Four archetypes of process improvement: a Q-methodological study

This paper explores the process improvement approaches of organisations. It seeks to identify process redesign principles and the combinations of these principles that are used successfully in industry. We use Q-methodology to explore the viewpoints of a range of highly experienced process experts about the success of 16 improvement practices. Q-methodology enables the examination of the similarities and differences in the success of the improvement principles used by organisations in order to inform archetypes of process improvement. Overall, our findings suggest that process improvement is determined through the application of two foundational principles combined with one of four archetypes. ‘Remove non-value-adding tasks’ and ‘re-sequence tasks’ are described as foundational principles of process improvement, whilst outsourcing needs to be approached with caution. Furthermore, we articulate four distinctive archetypes comprising unique configurations of improvement principles that can be used to redesign operational processes. Based on this evidence we propose a typology of process improvement. This work suggests that rather than adopting generic improvement frameworks, managers should consult the typology to determine the archetype in closest proximity to their specific requirements. This study has several limitations including the small number of items populating the concourse and the fact that implementation problems are not taken into account.     

Design of high performance badminton shuttlecocks: virtual and rapid prototyping approach

In this paper, a framework utilising virtual and rapid prototyping to aid design of a shuttlecock skirt was proposed and implemented. A standard template for flow simulation on ANSYS® CFX was developed to predict the aerodynamic performance of the virtual prototypes, with focus on reduced simulation time and complexity. This forms the basis of the computer aided design model – computational fluid dynamics – performance evaluation loop in the proposed framework. Steady state flow simulation was conducted for three simple computer aided design models of shuttlecocks, with different gap dimensions on the skirt. Wind tunnel drag study of the models reproduced through rapid prototyping validated the simulation result. The proposed methodology can also be applied to the existing design process for integration of virtual and rapid prototyping to reduce the burden of design iteration.     

A formal method for subjective design evaluation with multiple attributes

This paper contributes toward a more formal theory and methodology for design by mathematically modeling the functional relationships between design decisions and the ultimate overall worth of a design. The conventional approach to design evaluation is limited in two respects. First, the direct measurement of attribute performance levels does not reflect the subsequentworth to the designer. Second, ad hoc methods for determining the relative importance or priority of attributes do not accurately quantify beneficial attribute tradeoffs. This information is critical to the iterative redesign process. A formal Methodology for the Evaluation of Design Alternatives (MEDA) is presented which resolves these problems and can be used to evaluate design alternatives in the iterative design/redesign process. Multiattribute utility analysis is employed to compare the overall utility or value of alternative designs as a function of the levels of several performance characteristics of a manufactured system. The evaluation function reflects the designer's preferences for sets of multiple attributes. Sensitivity analysis provides a quantitative basis for modifying a design to increase its utility to the decision-maker. Improvements in one or more areas of performance and tradeoffs between attributes which would increase desirability of a design most are identified. A case study of materials selection and design in the automotive industry is presented which illustrates the steps followed in application of the method.     

Development of metric method and framework model of integrated complexity evaluations of production process for ergonomics workstations

Staff in manufacturing sites not only need certain physical requirements for their allotted tasks but also utilise a large amount of information processing in the looming industrial age 4.0. This work established the Principles of Information Processing Economy in the production process and proposed a framework model of integrated complexity evaluation method for the production process, which combines both physical and cognitive loads while accounting for the effect of time stress. The method proposed in this study can be used for ergonomics evaluation of workstations. Compared with traditional evaluation methods, this method has good flexibility to account for the changes in labour loads in the industrial 4.0 eras and the role of various intelligent auxiliary systems. The proposed operational framework model can provide useful information for task assignment, operator selection and training, work organisation, and performance prediction.     

Models and abstractions in design

The use of abstractions and models helps designers to focus on interesting characteristics of a design and to simplify the complex relationship among behaviour and form. Designers create and utilize incomplete models which capture limited aspects of the design's behaviour. A designer might, for example, create a kinematic model, a stress model, or a geometric model at different stages in the design process. Designers create these abstract models of incomplete designs to test design decisions and to provide a framework for making design refinements The quality of the completed design depends on the ability of the designer to select useful abstractions, to use them to model the performance of the design, and to use the results of the evaluation to guide further design refinements. We review the evidence for the uses and effectiveness of abstractions in the design process. Based on these findings, we review how abstractions can be created and used during the design process.     

A holistic approach to thermomechanical processing of alloys

New process design and control methods are needed for significantly improving productivity and reducing costs of thermomechanical processes such as hot metal forging. Current practices for accomplishing basic design tasks such as selecting the number of forming steps and specifying the processing conditions for each thermomechanical operation produce feasible solutions that are often far from optimal. Substantial improvements in effectiveness and efficiency can be realized through holistic approaches that optimize the whole system performance and not just individual subsystems such as workpiece material behavior, material flow in dies, and equipment responses. Recent progress in the application of dynamical modelling and process design techniques using ideal forming concepts and trajectory optimization are discussed. Monitoring methods for the on-line monitoring of the process and an intelligent forging system has been proposed.     

基于航线规划任务的无人机数字界面布局设计

视觉显示界面中的信息布局方式作为界面构成要素之一,其设计会显著影响操作人员的判读绩效。以提高系统操作绩效为目的,从视觉流程角度探讨远程操控无人机数字界面布局设计,可为相关设计提供新的思路。研究针对某专业无人机数字界面进行界面功能模块构成解析,以无人机航线规划任务为例,以格式塔原则为指导,进行基于任务操作流程的信息布局设计,形成多个布局设计方案,并比较被试在不同方案下的任务完成时间等绩效指标。发现不同方案下被试的视觉动线流程不同,从而造成视线往复距离差异,是影响工作绩效的因素之一。基于任务操作流程的无人机数字界面布局设计,可将视觉动线流程、视线往复距离作为布局方案评价依据之一,为改进无人机数字界面设计提供新的思路。     

Production system redesign using realistic visualisation

The process of redesigning production systems is usually complex, for which virtual design tools are available. These tools are used to analyse and evaluate planned changes prior to implementation, making it possible to identify and prevent costly design mistakes. Despite this, design mistakes arise during and after the implementation. A source for design mistakes is incorrect or insufficient spatial data of the production systems used in the virtual design tools. The aim of this paper is to show how to reduce the time required for planning and implementing the redesign by supporting the process with realistic visualisation, created from accurate spatial data of the real production systems. Three industrial studies were carried out to evaluate how address realistic visualisation in order to support the redesign process. The result shows terrestrial 3D laser scanning to be suitable for capturing spatial data for realistic visualisation of production systems. The realistic visualisation can be used to virtually analyse design alternatives of the production systems, by, for example, combining the 3D laser scan data with 3D CAD models. The realistic visualisation enabling effective and accurate planning, which gives the opportunity to reduce the time required for planning and implementing redesigned production systems.     

One-off or batch upgrading of complex products and systems: concepts,data model and analysis framework

One-off or Batch upgrading is the term given to the process of improving one or several operational instances of complex products or systems (e.g., trains, aircrafts, etc.) during their life span. Other products such as cars or personal computers are regularly improved through redesign, generation after generation; however, redesign never concerns only one or several instance(s). The main challenge presented in this paper is to provide a suitable framework to analyse one-off and batch upgrading processes. This framework targets at containing required concepts and drivers for upgrade problem posing. The axiom beneath this research is that the goal of upgradings is to improve the performances of products or systems. Upgrade-to-performance, UtP in short, represents this paradigm that will be defined and illustrated through examples. To reach this goal, necessary concepts are defined and linked together through a generic data model. The UtP data model can be used in a conceptual way clarifying the scope of the upgrading process. It can also be specialized to specific industrial domain and used as the main driver of the design of a database for a given upgrading projects. The use case reported concerns the conversion of a passenger train into an express freight where the focus is put on enlarging a coach’ door. The results are then discussed to figure out the links between the UtP problem-posing and problem-solving methods and the gaps to fill. Finally, further research niches are described.     

From loop structure to policy-making: a CONWIP design framework for hybrid flow shop control in one-of-a-kind production environment

A feasible constant work in process (CONWIP) policy can guide developer to better implement CONWIP system. The feasible policy should be selected from alternatives by evaluation. Therefore, how to generate more than one CONWIP alternative policy to evaluate is an inevitable problem in CONWIP practice. From the perspective of loop structure, we propose CONWIP design framework (CDF) which is a systematic design approach to obtain CONWIP alternative policies. The basic concepts and components for CDF are discussed in this paper. Based on CDF, we make 10 CONWIP alternative policies for hybrid flow shop in one-of-a-kind production environment, and these alternative policies are evaluated by simulation. The simulation result implies that (i) the CONWIP alternative policy with robustness has the potential to cope with more fluctuations in high-variety production environment; (ii) a better design for CONWIP policy will be able to enhance the system performance in practice; and (iii) the loop structure can serve as a parameter of CONWIP.     

Automatic differentiation of micromechanics incremental schemes for coupled fields composite materials: Effective properties and their sensitivities

A modeling approach based on automatic differentiation and micromechanics incremental schemes for coupled fields composite materials is presented in this work. In the multi-sites framework, the micromechanics incremental schemes presented herein are able to account for the anisotropic behavior of the constituents, the morphological and the topological textures and the strong contrast between the properties of the individual phases of these composite materials. By applying automatic differentiation to these micromechanics incremental schemes, the first order and high order sensitivities of the effective material properties can be easily computed in the same analysis. An application on three-phase magneto-electro-elastic composite material is presented in the framework of mono-site micromechanics to show the effectiveness of this composite materials modeling approach. The details on the implementation of this modeling approach in the multi-sites framework will be discussed in a future work. The composite materials modeling methodology reported here may be used for material microstructure sensitive design in material by design strategies.     

Pattern-based reasoning for rapid redesign: a proactive approach

This paper describes our continued effort in the development of the model-based rapid redesign methodology. In the prior work (Chen et al. in ASME J Mech Des 129:283–294, 2007), we have explored and applied various decomposition patterns for rapid redesign to effectively control design change propagation. Since the decomposition process for redesign is not activated until the presence of a redesign request, this prior work represents a reactive approach where a new set of decomposition patterns should be generated in accordance with a different redesign request input. As an extension to our redesign methodology, this paper presents a proactive approach to complement the existing methodology for rapid redesign. In this approach, the decomposition patterns capturing generic decomposed structures of a given design model are created in advance and stored in a design library before any redesign request emerges. These pre-generated patterns are able to address any upcoming redesign request without further decomposition procedures in redesign. This proactive approach is developed in a new framework of pattern-based reasoning that is built on the mechanism “case → pattern → strategy.” Two methodological components, Proactive Redesign Decomposition and Redesign Condition Analysis, are introduced along with a redesign application to an existing air-cooled condenser for illustration. This redesign approach is particularly useful when it requires only minor yet frequent modifications for the existing design.     

Analysis and prediction of microstructural effects on long-term fatigue performance of an aluminum aerospace alloy

A program of experimental and analytical tasks has been conducted to define the linkage(s) between microstructural characteristics and fatigue performance in an aluminum alloy typically used for airframe structural applications. The first goal was to develop data for quantitatively linking measurable characteristics of material microstructure with long-term fatigue performance. The second goal was to develop models to predict fatigue performance based on the microstructural characteristics. The work focused on several process variants of aluminum alloy 7050-T7451 plate. This material was chosen because of its widespread use for flight-critical airframe structural components, and the particular characteristics associated with the manufacturing, service and maintenance of thick section components. Within the framework of this objective, life-limiting microstructural features have been identified and ranked by severity, and models to quantitatively describe the evolution and growth of macrostructural cracks from those features have been developed.The modeling framework has been applied to predict the cyclic lifetime of the 7050 alloy process variants based on the populations of life-limiting microstructural features. In addition, the models have been used to show how changes in the material characteristics may affect the fatigue performance. This includes predictions of the effect of changing the life-limiting microfeature size and shape distributions, and the effect of changing material strength properties.The use of this modeling approach to probabilistically describe the implications of changes in the microstructure has been demonstrated, thereby allowing the effects of material pedigree to be predictively linked with the structural integrity of end components. The modeling framework has potential applications in airframe design support processes, and as a tool for use in material and product form selection processes.     

Desired organisational capabilities (DOCs): mapping in BPR context

This study establishes and examines desired organisational capabilities (DOCs) that affect the readiness and implementation of business process reengineering (BPR). This research uses a case study and review methodology (second hand material) to extract events and actions about how DOCs are caused by these events and actions. Preliminary organisational capabilities were established from a review of BPR projects’ reports. Twenty-one preliminary capabilities were refined and validated through interviews with BPR executives and experts. In this way, this study presented 21 DOCs, with their influence (strength) on the success of BPR initiatives and implementation. Additionally, these DOCs are ranked according to the value of creating each, before and during BPR efforts. So, a graphical aid is provided to enable decision makers to concentrate their efforts on the most influential (strongest), considering before and during implementation. Finally, the refined organisational capabilities formed the basis of a self-assessment framework that can be used by firms to analyse their readiness to undertake a reengineering project.     

Performability of automated manufacturing systems with centralized material handling

We present a framework for performance evaluation of manufacturing systems subject to failure and repair. In particular, we determine the mean and variance of accumulated production over a specified time frame and show the usefulness of these results in system design and in evaluating operational policies for manufacturing systems. We extend this analysis for lead time as well. A detailed performability study is carried out for the generic model of a manufacturing system with centralized material handling. Several numerical results are presented, and the relevance of performability analysis in resolving system design issues is highlighted. Specific problems addressed include computing the distribution of total production over a shift period, determining the shift length necessary to deliver a given production target with a desired probability, and obtaining the distribution of Manufacturing Lead Time, all in the face of potential subsystem failures.     

Identifying inventory problems in the aerospace industry using the theory of constraints

In the aerospace industry, where each component is time-critical, many operation management tools are applied to improve material management efficiency. By using the theory of constraints (TOCs), this study diagnoses the undesirable effects (UDEs) of material management systems and identifies root problems or conflicting material management actions. In the second step, via UDEs, this study constructs a current reality tree (CRT) to identify a company's material management objectives and requirements, and the actions it takes to meet these objectives. In addition, the UDEs and CRT are applied to redesign the future reality tree (FRT) to develop strategies and eliminate the problems in the case company. By eliminating the conflicting inventory management activities of different departments, inventory management performance for the entire system is improved.     

A heuristic for designing manufacturing focus units with resource considerations

This paper presents a model of the plant-within-a-plant (PWP) design problem and demonstrates a heuristic for analysing the problem. Although the benefits of a manufacturing focus have been articulated in the literature, methods for implementation with consideration for resource requirements have not been developed previously. In this study, we discuss the importance of including resource considerations and propose a methodology that can help managers arrive at a facility design with a high degree of focus and minimum resource needs. A heuristic is developed that incorporates the concept of order-winning criteria and volume into the focus design. The heuristic not only recognises the effects of conflicting manufacturing tasks, but also considers resource costs and material flows between PWP units. Experimental results show that the proposed methodology offers managers the opportunity to generate and assess alternative PWP designs, which are otherwise unavailable. Overall, this research provides an analytical framework for further research in focused manufacturing.     

Assembly/disassembly task planning and simulation using expert Petri nets

Automatic assembly/disassembly planning is recognized as an important tool for reducing the manufacturing costs in concurrent product and process development. This paper developed a knowledge-based expert Petri net model by incorporating expert system techniques in artificial intelligence into ordinary Petri nets for an analytical framework of understanding, representing and reasoning the assembly/disassembly tasks. Substantial extensions have been made to ordinary Petri nets by adding control places, time constraints, and place and transition knowledge annotations. The proposed expert Petri net model can be considered as the hybrid of expert systems and ordinary Petri nets. Through these extensions, the capacities of modelling and representation of ordinary Petri net models are largely enhanced, and thus the expert Petri net models are more powerful than ordinary Petri nets. Such intelligent Petri net models can combine the abilities of modelling, planning, and performance evaluation for assembly/disassembly tasks in an integrated and intuitive way, and can therefore be applied to either linear/non-linear, static/dynamic, or on-line/off-line assembly/disassembly tasks at both high and low levels. The developed assembly/disassembly planning system can generate the best strategies and plans for assembly/disassembly. The research findings are exemplified with a real assembly to show the effectiveness of the method.