Cost-effective propagation paths for multiple change requirements in the product design

A process simulation based method for scheduling product design change propagation

Lean concepts are routinely used in manufacturing but are still relatively new to New Product Development (NPD) process. If manufacturing can be modeled as flow of material, an analogous model for NPD process would be flow of information. This paper addresses the issue of eliminating wastes in new product development process by bringing lean concepts through an assessment system. The paper first defines wastes in the context of NPD process. A large number of waste drivers which add to wastes in any NPD process are identified. Similarly lean enablers and lean tools which if implemented can reduce wastes are also identified. A model connecting wastes and lean enables is arrived which gives a holistic picture of relationship to address and assess wastes in any NPD process. In order to measure the effectiveness of NPD process five lean performance measures are used which include design cost overrun, product cost overrun, schedule overrun, knowledge capture and customer satisfaction. Industrial inputs are used to arrive at assessment system proposed in this work and a further feedback from industry is used to enrich the assessment system after it is developed. Though the proposed system is developed for machine tool development process, it is generic in nature and can be used to assess any new product development activity.KeywordsNew product developmentLean product developmentLeanness assessment

A substantial amount of mining infrastructure projects experience cost and schedule overruns, and this situation is largely brought about by poor requirements management. More specifically, evidence suggests that overruns are primarily due to inadequate requirements definition and scoping, as well as the poor handling of requirements information throughout the project lifecycle.
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\nWith many parallels to mining infrastructure, the construction management literature agrees that there are some common compromising conditions associated with poor requirements management: clients are not fully engaged in the requirements gathering/identifying process; client’s requirements are not properly elicited, identified and captured; decisions made about requirements specifications are solution biased by partisan factions; manual requirements documentation suffers from version control; and the end user’s identification and involvement is usually too late.
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\nOf concern to the mining industry and their infrastructure projects, is that the implications of cost and schedule overruns is significant, to the extent that on average cost overruns can be 95% above the original estimate. This suggests that for the mining industry, overrunning the sanctioned budget and schedule commitments are a regular occurrence. Therefore, the research problem for this study is to the explore requirements management conditions and establish the subsequent contributing factors in mining infrastructure projects that persistently makes them vulnerable to costly overruns.
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\nThis research was divided into two stages, with Study 1 exploring the comprising conditions in requirements management, which subsequently informed Study 2 to establish the contributing factors. This study used semi-structured interviews and some internal documentation reviews to develop a theory to explain why the situation is not improving for mining infrastructure projects. Interview data was collected from a cross-section of professionals currently in owner teams, consulting, and delivering infrastructure projects in the Australian Coal Mining industry. The results of a thematic analysis on interview transcripts finds the claims of the previously identified compromising conditions of construction projects to also be true of mining infrastructure projects, with the additional compromising conditions of ‘late changes to projects by new stakeholders’, which may be peculiar to mining infrastructure projects.
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\nHowever, more pertinently to the development of a theory to explain the situation, a second round of analysis and coding on the transcripts and documentation applied with a Husserlian lens revealed that the requirements management documentation was not fit for purpose, in terms of how it is dominated by exchange-value and fails to adequately capture the use-value and benefits of the project.
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\nThe terms exchange-value is defined as the monetary amount realized at a certain point in time, whereas use-value refers to the specific qualities of the product perceived by customers in relation to their needs, which for example could be functionality. The preferencing of exchange-values is considered a result of the influence of management discourse. This discourse is evident in the requirements documentation that management sanction. However, in the interviews, participants appeared to feel less pressured or bound to adopt the management discourse. As many of them are mining engineers or engineering/mining workers who have
\nmoved into management roles, they tend to speak in terms of use-value (a things ability to satisfy a need) as well as exchange-value (the price or cost of production).
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\nThe findings of this study include the determination of an additional compromising condition to requirements management, which is that of late changes by new stakeholders. Another finding is that a contributing factor to cost and schedule overruns in mining infrastructure projects is the misalignment of values inculcated in requirements management documentation, which privilege the values of management (exchange-value) rather than the values of the client and end-users (use-value).
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\nWhilst these documents and processes are intended to describe, convey, and ultimately safeguard the project’s use-value for the client through to delivery, management is largely the consumers of these documents, and they have unwittingly biased these documents to communicate exchange-value. Furthermore, the exchange-value biased requirements management documentation, influences the processes and discourse around the project, and consequentially marginalizes use-value discourse, which ironically in the long run, drastically increases the cost of the project.

The relationship between system theory and the product design, the process of product development has been described. It compared the merits and demerits of serial and parallel product development processes and, with the guidelines of system theory, put forward and analyzed the planning actions and corresponding necessity existed in the indistinct initial phase in product development process. It also analyzed the optimizing effect of planning actions in product design & development process. Thus, it obtained the model of product design & development process based on system theory so as to clarify the indistinct initial phase, shorten product development time and, improve the effectiveness of enterprise's product development.

Engineering changes are inevitable in product design, especially during the development of complex products, where they often affect multiple-domain engineering entities. Traditional single-domain change models cannot capture the multidimensional nature of products; thus, they may fail to effectively predict change propagation paths or assess impacts. To address this challenge, a multilayer network change model is proposed, consisting of the assembly, feature, face, and parameter layers. This model enables the coupled propagation of changes between parameters and structures. The first three layers represent the product's geometric topology and shape, whereas the parameter layer defines functional relationships among parameters. A parameter change prediction method based on the breadth-first search (BFS) algorithm is introduced to automatically identify and optimize change propagation paths within the parameter layer. Meanwhile, through the interlayer connections between parameters and structures, the structural entities affected by parameters can be identified. A graph isomorphism algorithm is used to accurately locate and identify structural topology change entities. Structural topology change propagation among parts is predicted based on their mating entities. The identified change entities are further used to assess their impact on manufacturing processes. A software system based on the multilayer network change model is developed, and a case study is presented to demonstrate its application in product change design, which shows that the affected manufacturing entities can be pinpointed even when design parameters are changed, and change solutions can be determined in a time-consuming and cost-effective way.

DFMEA is a systematic and scientific method for new product design and development, which is applicable throughout the entire process of new product design and development. In this paper, DFMEA method is adopted in the systematic analyzing of the million-kilowatt nuclear power steam turbine rotor new product design and development process. On the basis of the introduction of product characteristics and current development requirement, DFMEA is introduced to the design and development process, applying the block diagram and structure-function matrix to locate the possible failure factors. Subsequently, the evaluation criteria of Severity (S), Occurrence (O), and Detection (D) are introduced and defined. According to the criteria, the Risk Priority Numbers (RPN) and Action Priority (AP) of key risks are sorted, therefore indicating the terms critical to product quality improvement. Through the application of DFMEA, an effective risk identification and analysis of the million-kilowatt nuclear power steam turbine rotor is carried out, achieving the results that operational failures are advanced to the design stage to implement countermeasures, therefore realizing the improvement of product and system operation reliability, optimization of project cycle and manufacturing cost reduction. DFMEA promotes the optimization of overall new product development process. Meanwhile it provides ideas for the subsequent design optimization methods of similar kinds.

In optimizing the propagation paths of automotive product design changes, we applied the complex network theory to automotive product structure modeling and established a directed weighted auto part network model. In this model, we defined the parts as the nodes, the physical connections between the parts as the edges, and the impacts of change propagation as the weights of the edges. According to the characteristics of change propagation, we constructed a multiobjective optimization model that simultaneously considered the development time, development cost, and change risk. Using a multiobjective particle swarm optimization (MOPSO) algorithm, we solved the model and obtained the Pareto set of optimal solutions, which provided a basis for designers to choose the optimal design change plan. We conducted the multiobjective optimization of the air-conditioning system design change propagation path in a car model to verify the feasibility and effectiveness of the method.

Propagation path optimization of product attribute design changes based on Petri Net fusion ant colony algorithm

In the last two decades, lean product development and design processes, which have rapidly penetrated the automotive industry companies with all their functions and spread globally, have come to life with measurements, benchmarks and flow maps on value creation or value addition in new product project stages. In the literature review, two customer-oriented approaches, namely lean product development and user experience design, have been widely adopted within the discipline of new product design. However, the lack of comparative efficiency measurements or studies addressing their integration in scientific publications constitutes the primary motivation of this research. Furthermore, the selection of the research scope and boundaries is based on convenience sampling, enabled by direct qualitative research with companies managerial or design positions in the Turkish automotive supplier industry. The main objective of this study is to conduct a comparative analysis aimed at integrating user experience activities with lean product development process flows, and to reveal metric values that enhance efficiency through overall system optimization. On the other hand, the most important recommendation of the study is that the basic process will benefit positively by including user experience activities, which are the most important application of customer-oriented design approaches, into the highly efficient lean product development flow. Therefore, the study conducted with the mixed research method was completed under the preference of quantitative face-to-face interview method in the in-depth questioning of the qualitative numerical data obtained by the questionnaire method. User experience activities, which are newer and less widespread than lean product development processes, have also revealed the frequency of project-based, customer-oriented design activities, along with the demographic organizational structure of the participating companies in the automotive industry, such as the age of establishment, number of employees, number of designers, etc.

Design changes are frequently encountered in the product development process. The complexity of the design changes is multiplied when the product design involves multiple engineering disciplines. Very often, a simple change in one part may propagate to its neighboring parts, therefore, affects the entire product assembly. Both parts and assembly must be regenerated for a physically valid product model, at the same time, the regenerated product model must meet designer’s expectations. When a product is being developed in a Concurrent Design and Manufacturing (CDM) environment, the design changes are usually implemented first by altering geometry of the product represented in computer-aided design (CAD) solid models. If the product solid model is not parameterized properly, the changes in geometry often lead to invalid parts or assembly. At the part level, the changes may yield a solid model with invalid geometric features if it is not properly parameterized. In this case, the entire product assembly is in vain. Even when individual parts of the product are regenerated correctly, parts may still penetrate to their neighboring parts or leave excessive gaps among them, if the solid model is not properly parameterized at the assembly level. In this paper, solid modeling and assembly techniques implemented in two major CAD tools, Pro/ENGINEER and SolidWorks, will be discussed. A set of guidelines will be proposed for the designers to parameterize the solid models in order to capture the design intents more effectively in the product virtual mockup. These guidelines at both part and assembly levels will support designers to successfully conduct product design in the CDM environment. A number of examples, including a slider-crank mechanism and its crankshaft, a single-piston airplane engine and its components, as well as a number of simpler parts are presented to illustrate and demonstrate the parameterization method and guidelines proposed for both Pro/ENGINEER and SolidWorks.

Industrial revolutions (IRs) are mostly associated with how transformations regarding the operations of an enterprise affect said enterprise’s manufacturing systems. However, the impact of these transformations exceeds the production systems themselves; rather, they affect the entire value chain, from the product design and development process (PDDP) through manufacturing and supply-chain management to marketing and disposal. As the new PDDP to a large extent defines the value chain for a company, the challenge lies in ensuring that the designed product will help the company fully benefit from the IRs. By analysing the 4th IR, the authors reveal that few publications shed light on this aspect. Consequently, the purpose of this study is to establish features and properties that will shape the PDDP throughout the 4th IR and into a smart design engineering. To accomplish this, the authors conduct a systematic review of the literature, which provides ten findings. These findings are then analysed by 11 specialists both from academia and the industry, and the findings’ relations to the 4th IR and their impact on the product development process is discussed. By establishing these findings, this paper provides a platform for the understanding of what could potentially shape smart design engineering and its design-related activities.

This data article explores the factors that contribute to maintaining steady cost projection on construction projects. The data was obtained using structured questionnaire designed in Likert scale. The responses were solicited from category of construction practitioners. Simple random sampling was employed in the distribution of the questionnaires to the respondents. Data samples were analysed using severity index, ranking and simple percentages. The analysis of the data brought to fore some important data on factors that causes cost overrun, they include: contractor's inexperience, inadequate planning, inflation, incessant variation order, and change in project design. They are critical to causing cost overrun, while project complexity, shortening of project period and fraudulent practices are found to be responsible. The data fall within the percentages of possible consequences of cost overrun when compared with those available in scientific literature. The data can provide insights on how to mitigate the risks of project deviation from initial cost and as-built project.

Performance in the construction industry is wrought with challenges and owners often are victim to cost and schedule overruns, particularly on high profile projects that are large, complex, and risky. Alternative project delivery methods and techniques are continually being developed and implemented by buyers of construction services to address these problems. The Best Value Business Model (BVBM) has been rigorously tested and shown to improve project performance via its three-phased approach to project delivery. BVBM increases performance throughout the construction project lifecycle by utilizing value-based selection processes, pre-contract planning methodologies, and performance measurement systems. The objective of this research is to provide a detailed case study of BVBM application on a design-build project to deliver a highly complex research facility with tight schedule and budget thresholds. The implementation process is discussed in detail and project results are provided and analyzed to demonstrate the ability of BVBM to improve project performance. Special attention is paid to the ability of BVBM to optimize project cost and schedule performance through the application of a value-based selection methodology, a pre-contract preplanning period, and a weekly risk management system.

Pressures and procedures for the design of safe consumer products

This article presents a multi-level modelling approach for supporting the management of evolving new product development (NPD) processes. Following its articulation, an example of implementing process changes during the development process is presented. Such changes cannot be modelled by existing design/dependency structure matrix (DSM) approaches. A conceptual change in the product design occurs during the development process, in order to standardise the product components, and yields changes in the process plans that are simulated for decision-making. Implementation implications of dynamic changes to a development process are demonstrated, including business rules used to choose between process change options, while considering iteration learning effects. From the demonstration, it becomes clear that either DSM or Petri nets alone do not offer complete modelling capabilities for NPD processes and a multi-level approach must be adopted. Such a complete cycle of modelling would start from product knowledge through the DSM and DSM nets, which are process scheme models, with potentially additional patterns, and would end with a simulation in order to obtain insight into the dynamic changes in the process planning.