Production Process Of Components Research Articles

The Use of Infrared Thermography for Maintenance Purposes in the Production Process of Components for Automotive Alternators

This work reports an investigation concerning the employment of infrared thermography in the production environment of claw pole alternators, aimed for early detection of anomalies during the stamping stage at the press. The investigated process consists of a number of steps, starting from a raw workpiece in the form of a star, sheared from a low carbon steel plate, is brought to its final shape through bending and coining operations, using a progressive die. The process is characterized by a high production rate since the component is destined for the automobile market, therefore the controlling of both the die conditions as well as the mechanical press is crucial in order to reduce unexpected stops of the process.After having analysed each production stage, a series of experimental tests have been carried out and a series of thermal snapshots were taken during the normal production run and analyzed in order to detect any process signature which were capable of giving information concerning the process conditions. An FEM model has also been developed for each step of the process in order to characterize the material flow and, in addition, the thermal field related to the transformation of the mechanical energy into heat, due to plastic deformation of the material and frictional effects. Correlations between the geometry resulting from material flow and thermal maps detected in the production environment have allowed to address of the maintenance activity in order to eliminate defects which can affect significantly the functionality of the product as well as the die life.

On the fatigue properties of metals manufactured by selective laser melting – The role of ductility

Abstract

Design of a multifunctional cell for aerospace CFRP production

Due to the rising demand in efficiency and sustainability in commercial aviation, aircraft manufacturers increase the usage of high performance, lightweight materials like carbon fiber reinforced plastics (CFRP). These materials pose new challenges to manufacturing processes concerning cost-effectiveness and quality requirements. To meet these challenges the Institute of Structures and Design within the German Aerospace Center (DLR) designed a flexible robotic manufacturing cell at the Center for Lightweight Production Technology (ZLP) in Augsburg. The multifunctional cell (MFZ) can integrate processes for production and inspection on an industrial scale. Due to large workpieces like fuselage components or wing skins and low production quantities, workshop space, and investment cost are major concerns for effective CFRP production. The large size of the cell (30 × 15 × 7 m) demands a highly reconfigurable space. The platform is composed of five ceiling mounted robots on a gantry like machine frame and may be divided in smaller independent cells. The multifunctional cell will improve the understanding of requirements of future production processes for lightweight components by providing a highly flexible platform on an industrial scale.

Selective Solar Absorber Coatings on Receiver Tubes for CSP – Energy-efficient Production Process by Sol-gel dip-coating and Subsequent Induction Heating

The energy efficiency of production processes for components of solar energy systems is an important issue. Other factors, which are important for the production of black selective solar coatings include production speed, cycle time and homogeneity of the coating, as well as the minimization of the quantity of the needed chemical precursors. In this paper a new energy-efficient low-cost production process is presented for production of optically selective coatings for solar thermal absorbers.The used method to produce such coatings is sol-gel dip-coating for which all the solutions have been synthetized at the Solar Energy and Building Physics Laboratory of EPFL. The used precursors are tetraethyl orthosilicate, manganese acetate tetrahydrate, copper chloride dihydrate and cobalt chloride hexahydrate. Solutions were obtained by dissolving these precursors in a solution based on a mixture of absolute ethanol, nitric acid and demineralized water.The layers deposited on sheetlike substrates were annealed in a benchtop furnace. For 2 meter long austenitic stainless steel tubes, a novel, fast and energy-efficient process based on induction heating was developed for the thermal annealing. An induction coil passes along the tube. An alternating current flowing in the coil induces a current in the tube. By resistive heating, the temperature of both the metallic tube wall and the deposited film increases. The homogeneity of the temperature distribution of the tube after a single passage of the coil was monitored by infrared imaging.The optical and morphological properties of the Cu-Co-Mn-Si-O based triple layer have been characterized by spectrophotometry, transmission electron microscopy (TEM), time-of-flight secondary ion mass spectroscopy (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS). After optimization of the multilayer design, a solar absorptance of 0.95 and a thermal emissivity of 0.12 at 100°C have been achieved. The intermediate Cu-Co-Mn-Si-O layer was analyzed by transmission electron microscopy. The likewise obtained images show an agglomeration of crystalline grains with 5-20nm in diameter. Therefore, we can consider that the Cu-Co-Mn-Si-O phase is nanocrystalline.In order to roughly estimate the corrosion resistance of the coating in an acidic environment, a simple corrosion test in harsh conditions confirmed the durability of the novel sol-gel coating. Moreover, the excellent stability at elevated temperatures in ambient air makes the coating an interesting candidate for solar applications involving concentrated solar radiation, such as the generation of solar electricity (concentrated solar power), industrial process heating and solar cooling. For that reason, prototype coatings consisting of stacks of three individual layers were deposited on 2 meter long stainless steel tubes.

Active scheduling for hybrid flowshop with family setup time and inconsistent family formation

This research is motivated by a real-life hybrid flowshop scheduling problem where jobs are organized in families according to their machine settings and tools. This type of problem is common in the production process of standard metal components. The problem is complicated by the requirement of family setup time when a machine changes from processing one job family to another and the formation of job families varies in different stages. This problem has been previously solved with a non-delay scheduling heuristic in which no machine is kept idle. This research illustrates that inserting intentional idle time into a non-delay schedule can further reduce the total setup time as well as makespan. With the inserted idle time, the non-delay schedules are extended to active schedules. This paper presents a mechanism to determine the locations and lengths of intentional idle times in the efficient active schedules. Four active scheduling approaches are developed by integrating two types of waiting factor operators into two non-delay approaches. Computational experiments have been conducted to compare the proposed active scheduling approaches in terms of effectiveness and efficiency. The results have shown that the proposed active scheduling approaches are superior to non-delay scheduling. The analysis of variance has been applied on the factors related to scheduling environment, problem size and scheduling approach. The analysis has identified factors that are most influential on the scheduling result.

Underlying mechanisms involved in the decrease of milk secretion during Escherichia coli endotoxin induced mastitis in lactating mice

Mastitis, the inflammation of mammary glands resulting from bacterial infection, disrupts milk production in lactating mammary glands. In this study, we injected lipopolysaccharide (LPS), one of the endotoxins from Escherichia coli into mouse mammary glands to disrupt milk production, and we investigated the influence of LPS on nutrient uptake, synthesis, and secretion processes for milk component production in alveolar epithelial cells (AEC). The expression of genes relevant to the three-staged milk component production process (nutrient uptake, synthesis, and secretion of milk components) were down-regulated within 12 h after LPS injection in AEC. The internalization of glucose transporter 1 (GLUT-1) from the basolateral membrane to the cytoplasm occurred in accordance with the down-regulation of gene expression 3 h after LPS injection. The abnormal localization of adipophilin and beta-casein was also observed in the LPS-injected mammary glands. SLC7A1, an amino acid transporter, was up-regulated 3 and 6 h after LPS injection. Furthermore, the inactivation of signal transducer and activator of transcription 5 (STAT5) and the activation of STAT3 and nuclear factor-kappa B (NFkappaB) occurred 3 h after LPS injection. These results indicate that the nutrient uptake, synthesis, and secretion of milk components in AEC are rapidly shut down in the lactating mammary glands after LPS injection.

An evaluation of statistical process control techniques applied to blood component quality monitoring with particular reference to CUSUM

Statistical process control (SPC) is used to monitor the performance of blood component collection and production processes in the UK and elsewhere. The sensitivity of the applied technique(s) needs to be matched to the clinical importance of the parameter being monitored such that significant deviations in the process mean and/or variability of critical parameters (e.g. the leucocyte content of leucodepleted components) are detected and investigated immediately. This study assessed the sensitivity and specificity of a range of techniques for variable and attribute (proportion non-conforming) data. Comparison was based on a range of simulated and 'live' blood component quality monitoring data including X/R, cumulative sum (CUSUM) procedures, the scan statistic and np charts. X/R and CUSUM could detect shifts of two standard deviations in the process mean within 5 days. Current leucocyte count data (substantially skewed even after log transformation) was found to be better suited to attribute analysis. CUSUM alone was able to detect shifts on the same day when based on 20 or more samples and achieved acceptable specificity. CUSUM procedures for proportion non-conforming can usefully augment existing X/R techniques for leucodepletion monitoring, provide valid control limits and the required sensitivity. The scan statistic and 'np' charts offered no obvious advantages.

Platelet lysate from whole blood-derived pooled platelet concentrates and apheresis-derived platelet concentrates for the isolation and expansion of human bone marrow mesenchymal stromal cells: production process, content and identification of active components

Background aimsThe clinical use of human mesenchymal stromal cells (MSC) requires ex vivo expansion in media containing supplements such as fetal bovine serum or, alternatively, human platelet lysate (PL).MethodsPlatelet concentrates were frozen, quarantine stored, thawed and sterile filtered to obtain PL. PL content and its effect on fibroblast-colony-forming unit (CFU-F) formation, MSC proliferation and large-scale expansion were studied.ResultsPL contained high levels of basic fibroblast growth factor (bFGF), soluble CD40L (sCD40L), vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), platelet-derived growth factor AA (PDGF-AA), platelet-derived growth factor AB/BB (PDGF-AB/BB), chemokine (C-C) ligand 5 (CCL5; RANTES) transforming growth factor-β1 (TGF-β1) and chemokine (C-X-C) ligand 1/2/3 (GRO), with low batch-to-batch variability, and most were stable for up to 14 days. Inhibition of PDGF-BB and bFGF decreased MSC proliferation by about 20% and 50%, respectively. The strongest inhibition (about 75%) was observed with a combination of anti-bFGF + anti-PDGF-BB and anti-bFGF + anti-TGF-β1 + anti-PDGF-BB. Interestingly, various combinations of recombinant PDGF-BB, bFGF and TGF-β1 were not sufficient to promote cell proliferation. PL from whole blood-derived pooled platelet concentrates and apheresis platelet concentrates did not differ significantly in their growth-promoting activity on MSC.ConclusionsPL enhances MSC proliferation and can be regarded as a safe tool for MSC expansion for clinical purposes. \\in particular, PDGF-BB and bFGF are essential components for the growth-promoting effect of PL, but are not sufficient for MSC proliferation.

Hybrid flowshop scheduling with family setup time and inconsistent family formation

This research considers a hybrid flowshop scheduling problem where jobs are organised in families according to their machine settings and tools. The family setup time arises when a machine shifts from processing one job family to another. The problem is compounded by the challenges that the formation of job families is different in different stages and only a limited number of jobs can be processed within one setup. This type of problem is common in the production process of standard metal components. This paper aims to propose two approaches to solve this problem. One is a metaheuristic in the form of a genetic algorithm and the other is a heuristic. The proposed approaches are compared and contrasted against the two relevant metaheuristic and heuristic adapted from solving a generalised sequence-dependent setup flowshop problem. Comparative results indicate that the proposed genetic algorithm has better performance on minimising makespan and the heuristic is more effective on reducing family setup time.

Design of Detection System of Quartz Wafer's Defect

The natural frequency of crystal is affected by the shape of chip, minor defects will have significant impact on the natural oscillation frequency of the crystal. Therefore, the quartz wafer defect detection is an extremely important part in the component production process. In this paper, the hardware and software architecture of quartz wafer defect inspection system is introduced. Software part consists of three modules, including image acquisition, image processing and defect detection, and it is also given in VC++ code to achieve some of the functions.

Towards a distribution-based formulation of FEM for micro-scale components

Increasing demands for reliable production processes of micro-scale components in large quantities has promoted the research on micro cold forming processes. The need to accelerate product design by the use of simulation has revealed limitations of the classical finite element method (FEM) in the sub-millimeter domain where the local behavior may be dominated by one or a few grains only. As a consequence, average material characteristic values obtained from macroscopic specimens are no longer sufficient to describe the local work-piece behavior. Instead, an uncertainty of the material parameters is encountered, which can be characterized mathematically by probability distributions.The research activities presented here focus on the feasibility of FEM simulations based on distributed material parameters. In order to reduce the computational load, pre-calculation of a sufficient number of load cases in representative volume elements (RVE) for usage in a material data base is proposed. Work-piece simulations are then performed as a multi-scale approach with different levels of interactions between adjacent RVEs.Material characterizations of DC01 sheets and their application to numerical simulation of bulge-tests are presented.

Upscaling of the investment casting of the intermetallic alloy IC75

This research work is based on a specially developed SiO2-free shell mold system for the investment casting of NiAl alloys. Hitherto, this shell system has only been used for scientific work on small, laboratory scale samples made of IC75 alloy. The main focus of the research is to examine the feasibility of upscaling of the shell mold system for production scale samples. For this reason, 200 mm long dummy turbine blades were cast. Nondestructive analysis of the castings by visual examination of the blades’ surface quality, computed tomography scans of their internal structures and three-dimensional measurements showed very good results for the shell mold system. In particular, the good dimensional stability of the shell mold with average deviations of +0.3 mm and a local maximum deviation of −0.73 mm are excellent for a water-soluble shell mold system. The results of this work demonstrate that the investigated mold system is suitable for large samples and melt weights of up to 5 kg and is thus adaptable for the production process of NiAl components.

Proteomics for quality-control processes in transfusion medicine

Following the publication of recent retrospective and highly debated studies, transfusionists are increasingly asking for improved tools to assess the quality of transfusion-relevant products. At its dawn, proteomics emerged as a potential candidate for in-depth investigations of blood components and plasma derivatives. As its maturity is now at hand, the proteomic expertise seems to be ready to be massively transferred to the clinical setting, where it could be potentially used as a valid tool to test, from bench to bedside, the quality of collected blood components prior to or during storage. Proteomic strategies have been demonstrated to be also suited to verify the effects of the production and pathogen-reduction processes of plasma derivatives and blood components on the protein fractions, or to discover particular biomarkers readily adoptable for targeted evaluation of blood-component integrity or functionality. Although the technical background is in continuous and rapid expansion, the spread of proteomics in clinical routine practice has been hitherto hampered by high costs for dedicated facilities and specialized personnel.

Proteomics and blood transfusion

Transfusion medicine is a clinical discipline characterized by one of the most advanced quality management systems, which is structured so as to assure the production of blood components and raw materials, for biopharmaceutical fractionation, that are safe, efficient and effective.During the production, pathogen inactivation and storage processes there is the risk of changes in the integrity of blood components, especially at the protein level. These changes could be the cause of some of the negative effects of transfusion therapy. It is therefore a major challenge to identify significant alterations of these products, and, in this context, proteomics can play a potentially relevant role in transfusion medicine to assess the protein composition of blood‐derived therapeutics, particularly for identifying modified proteins.Proteomics can also provide a more detailed understanding of the proteins found in plasma derivatives, with particular regard to peptide and protein changes related to the various procedures used for protein purification and pathogen inactivation during the modern plasma industrial factionation. The latter could cause protein modifications and/or degradation and neoantigen production, with the potential to induce adverse effects in recipients.At present, blood component quality control is mainly focused on standardized quantitative assessment, providing relatively limited information about products. Proteomics allows a comprehensive study of protein modifications, qualitative and quantitative analysis, and high‐throughput protein identification. Moreover, being the only tool to evaluate structural changes in proteins (or their degradation products) after their manipulation, and having the capacity to identify many new proteins, proteomics seems to be the most promising tool for global quality assessment and possible improvement of the production process of blood components and plasma derivatives. It can also provide comprehensive information about possible contaminants and neoantigens that may influence the immunogenic capacity of blood‐derived therapeutics.

Proteomics and transfusion medicine.

Proteomics is becoming an important research tool which, together with genomics, will, in the near future, presumably have an impact on disease diagnosis and prognosis as well as on further advances in the production and storage processes of blood-based therapeutics.

A micromechanical model for pretextured polycrystalline shape-memory alloys including elastic anisotropy

We present a micromechanical model for polycrystalline shape-memory alloys which is capable of reproducing important aspects of the material behavior such as pseudoelasticity, pseudoplasticity, tension–compression asymmetry and the influence of texture inhomogeneities which may occur from the production process of components or specimens. Our model is based on the optimization of the material’s free energy density and uses a dissipation ansatz which is homogeneous of first order. Considering the full anisotropic material properties of both the austenite and the martensite phase, we compute the evolution of the orientation distributions of austenite and martensite as internal variables of our model.

Adhesion enhancement by a dielectric barrier discharge of PDMS used for flexible and stretchable electronics

Currently, there is a strong tendency to replace rigid electronic assemblies by mechanically flexible and stretchable equivalents. This emerging technology can be applied for biomedical electronics, such as implantable devices and electronics on skin. In the first step of the production process of stretchable electronics, electronic interconnections and components are encapsulated into a thin layer of polydimethylsiloxane (PDMS). Afterwards, the electronic structures are completely embedded by placing another PDMS layer on top. It is very important that the metals inside the electronic circuit do not leak out in order to obtain a highly biocompatible system. Therefore, an excellent adhesion between the 2 PDMS layers is of great importance. However, PDMS has a very low surface energy, resulting in poor adhesion properties. Therefore, in this paper, PDMS films are plasma treated with a dielectric barrier discharge (DBD) operating in air at medium pressure (5.0 kPa). Contact angle and XPS measurements reveal that plasma treatment increases the hydrophilicity of the PDMS films due to the incorporation of silanol groups at the expense of methyl groups. T-peel tests show that plasma treatment rapidly imparts adhesion enhancement, but only when both PDMS layers are plasma treated. Results also reveal that it is very important to bond the plasma-treated PDMS films immediately after treatment. In this case, an excellent adhesion is maintained several days after treatment. The ageing behaviour of the plasma-treated PDMS films is also studied in detail: contact angle measurements show that the contact angle increases during storage in air and angle-resolved XPS reveals that this hydrophobic recovery is due to the migration of low molar mass PDMS species to the surface.

Close co-operation the key for PM component success

New applications for PM have resulted in substantial market growth during the last 30 years. The clue to this success lies in the use of new powders and component production processes. To reduce development time and increase the likelihood of commercial success it is essential for the whole chain from powder supplier to component manufacturers and end users to work in close co-operation…

Exterior components based on renewable resources produced with SMC technology—Considering a bus component as example

The importance of renewable resources in technical applications has increased. Within the framework of the studies, a bus body component based on natural fibres and PTP ®, a vegetable based thermoset resin, is produced with the sheet-moulding-compound technology (SMC). Hitherto, the conventional component was produced of glass fibre reinforced polyester resin. The mid-term results of the studies show that it is possible to optimise the production of this textile semi-finished part by selecting qualified hemp fibres and developing a technically matured PTP ®-SMC variant in such a way that the component production process based on the semi-finished parts need not be changed. All in all, it was possible to produce a homogeneous body part with the hemp/PTP ®-prepreg due to the flow ability that was achieved for the natural fibres. The technical feasibility of producing an SMC-component based on renewable resources was demonstrated. The properties of the component, e.g. tensile strength, burning behaviour and water absorption, are shown and compared to the results of the series component. An assessment of the component from the end-user perspective is presented. According to the End-of-Life Vehicles Regulation, there is no advantage in components based on renewable resources over components based on petrochemical resources. However, the application of renewable resources has advantages in terms of recycling technologies, which are accepted for SMC and which will become economically more important in the future. In comparison with the polyester system, the life-cycle assessment of the polymer material PTP ® shows lower values in nearly all impact categories.

Micro assembly injection moulding

Injection moulding is established as one of the most common manufacturing processes of thermoplastics due to its high degree of automation and the short cycle times. Micro injection moulding is a rapidly growing technology that allows for the efficient production of very complex micro parts in high series. The “Market Analysis for Microsystems II 2002–2005” of the Nexus Task Force anticipates a yearly growth in the field of micro system technology of about 20% (Wechsung et al. 2002). This study identifies in addition to the continuous miniaturization the growing use of polymers in micro systems (Schneider et al. 2001). No other material group offers this wide range of material properties and permits to choose processing parameters and application properties according to necessities (Gachter 2000). While the production processes of micro technical components are mainly controllable, the assembly of these components to hybrid micro systems is a bottleneck to the industrial large scale production. The assembly itself represents a large fraction of the added product value and gains in importance with growing complexity and miniaturization of the systems.