In manufacturing, the determination of a (near) optimal sequence of machining operations to create a part is a non-trivial task. The paper presents the use of datum hierarchy trees in operation sequencing to ensure the finished part satisfies the design tolerances. Based on this technique, a framework is proposed to automate not only the retrieval of relevant plans for evolving the datum hierarchy tree of a new part, but also the optimisation of the operation sequence subjected to constraints on group cell layout, cut sequence, and machine tolerances. The retrieval process is based on the classification of parts using a back propagation neural network while the operation sequence is optimised using an evolutionary algorithm. Results showed that both geometrical and part features may be needed to assist the categorisation of the parts investigated. The results from a case study using industry parts from an aerospace company revealed the potential practical value of the proposed approach in deriving operation sequence for minimal machine and datum changes, both including and excluding manufacturing sequence constraints imposed by group cell layout.

The paper presents a formal graph representation scheme for stamping operation sequencing for sheetmetal progressive dies and a graph theoretic method for automatic determination of the stamping operation sequence. Operation relations are represented by two graphs: an operation precedence graph and an adjacency graph. The first represents precedence constraints defined by best manufacturing practices. The second represents geometric infeasibility relations between operations. Each operation is a member of both graphs. The graphs are automatically generated from a set of stamping operations, which in turn are associated with stamping features of a part. The operation precedence graph is then verified to be acyclic using a coloured Depth First Search. Based on the operation precedence graph, a modified topological sort algorithm is applied to cluster the operations into partially ordered sets. Finally, a graph-colouring algorithm is applied to the operation adjacency graph on the partially ordered operation sets. The algorithm is implemented in C++ and is fully integrated with SolidWorks computer-aided design system. A case study is presented to illustrate the algorithm.

This paper presents an expert functional design model and software modeling environment for designing the architecture of industrial robots. The modeling environment comprises an integrated knowledge base, an inference engine, a working memory, and an explanation unit and is implemented in CLIPS. The functional design model is based on the authors’ behaviour-driven, function-environment-structure (B-FES) formalism, which has been tailored to meet the special requirements of industrial robot design. A universal robot template has been created and a library of typical components of a robot has been compiled. Nine customized templates were generated from the universal template. Web links to the websites of manufacturers/suppliers provide easy access to data on robot components. The architectural design solutions are assessed by a set of user-defined performance criteria, such as precision, flexibility and short cycle time. Application of the approach is demonstrated through a case study of the functional design of a printed circuit board assembly robot. The authors argue that this approach is new for configuring robots and can significantly reduce the time, effort and number of errors made.

This paper presents a new type of feature, associative assembly design feature. Its concept, implementation, and application are introduced. This new feature allows the following associations: (1) between parts that have not been defined geometrically; (2) between geometric entities defining interfaces between parts; and (3) between part geometry and intermediate geometry used to define a part. The associations can be geometric or non-geometric. Our extension to traditional assembly feature properties allows product architectures to be defined using features. These architectures, in turn, can be used to constrain the modular design of assembly geometry. The application is a mould base library for injection mould design.

Injection-moulded-plastic-part design must ensure that the part can be manufactured to the desired quality level by the injection moulding process. Simulation software has been widely used in industry to assess mouldability and measures of quality. However, it cannot be used to improve a design directly. Design modifications must be performed by the designer after evaluation of the simulation results. Based on the authors' previous work on injection moulding CAD-CAE integration, this paper explores the strategies and methods for automatic-part-shape-modification to attain a desired part quality. An enhanced CAD-CAE integration model is developed. This model is used to specify the shape-modification variables, as well as the mouldability and other quality measuring criteria. The shape modification variables include positional and sizing parameters of each individual feature, as well as those associated with the part, such as part thickness. With this information, an iterative process of part-shape modification and execution of simulation subroutines is carried out automatically, and the results are verified and evaluated. Optimal shape, according to the specified criteria can thus be derived from the evaluation results. A software prototype has been developed. A design case study is presented to illustrate and demonstrate the usefulness of the proposed strategies and methods.

This paper reports preliminary work to investigate the suitability of using a blackboard framework as a problem-solving model for stamping process planning in progressive die design. The model is described at two levels: knowledge level and computational level. The knowledge level describes how the stamping process planning domain is represented in a blackboard architecture. The computational level describes how the blackboard architecture is modeled and implemented using object technology. A software prototype has been developed using CLIPS and C++ interfaced with Solid Edge CAD system. An example is presented to illustrate the feasibility and practicality of the proposed approach.

Engineering design is a process of inventing new physical products and systems to fulfill human needs. It is one of the most important and challenging phases in the development lifecycle of a product (Figure 1). Note that the figure depicts the feedback loops for design only; the other feedback loops have been omitted for clarity. Figure 1. Design process and the product lifecycle.

This paper presents a graph and matrix representation scheme for the functional design of mechanical products, which provides a good basis to generate an explicit and comprehensive functional model used for functional reasoning. Three key features of the scheme are (1) The representation of the causal way behaviors are interconnected; (2) The representation of two types of functional relations: decomposed into and supported by ; and (3) Support for diverse functional reasoning paths: three alternative B-FES/e paths are currently available. The scheme can guide functional design of mechanical products through functional reasoning steps including functional supportive synthesis, causal behavioral reasoning and functional decomposition. The developed functional model and its representation applied in a knowledge-based design environment can speed up the functional design process by automating functional reasoning steps. The proposed approach has been evaluated with a functional design example of a terminal cutoff unit in an automatic assembly system for manufacturing electronic connectors.

This paper presents a case-based reasoning (CBR) methodology for computer-aided process planning (CAPP) for multi-stage, non-axisymmetric sheet metal deep drawing. The methodology addresses the indexing and retrieval of process planning cases. Planning cases are indexed via a feature-based representation of deep drawn parts. Efficient case retrieval is achieved by a feature-based similarity analysis between a new deep drawn part and existing parts in the case library. An illustrative example is included to demonstrate the operation of the proposed approach and show its effectiveness in speeding up CAPP for multi-stage non-axisymmetric deep drawing.

Recent market transition from mass production to mass customization forces manufacturers to develop product families with a common platform to increase design variety, shorten time-to-market, and reduce production costs. This paper presents a new functional modeling approach to support identification of both shared and individual behavioral modules across a family of products for module-based product family design. After separate functional modeling of each product variant, the individual functional models are merged into a single, coherent, and unified family functional model to determine all the shared and individual behavioral modules. The modularity in the family functional model is further explicitly identified using a behavioral modularity matrix of product variants versus behavior. The proposed approach provides a fast method for generating new concept variants during the conceptual design of a family of products. The rationale of managing modularity in product family design with functional modeling is manifested using a modular design example of a family of automatic assembly devices.

Modular product design has received a significant amount of attention by the business community over the past two decades. However, a widely adopted engineering approach that increases the modularity of a product has not been well developed until recently. Based upon functional modeling, this paper presents a new approach for identifying behavioral modules for modular product architecture development. An industrial case study on a terminal insertion machine for manufacturing electronic connectors is used to illustrate the upstream stage of modular product design. © Professional Engineering Publishing 2004.

Engineering education is facing an ever-increased challenge, i.e. the balance of teaching values and commercial interests. It has four social measures to be closely investigated; they are knowledge transfer, the output of qualified engineers, excellent research, and industrial impact. When an engineering institute executes its integrated approach for improving the social measures, a clear strategy is required. The authors would suggest an industrial research oriented education system that can effectively associate the above-mentioned measures together with an explicit and integrated model. The commercialization of products and the licensing of technologies from researches are the means to realize the values. This paper will also discusses the current international trends in engineering education, the challenges, and how the proposed approach can address them in Singapore as well as other countries.

Traditionally strip layout is a manual, experience-based activity. Automation of strip layout is desirable to improve productivity and the quality of design, and to provide computer-aided tools for design. One important, but very difficult, task in automated strip layout design is the determination of a good sequence of stamping operations so that the part can be stamped correctly and efficiently. This paper presents our work to develop a novel, graph-theoretic, operations sequencing method that is capable of generating a stamping sequence automatically, taking into account practical stamping constraints. A graph is used to represent a stamping part and define the relationships between its stamping features. These stamping features are then clustered into workstation sets using a graph colouring algorithm. Next, the sets are ordered to determine an optimal sequence of workstations. The objective function for the optimisation is 'minimisation of the torque difference between two sides of the progressive die'. The proposed approach can speed up the progressive die design process by automating the strip layout design.

Ribbons may be used for the modeling of DNAs and proteins.The topology of a ribbon can be described by the link Lk, while its geometry is represented by the writhe Wr and the twist Tw.These three quantities are numerical integrals and are related by a single formula from knot theory.This article discusses the meanings of these three quantities, offers an approach for calculating their numerical values, and provides some examples.

The purpose of this paper is to identify the key requirements to develop SWARM, or any other agent-based system, as an expert system for engineering design. The paper first discusses a commonly used, agent-based, expert system for design, the blackboard system. There is no control component specified in the blackboard model; this is both its strength and its weakness. The main part of the paper addresses the question “what are the key requirements for distributed control of a blackboard system for design?” The authors identify several key requirements and suggest that such a system could be implemented by modifying the distributed control concept of the CASSANDRA architecture.

In previous work the authors have developed graph-theoretic efficiency measures of process plans for rotational parts. The measures assess the technical efficiency under which a particular design can be manufactured, i.e. its manufacturability. This paper extends the earlier work by incorporating geometric dimensioning and tolerancing and developing a new technique for assessing the manufacturability of any part (prismatic and rotational). The aim is to develop an automated technique for assessing part designs.

Ribbons may be used for the modeling of DNAs and proteins.The topology of a ribbon can be described by the link Lk, while its geometry is represented by the writhe Wr and the twist Tw.These three quantities are numerical integrals and are related by a single formula from knot theory.This article discusses the meanings of these three quantities, offers an approach for calculating their numerical values, and provides some examples.

It is widely accepted that stamping process planning for the strip layout is a key task in progressive die design. However, stamping process planning is more of an art rather than a science. This is in spite of recent advances in the field of artificial intelligence, which have achieved a lot of success in incorporating built-in intelligence and applying diverse knowledge to solving this kind of problem. The main difficulty is that existing knowledge-based expert systems for stamping process planning lack a proper architecture for organizing heterogeneous knowledge sources (KSs) in a cooperative decision making environment. This paper presents a knowledge-based blackboard framework for stamping process planning. The proposed approach speeds up the progressive die design process by automating the strip layout design. An example is included to show the effectiveness of the proposed approach.

Historically, gating design relied heavily on the knowledge and experience of the mould designer. A number of automated gating design systems have been developed to overcome this difficulty. While it is important to consider design constraints in real applications, they are not considered in most of the aforementioned automated gating design systems. Moreover, considerable effort and expertise in both CAD and CAE operations are still required in these systems, especially when design constraints are considered. In this investigation, an automated routine is developed to handle design constraints in automated gating synthesis, taking advantages of functionality of both CAD and CAE systems. Standard deviation of filling time is used as the objective function during the gate optimisation process. Design constraints considered so far are no-gate constraints for three-plate moulded part and edge-gate constraints for two-plate moulded part.