A Framework for Developing Portfolios of Improvements Projects in Manufacturing

AbstractThe outcome of improvement programmes such as Lean Manufacturing or Six Sigma is only partially determined by the success or failure of its individual projects. Also of significance is how well the programme and its projects are aligned to the company's strategy. Frequently practitioners will select projects on their individual merits, rather than with proper reference to their contribution to business strategy. In this manner, it is therefore possible to build portfolios of projects that are at best suboptimal and at worst counter to the company's overall strategic direction. The construction of project portfolios is thus a critical step in effective programme management and this would suggest that organizations would benefit from a framework to assist them with the selection of projects and portfolios that are aligned with the company's overall strategy. While tools such as Critical to Quality Flow-down are available to translate the voice of the customer to metrics and goals, practitioners do not have a structured approach to construct and assess portfolios.In this paper we present a framework to assist programme managers to develop portfolios of improvement projects targeted to fulfil their company's strategic needs and also align with the organisation's objectives and measures. Consideration is given to quantitative and qualitative aspects of strategy and how these may best be related to provide a set of orthogonal and common metrics

Stability and solubility of arsenopyrite, FeAsS, in crustal fluids.

The stability and solubility of natural arsenopyrite (FeAsS) in pure water and moderately acid to slightly basic aqueous solutions buffered or not with H2 and/or H2S were studied at temperatures from 300 to 450°C and pressures from 100 to 1000 bar. The solubilities of FeAsS in pure water and dilute HCl/NaOH solutions without buffering are consistent with the formation of the As(OH)30(aq) species and precipitation of magnetite. At more acid pH (pH ≤2), arsenopyrite dissolves either stoichiometrically or with formation of the As-FeAsS assemblage. In H2S-rich and H2-rich aqueous solutions, arsenopyrite dissolution results in the formation of pyrrhotite (±pyrite) and iron arsenide(s), respectively, which form stable assemblages with arsenopyrite. Arsenic concentrations measured in equilibrium with FeAsS in slightly acid to neutral aqueous solutions with H2 and H2S fugacities buffered by the pyrite-pyrrhotite-magnetite assemblage are 0.0006 ± 0.0002, 0.0055 ± 0.0010, 0.07 ± 0.01, and 0.32 ± 0.03 mol/kg H2O at 300°C/400 bar, 350°C/500 bar, 400°C/500 bar, and 450°C/500 bar, respectively. These values were combined with the available thermodynamic data on As(OH)30(aq) (Pokrovski et al., 1996) to derive the Gibbs free energy of FeAsS at each corresponding temperature and pressure. Extrapolation of these values to 25°C and 1 bar, using the available heat capacity and entropy data for FeAsS (Pashinkin et al., 1989), yields a value of −141.6 ± 6.0 kJ/mol for the standard Gibbs free energy of formation of arsenopyrite. This value implies a higher stability of FeAsS in hydrothermal environments than was widely assumed. Calculations carried out using the new thermodynamic properties of FeAsS demonstrate that this mineral controls As transport and deposition by high-temperature (>not, vert, similar300°C) crustal fluids during the formation of magmatic-hydrothermal Sn-W-Cu-(Au) deposits. The equilibrium between As-bearing pyrite and the fluid is likely to account for the As concentrations measured in modern high- and moderate-temperature (150 ≤ T ≤ 350°C) hydrothermal systems. Calculations indicate that the local dissolution of arsenopyrite creates more reducing conditions than in the bulk fluid, which is likely to be an effective mechanism for precipitating gold from hydrothermal solutions. This could be a possible explanation for the gold-arsenopyrite association commonly observed in many hydrothermal gold deposits

Integrated Analysis of Energy, Material and Time Flows in Manufacturing Systems

AbstractEnvironmental objectives (e.g. energy and resource demand, emissions, waste) become increasingly relevant for manufacturing companies in addition to traditional economic objectives (e.g. throughput time, output). Currently, different methods and tools are available to address those objectives individually, such as value stream mapping (economic), material and energy flow analysis/MEFA as well as Life Cycle Assessment/LCA (environmental). However, there is a lack on approaches that bring together benefits of those tools and allow simultaneous consideration of all objectives. Against this background, a methodology is developed to analyses the energy, material and time flows of manufacturing systems in an integrated manner. The proposed method is exemplary applied to the case of an Australian manufacturing company

A comparative LCA method for environmentally friendly manufacturing: Additive manufacturing versus Machining case

Additive Manufacturing (AM) technologies revolutionized the common understanding of manufacturing with their layer-by-layer building principle. However, the literature has documented their high energy requirements, which is not in-line with the current policies of energy and emission reduction. This ambivalence of AM opens the question for the research community about the wise choice of the manufacturing process to be adopted. This paper proposes a comparative LCA method to select the best manufacturing technology between Conventional Manufacturing (CM) and EBM plus Finish Machining (EBM+FM). The Life Cycle Assessment (LCA) is conducted under cradle-to-gate boundaries. Three metrics, namely the Cumulative Energy Demand (CED), cost and CO2 emissions are considered. Characterization of unit processes is done by using the recent findings in the literature which are included in the model for both process technologies. The Specific Energy Consumption (SEC) is connected to the Material Removal Rate (MRR) and to the average Deposition Rate (DRa), respectively for machining and EBM. The main finding of this research is the description of breakeven surfaces, which separate the regions of validity between machining and EBM, as function of the Solid-to-Cavity Ratio (SCR) and the DRa. Moreover, the presented methodology gives the possibility to compare the goodness of the different sets of design rules that can be chosen for EBM, thanks to the proper evaluation of the SEC parameter. Finally, a sensitivity analysis is conducted to assess the effect of the remaining key variables

Set-up reduction in injection molding process- A case study in packaging industry

The competitiveness of manufacturers can be significantly enhanced through implementation of Setup Reduction (SUR) initiatives. This paper presents a simplified SUR approach which was trialed and fully implemented in an injection molding facility. The identification of bottlenecks in production was carried out by using extensive data gathering on machine down-time and/or changeover time records. The detailed analysis of the operations carried out by employees were investigated by using the Single Minute Exchange of Dies (SMED) philosophy. Close collaboration with employees and formation of SUR teams facilitated the development of a system for the organization and storage of molds. The system developed ensures mold readiness conditions, reduces lead times and improves the storage, monitoring and accessibility of machine programs

Investigation of the potential for an automated disassembly process of BEV batteries

Current electric vehicle battery recycling processes often begin with the manual dismantling of the battery packs. In consideration of occupational safety and in view of the increasing sales of electric vehicles, an automated dismantling of batteries has to be investigated. Therefore, different manufacturers' battery pack designs are examined first and especially the common joining elements are determined and characterized. The results show a high diversity between the individual systems, which influences the potential for automation. Based on these investigations, a possible layout of an automated dismantling cell is developed