Manufacturing complexity evaluation at the design stage for both machining and layered manufacturing

International audienceIn this paper, a methodology to estimate manufacturing complexity for both machining and layered manufacturing is proposed in order to realize tools (dies or molds) by a combination of a subtractive and an additive process. Manufacturability indexes are calculated at the tool design stage, these indexes provide an accurate view of which areas of the tool will advantageously be machined or manufactured by an additive process. In this case, tools are not seen as single pieces but as 3-D puzzles with modules, manufactured aside by the best process and further assembled

Environmental Impact Assessment Studies in Additive Manufacturing

International audienceThis chapter focuses on the environmental studies in additive manufacturing. For a cleaner production, environmental impacts that occur during the manufacturing phase should be assessed with accuracy. First, the literature on all the studies led to the characterization of the environmental impact of additive manufacturing processes. The studies on electric energy consumption of these processes are analyzed here, and then some studies taking into account raw material and all the flows through the process are detailed. Secondly, a new methodology in order to evaluate, with accuracy, the environmental impact of a part from its CAD model is presented. In this methodology, the work is not focused only on electrical consumption but also on fluids and material consumption which also contribute to the environmental impact. In addition, the inputs of this methodology correspond to the set part process, which allows taking into account different manufacturing strategies and their influences on the global environmental impact. The methodology developed is based on both analytic models (validated by experiments) and experimental models. And finally, an industrial example shows that for some manufacturing strategies, the environmental impact due to electrical consumption is not the predominant one. In this case study, material consumption has an important impact and has to be taken into consideration for a complete environmental impact assessment

Environmental performance modeling for additive manufacturing processes

International audienceSustainability means considering economic, social and environmental aspects. In the mechanical product design field, sustainability means thinking about eco-design and life cycle analysis, when the whole life cycle of the product (from raw material extraction to end of life) is concerned with environmental impacts. Nowadays, most of the manufacturing methods are driven only by money, and the environmental and social aspects are not taken into account. The goal of this paper is to propose an environmental assessment methodology of the manufacturing processes. In this methodology, all flows consumed and produced (material, fluids, electricity) are considered. A predictive model of flow consumption is defined from the CAD model of the product and the manufacturing program. The aim is to be able to minimize the environmental impacts of the manufacturing during the design stage. In this paper, the focus is put on additive manufacturing

Vacuum Casting to Manufacture a Plastic Biochip for Highly Parallel Cell Transfection

International audienceA novel polymer microarray fabrication technique is presented and applied to the realization of a biochip for highly parallelized cell transfection. The proposed microfabrication technique is derived from a macroscale rapid prototyping technique called vacuum casting. It was optimized to reduce production cost, in order to produce small series (100-10 000 chip series) of chips to meet demand in today's market of cellulomics. Microfabrication technologies and rapid prototyping technologies are combined to shape the master part, which can thus involve microsized features. The corresponding female structure is moulded in a flexible silicone material. The duplicated polymer chips are obtained by casting a thermosetting plastic under vacuum. The dimensional replication accuracy between the master part and the duplicated parts is uniform over the duplicated parts and better than 1%. Advantages of the proposed technique over existing plastic microfabrication techniques are discussed in the paper. Using this microfabrication technique, we produced a plastic biochip for highly parallelized transfection of arrays of living cells. The feasibility of parallel lipofection was demonstrated: two different plasmids encoding, respectively, eGFP and DsRED2 were inserted into HEK293T cells. The transfection was monitored through fluorescence observation after 72 h showing successful expression of both genes

Évaluation de la performance environnementale des procédés de fabrication

Le développement durable repose sur le couplage de trois piliers : économie / environnement / social. Pour la conception des produits manufacturés, la prise en compte de ces aspects se fait classiquement en utilisant le concept d’écoconception, basé sur l’étude du cycle de vie complet du produit (de l’extraction des matières premières à la fin de vie du produit). Cependant, les choix faits lors de la phase de fabrication sont encore majoritairement dirigés par un seul pilier : l’économie. Ainsi, les outils qui visent à optimiser la phase de fabrication sont dictés par une réduction des coûts, une diminution des délais de développement ou une amélioration de la qualité des produits, mais rarement par une maîtrise de l’impact environnemental. Il convient alors de s’interroger sur les moyens de prendre en compte les deux piliers environnement et social pour la phase de fabrication des produits mécaniques, ainsi que leurs couplages forts et nécessaires dans une démarche globale de développement durable. Cet article propose une méthodologie d’évaluation de la performance environnementale des procédés de fabrication. Il s’agit d’estimer quantitativement les consommations de matières, fluides et énergie lors de la fabrication de produits, afin de proposer un modèle prédictif des impacts environnementaux à partir de la définition numérique du produit, associée au programme de pilotage de la machine de production. L’objectif est de proposer des pistes de réduction des impacts environnementaux liés à la phase de fabrication dès la conception du produit ou lors de la génération du programme de fabrication. Dans cet article, la méthodologie est appliquée à la fabrication additive

A new DFM approach to combine machining and additive manufacturing

Design For Manufacturing (DFM) approaches aim to integrate manufacturability aspects during the design stage. Most of DFM approaches usually consider only one manufacturing process, but products competitiveness may be improved by designing hybrid modular products, in which products are seen as 3-D puzzles with modules realized aside by the best manufacturing process and further gathered. A new DFM system is created in order to give quantitative information during the product design stage of which modules will benefit in being machined and which ones will advantageously be realized by an additive process (such as Selective Laser Sintering or laser deposition). A methodology for a manufacturability evaluation in case of a subtractive or an additive manufacturing process is developed and implemented in a CAD software. Tests are carried out on industrial products from automotive industry

Method to obtain hybrid rapid tools with elementary component assembly

M. Rivette, P. Mognol, J.Y. Hascoet, (2013) "Method to obtain hybrid rapid tools with elementary component assembly", Rapid Prototyping Journal, Vol. 19 Iss: 2, pp.77 - 87 DOI : 10.1108/13552541311302923Purpose – The purpose of this paper is to propose a method to obtain hybrid rapid tools with elementary component assembly. Design/methodology/approach – The authors' method proposes a functional representational model, starting with the product features, analyzed from three points of view: a feasibility analysis; a manufacturing analysis; and an assembly and synthesis analysis. This method, based on CAD STEP AP-224 data, makes it possible to obtain an exhaustive list of solutions for the module. The work is illustrated with an industrial example. To construct the Assembly Identity Card (AIC) and test the various parameters that influence the quality of the injected parts, a hybrid injection mold has been produced. The methodology associated with the use of this AIC uses a “representation graph”, which makes it possible to propose a set of valid solutions for assembling the various tooling modules. This method is validated by industrial example. Findings – The product part is decomposed into a multi-component prototype (MCP), instead of being made as a single part, which optimizes the manufacturing process and enables greater reactivity during the development of the product. Research limitations/implications – The final goal is to propose a software assistant used in association with CAD system during the design of hybrid rapid tooling. An important work concerning the features recognition must be implemented. The assembly of the different parts of the hybrid rapid tooling must be considered and optimized. Practical implications – This method allows the selection of the best process technologies from manufacturing tools. Originality/value – The analysis of manufacturing hybrid rapid tooling has not been studied previously

Framework to combine technical, economic and environmental points of view of additive manufacturing processes

International audienceAdditive manufacturing is an innovative way to produce complex parts. Nowadays, knowledge about mechanical properties and production costs are well known. Many studies found in the literature present comparisons between different additive manufacturing technologies based on technical or economical criterions. However, the environmental analysis of the phenomena that occur during the manufacturing step is still limited. To ensure the development of these processes it seems important to get predictive models of the environmental impacts, allowing to evaluate the product from a technical, economic and environmental point of view. This paper presents a new methodology for the environmental impact evaluation, combined with a technical and economical assessment. This methodology is applied on multiple additive manufacturing processes and will help manufacturers like a decision-making tool to make a choice of manufacturing process based on multiple criterion

Modeling and Optimization of Laser Polishing Process

International audienceLaser polishing is a finishing process based on melting material, with the objective of improving surface topography. Some operating parameters must be taken into consideration, such as laser power, feed rate, offset, and overlapping. Moreover, because of its dependence on the primary process, the initial topography has also an impact on the final result. This study describes a quadratic model, conceived to optimize final topography according to the primary process and laser polishing. Based on an experimental matrix, the model takes into account both laser operating parameters and the initial topography, in order to predict polished surfaces and to determine optimal set of parameters. After the phase of experimentation and the creation of the quadratic model, an optimal final topography is introduced, taking into account the initial surface and the laser parameters

Exploring the Limits of Vacuum Casting Technique for Micron and Submicron Features

International audienceA study of resolution limits in standard rapid prototyping vacuum cast molding processes and adaptation of this technique to reach subm icron accuracy is proposed. Micro-fabrication technologies are used to fabricate micron a nd submicron high aspect-ratio patterns on the original parts. The molding of the original part s is optimized to allow replication of submicron features. In carefully exploring materials a nd surface treatments, cast parts are successfully replicated with submicron and high aspect ratio micron structures. These encouraging results enable the use of such processes for micro- and nano-systems applications and open the door to development and production of low cost, high resolution biochips