Application of lean scheduling and production control in non-repetitive manufacturing systems using intelligent agent decision support

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Lean Manufacturing (LM) is widely accepted as a world-class manufacturing paradigm, its currency and superiority are manifested in numerous recent success stories. Most lean tools including Just-in-Time (JIT) were designed for repetitive serial production systems. This resulted in a substantial stream of research which dismissed a priori the suitability of LM for non-repetitive non-serial job-shops. The extension of LM into non-repetitive production systems is opposed on the basis of the sheer complexity of applying JIT pull production control in non-repetitive systems fabricating a high variety of products. However, the application of LM in job-shops is not unexplored. Studies proposing the extension of leanness into non-repetitive production systems have promoted the modification of pull control mechanisms or reconfiguration of job-shops into cellular manufacturing systems. This thesis sought to address the shortcomings of the aforementioned approaches. The contribution of this thesis to knowledge in the field of production and operations management is threefold: Firstly, a Multi-Agent System (MAS) is designed to directly apply pull production control to a good approximation of a real-life job-shop. The scale and complexity of the developed MAS prove that the application of pull production control in non-repetitive manufacturing systems is challenging, perplex and laborious. Secondly, the thesis examines three pull production control mechanisms namely, Kanban, Base Stock and Constant Work-in-Process (CONWIP) which it enhances so as to prevent system deadlocks, an issue largely unaddressed in the relevant literature. Having successfully tested the transferability of pull production control to non-repetitive manufacturing, the third contribution of this thesis is that it uses experimental and empirical data to examine the impact of pull production control on job-shop performance. The thesis identifies issues resulting from the application of pull control in job-shops which have implications for industry practice and concludes by outlining further research that can be undertaken in this direction

Steel lives: An ethnography of labour in contemporary Sheffield.

My doctoral research focuses on the experience of labour in a deprived area of Sheffield, UK, where I lived and worked in two steel factories for eighteen months. In my thesis, I study the factory as a physical, economic and political space located between society and the state, and explore how state neo-liberal policies and globalisation affect working class productive and reproductive strategies, and narratives of labour; and reshape the spaces of the factory, the family and the neighbourhood. In the first part of the thesis I reconstruct the history of steel labour on the shopfloor and in the neighbourhood. In Chapter 1, I show that industrial capitalism fragmented the workforce into 'artisans' - skilled casual labourers - and 'proletarians' - unskilled wage workers. In Chapter 2, I show how this fragmentation was reproduced in the neighbourhood by public social and economic policies and by the 'medical discourse' centred on the health of working classes. The two shopfloor ethnographies in Chapter 3 and 4, show that the historical fragmentation between 'artisans' and 'proletarians' is reproduced in the capitalist labour processes today. The neighbourhood ethnographies in Chapter 5 and 6 challenge the hypothesis of 'late capitalism' scholars of the social fragmentation of the artisan-labourers and of the social stability of the families of the aristocracy of labour, and show the relative economic and social stability of the former and the fragility of the productive and reproductive institutions of the latter. I the conclusion I claim that 'late capitalism' does not entail the dissolution of the working class and the consolidation of an aristocracy of labour under the impulse of technological innovation and capital intensification. Rather, it increases both the fragmentation, and the close interaction, between the spaces of wage labour, nuclear families and civil society and the spaces of casual labour, extended families and local politics

Industrial waste minimisation in South Africa : a case study in the textile and metal finishing sectors.

Thesis (M.Sc.Eng.)-University of Natal, Durban, 2002.Environmental legislation is becoming more stringent as people are realising the need for conservation and a reduction of environmental degradation in order to facilitate sustainable development. To ease legislative pressures, companies need to work together in symbiotic networks, whereby co-operation between companies results in far more innovative practices than if the companies acted individually. Success in an industrial network is largely dependent on cleaner production, where industries seek to redirect from waste treatment to waste minimisation. Cleaner production has already received international recognition and waste minimisation initiatives have been used as a tool of cleaner production. Two polluting industrial sectors within South Africa, the textile and metal finishing sectors, were chosen to investigate waste minimisation concepts. One company from each sector was used as a case study. The dissertation followed company network identification, potential to participate within an industrial symbiotic network, and waste minimisation opportunities. Suppliers and buyers, up and down the product line were identified. Relationships with these partners should be advanced such that environmental concerns are at the forefront of any decision-making. In light of developing industrial networks and maintaining symbiotic relationships, the company's potential was investigated by interviewing employees of various ranks. Both companies were partially suited to participate within an industrial symbiotic network and company-specific barriers were identified, such as ineffective internal communication. The waste minimisation investigation followed a four-phase approach of planning and organisation; pre-assessment; assessment; and feasibility study. In both the companies investigated, water savings were identified as the waste minimisation focus area with potential for improvement. In total, potential water savings of over R80 000 per annum were identified. In the textile company, the weaving department and bleach house were further investigated. Cloth weaving errors were attributed to machine stops, as each stop has the potential to result in a cloth fault. In the bleach house the potential existed to reduce the number of rinse tanks. Although a modem and automated process, the plating plant in the metal finishing company was identified as having potential waste minimisation opportunities. Of particular interest was the reduction of solution carry over from the plating tanks into subsequent tanks. Extended drip times were investigated. Additional waste minimisation opportunities included repairing pipe leaks, replacing the degreasing solvent, trichloroethylene, with a less harmful cleaning agent and establishing a symbiotic relationship with the oil supplier, Castrol. Over and above the main waste minimisation opportunities highlighted, other recommendations and potential savings were identified. Each case study emphasises that simple waste minimisation initiatives, without expending capital, reduce demands on natural resource, such as water, and benefit the company financially. Successful waste minimisation leads to further cleaner production initiatives, which may then initiate better network interactions with the further potential of promoting sustainable development

Four decades of research on the open-shop scheduling problem to minimize the makespan

One of the basic scheduling problems, the open-shop scheduling problem has a broad range of applications across different sectors. The problem concerns scheduling a set of jobs, each of which has a set of operations, on a set of different machines. Each machine can process at most one operation at a time and the job processing order on the machines is immaterial, i.e., it has no implication for the scheduling outcome. The aim is to determine a schedule, i.e., the completion times of the operations processed on the machines, such that a performance criterion is optimized. While research on the problem dates back to the 1970s, there have been reviving interests in the computational complexity of variants of the problem and solution methodologies in the past few years. Aiming to provide a complete road map for future research on the open-shop scheduling problem, we present an up-to-date and comprehensive review of studies on the problem that focuses on minimizing the makespan, and discuss potential research opportunities

Risk-Based Optimal Scheduling for the Predictive Maintenance of Railway Infrastructure

In this thesis a risk-based decision support system to schedule the predictive maintenance activities, is proposed. The model deals with the maintenance planning of a railway infrastructure in which the due-dates are defined via failure risk analysis.The novelty of the approach consists of the risk concept introduction in railway maintenance scheduling, according to ISO 55000 guidelines, thus implying that the maintenance priorities are based on asset criticality, determined taking into account the relevant failure probability, related to asset degradation conditions, and the consequent damages

Development of a machine-tooling-process integrated approach for abrasive flow machining (AFM) of difficult-to-machine materials with application to oil and gas exploration componenets

This thesis was submitted for the degree of Doctor of Engineering and awarded by Brunel UniversityAbrasive flow machining (AFM) is a non-traditional manufacturing technology used to expose a substrate to pressurised multiphase slurry, comprised of superabrasive grit suspended in a viscous, typically polymeric carrier. Extended exposure to the slurry causes material removal, where the quantity of removal is subject to complex interactions within over 40 variables. Flow is contained within boundary walls, complex in form, causing physical phenomena to alter the behaviour of the media. In setting factors and levels prior to this research, engineers had two options; embark upon a wasteful, inefficient and poor-capability trial and error process or they could attempt to relate the findings they achieve in simple geometry to complex geometry through a series of transformations, providing information that could be applied over and over. By condensing process variables into appropriate study groups, it becomes possible to quantify output while manipulating only a handful of variables. Those that remain un-manipulated are integral to the factors identified. Through factorial and response surface methodology experiment designs, data is obtained and interrogated, before feeding into a simulated replica of a simple system. Correlation with physical phenomena is sought, to identify flow conditions that drive material removal location and magnitude. This correlation is then applied to complex geometry with relative success. It is found that prediction of viscosity through computational fluid dynamics can be used to estimate as much as 94% of the edge-rounding effect on final complex geometry. Surface finish prediction is lower (~75%), but provides significant relationship to warrant further investigation. Original contributions made in this doctoral thesis include; 1) A method of utilising computational fluid dynamics (CFD) to derive a suitable process model for the productive and reproducible control of the AFM process, including identification of core physical phenomena responsible for driving erosion, 2) Comprehensive understanding of effects of B4C-loaded polydimethylsiloxane variants used to process Ti6Al4V in the AFM process, including prediction equations containing numerically-verified second order interactions (factors for grit size, grain fraction and modifier concentration), 3) Equivalent understanding of machine factors providing energy input, studying velocity, temperature and quantity. Verified predictions are made from data collected in Ti6Al4V substrate material using response surface methodology, 4) Holistic method to translating process data in control-geometry to an arbitrary geometry for industrial gain, extending to a framework for collecting new data and integrating into current knowledge, and 5) Application of methodology using research-derived CFD, applied to complex geometry proven by measured process output. As a result of this project, four publications have been made to-date – two peer-reviewed journal papers and two peer-reviewed international conference papers. Further publications will be made from June 2014 onwards.Engineering and Physical Sciences Research Council (EPSRC) and the Technology Strategy Board (TSB

Integrated knowledge-based hierarchical modelling of manufacturing organizations

The objective of this thesis is to research into an integrated knowledge-based simulation method, which combines the capability of knowledge based simulation and a structured analysis method, for the design and analysis of complex and hierarchical manufacturing organizations. This means manufacturing organizations analysed according to this methodology can manage the tactical and operational planning as well as the direct operation of shop floor. [Continues.

Managerial culture and company survival: Technological change and output-mix optimisation at Fiat, 1960-1987.

This dissertation contributes to the debate on the decline and transformation of mass production in the 1970s and 1980s by analysing the case of the Italian car manufacturer Fiat. In particular, the thesis addresses the question whether the company's restructuring led to a discontinuity in management. The established literature on Fiat depicts the company as one of the first movers in the development of flexible manufacturing systems, and traces the move towards flexible mass production back to the late 1970s. In doing so, the literature implies a discontinuity between the group of managers who had developed Fordist production at Fiat in the 1950s and 1960s and the set of managers who gradually came to dominate the company after 1973. Crucially, the established literature on Fiat is locked in a circular argument. Firstly, it explains the deployment of robotics as a move in the quest for production flexibility, and then uses the deployment of robotics as compelling evidence that the Fiat production setting during the 1980s was flexible. This dissertation breaks this circularity by testing the flexibility of Fiat production system during the 1980s against an independent variable, namely the rate of capacity utilisation of the production lines. This dissertation demonstrates that during the 1980s, Fiat production remained inflexible. It also shows that Fiat did not maximise flexibility because the output-mix optimisation strategy pursued by the management did not require the maximisation of flexibility. The new contribution of the thesis to the international literature emerges from three key elements. Firstly, the thesis departs from common wisdom by showing that the managerial culture underpinning the restructuring of the company and its recovery from the crisis of the 1970s was essentially "Fordist". Secondly, the thesis investigates flexibility by analysing the behaviour of the utilisation rate of both robotised and traditional lines. The methodology has been implemented for the first time, thanks to a set of unpublished data discovered during extensive fieldwork in the Fiat Archives, and is based on the assumption that the main drive for investment in flexible manufacturing systems is the stabilisation of the utilization of production lines at about the optimal rate. Finally, the thesis underlines the complex relationship between technological change, product development and output-mix optimisation, which has been often overlooked by the post-Fordism debate

Mining the future: post-market society and the capital-labour conflict

Graeme Cotter investigated a history of the recurrent conflict between capital and labour. In a study of the mining industry he found that in the 21st-century capitalists are sidestepping this conflict by an increasing focus on technology-labour substitution which is threatening a future society without work for many who want it