prevent starvation, thus ensuring lower friction, less wear, and a longer lifetime of the contact.

Copyright of Automobile Technology & Material is the property of Automobile Technology & Material 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.)

• One of the rare researches about the restoration of defaced characters on wooden surfaces. • Pioneering use of different types of wooden surfaces for forensic marks examination. • Easy, rapid, and cost-effective recovery of scraped characters on wooden surfaces. • Possible on-site method for restoration of the marks on wooden surfaces. The stamp markings on wooden surfaces, which are placed on trees and products including antiques, indicate the status of trees and involve identifying data regarding the products. Such markings are obliterated either to facilitate illegal logging or to conceal product information. Despite the wide literature on the restoration of obliterated characters on metal and polymer surfaces, the recovery of defaced characters on wooden surfaces appears to be understudied. Several reference texts in the forensic marks' examination literature suggest that water, water vapor, and alkaline solutions are useful in restoring the abraded markings on the wood. Since there does not seem to be any experimental study proving such success, this study aimed to fill this gap. This study conducted experimental research by using water, ethanol, ammonia, and chloroform to recover the scraped characters on samples obtained from walnut, beech, spruce, oak, and cedar trees. The cold-stamped characters, which were defaced at varying depths, were restored using vapor and liquid phases of four solvents. While the vapor phases of water, ethanol, and ammonia yielded good outcomes on all types of wooden surfaces, the liquid phases did not seem to be useful in the revisualization process. The response of the vapors, which varied between 62 and 220 s, depended on the type of wood. The restoration technique developed in this research offers the possibility of on-site usage, easy application, utilization of low-cost solvents, rapid recovery, and effectiveness on various wooden surfaces. Overall, the restoration methodology used in this research appears to be fruitful in retrieving identifying information on wooden samples. [ABSTRACT FROM AUTHOR]

Copyright of Automobile Technology & Material is the property of Automobile Technology & Material 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.)

Understanding the thermo-stamping shear characteristics is not only essential to improve the forming quality of the glass fiber reinforced polypropylene (GFRPP) products but also critical to ensure their structure design reliability. Most previous studies primarily focused on the fiber yarn shear characteristics in the outer surface of the composite product, and omitted the shear angle variations of the inner layers, which might increase the failure risk to the product design. In this study, the U-shaped GFRPP rail was manufactured by the thermo-stamping process and scanned layer-by-layer through the X-ray micro-CT technology. Based on the scanning results, the differences in the shear angle variations of different layers at the same position, and within the same layer but different zones were analyzed, respectively. Finally, the effect of the temperature variation on the shear angle variation was analyzed by the simulation method. Results indicate that the interlaminar shear forces and slippages lead to the differences in shear angle variations among different layers. Intralaminar fiber yarn slippages and bending deformations caused the differences in shear angle variations within the same layer. The heat loss of the stamping molds resulted in a lower stamping temperature and further led to shear angle variation reduction. [ABSTRACT FROM AUTHOR]

Residual stresses induced during forming process are one of the key parameters that influence springback behavior and mechanical properties of formed sheet metal products. However, there is a limited understanding of the residual stresses present in parts formed by single-point incremental sheet forming (ISF) process. In the current research, an in-depth understanding of the residual stress distribution is developed through experimental characterizations and numerical simulation for ISF, and only numerical analysis was performed for stamping process. AA2024 square-truncated-pyramidal parts with three distinct geometrical characteristics are investigated to elucidate their effects on part qualities with respect to the competing forming processes, i.e., ISF and stamping. Residual stresses, part wall thinning and part deviation generated in ISF process are compared with its counterpart stamping process. It was revealed that the residual stresses induced by ISF process are mostly tensile on the inner surface and compressive on the outer surface of the sheet in all formed geometries. However, a transition of residual stress state from tensile to compressive and vice versa is observed for the stamping process. The magnitude of residual stresses generated in ISF formed parts is relatively high as compared to those from the stamping process due to localized hardening. The fundamental understanding of residual stresses developed in this study could be useful to improve dimensional accuracy and mechanical performance of sheet metal products in industrial applications. [ABSTRACT FROM AUTHOR]

This paper presents an overview of the stamping process in the manufacturing of electrical motor laminations, a critical component in electric motor construction. The stamping process plays a vital role in achieving precise and efficient laminations, thereby improving motor performance and energy efficiency. The manufacturing process for electric motor laminations were studied, focusing on the crucial role of material selection for the active parts of the dies. The study elucidates the significance of understanding the manufacturing process and selecting appropriate materials to ensure optimal performance and functionality of electric motor laminations. [ABSTRACT FROM AUTHOR]

Drawing operations are commonly used to shape metallic thin-walled products for variety of industries – automotive, aerospace, household appliances etc. The basic indicator characterizing cold drawing process is possibility to decrease weight of a product, while at the same time increasing its stiffness in comparison to other conventional manufacturing technologies such as casting, forging or machining. In this research authors presented results of a numerical study on the influence of parameters such as blankholder pressure, forming force, tooling shape and part shape design on the success in manufacturing a part of complicated shape designed as an element of a phase change material heat accumulator. The subject of wrinkling (first and second degree of buckling) was discussed, and the research presented the manufacturing process design which allowed manufacturing discussed drawpiece without defects and within dimensional tolerances. The paper analyzes the phenomenon of drawpiece folding during the forming process for various groups of materials. Experimental research was carried out on a prototype tool for stainless steel (X5CrNi18-10), aluminum alloy (AW-5754) and copper alloy (CW024A).

The production of parts by pressing and subsequent welding is commonly used in the automotive industry. The disadvantage of this method of production is that inaccuracies arising during pressing significantly affect the final dimension of the part. However, this can be corrected by the choice of the technological parameters of the following operation—welding. Suitably designed parameters make it possible to partially eliminate inaccuracies arising during pressing and thus increase the overall applicability of this technology. The paper is focused on the upper arm geometry of a car produced in this manner. There have been two neural networks proposed in which the optimal welding parameters are determined based on the stamped dimensions and the desired final dimensions. The Levenberg–Marquardt back-propagation algorithm and the Bayesian regularised back-propagation algorithm were used as the learning algorithm for ANNs in multi-layer feed-forward networks. The outputs obtained from the neural networks were compared with a linear prediction model based on a on the design of experiment methodology. The mean absolute percentage error of the linear regression model on the entire dataset was 3 × 10−3%. A neural network with Levenberg–Marquardt back-propagation learning algorithm had a mean absolute percentage error of 4 × 10−3. Similarly, a neural network with a Bayesian regularised back-propagation learning algorithm had a mean absolute percentage error of 3 × 10−3%. [ABSTRACT FROM AUTHOR]

The present study is conducted on forming of the metallic bipolar plates made of 316 stainless steel sheet with a parallel serpentine flow field. The plastic deformation of straight and curved microchannels, forming limit criteria, and deformation mechanics during the process are investigated partially to present a reliable model for estimating fracture initiation. For this purpose, experimental stamping tests are employed to fabricate metallic bipolar plates and the process is simulated by finite element software. The validity of simulation results is examined by comparing thickness distribution and force-displacement curves reflecting 4.76% and 3.85% error rates, respectively. According to experimental observations, fracture starts at a channel depth of 0.610 mm. Hence, for determining the forming limit and predicting the fracture during the process, the deformation mechanic is studied at different points of the microchannels. Results of stress states analysis indicate that the stress state of plane-strain tension up to biaxial tension governs this process. Despite the presence of different loading paths during the process, the critical element in each channel is deformed under plane-strain tension. Therefore, a fracture model is developed based on thinning percentage and equivalent strain to predict the instability of metallic bipolar plates. According to the results, both the equivalent strain and thinning percentage criteria with critical limits of 0.56 and 33.45%, respectively, are considered as an allowable range of plastic deformation during the conventional stamping process of bipolar plates. Results indicate that maximum thinning in all directions is lower than 33.45% by using the modified stamping process. [Display omitted] • MBPP with higher depth/width is studied for raising power density and efficiency. • Detailed study of deformation mechanics of metallic bipolar plates is conducted. • An appropriate forming and fracture limit criteria is proposed. • Process is modified regarding thinning and equivalent plastic strain analysis. [ABSTRACT FROM AUTHOR]

The production of wire cores by notch rolling and cyclic bending promises an ecologically and economically efficient manufacturing option for steel fibers. The paper at hand evaluates the influence of wire strips on cyclic bending by applying rolled wire strips of DP600 sheet metal (t0 = 0.8 mm) and a new cyclic bending testing tool. Analysis of material separation with varying parameters, rolling gap d and bending angle β, proves the interdependency of both process step, but indicates reduced adjustability of the notch rolling process. To enable better adjustability of the wire strip's characteristics and analysis of their effects, wire strip production in the laboratory by notch stamping instead of rolling is aspired. The prior interaction analysis states the web height b, the notch angle α, and the hardening distribution as relevant wire strip's characteristics to be replicated. Based on experimental analysis, an equivalent of notch rolling by notch stamping is deduced by considering the web height b identical for stamping and rolling, by adjusting the tool's notch angle αt based on an equation considering geometric evaluations of α, and by taking advantage of the asymmetric hardening distribution of the outer notch which is comparable to rolled wire strip. [ABSTRACT FROM AUTHOR]

The decrease in mass of ball plugs when manufactured by stamping is studied experimentally. A new design is proposed: two tubular workpieces with an internal junction. A manufacturing technology is discussed, and methods of surface hardening are considered. [ABSTRACT FROM AUTHOR]