Process planning as an integration of knowledge in the detailed design phase

This paper deals with knowledge integration during product design. An integrated design approach is presented based on two phases: The initial design and the detailed design phase. Those two phases must be as concurrent as possible. Nevertheless, minimal structural definition of the product is necessary prior to manufacturing process planning as part of the detailed design phase. During the initial design phase, the structural technology is chosen according to the product main functions. This phase aims at defining minimal functional data that are used as a starting point for other knowledge integration in the detailed design phase. During the detailed design, other people that are actively involved in the product development process evaluate the product with their own point of view and their own tools. This paper presents the use and the limits of two features-based tools for process planning knowledge integration: a What-if system and a CAPP system. Both tools make an analysis of the product. As a result of these analyses, designers add new data to the product definition. Thus, the design solution is progressively defined. A Cooperative Design Modeller supports this knowledge integration and gathers the data provided by the What-if and the CAPP systems

Towards digital metal additive manufacturing via high-temperature drop-on-demand jetting

Drop-on-demand jetting of metals offers a fully digital manufacturing approach to surpass the limitations of the current generation powder-based additive manufacturing technologies. However, research on this topic has been restricted mainly to near-net shaping of relatively low melting temperature metals. Here it is proposed a novel approach to jet molten metals at high-temperatures (>1000 °C) to enable the direct digital additive fabrication of micro- to macro-scale objects. The technique used in our research – “MetalJet” - is discussed by studying the ejection and the deposition of two example metals, tin and silver. The applicability of this new technology to additive manufacturing is evaluated through the study of the interface formed between the droplets and the substrate, the inter-droplets bonding, the microstructure and the geometrical fidelity of the printed objects. The research shows that the integrity of the samples (in terms of density as well as metallurgy) varies dramatically in the two investigated materials due to the different conditions that are required to melt the interface of the stacked droplets. Nevertheless the research shows that by a careful choice of the jetting strategy and sintering treatments 3D structures of various complexity can be formed. This research paves the way towards the next generation metal additive manufacturing where various printing resolutions and multi-material capabilities could be used to obtain functional components for applications in printed electronics, medicine and the automotive sectors

Unified Feature Definition for Feature Based Design and Feature Based Manufacturing

In this paper, interactive "constraint based feature definition" is used to drive both feature based design and feature recognition. At present, hardly any feature based CAD or CAPP system does offer adequate facilities to easily define application specific features. Feature definition by means of programming is an error prone and difficult task. The definition of new features has to be performed by domain experts in the fields of design and manufacturing. In general they will not be programming experts. This paper elaborates on interactive feature definition, aiming at facilitating the definition of features by non--programming experts. The interactive feature definition functionality is implemented in a re--design support system called FROOM. It supports feature based design. Feature definition is also used in a Computer Aided Process Planning system, called PART, for the definition of features to be recognized. Conceptual graphs are used as an aid in the definition of features and f..