Early Stages Of Product Design Research Articles

Cost Estimation in Engineer-to-Order Manufacturing

Abstract In Engineer-to-Order (ETO) manufacturing the price of products must be defined during early stages of product design and during the bidding process, thus an overestimation of product development (PD) costs may lead to the loss of orders and an underestimation causes a profit loss. What many ETO systems have in common is that the products have to be developed based on different customer requirements so that each order usually results in a new variant. Furthermore, many customer requirement change-requests may arise in different phases of the PD, which is to be considered properly. Thus it is utmost important for ETO systems to have an accurate cost estimation in first stages of the product design and to be able to determine the cost of customer requirement changes in different phases of PD. This paper aims to present a cost estimation methodology as well as a cost estimation model, which estimate the cost of products by relative comparison of the attributes of new product variants with the attributes of standard product variants. In addition, as a necessity in ETO manufacturing, the cost calculation of customer requirement changes in different phases of PD is integrated in the presented method.

A theoretical framework for product relationships description over space and time in integrated design

ABSTRACTThis paper presents a novel qualitative description theory in the context of integrated design, which here incorporates assembly sequence planning in the early product design stages (also called assembly oriented design – AOD). Based on a literature review of current AOD approaches, product models and mereotopology-based theories, the authors introduce a promising mereotopological theory which enables the formal product relationships description in integrated design by introducing an emerging framework, four-dimensionalism (i.e. perdurantism in philosophy). The proposed efforts aim at providing a concrete basis for describing the evolution of spatial entities (i.e. product parts) and their relationships over time and space during the design phases by considering their related assembly processes. In product design, the interpretation of engineering reality from a perdurantist point of view leads to a seamless consideration of relationships between spatial, temporal and spatiotemporal dimensions. Indeed, with such a mereotopological theory, formal product design description is enabled by proactively considering its assembly sequence from a temporal point of view in the early stages of the product development process, and ensures information and knowledge consistency over space and time. Finally, an ontological implementation is presented within Protégé through a mechanical assembly as a case study, so as to illustrate the applicability and the relevance of the theory.

One-step Inverse Forming Simulation on Hot Forming Process of High-strength Food-can Tinplate

Hot stamping process is a complex process and the performance of food-can tinplate under high-temperature state is completely different from at room temperature. It will bring out some difficulties for the application of incremental method in early stages of food-can product design. In this study, it is the first time to put forward that the Finite Element Method of One-Step Inverse Forming can be used in hot stamping process of High-Strength food-can tinplate, which can evaluate the high temperature formability of sheet metal. The results show that: One-Step Inverse Forming FEM of High-Strength food-can tinplate is suitable for the initial die design stage because of its simple simulation method and high speed and is used to evaluate the high temperature formability of food-can tinplate.

Numerical Analysis of Residual Stresses and Distortions in Aluminium Alloy Welded Joints

Simulation software based on a finite element method have significantly changed the possibilities of determining welding strains and stresses at early stages of product design and welding technology development. But the numerical simulation of welding processes is one of the more complicated issues in analyses carried out using the Finite Element Method. A welding process thermal cycle directly affects the thermal and mechanical behaviour of a structure during the process. High temperature and subsequent cooling of welded elements generate undesirable strains and stresses in the structure. Knowledge about the material behaviour subjected to the welding thermal cycle is most important to understand process phenomena and proper steering of the process. The study presented involved the SYSWELD software-based analysis of MIG welded butt joints made of 1.0 mm thickness, 5xxx series aluminium alloy sheets. The analysis of strains and the distribution of stresses were carried out for several different cases of fixing and releasing of welded elements.

An integrated supplier selection and procurement planning model using product predesign and operational criteria

The literature of supply chain management and concurrent engineering indicates that many benefits can be achieved if suppliers are involved in product design and development. This paper proposes a single product, multiple sourcing model for evaluating and ranking potential suppliers using a multi-criteria decision making tool, the analytic hierarchy process (AHP). In addition to the criteria related to the operational aspects of the production process, such as quality and price, AHP considers other criteria related to the early stage of product design, such as end customer requirements satisfaction, technical product specifications, and supplier flexibility. The integration between operational criteria and predesign criteria, gives the decision makers the opportunity to select the suppliers that have the potential to satisfy their future demand of raw materials, components, subassemblies or services effectively and efficiently, as well as the capability to satisfy the end customers’ requirements by positively affecting the design of the finished products. The output from AHP is then used in a two-stage optimization model where a utility function that includes suppliers’ relative weights is first maximized to select the best suppliers, then a cost function is minimized to determine the amounts of raw materials, components, subassemblies or services to be ordered from every selected supplier. An application to the lubricants industry is carried out where predesign criteria such as base oil dynamic viscosity and kinematic viscosity are taken into account in the supplier selection phase to show the effectiveness of the model.

AI-based methodology of integrating affective design, engineering, and marketing for defining design specifications of new products

In the early stage of product design, particularly for consumer products, affective design, engineering, and marketing issues must be taken into considerationand they are commonly performed respectively by product designers, engineers, and marketing personnel. However, they have different concerns and focuses with regard to the new product design. Thus, these three processes are commonly conducted separately, leading to a sub-optimal and even sub-standard design. Such scenario indicates the need to incorporate the concerns of the three processes in the early stage of product design. However, no study has explored the incorporation of the concerns of the three processes into the product design. In this paper, an artificial intelligence (AI)-based methodology for integrating affective design, engineering, and marketing for defining design specifications of new products is proposed by which the concerns of the three processes can be considered simultaneously in the early design stage. The proposed methodology mainly involves development of customer satisfaction and cost models using fuzzy regression, generation of product utility functions using chaos-based fuzzy regression, formulation of a multi-objective optimization model and its solving using a non-dominated sorting genetic algorithm-II (NSGA-II). A case study was conducted for electric iron design to evaluate the effectiveness of the proposed methodology.

An integrated AHP and VIKOR for design concept evaluation based on rough number

Design concept evaluation at the early stage of product design has been widely recognized as one of the most critical phases in new product development as it determines the direction of the downstream design activities. However, the information at this stage is mainly subjective and imprecise which only depends on experts’ judgments. How to handle the vagueness and subjectivity in design concept evaluation becomes a critical issue. This paper presents a systematic evaluation method by integrating rough number based analytic hierarchy process (AHP) and rough number based compromise ranking method (also known as VIKOR) to evaluate design concepts under subjective environment. In this study, rough number is introduced to aggregate individual judgments and preferences and deal with the vagueness in decision-making. A novel AHP based on rough number is presented to determine the weight of each evaluation criterion. Then an improved rough number based VIKOR is proposed to evaluate the design concept alternatives. Sensitivity analysis is conducted to measure the impact of the decision makers’ risk to the final evaluation results. Finally, a practical example is put forward to validate the performance of the proposed method. The result shows that the proposed decision-making method can effectively enhance the objectivity in design concept evaluation under subjective environment.

Optimisation of the structural modes of automotive-type panels using line stiffeners and point masses to achieve weak acoustic radiation

In this paper, an optimisation method is presented that turns the structural modes of an automotive-type panel into weak acoustic radiators. The advantage of the proposed method is that the optimum design does not depend upon a specific excitation mechanism. Hence, the optimised panel can be used in the early stages of vehicle product design when specific knowledge about the excitation forces is not available. In the proposed method the boundary conditions of the panel are specified such that the panel can be considered in isolation from the rest of the structure. The optimisation of the structural modes of the panel is then achieved by placing a number of constraint masses and stiffeners of optimum size and weight at optimum locations on the plate. Firstly, a theoretical model of a simply-supported plate is developed that takes into account the constraints at arbitrary positions and orientations. Then a genetic algorithm is used to minimise the sound power radiated by different modes on the plate by finding the optimum design for the constraints. Secondly, the use of added masses and stiffeners is then applied to a floor panel of a simplified model of a vehicle body structure in order to reduce the radiated sound. Predicted and experimental results of the radiated sound power from a reference flat panel and from various optimised panel designs are presented to illustrate the effectiveness of the optimised designs in reducing radiated sound from the structure. A combination of masses and stiffeners is shown to be an effective way of constructing weakly radiating structural modes on the panel.

The Quality of a Design will not Exceed the Knowledge of its Designer; an Analysis Based on Axiomatic Information and the Cynefin Framework

Knowledge is essential to the product designer. It contributes to a better understanding of the difficulties in a design. With the right knowledge, design errors can be recognised in the early stage of product design, and appropriate measures can be applied before these errors escalate and delay the project. The axiomatic complexity theory, part of the Axiomatic Design methodology, can warn the designer in this process by disclosing his lack knowledge to fully understand the design. The Cynefin framework is a sense-making framework that distinguishes an organisational situation within four contexts. The state of relevant knowledge is the most important parameter to determine the actual context where an organisation, system, or design process is currently located. When knowledge is acquired, the context changes. Axiomatic Design and the Cynefin framework are applied in this paper to characterise the relation between the quality of the design and the knowledge of its designer. It is investigated if one follows the other, and how prompt that relation is. The outcome is that the quality of a design is proportional to the accumulation of applied knowledge to the product design. Therefore the quality of the design follows knowledge implementation but does not exceed the level of relevant knowledge of the designer. Knowledge should not be restricted to the designers only. Other people, e.g. production- and maintenance-engineers, will also need the knowledge to take care of the product as the life cycle advances.

Developing integrated sustainable product-process-service systems at the early product design stages

The paper describes a systematic approach that aims to foster the development of sustainable integrated systems of products and services since the very early phases of conceptual design. The procedure helps the designer in redesigning a product (as well as the related processes and services) to reduce its overall impacts. The method takes into account environmental, social and economic aspects concerning a wide range of stakeholders. The proposed approach adopts the functional analysis methodology, which is used to: 1) characterise the product (either an artefact or a service) as an integrated product-process-service system; 2) identify the design analogies with existing products in order to identify the similarities in terms of sustainability impacts. The improved design concept, along with the related environmental, economic and societal characteristics, is used as a starting point for the successive detailed design. A case study illustrates the method and proposes a redesign of the product-process-service for carrying babies.

A methodology of integrating affective design with defining engineering specifications for product design

Affective design and the determination of engineering specifications are commonly conducted separately in early product design stage. Generally, designers and engineers are required to determine the settings of design attributes (for affective design) and engineering requirements (for engineering design), respectively, for new products. Some design attributes and some engineering requirements could be common. However, the settings of the design attributes and engineering requirements could be different because of the separation of the two processes. In previous studies, a methodology that considers the determination of the settings of the design attributes and engineering requirements simultaneously was not found. To bridge this gap, a methodology for considering affective design and the determination of engineering specifications of a new product simultaneously is proposed. The proposed methodology mainly involves generation of customer satisfaction models, formulation of a multi-objective optimisation model and its solving using a chaos-based NSGA-II. To illustrate and validate the proposed methodology, a case study of mobile phone design was conducted. A validation test was conducted and the test results showed that the customer satisfaction values obtained based on the proposed methodology were higher than those obtained based on the combined standalone quality function deployment and standalone affective design approach.

CFD Simulation and Validation of Phase Particle Entrapment

A cost-effective and efficient technology was developed to remove particulate and fibrous matter from a container while avoiding dispersing the particles in the environment. This paper presents the whole process of computationally developing a conceptual system which can efficiently remove particles in the size range of 5–1000 μm from the container. The present work offers the unique virtue that prototyping can be easily followed and it shows an efficient, safe, low-cost method in the early product design stage. In the presented system, a viscous medium was designed to capture and flocculate the particulate matter. One of the factors which will lower the operating costs is that the viscous medium can be easily recycled and the flocculated particles with minimal volume can be disposed of safely. The ANSYS FLUENT package was used to simulate our proposed design. The effects of various particle size, specific gravity, and pressure-velocity boundary conditions on separation efficiency of the design have been studied by using different multiphase models along with viscous and discreet phase models.

Compensation-based methodology for maintenance time prediction in a virtual environment

This study presents a novel compensation-based methodology for maintenance time prediction in a virtual environment during the early stage of product design. According to the work procedure in assigning maintenance tasks, a maintenance process simulation is generated on the virtual maintenance platform by following the simulation principle. The basic compensation time or ratio is acquired by analyzing the relationship between practical human motions and corresponding virtual human motions. After that, the compensation principle is confirmed based on the generated simulation principle. Finally, the simulation time and compensation time are approached according to the compensation model to obtain the predicted time. The obtained predicted time of several cases are accurate to a certain extent compared with feedback information.

A predictive risk evaluation framework for modular product concept selection in new product design environment

The purpose of this research is to help product managers in an original equipment manufacturer at early stages of new product design (NPD) to choose the best design concept for subsequent development and commercialisation that is associated with least risk to the enterprise. The product considered in this research is modular and repairable in nature. Considerations such as the availability of different module instances for different modules and the respective mean time to repair reflect the modularity and reparability aspect of the product considered in this research. In order to develop a comprehensive risk evaluation framework, generic and high-level risk characteristics pertaining to multiple functional agencies involved in NPD are considered. These risk characteristics represent relevant technical and commercial risk parameters corresponding to the six different functional agencies, i.e. design, supply chain, manufacturing, marketing, quality assurance, and after-sales support. Bayesian network methodology is adopted to map the relationship among various risk parameters denoted by parent and root nodes. Thereafter, a new measure, i.e. Overall Enterprise Risk Index is devised that weighs all possible design concepts in terms of an aggregate risk number. The proposed methodology is illustrated using a real-life case of ROPS canopy of heavy construction machinery.

Trend Analysis of Product Function Using Sequential Pattern Mining

During the early stage of product design, it is important for design engineers to decide the most appropriate functions for various customers. To facilitate this time consuming task, sequential pattern mining is applied to uncover the useful patterns in historical database. The mined sequential patterns can reflect the dynamic change of product functions, which can help design engineers find the most suitable product functions for customers. Based on the historical sales transactions of computer, a case study is conducted to illustrate the proposed method.

Trend Analysis of Product Function Using Sequential Pattern Mining

During the early stage of product design, it is important for design engineers to decide the most appropriate functions for various customers. To facilitate this time consuming task, sequential pattern mining is applied to uncover the useful patterns in historical database. The mined sequential patterns can reflect the dynamic change of product functions, which can help design engineers find the most suitable product functions for customers. Based on the historical sales transactions of computer, a case study is conducted to illustrate the proposed method.

Information exchanges between experts for thermoset composites design for recycling

The use of composites in industry is ever increasing. However, end-of-life solutions for composites are still under development. In this paper, a solution linking design strategies with a recycling process for thermoset composite materials is proposed. The recovery solution for these materials is a supercritical water solvolysis process. The needs and multi-disciplinary skills required for taking recycling possibilities into account in the early stages of product design and the necessity to standardise product-recycling capabilities based on design requirements will be discussed. The paper highlights the need for designers to take a functional approach into consideration, including characterisation of materials behaviour, recycling process limits, constraints and opportunities. This paper will show the first lessons learned from experiments, using this technique.

User-Adaptive Sketch-Based 3-D CAD Model Retrieval

3-D CAD models are an important digital resource in the manufacturing industry. 3-D CAD model retrieval has become a key technology in product lifecycle management enabling the reuse of existing design data. In this paper, we propose a new method to retrieve 3-D CAD models based on 2-D pen-based sketch inputs. Sketching is a common and convenient method for communicating design intent during early stages of product design, e.g., conceptual design. However, converting sketched information into precise 3-D engineering models is cumbersome, and much of this effort can be avoided by reuse of existing data. To achieve this purpose, we present a user-adaptive sketch-based retrieval method in this paper. The contributions of this work are twofold. First, we propose a statistical measure for CAD model retrieval: the measure is based on sketch similarity and accounts for users' drawing habits. Second, for 3-D CAD models in the database, we propose a sketch generation pipeline that represents each 3-D CAD model by a small yet sufficient set of sketches that are perceptually similar to human drawings. User studies and experiments that demonstrate the effectiveness of the proposed method in the design process are presented.

FORECASTING MODEL OF MANUFACTURING TIME AT THE EARLY DESIGN STAGE OF PRODUCT AND PROCESS

This paper considers the developed forecasting model of a manufacturing time at the early product and process design stage. Developed model forecasts the manufacturing time of machining operations by removed material volume and achieved part’s quantitative-qualitative characteristics. Presented methodology of manufacturing time forecasting on products and their design features classification is based. The design features into two separate class level – rotational and prismatic geometrical form are classified. Consideration on the virtual environment is made; the mathematical formalization of forecasting manufacturing time and repartition of design features in mechanical parts and products applying statistical analyses methods are defined. The proposals how would be possible to classify the design features of products’ and how to define their influence to the manufacturing time by the removed material volume of separate design features.DOI: http://dx.doi.org/10.5755/j01.mech.19.1.3620

A modeling approach for maintenance safety evaluation in a virtual maintenance environment

This paper presents a novel virtual maintenance application for maintenance safety evaluation (MSE) to provide recommendations on maintenance safety during the early stages of product design. The proposed methodology detects the potential defects via virtual maintenance technology, and safety evaluation could be carried out in a predictive way intuitively and systemically to decrease the possibility of accidents. After reviewing relevant publications, a MSE model with thorough consideration of the characters in the virtual maintenance environment was addressed. The model consists of evaluation contributors, evaluation criteria, and evaluation methodology. A case study on APU system maintenance was used to illustrate the performance of the evaluation model. The result showed the feasibility of virtual maintenance in improving maintenance safety designs.