With the advent of commercial solid modelling systems some fifteen years ago, the opportunity for three-dimensional parametric geometry was opened to industry. Today solid modelling systems are the dominating CAD tool among advanced engineering companies, but despite the time and money saving implications, industry has been slow to exploit the parametric capabilities of these systems (Amen and Sunnersjö, 1996).

One reason for the slow adoption of parametric modelling is that originally many solid modellers suffered from lack of stability under parametric changes. This situation is now changed and if a model in a modern CAD system collapses, this is usually due to modelling deficiencies rather than numerical failures. Straightforward dimensional variations rarely cause any problems. However, to fully exploit the parametric capability for complex features with a variable topology, there is a need for a systematic approach to build stable and purposeful parametric models.

The purpose of this work is to discuss how different modelling approaches relate to the ease of use and robustness of the CAD model in terms of creating variants and product families. We use the term Design for Variability, DFV, for a modelling approach that ensures that parametric models are well suited for variation design.

For many products, the adaption to customer specifications is essential and requires flexible product design and manufacture while maintaining competitive pricing. A large category of design work in industry has the character of the redesigning of an existing product concept in terms of dimensional changes, topology variations and the configuration of components. In order to evaluate design proposals, costs, controlled by the product design, selected materials and manufacturing processes, need to be estimated. Cost estimates are normally based on the manufacturing process plans. They, in turn, can only be formed when production preparation is finalised. The widespread industrial use of solid modelling opens up new possibilities for automating this process. The purpose of this work is to demonstrate and test a method of extracting product information from a CAD model in order to allow process planning and cost calculation to be carried out automatically for a given class of products. With such a system, cost estimates can be made available to the designer the instant a design proposal has been presented. This allows design iterations to be carried out, in order to govern the design work towards solutions with an optimal balance between product and production properties.

With today’s high product variety and shorter life cycles in automobile manufacturing, every new car design must be adapted to existing production facilities so that these facilities can be used for the manufacturing of several car models. In order to ensure this, collaboration between engineering design and production engineering has to be supported. Sharing information is at the core of collaborative engineering. By implementing an ontology approach, work within domains requirement management, engineering design and production engineering can be integrated. An ontology approach, based on an information model implemented in a computer tool, supports work in the different domains and their collaboration. The main objectives of the proposed approach are: supporting the formation of requirement specifications for products and processes, improved and simplified information retrieval for designers and process planners, forward traceability from changes in product systems to manufacturing systems, backward traceability from changes in manufacturing system to product systems, and the elimination of redundant or multiple versions of requirement specifications by simplifying the updating and maintenance of the information.

Many companies base their business strategy on customized products with a high level of variety and continuous functional improvements. For companies to be able to provide affordable products in a short time and be at the competitive edge, every new design must be adapted to existing production facilities. In order to ensure this, collaboration between engineering design and production engineering has to be supported. With the dispersed organisations of today combined with the increasing amount of information that has to be shared and managed, this collaboration is a critical issue for many companies.

In this article, an approach for sharing and managing product and production information is introduced. The results are based on the experiences from a case study at a car manufacturer. By ontology-based integration, work within domains engineering design, production engineering and requirement management at the company was integrated. The main objectives with the integration were: support the formation of requirement specifications for products and processes, improve and simplify the information retrieval for designers and process planners, ensure traceability from changes in product systems to manufacturing systems and vice versa, and finally, eliminate redundant or multiple versions of requirement specifications.

With today’s high product variety and shorter life cycles in motor car manufacture, every new car design must be adapted to existing production facilities so that these can be used for several car models. Sharing information is at the core of collaborative engineering. With an ontology approach, the work within the domains requirement management, engineering design and production engineering can be integrated. An ontology approach based on an information model implemented in a computer tool supports the work in the different domains and their collaboration. In our work we make use of the existing structures and link those using appropriately named links. We also propose the introduction of a new structure describing the generic functions of the manufacturing system, MSF. This tree structure is a suitable tool to link product related objects to their associated production equipment at varying levels of detail. The manufacturing requirements are modelled using a concept for the definition of the requirement content, called Manufacturing Requirement (MR). To enable the MR to cover different ranges and levels, and enhance the maintenance of the system integrity, the concept of Requirement Object is introduced. The RO is used to collect the instances for which a specific MR is valid. We also use the rule inference facility to reduce the number of explicitly defined relations.

For parts suppliers in the manufacturing industry the process of preliminary production preparation and subsequent calculation of offers are critical business activities. A vital part of production preparation is the design of fixtures and tooling necessary for many processes of metal forming. For a company to give quick responses to customer enquiries, or changes in prior specifications, it would be highly beneficial with a degree of automation in this design process. This implies the development of a computer based system able to capture existing design procedures and associated knowledge for the classes of tooling required for the forming process.

In this work we exemplify an automated design system for tooling by an implementation for rotary draw bending of aluminium tubing. The system is based on established design practice and heuristic knowledge developed over many years of practical experience. The system will evaluate whether a given specification is producible with existing materials and equipment, select suitable machine, determine process parameters and determine type and dimensions of components of form die, clamp die, follower or pressure die, wiper and mandrel. The system is built on readily available commercial software packages. When building a system of this kind it is essential that the knowledge documentation and structure is such that the functions of the system can be easily understood by the users of the system and by future developers. Aspects of user friendliness, transparency and scalability are addressed in the summary of this paper.

In recent years the computing power and meshing algorithms have developed to a state where FEA problems can often be solved directly using the solid geometry. However for complex geometry and complicated calculations there will for the foreseeable future be a need for geometrical idealizations.

To reduce the time spent on making geometrical idealizations in repetitive FEA, a CAD-integrated KBES (Knowledge Based Engineering System) has been developed. The KBES creates a surface idealization from a thin-walled solid by utilizing generic modelling knowledge and by registering information about the CAD-specific features which the designer uses to define the solid geometry. From this information a corresponding surface idealization is created in the same CAD-system. This allows an updated and parametric geometry idealization of the complete CAD-geometry to be created with a degree of automation directly in the CAD-system.

Primarily the mid-surfaces oriented in the tooling draft direction are created by evaluating the sketches which the features of the CAD-model are based on. The KBES also trims the created surfaces, thus facilitating the subsequent meshing.

The KBES has been developed in CATIA V5 (Dassault systemes). It contains rules defined in CATIA knowledgeware which trigger sequential routines written in VBA (Visual Basic for Applications). An industrial application example where the system is used to automatically create a surface idealization for a die-cast part is also presented.

This introductory book discusses how to plan and build useful, reliable, maintainable and cost efficient computer systems for automated engineering design. The book takes a user perspective and seeks to bridge the gap between texts on principles of computer science and the user manuals for commercial design automation software. The approach taken is top-down, following the path from definition of the design task and clarification of the relevant design knowledge to the development of an operational system well adapted for its purpose. This introductory text for the practicing engineer working in industry covers most vital aspects of planning such a system. Experiences from applications of automated design systems in practice are reviewed based on a large number of real, industrial cases. The principles behind the most popular methods in design automation are presented with sufficient rigour to give the user confidence in applying them on real industrial problems. This book is also suited for a half semester course at graduate level and has been complemented by suggestions for student assignments grown out of the lecture notes of two postgraduate courses given annually or biannually during the last ten years at the Product development program at the School of Engineering at Jönköping University.