Improving producibility in aerospace engine manufacturing : process automation vs. process reengineering

Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering; in conjunction with the Leaders for Manufacturing Program at MIT, 2008.Includes bibliographical references (p. 43).In any aerospace manufacturing operation, including Pratt & Whitney's Compression Systems Module Center, producibility problems can be major drivers of cost. Much of the literature focuses on design for manufacturability as a solution to producibility problems. While this is a valuable approach, this study focuses on manufacturing process improvement as a solution to producibility issues. Two methods of process improvement are discussed, process automation and process reengineering. This thesis first surveys some of the major producibility problems at Pratt & Whitney's Compression Systems Module Center, as well as some of the efforts underway to address them. One of the largest issues, operator data input errors, is described in detail as a case study. Wireless gauging with automatic offset adjustment is proposed as a focused technological solution to this issue. As part of this study, funding has been obtained to implement the solution and testing has been conducted. This is an example of process automation. However, a broader process reengineering effort is also proposed. The fundamental question of why producibility problems tend to persist is also examined.by Daniel Hoopes.S.M.M.B.A

A Case Study for Financial Feasibility of Automated Costing Support in A Small Machine Shop

A knowledge-based cost estimating expert system is chosen by a Mexican machine shop. Differences between the traditional experience-based system employed and the automated system are studied. Data is gathered to analyze time effectiveness, accuracy and payback of the software. Data from seventy part models is recorded to study the time experiment, and data from fifty part models is used to study the accuracy and consistency. Data is analyzed by calculating mean, standard deviation, and test of hypothesis. The results indicate that the software is faster than the traditional quoting system; however, the payback point is high. Also, results show the software has a smaller average time-to-manufacture percentage difference between the automated system and the actual time-to-manufacture (TTM) compared to the percentage difference between the traditional’s TTM and actual TTMs, and this difference is statistically significant. The standard deviation for the automated system is also less implying better consistency

Human‑centred design in industry 4.0: case study review and opportunities for future research

The transition to industry 4.0 has impacted factories, but it also afects the entire value chain. In this sense, human-centred factors play a core role in transitioning to sustainable manufacturing processes and consumption. The awareness of human roles in Industry 4.0 is increasing, as evidenced by active work in developing methods, exploring infuencing factors, and proving the efectiveness of design oriented to humans. However, numerous studies have been brought into existence but then disconnected from other studies. As a consequence, these studies in industry and research alike are not regularly adopted, and the network of studies is seemingly broad and expands without forming a coherent structure. This study is a unique attempt to bridge the gap through the literature characteristics and lessons learnt derived from a collection of case studies regarding human-centred design (HCD) in the context of Industry 4.0. This objective is achieved by a well-rounded systematic literature review whose special unit of analysis is given to the case studies, delivering contributions in three ways: (1) providing an insight into how the literature has evolved through the cross-disciplinary lens; (2) identifying what research themes associated with design methods are emerging in the feld; (3) and setting the research agenda in the context of HCD in Industry 4.0, taking into account the lessons learnt, as uncovered by the in-depth review of case studies

DEVELOPMENT OF A NOVEL HIGH TEMPERATURE FAN HUB DESIGN

As the process temperature of a fan system increases, the amount of heat that gets transmitted to the bearings and/or motor increases. If this is not accounted for, it can lead to catastrophic failure. The main heat conduction path is through the shaft, and certain mechanisms must be considered when looking for new solutions. These include; how heat is transmitted through the shaft or increasing the thermal resistance of the shaft, and dissipating heat as it is conducted through the shaft. These aspects must always be considered in addition to the impact of the manufacturing complexity. In the present study, an existing heat dissipation arrangement is reviewed and replaced by a new hub which reduces the time taken to machine the part, and ultimately the overall cost of the product. Techniques are employed to determine in detail the manufacturability of the existing design and determining what should be done to reduce the overall cost to manufacture. Finite Element Analysis (FEA) based techniques have been adopted to simulate the stresses the model experiences under the operating loads. Computation Fluid Dynamics (CFD) based techniques have been used to numerically simulate the designs under operating conditions, and the resulting heat transfer through the shaft compared with respect to the heat dissipation properties are analysed. Currently, a special hub is utilised for high temperature applications such as within industrial ovens and furnaces in order to dissipate heat. The hub connects the impeller to the motor shaft, the impeller would be subjected to the high temperatures whilst the motor would remain below 70°C. According to Fourier’s law heat transfer will take place through the shaft. The material the shaft is manufactured from and its geometric properties both affect the shafts overall temperature. Should the temperature become too high at the point along the shaft where the motor bearings sit, permeant damage will occur and result in bearing failure. The current hub utilised is designed to reduce the heat within the shaft through the use of fins. The is current hub design is quite labour intensive to produce leading to potentially unnecessary costs. Subsequently a new hub has been created that can be easily machined, thus reducing the overall manufacturing time leading to cost savings. The results demonstrate that although the new hub is less effective at dissipating heat, it provides a substantial cost reduction compared to the existing design, while substantially reducing the impact of the design on various aspects of production

Links between modularization critical success factors and project performance

textThrough the exporting of a portion of site-based work to fabrication shops, modularization (MOD) can enhance efficiency in the construction industry. The industry, however, applies modularization at only a low level. To reach higher levels of modularization, the EPC industry needs new approaches. Previous studies have identified the current trends in and barriers to the industry's application of modularization. Moreover, in 2013, the Construction Industry Institute's (CII) Research Team 283 identified 21 critical success factors (CSFs) that create an optimum environment for a broader and more effective use of modularization. However, the researcher has identified a need to better understand the relative significance of MOD CSFs and their associations with project performance. Thus, the research was conducted to provide recommendations for better project performance by identifying correlations between the accomplishment of MOD CSFs and project performance and examining actual modular projects' MOD CSF accomplishment. This study identified four statistically significant positive correlations. Those are between the accomplishment of MOD CSFs and: 1) cost performance; 2) schedule performance; 3) Construction performance; and 4) Startup performance. In addition to the correlation analysis, the study also identified the CSFs that appear to contribute the most to 1) "Modular Project Success", 2) Construction success, 3) Startup success, 4) Cost performance, and 5) Schedule performance. To collect information on the actual industrial modular projects, the study surveyed industry experts. By using this study, many industrial project stakeholders from owners to fabricators, designers and EPC contractors, will be able to understand the relationships between MOD CSFs and project performance. Such an understanding should motivate them to achieve better project performance through implementing modularization CSFs.Civil, Architectural, and Environmental Engineerin

A framework for whole lifecycle cost of long-term digital preservation

Digital preservation, also known as digital curation, is the active management of digital information, over time, to ensure its accessibility and usability. Digital preservation is nowadays an active area of research, for many reasons: the rapid evolution of technology, which also results in the rapid obsolescence of old technologies; degradation of physical records; constantly increasing volumes of digital information and, importantly, the fact that it has started to become a legal obligation in many countries. This research project aims to develop an innovative framework estimate costs of long term digital preservation. The framework can lead to generating a cost model that quantifies costs within different business sectors, while capturing the impact of obsolescence and uncertainties on predicted cost. Case studies from financial, healthcare and clinical trials sectors are used to prove the framework concept. Those sectors were chosen because between them they share all file types that are required to be preserved and all are either obliged by European or local laws, e.g. EU Data Retention Directive (2006/24/EC) and/or UK Data Retention Regulations 2014 No. 2042, or interested in preserving their digital assets. The framework comprises of three phases: assessing digital preservation activities, cost analysis and expansion and cost estimation. The framework has integrated two processes that will enable the user to reach a more accurate cost estimate; a process for identifying uncertainties with digital preservation activities and a cost modelling process. In the framework cloud computing was used as an example for storage and compute technologies. Combining different research methodology techniques was used in this research project. Starting with conducting a thorough literature review covering digital preservation and cost modelling. Following the literature review; is a combination qualitative and quantitative approaches, using semi-structured interview technique to collect data from industry experts. Industry experts were chosen from companies, firms and government bodies working with or researching digital preservation. Finalising with validating results by real-life case studies from businesses in selected sectors and experts’ verdict. Comparing the output of the framework to real-life case studies, demonstrated how companies/firms, who target to preserve their digital assets, can utilise it to predict accurately future costs for undertaking such investment. By applying industrially-based cost modelling approaches the framework generates a cost model that predicts single-point and three-points cost estimates, an obsolescence taxonomy, uncertainties identification process and quantifying uncertainties and obsolescence impact on cost prediction. Providing decision makers with all the framework outputs, will provide them with quantifiable information about their future investment, while remaining clear to understand and easy to amend. This makes the framework provide long-term total cost prediction solution for digital preservation to firms; helping, guiding and adding insight into digital preservation added value

An intelligent knowledge based cost modelling system for innovative product development

This research work aims to develop an intelligent knowledge-based system for product cost modelling and design for automation at an early design stage of the product development cycle, that would enable designers/manufacturing planners to make more accurate estimates of the product cost. Consequently, a quicker response to customers’ expectations. The main objectives of the research are to: (1) develop a prototype system that assists an inexperienced designer to estimate the manufacturing cost of the product, (2) advise designers on how to eliminate design and manufacturing related conflicts that may arise during the product development process, (3) recommend the most economic assembly technique for the product in order to consider this technique during the design process and provide design improvement suggestions to simplify the assembly operations (i.e. to provide an opportunity for designers to design for assembly (DFA)), (4) apply a fuzzy logic approach to certain cases, and (5) evaluate the developed prototype system through five case studies. The developed system for cost modelling comprises of a CAD solid modelling system, a material selection module, knowledge-based system (KBS), process optimisation module, design for assembly module, cost estimation technique module, and a user interface. In addition, the system encompasses two types of databases, permanent (static) and temporary (dynamic). These databases are categorised into five separate groups of database, Feature database, Material database, Machinability database, Machine database, and Mould database. The system development process has passed through four major steps: firstly, constructing the knowledge-based and process optimisation system, secondly developing a design for assembly module. Thirdly, integrating the KBS with both material selection database and a CAD system. Finally, developing and implementing a ii fuzzy logic approach to generate reliable estimation of cost and to handle the uncertainty in cost estimation model that cannot be addressed by traditional analytical methods. The developed system has, besides estimating the total cost of a product, the capability to: (1) select a material as well as the machining processes, their sequence and machining parameters based on a set of design and production parameters that the user provides to the system, and (2) recommend the most economic assembly technique for a product and provide design improvement suggestion, in the early stages of the design process, based on a design feasibility technique. It provides recommendations when a design cannot be manufactured with the available manufacturing resources and capabilities. In addition, a feature-by-feature cost estimation report was generated using the system to highlight the features of high manufacturing cost. The system can be applied without the need for detailed design information, so that it can be implemented at an early design stage and consequently cost redesign, and longer lead-time can be avoided. One of the tangible advantages of this system is that it warns users of features that are costly and difficult to manufacture. In addition, the system is developed in such a way that, users can modify the product design at any stage of the design processes. This research dealt with cost modelling of both machined components and injection moulded components. The developed cost effective design environment was evaluated on real products, including a scientific calculator, a telephone handset, and two machined components. Conclusions drawn from the system indicated that the developed prototype system could help companies reducing product cost and lead time by estimating the total product cost throughout the entire product development cycle including assembly cost. Case studies demonstrated that designing a product using the developed system is more cost effective than using traditional systems. The cost estimated for a number of products used in the case studies was almost 10 to 15% less than cost estimated by the traditional system since the latter does not take into consideration process optimisation, design alternatives, nor design for assembly issue