Hasil untuk "Production capacity. Manufacturing capacity"

Petr M. Pivkin, Mikhail P. Kozochkin, Artem A. Ershov et al.

In this work, a new approach to high-speed multi-coordinate milling was developed. The new approach is based on a new model of trochoidal machining; this is, in turn, based on the theoretical thickness of a chip and its ratio to the cutting edge’s radius, allowing us to establish the vibroacoustic indicators of cutting efficiency. The new model can be used for the real-time assessment of prevailing cutting mechanisms and chip formation. A set of new indicators and parameters for trochoidal high-speed milling (HSM), which can be used to calculate tool paths during technological preparation of slotting, was determined and verified. The size effect in the multi-coordinate HSM of slots on cast iron was identified based on the dependency of vibroacoustic signals on the cutting tooth’s geometry, HSM’a operational machining modes, theoretical chip thicknesses, the sizes of the cut chips, and the quality/roughness of the surface being machined. Based on the analysis of vibroacoustic signals, a set of the most important indicators for monitoring HSM and determining cutting and crack-formation mechanisms during chip deformation was derived. Based on the new model, recommendations for monitoring HSM and for assigning the tool path relative to the workpiece during production preparation were developed and validated.

Erbo Liu, Qingchun Li, Xufeng Song et al.

To explore the effects of ultrasonic burnishing strengthening technology on the surface morphology and mechanical properties of 40Cr rods for hydraulic applications, a conical transition composite amplitude transformer was designed using ANSYS (Workbench 2024 R1) finite element analysis software, with a frequency of 18,158 Hz, an amplification factor (<i>M_p</i>) of 2.0, and a maximum stress of 122.9 MPa. The ultrasonic burnishing strengthening process was numerically simulated via ABAQUS finite element analysis software. Based on the single-factor analysis method, the influence of spindle speed, ultrasonic amplitude, and burnishing passes on the maximum residual compressive stress of the hydraulic rod was investigated, and key parameters such as surface roughness and microhardness of the rod before and after ultrasonic burnishing strengthening were comparatively analyzed. The results show that ultrasonic burnishing strengthening technology can reduce the surface roughness of the hydraulic rod, enhance its microhardness, and increase the depth of the plastic deformation layer. Ultrasonic amplitude and burnishing passes exert a significant influence on the maximum residual compressive stress on the rod surface, while the effect of spindle speed is relatively minor. When the ultrasonic amplitude is 10 μm, the spindle speed is 120 r/min, and the burnishing passes are 3, the surface residual compressive stress of the hydraulic rod reaches the maximum experimental value of 433.39 MPa. This study reveals the influence law of process parameters on the surface properties of rods for hydraulic applications, verifies the feasibility of the ultrasonic burnishing system, and provides a technical reference for improving the performance of rods for hydraulic applications.

Artis Kromanis, Arturs Vevers, Gatis Muiznieks et al.

Additive manufacturing (AM) is finding increasing application in engineering, especially in manufacturing. As a result, new designs and machines not previously possible due to the restrictions of conventional manufacturing methods may be made. Nevertheless, the same AM parts require post-processing using conventional machining methods such as turning which is the subject of this study. This study provides a comparative analysis of the technological assurance of Ti-6Al-4V parts made via AM using selective laser melting (SLM) and conventional manufacturing methods. The effects of machining parameters such as cutting speed, depth of cut, and feed on the surface roughness of machined Ti-6Al-4V parts are studied. The study concluded that at low feed (0.12 mm/rev.) and low and average depth of cut (0.3 mm and 0.5 mm), the best surface roughness was obtained on the 3D printed samples rather than on the samples obtained using the conventional manufacturing method. In addition, an alternative surface roughness measurement scheme is proposed, which not only allows for measuring the surface roughness, including multiple aspects, but also for identifying possible surface defects in AM parts.

Nismath Valiyakath Vadakkan Habeeb, Kevin Chou

Laser powder-bed fusion (L-PBF) additive manufacturing has been widely explored for fabricating intricate metallic parts such as lattice structures with thin struts. However, L-PBF-fabricated small parts (e.g., thin struts) exhibit different morphological and mechanical characteristics compared to bulk-sized parts due to distinct scan lengths, affecting the melt pool behavior between transient and quasi-steady states. This study investigates the keyhole porosity in Ti6Al4V thin struts fabricated by L-PBF, incorporating a range of strut sizes, along with various levels of linear energy densities. Micro-scaled computed tomography and image analysis were employed for porosity measurements and evaluations. Generally, keyhole porosity lessens with decreasing energy density, though with varying patterns across a higher energy density range. Keyhole porosity in struts predictably becomes severe at high laser powers and/or low scan speeds. However, a major finding reveals that the porosity is reduced with decreasing strut size (if less than 1.25 mm diameter), plausibly because the keyhole formed has not reached a stable state to produce pores in a permanent way. This implies that a higher linear energy density, greater than commonly formulated in making bulk components, could be utilized in making small-scale features to ensure not only full melting but also minimum keyhole porosity.

Peng Hu, Kun Liu, Lei Pan et al.

The effects of minor additions of the transition elements Zr, Ti, and V on the microstructure, mechanical properties, and out-of-phase thermomechanical fatigue behavior of 224 Al-Cu alloys were investigated. The results revealed that the introduction of the transition elements led to a refined grain size and a finer and much denser distribution of θ″/θ′ precipitates compared to that of the base alloy, which enhanced the tensile strength but reduced the elongation at both room temperature and 300 °C. Constitutive analyses based on theoretical strength calculations indicated that precipitation strengthening was the primary mechanism contributing to the strength of both tested alloys at room temperature and 300 °C. The out-of-phase thermomechanical fatigue test results showed that the addition of transition elements caused a slight decrease in the fatigue lifetime, which was mainly attributed to the reduced ductility and higher peak tensile stress at low temperatures. During the fatigue process, the transition element-added alloy exhibited a lower coarsening ratio, indicating higher thermal stability, which mitigated the negative impact of the reduced ductility on the fatigue performance to some extent. Considering their various properties, the addition of Zr, Ti, and V is recommended to improve the overall performance of Al-Cu 224 cast alloys.

Salma Mozaffari, Rahasadat Kamravafar, Yunyan Li et al.

Robotic clay formwork three-dimensional printing combined with incremental concrete casting controls concrete's hydrostatic pressure and enables the production of building-scale structures. Clay formwork is self-demolding and less carbon intensive than concrete and polymer, often used in formwork additive manufacturing. This research investigates the recycling and reuse of clay to re-print formworks and tailors a self-compacting concrete formula with 60% reduced cement content and 90% larger maximum aggregate size. The study then explores integrating steel fibers and longitudinal rebars into the fabrication process to provide shear and bending reinforcement. When comparing the load-bearing behaviour of the fabricated beams against those cast traditionally using wooden formworks, the fabricated beams demonstrated 20% lower load-bearing capacity, with peak load mid-span deflections staying in a similar range. While more investigation is required to address formwork deformations using mixed steel fibers and recycled clay, this research paves the way for more sustainable concrete construction practices.

María del Rosario Demuner Flores

Abstract Purpose: This research analyzed the influence of the acquisition, assimilation, and exploitation of knowledge on the organizational response capacity, given the moderation of the technological level in Mexican manufacturing companies. Originality/value: A conceptual contribution of response capacity as an understanding of organizational agility is fundamentally necessary for organizations facing changing conditions to use new knowledge to achieve the objectives of the organization, employees, and shareholders. An empirical contribution from the absorptive capacity to make companies respond with innovations to environmental changes and help them develop their absorptive capacity so the opportunities and restrictions in their technological level within a company can be seen. Design/methodology/approach: The quantitative study was conducted through a survey with a sample of 102 manufacturing companies that promoted some innovation activity in the State of Mexico, Mexico. The data were analyzed using a hierarchical regression model. Findings: The results showed that the technological level only moderated the relationship between the assimilation of knowledge and organizational response capacity. Also, this study contributed empirically by showing that companies have the same opportunity to improve their absorptive capacity and respond to changes in the environment regardless of their technological level.

Thomas Borgert, Maximilian Henke, Werner Homberg

The demands on joining technology are constantly increasing due to the consistent lightweight construction and the associated increasing material mix. To meet these requirements, the adaptability of the joining processes must be improved to be able to process different material combinations and to react to challenges caused by deviations in the process chain. One example of a highly adaptable process due to the two-step process sequence is thermomechanical joining with Friction Spun Joint Connectors (FSJCs) that can be individually adapted to the joint. In this paper, the potentials of the adaption in the two-stage joining process with aluminium auxiliary joining elements are investigated. To this end, it is first investigated whether a thermomechanical forming process can be used to achieve a uniform and controlled manufacturing regarding the process variable of the temperature as well as the geometry of the FSJC. Based on the successful proof of the high and good repeatability in the FSJC manufacturing, possibilities, and potentials for the targeted influencing of the process and FSJC geometry are shown, based on an extensive variation of the process input variables (delivery condition and thus mechanical properties of the raw parts as well as the process parameters of rotational speed and feed rate). Here it can be shown that above all, the feed rate of the final forming process has the strongest influence on the process and thus also offers the strongest possibilities for influencing it.

Renata Lapenda Lins, Carolina Rodriguez Romeira, Filipe de França Monteiro Vasconcelos et al.

O advento da pandemia da COVID-19 trouxe desafios que vão além dos problemas de saúde. O centro de formação de servidores do estado de Pernambuco (CEFOSPE), uma das escolas corporativas do estado, precisou se reinventar para continuar exercendo sua missão organizacional diante dessa nova situação. Dessa forma, o objetivo desta pesquisa é entender como ocorreu o processo de aprendizagem organizacional na escola de governo CEFOSPE durante a pandemia da COVID-19, analisando quais foram as ferramentas aplicadas. A metodologia adotada foi um estudo de caso do CEFOSPE, realizado por meio de entrevista não estruturada. Os resultados apontam a formação à distância, por meio de recursos da tecnologia da informação, como alternativa eficaz para a indisponibilidade de encontros presenciais, bem como a integração de locais distintos em um ambiente comum. Logo, o desafio do gerenciamento foi ampliado, mas foi comprovado por meio dos relatórios posteriores que os resultados almejados foram alcançados.

Emmanuil Beygelzimer, Yan Beygelzimer

To verify the mathematical model of the water-jet cooling of steel plates developed by the authors, previously performed experimental studies of the temperature of the test plates in a roller-quenching machine (RQM) were used. The calculated temperature change in the metal as it moved in the RQM was compared with the readings of thermocouples installed at the center of the test plate and near its surface. The basis of the model is the dependence of the temperatures of the film, transition and nucleate boiling regimes on the thickness of the oxide scale layer on the cooled surface. It was found that the model correctly accounts for the oxide scale on the sheet surface, the flow rates and combinations of the RQM banks used, the water temperature, and other factors. For all tests, the calculated metal temperature corresponded well with the measured one. In the experiments with interrupted cooling, the calculated temperature plots repeated the characteristic changes in the experimental curves. The main uncertainty in the modeling of cooling over a wide temperature range can be attributed to the random nature of changes in the oxide scale thickness during water cooling. In this regard, the estimated thickness of the oxide scale layer should be considered the main parameter for adapting the sheet temperature-control process. The data obtained confirm the possibility of effective application of the model in the ACS of industrial TMCP (Thermo-Mechanical Controlled Process) systems.

Kai S. Johann, Adrian Reißing, Christian Bonten

The shape and size of processed materials play a crucial role in the solid conveying characteristics of single-screw extruders. Thus, the increasing amount of plastic regrind leads to new challenges in screw extrusion. This work investigates the conveying behavior of three distinctly different material shapes in an axially as well as a helically grooved solid conveying zone. A uniform virgin polypropylene (PP) granule, an irregularly plate-shaped PP regrind and a powdery polyethylene (PE) are processed at screw speeds up to 1350 rpm. Thereby, frictionally engaged conveying in the grooves is visualized for the utilized powder. Similarly, the virgin granule is subject to forced conveying by interlocking in the grooves. The experimentally determined throughput is furthermore compared to analytical calculations which assume a so-called nut–screw conveying. It is found that these calculations perfectly predict the throughput when processing the virgin granule and the powder in a helically grooved barrel. In contrast, the analytical calculation significantly underestimates the throughput for the regrind. This underestimation is expected to be mainly caused by its plate shape and a difference in bulk density. The actual bulk density in the extruder is probably significantly higher due to both orientation and compaction effects compared to the measured bulk density that is used for the analytical calculation. Additionally, the regrind exhibits a fluctuating throughput due to the non-constant bulk density, which results from an irregular regrind shape and a broad size distribution.

Hadi Mokhtari, Aliakbar Hasani, Ali Fallahi

One of the basic assumptions of classical production-inventory models is that all products are of perfect quality. However, in real manufacturing situations, the production of defective items is inevitable, and a fraction of the items produced may be naturally imperfect. In fact, items may be damaged due to production and/or transportation conditions in the manufacturing process. On the other hand, some reworkable items exist among imperfect items that can be made perfect by additional processing. In addition, the classical production-inventory models assume that there is only one product in the system and that there is an unlimited amount of resources. However, in many practical situations, several products are produced and there are some constraints related to various factors such as machine capacity, storage space, available budget, number of allowable setups, etc. Therefore, we propose new constrained production-inventory models for multiple products where the manufacturing process is defective and produces a fraction of imperfect items. A percentage of defective items can be reworked, and these products go through the rework process to become perfect and return to the consumption cycle. The goal is to determine economic production quantities to minimize the total cost of the system. The analytical solutions are each derived separately by Lagrangian relaxation method, and a numerical example is presented to illustrate and discuss the procedure. A sensitivity analysis is performed to investigate how the variation in the inputs of the models affects the total cost of the inventory system. Finally, some research directions for future works are discussed.

Laura Nisa Tilqadri, Ikhwan Nofitra, Isnanda et al.

Dengan pesatnya perkembangan teknologi saat ini refrigerator freezer (lemari es) sebagai salah satu alat untuk membantu kita dalam menyimpan makanan agar tahan lama. Refrigerasi adalah suatu proses penyerapan panas dari suatu zat atau produk sehingga temperaturnya berada di bawah temperatur lingkungan. Refrigeran adalah zat yang digunakan sebagai fluida kerja dalam proses penyerapan panas. Zat inilah yang bersikulasi dalam mesin refrigrasi, yang menyerap panas dari benda atau udara yang didinginkan, kemudian membuangnya ke udara sekeliling di luar benda atau ruangan yang didinginkan. Dalam penggunaannya refrigenerator sering mengalami kerusakan, sehingga perlu dilakukan analisa kerusakan tersebut. Hasil analisa menunjukan terjadi kerusakan pada refrigerator freezer AR 763, yaitu pada system pendingin terjadi penyumbatan disebabkan refrigerator tidak beroperasi (rusak) dan menyebabkan refrigerant di dalam system membeku yang menyebabkan system tidak bekerja. Selanjutnya filter harus diganti karena filter banyak menyimpan kotoran dan komponen kelistrikannya ada yang rusak seperti thermo fuse dan timer disebabkan batas umur pakai dari komponen.

Loucas Papadakis, Stelios Avraam, Demetris Photiou et al.

Injection moulding is one the most familiar processes for manufacturing of plastic parts by injecting molten thermoplastic polymers into a metallic mould. The cycle time of this process consists of the phases of injection, packing, cooling, and ejection of the final product. Shortening of cycle time is a key consideration to increase productivity. Therefore, in this manuscript the adoption of additively manufactured mould inserts with conformal cooling channels by means of selective laser melting (SLM) with the aim to reduce process cycles is presented. The design and manufacture of a mould insert with conformal cooling channels for producing pressure fitting thermoplastic parts is described. Numerical analysis of the injection process and simulation of shape distortions after SLM were conducted providing useful results for the design and manufacture of the mould insert. The results of the numerical analyses are compared with experimental 3D geometrical data of the additively manufactured mould insert. Temperature measurements during the real injection moulding process demonstrating promising findings. The adoption of the introduced method for the series production of injection moulded thermoplastics proves a shortening of cycle times of up to 32% and a final product shape quality improvement of up to 77% when using mould inserts with conformal cooling channels over the conventional mould inserts.

Sidnei Alves de Araújo, Stanley Jefferson Araujo Lima

O Algoritmo Genético (AG) é um método otimização inspirado na teoria de evolução das espécies que tem sido largamente empregado na solução de problemas classificados como NP-Hard (Non-deterministic Polynomial Time), entre os quais estão o Problema de Sequenciamento da Produção (Job Shop Scheduling Problem - JSP) e o Problema de Roteamento de Veículos (PRV). Entretanto, encontrar soluções para qualquer problema de otimização empregando o AG pressupõe a adoção de um esquema de codificação das soluções e a configuração dos operadores genéticos. Diferentes esquemas e configurações podem produzir comportamentos diferentes na população do AG, mas observar tais comportamentos não é uma tarefa fácil e, por este motivo, vem atraindo a atenção de muitos pesquisadores ao longo dos últimos anos. Neste trabalho propõe-se uma ferramenta computacional que permite analisar como o esquema de codificação e os operadores genéticos afetam o comportamento da população do AG no espaço de soluções, por meio de visualização dos indivíduos projetados para um espaço bidimensional e de medidas de desempenho implementadas na ferramenta. Nos experimentos conduzidos analisou-se o comportamento da população do AG em função de três esquemas de codificação de soluções para o Problema de Roteamento de Veículos Capacitados (PRVC). Como resultados, além de uma discussão acerca da análise do comportamento do AG, pode-se constatar que as medidas de desempenho fornecidas pela ferramenta computacional desenvolvida podem auxiliar na proposição e/ou escolha de heurísticas que visem apoiar o processo de refinamento das soluções geradas pelo AG, melhorando o seu desempenho.

Arup Dey, Nita Yodo

Fused deposition modeling (FDM) is an additive manufacturing (AM) process that is often used to fabricate geometrically complex shaped prototypes and parts. It is gaining popularity as it reduces cycle time for product development without the need for expensive tools. However, the commercialization of FDM technology in various industrial applications is currently limited due to several shortcomings, such as insufficient mechanical properties, poor surface quality, and low dimensional accuracy. The qualities of FDM-produced products are affected by various process parameters, for example, layer thickness, build orientation, raster width, or print speed. The setting of process parameters and their range depends on the section of FDM machines. Filament materials, nozzle dimensions, and the type of machine determine the range of various parameters. The optimum setting of parameters is deemed to improve the qualities of three-dimensional (3D) printed parts and may reduce post-production work. This paper intensively reviews state-of-the-art literature on the influence of parameters on part qualities and the existing work on process parameter optimization. Additionally, the shortcomings of existing works are identified, challenges and opportunities to work in this field are evaluated, and directions for future research in this field are suggested.

Chandra Kurniawan, Ahmad Mubin, Heri Mujayin Kholik

Waste has a negative impact on the environment. Hospital medical waste is a hazardous waste for the environment. Environmental performance measurement systems are used to measure the performance of hospitals in handling waste. The measurement of its environmental performance in the hospital is expected to provide improved sewage treatment systems. AHP (Analytical Hierarchy Process) and OMAX (Objactive Matrix) methods are used to design environmental performance systems at hospitals. The data needed is medical and non medical treatment. Data were collected using pairwise comparison questionnaires. The questionnaire data shows the importance of key environmental performance indicators (KEPI). Results of questionnaires processed using Expert Choice. Expert Choice's output produces weight and consistency ratio. Weighted KEPI results are processed by OMAX method. The OMAX method is used to determine the value of environmental performance. There 41 KEPI aspects of the environment. Based on the results of the environmental performance assessment, liquid waste has the highest weight of 0.229.

T.L. Silva, V.H. Meinerz, J.M.M. Vidart et al.

Biosorbents have been used as a potential alternative to the conventional technologies for removal of toxic metals from water and wastewater. The use of waste material as adsorbent offers significant advantages like low-cost, availability, efficiency, biodegradability, etc. In this study, particles produced from a blend between sericin, alginate and Poly(ethylene glycol) diglycidyl ether (PEG) were used to remove toxic and precious metals from aqueous solutions. Precious metals are found in wastewaters of various industrial processes including metal, ore processing, electronic manufacturing and mining; and the recovery of these metals is profitable to those industrial processes. Sericin is a protein present in cocoon of silkworm (Bombyx mori) usually discharged in the effluent of silk production. Alginate is a natural polysaccharide extracted from abundant sources of brown algae (brown seaweed) properties to this material. The addiction of PEG into a blend of sericin-alginate induces chemical modification that can develop better properties to this material. The objective of this work is to evaluate the metallic affinity and adsorption capacity of particles produced by sericin-alginate blend and sericin-alginate- PEG blend. The blends were dripped in aqueous and alcoholic (ethanol) solutions of CaCl2 and Ca(NO3)2, and then the particles were dried at 100 °C. The simulation of speciation diagrams as functions of pH was performed using Hydra/Medusa software in order to establish the pH to be used in the experiments. The removal of chromium, cadmium, nickel, copper, lead, silver, palladium, platinum and gold ions from aqueous solution by sericin-alginate particles was evaluated through adsorption affinity testes. The results indicated that the presence of PEG improve the adsorption capacity of the biosorbents. For the noble metals the greatest values of reduction and adsorption capacity were obtained to gold (98 – 99 %) and palladium (87 – 89 %), and for the toxic metals it was obtained higher values of reductions to lead (66 – 83 %), cadmium (62 – 79 %), chromium (69 – 74 %) and copper (65 – 74 %).