Academic literature on the topic 'Manufacturing processes'

Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science; in conjunction with the Leaders for Manufacturing Program at MIT, 2008.<br>Includes bibliographical references (p. 61-62).<br>Global operations for multinational companies today pose a particularly challenging environment for maintaining fluid knowledge transfer and effective communication methodologies. In a continuous drive for product innovation, process development often takes on lower priority to other initiatives that directly affect the design and delivery of a product. However, existing literature shows that process development and governance are critical to sustainable growth in the global marketplace. Multinational companies must recognize the need to integrate process development in a product centric enterprise to maintain effective information flow and clear communication channels. Cisco faces this challenging in maintaining effective cross-functional communication while growing through acquisition and new product developments. Cisco also faces additional complexity in managing a global network of outsourced manufacturing activities. This research analyzes two case studies in process development within the Manufacturing organization at Cisco. Specifically, these two case studies focus on driving early engagement of manufacturing concerns in the product lifecycle and effective means of facilitating this initiative.<br>by Ilyssa Jing Lu.<br>S.M.<br>M.B.A.

<p>The innovation process is an important process for our primemotor of welfare, manufacturing. During this process, theprerequisites for manufacturing are set. To set the bestpossible prerequisites consideration about products,manufacturing processes, and manufacturing resources must bemade concurrently, which also means involving several differentdisciplines in a collaborative effort.</p><p>As a consequence of involving different disciplines, thecommunication of engineering information may be hindered. Thereason is that different disciplines use different terminologyfor the same concept and sometimes have the same terminologyfor different concepts. This may result in difficultiesunderstanding each other, which may, in turn, result inunnecessary loss of quality and productivity.</p><p>The main objective of this thesis is to identify informationconcepts (i.e. information requirements) for process planningin a concurrent engineering environment, and to formally definethe corresponding terminology. The work is based on casestudies at Volvo Car Corporation, involving management of weldspot and location system information, and at ABB Body-in-White,involving tender preparation information.</p><p>The results are presented in the thesis in terms of aninformation model, the Product-Process-Resource (PPR)information model, and two corroborated hypotheses. The PPRinformation model defines the identified informationrequirements in the scope of the thesis whereas the hypothesesconcern how, e.g., modularization can be used in informationmodeling.</p><p>The PPR information model provides the base for aninformation platform in a concurrent engineeringenvironment.</p><p>The PPR information model enable model based documentationand, thus, traceability of the evolution of the product,process, and manufacturing resource designs, and theirinterrelations.</p><p><b>Keywords:</b>Information Modeling, Process Planning,Concurrent Engineering, Information Management</p>

This thesis presents a study on the variation of the mechanical properties of some materials. These variations are registered for processes as bottom bending, wire drawing or round turning, which are performed under high density electropulses. This research implied the study of several issues related to the manufacturing processes and the electric pulses. For example, some isolated systems are developed for each process. This is required for protecting the monitoring devices and machinery from electric drifts. On the other hand, several electropulse generators are designed and manufactured to electrically assist the aforementioned manufacturing processes. The electrical connectors is the main technological issue in each process to ensure good electrical contact during experimentation. Once the manufacturing setup is under control, electropulses are applied on various materials whilst its physical properties are measured and recorded. In particular, the processes are achieved under different electric configurations to infer the influence of the electropulses. The obtained results show that different mechanical and manufacturing properties like elastic restoring forces, yield strength, power consumption, surface roughness and material hardness among others are modified when the manufacturing process is assisted with a pulsed electric field. Additionally, the machinability and formability is improved when the metallic material is affected by current pulses. However, it should be noted that the mechanical properties behavior under different electrical parameters, like current density, frequency discharge and pulse duration, is complex and does not follow an expected relationship. Furthermore, numerical simulation analyses is required to study and understand the complex behavior of the mechanical properties. The manufacturing process of bending, machining and drawing process was done at the Universitat Politècnica de Catalunya (Spain) in collaboration with the Northwestern University (USA), the Universidad Pontificia Universidad Católica de Chile (Chile) and the Universidad Tecnológica de Pereira (Colombia). This thesis is funded by the Ministry of Economy and Competitiveness of Spain, reference project: DPI2011-26326 (grant no. BES-2012-056760). Along the document detailed information on methodology for the aforementioned processes and some conclusions are provided<br>En el presente estudio se documenta la variación de las propiedades mecánicas registradas en diversos procesos de fabricación, doblado, mecanizado y trefilado, cuando estos procesos son asistidos con generadores de pulsos de alta densidad de corriente Para cada proceso de fabricación se ha realizado un utillaje específico para aislar eléctricamente la máquina de ensayo. Esto permite inducir los pulsos de corriente únicamente a través de las probetas metálicas, sin correr el riesgo de inhabilitar las máquinas de fabricación. Varios generadores de pulsos de corriente han sido diseñados y fabricados a lo largo de la tesis para asistir eléctricamente los procesos de fabricación mencionados. Para cada estudio se varía el área de contacto de los conectores eléctricos con el material para asegurar un buen contacto eléctrico durante la experimentación. La influencia de los pulsos de corriente eléctrica en los diferentes materiales manufacturados ha sido registrada y estudiada por varios equipos de medida. Además, se ha necesitado de programas de simulación numérica para estudiar y comprender el comportamiento de las propiedades mecánicas. Los resultados obtenidos en este trabajo demuestran que varias propiedades mecánicas como la recuperación elástica, esfuerzos de fluencia, potencia consumida, rugosidad superficial y dureza del material entre otras son modificadas cuando los procesos de fabricación son asistidos por un campo eléctrico. En resumen, se observa que la maquinabilidad del material metálico mejora cuando es fabricado bajo la influencia de los pulsos eléctricos. Esto es debido a que se reduce los esfuerzos de fluencia, mejora la rugosidad superficial, se atenúa la recuperación elástica y disminuye su dureza superficial. Aun así, cabe indicar que el comportamiento de las propiedades mecánicas anteriores bajo las condiciones eléctricas son complejas y no siguen una relación trivial. Indicar que los avances en el área de fabricación realizados en este trabajo en los procesos de doblado, mecanizado y trefilado han sido realizados en la Universitat Politècnica de Catalunya (UPC), Escola Universitaria d'Enginyeria Tècnica Industrial de Barcelona (EUETIB) en colaboración con la Pontificia Universidad Católica de Chile (PUC), la Universidad Tecnológica de Pereira (UTP) y la Northwes tern University. En consecuencia, a lo largo del documento se detalla la metodología de estudio y los resultados obtenidos de los diferentes procesos mencionados, comparando los procesos convencionales respecto a los asistidos. Además, se estudiará en profundidad la influencia de los pulsos de corriente en el comportamiento de las principales propiedades mecánicas, según el proceso.

The aim of this master thesis project was to statistically correlate various powder characteristics to the quality of additively manufactured parts. An additional goal of this project was to find a potential second source supplier of powder for GKN Aerospace Sweden in Trollhättan. Five Inconel® alloy 718 powders from four individual powder suppliers have been analyzed in this project regarding powder characteristics such as: morphology, porosity, size distribution, flowability and bulk properties. One powder out of the five, Powder C, is currently used in production at GKN and functions as a reference. The five powders were additively manufactured by the process of laser metal deposition according to a pre-programmed model utilized at GKN Aerospace Sweden in Trollhättan. Five plates were produced per powder and each cut to obtain three area sections to analyze, giving a total of fifteen area sections per powder. The quality of deposited parts was assessed by means of their porosity content, powder efficiency, geometry and microstructure. The final step was to statistically evaluate the results through the analysis methods of Analysis of Variance (ANOVA) and simple linear regression with the software Minitab. The method of ANOVA found a statistical significant difference between the five powders regarding their experimental results. This made it possible to compare the five powders against each other. Statistical correlations by simple linear regression analysis were found between various powder characteristics and quality of deposited part. This led to the conclusion that GKN should consider additions to current powder material specification by powder characteristics such as: particle morphology, powder porosity and flowability measurements by a rheometer. One powder was found to have the potential of becoming a second source supplier to GKN, namely Powder A. Powder A had overall good powder properties such as smooth and spherical particles, high particle density at 99,94% and good flowability. The deposited parts with Powder A also showed the lowest amount of pores compared to Powder C, a total of 78 in all five plates, and sufficient powder efficiency at 81,6%.

James Womack and his colleagues Daniel Jones and Daniel Roos changed the way western civilization approached manufacturing. In 1990, they published a book called ‘The Machine That Changed the World: The Story of Lean Production’. It was a concept that had slowly filtered from the east but had not made its mark on the manufacturing sector. The concept of lean, born out of the Japanese Toyota Manufacturing System, was first thought to be impossible to duplicate outside of Japan. Since Womack and company popularised this “new” way of producing goods and delivering services it spread across industries finding popularity in the medical, engineering, accounting and especially the manufacturing industries. Over the last few decades lean practices has been synonymous with efficiency, cost reduction, supply chain optimisation and innovative problem solving (Anvari Norzima, Rosnah, Hojjati and Ismail, 2010; Pieterse et al., 2010; Womack et al., 1990). Lean process implementation has been researched in abundance, as has failed attempts at lean implementation. The purpose of this study was to identify and assess enablers of lean sustainability in organisations where lean processes are already being implemented. The literature study found Organisational Culture, Leadership, Employee Engagement and Trade Unions participation as factors that contributed to successful lean implementations. The author developed a model to test Organisational Culture, Leadership, Employee Engagement and Trade Unions as enablers to sustain lean practices in organisations in South Africa’s manufacturing industries. The results proved that Organisational Culture, Leadership and Employee Engagement were considered enablers for lean sustainability. These three enablers have an interlinked relationship and together help sustainability. Lacking just one factor would surely result in unsustainable lean practices. The study was conducted in the quantitative paradigm, as the hypothesised relationship was statistically tested. The data was collected from a homogenous group via an email sent with a link to the questionnaire. The data was statistically analysed with Statistica software and Microsoft Excel.

This thesis presents work on the simulation of manufacturing chains, simulation of manufacturing processes (casting, forging, shot-peening and heat treatment) and fatigue life prediction by using the finite element method (FEM). The objectives and the contributions of this thesis consist of development of mathematical algorithms and techniques for mapping and transferring FE data (stresses, strains, displacements, etc.) from macro-to-macro and micro-to-macro FE models among different FE solvers and meshes. All these features have been implemented into a new finite element data exchange system (FEDES). FEDES has been developed to simulate manufacturing chains by using FE techniques. Extensive research has been carried out on the simulation of investment casting processes of aero-engine parts under equiaxed and directional cooling. Methodologies for predicting the component life undergoing low cycle fatigue (LCF) and high cycle fatigue (HCF) have been developed. Life prediction based on the effect of the residual stresses obtained from micro machining and shot-peening processes has been investigated. FEDES has been used to simulate two manufacturing chains where the residual stresses and the distortions after each manufacturing process have been passed to the next process of the chain. Manufacturing chain simulation including casting, forging and heat treatment has been carried out on a simple parallelepiped geometry. A second manufacturing chain simulation has been performed on an aero-engine vane component which includes the following manufacturing processes: metal deposition, welding, heat treatment, machining and shot-peening. An investment casting simulation under equiaxed cooling of the bottom core vane (BCV) component of the aero-engines vane has been performed. The gap formation and the gap conductance have been studied and implemented in the analyses. The main goal is to investigate the residual stresses in the BCV cast with Inconel 718 material. Two FE solvers (ABAQUS and ProCAST) have been used for validation purposes. An investment casting simulation under directional cooling in a Bridgman furnace of a high pressure turbine blade (HPTB) with CMSX-4 material has been carried out. The effect of the withdrawal velocity on the temperature and the residual stresses of the HPTB cast has been investigated.