Optimisation simultanée de la configuration de produits modulaires et de systèmes de fabrication reconfigurables : une offre orientée client pour la customisation de masse

Reconfigurable Manufacturing Systems (RMS) emerged from companies’ needs to increase their responsiveness to an uncertain market, in which customers are increasingly demanding mass-customised products. Companies focused on mass customisation mainly use the modular product design strategy to cost-effectively provide a large product variety. Hence, coupling the modular product design with the manufacturing in RMS seems to be a good strategy to effectively provide mass-customised products with lower costs. This work proposes a 0-1 nonlinear integer programming model to jointly optimize the modular product configuration and RMS configuration, which includes the process planning and layout design, for minimizing the total cost of manufacturing products driven by specific customer requirements in mass customization contexts. The costs include raw material, operations, material handling, and reconfiguration of machines and layout. The mathematical model is validated through an exact approach. The analysis carried out confirms the RMS configuration impact on the optimal product choice and its total cost. Two solution approaches based on an evolutionary algorithm are proposed and validated with the exact one. Two case studies are suggested to illustrate the ability of proposed approaches to minimize the total cost of concurrently selecting the product and RMS configurations for mid-size problems with relatively low computation time while ensuring all customer requirements satisfaction.Les systèmes de fabrication reconfigurables (SFR) sont nés du besoin des entreprises d'augmenter leur réactivité face à un marché incertain, caractérisé par une demande croissante de produits customisés en masse. Les entreprises axées sur la customisation de masse utilisent principalement la conception de produits modulaires pour fournir une grande variété de produits, tout en restant rentable. Par conséquence, coupler la conception de produits modulaires avec sa fabrication en SFR semble être une bonne stratégie pour fournir des produits customisés en masse à moindre coût. Ce travail propose un modèle de programmation à nombres entiers non-linéaire pour optimiser simultanément la configuration d’un produit modulaire et du SFR, qui comprend la planification de processus et la conception de l’atelier de production, afin de minimiser le coût total de fabrication du produit selon des exigences spécifiques du client. Les coûts comprennent les matières premières, les opérations, le transfert entre machines et la reconfiguration des machines et de l’atelier. Le modèle mathématique est validé par une approche exacte. L'analyse réalisée confirme l'impact de la configuration du SFR sur le choix optimal du produit et son coût total. Deux approches de solution basées sur un algorithme évolutionnaire sont proposées et validées avec l’approche exacte. Deux études de cas illustrent la capacité des approches proposées à minimiser le coût total de la sélection simultanée de la configuration du produit et celle du SFR pour les problèmes de taille moyenne à un temps de calcul relativement faible tout en garantissant la satisfaction de toutes les exigences du client

Otimização de um Processo Industrial de Filagem: uma Comparação entre Métodos Multiobjetivo.

Um dos principais indicadores de eficiência dos laticínios é o rendimento, principalmente quando se trata da fabricação de queijos, uma vez que esta se dá pela concentração dos nutrientes do leite. Além do rendimento, existem fatores relacionados à qualidade e composição do produto final que não podem ser negligenciados, visto que a modificação de uma determinada variável, pode implicar na alteração das demais. Um dos queijos mais consumidos no mundo é a mussarela, pertencente à variedade pasta-filata, a qual é composta por queijos que apresentam um processo adicional de estiramento e aquecimento da coalhada, chamado filagem. Neste contexto, o presente trabalho foi desenvolvido com o objetivo de otimizar um processo industrial de filagem de queijo mussarela, com o intuito de aumentar o rendimento, em termos de recuperação de gordura do leite, e padronizar o teor de umidade dos produtos. Para tal, utilizou-se a Metodologia de Superfície de Resposta, como técnica de planejamento de experimentos, assumindo-se duas variáveis de entrada: tempo de filagem e volume de água. Após a modelagem das funções, foi realizada a comparação entre dois métodos de otimização multiobjetivo: Desirability e o método de Interseção Normal à Fronteira. A partir dos resultados obtidos, é possível inferir que, se os parâmetros ótimos forem aplicados ao processo de filagem, o rendimento, em termos de recuperação de gordura, pode aumentar em quase 10%, atingindo-se, simultaneamente, o teor de umidade desejado para o queijo mussarela. Observou-se também que ambos os métodos de otimização utilizados apresentaram desempenho semelhante no presente estudo

Optimisation simultanée de la configuration de produits modulaires et de systèmes de fabrication reconfigurables : une offre orientée client pour la customisation de masse

Les systèmes de fabrication reconfigurables (SFR) sont nés du besoin des entreprises d'augmenter leur réactivité face à un marché incertain, caractérisé par une demande croissante de produits customisés en masse. Les entreprises axées sur la customisation de masse utilisent principalement la conception de produits modulaires pour fournir une grande variété de produits, tout en restant rentable. Par conséquence, coupler la conception de produits modulaires avec sa fabrication en SFR semble être une bonne stratégie pour fournir des produits customisés en masse à moindre coût. Ce travail propose un modèle de programmation à nombres entiers non-linéaire pour optimiser simultanément la configuration d’un produit modulaire et du SFR, qui comprend la planification de processus et la conception de l’atelier de production, afin de minimiser le coût total de fabrication du produit selon des exigences spécifiques du client. Les coûts comprennent les matières premières, les opérations, le transfert entre machines et la reconfiguration des machines et de l’atelier. Le modèle mathématique est validé par une approche exacte. L'analyse réalisée confirme l'impact de la configuration du SFR sur le choix optimal du produit et son coût total. Deux approches de solution basées sur un algorithme évolutionnaire sont proposées et validées avec l’approche exacte. Deux études de cas illustrent la capacité des approches proposées à minimiser le coût total de la sélection simultanée de la configuration du produit et celle du SFR pour les problèmes de taille moyenne à un temps de calcul relativement faible tout en garantissant la satisfaction de toutes les exigences du client.Reconfigurable Manufacturing Systems (RMS) emerged from companies’ needs to increase their responsiveness to an uncertain market, in which customers are increasingly demanding mass-customised products. Companies focused on mass customisation mainly use the modular product design strategy to cost-effectively provide a large product variety. Hence, coupling the modular product design with the manufacturing in RMS seems to be a good strategy to effectively provide mass-customised products with lower costs. This work proposes a 0-1 nonlinear integer programming model to jointly optimize the modular product configuration and RMS configuration, which includes the process planning and layout design, for minimizing the total cost of manufacturing products driven by specific customer requirements in mass customization contexts. The costs include raw material, operations, material handling, and reconfiguration of machines and layout. The mathematical model is validated through an exact approach. The analysis carried out confirms the RMS configuration impact on the optimal product choice and its total cost. Two solution approaches based on an evolutionary algorithm are proposed and validated with the exact one. Two case studies are suggested to illustrate the ability of proposed approaches to minimize the total cost of concurrently selecting the product and RMS configurations for mid-size problems with relatively low computation time while ensuring all customer requirements satisfaction

OPTIMAL INTEGRATION OF PRODUCT CONFIGURATION AND PROCESS PLANNING TO MEET INDIVIDUAL CUSTOMER REQUIREMENTS IN MASS CUSTOMIZATION

International audienceAccording to researchers and practitioners, modular products are considered as key enablers for Mass Customization (MC). Modular design is a strategy for designing products composed by many subparts (modules), which are developed separately and assembled later in different ways, enabling the configuration of several product variants. Customers do not always know how to translate their requirements into product configurations, thus an alternative could be 'co-configuring' the product with them. This is done by an automatic modules selection based on customer requirements to get a first product configuration, which can be subsequently adjusted by the customer, if necessary. Currently, the optimal module selection is mainly conducted without considering the process planning optimization. Nevertheless, integrating both optimizations would increase product/process flexibility and agility, reducing the overall manufacturing costs. Thereby, it is important to integrate the product configuration, driven by individual customer requirements, with the process planning for MC. This paper proposes a 0-1 integer linear programming model to optimize, in terms of cost-minimization, the integration of product configuration and process planning, for MC. Results obtained with a 2-steps approach composed by an exhaustive search algorithm (ESA) and CPLEX-solver show that total cost can be considerably minimized if both optimizations are considered together

Acacia gum as modifier of thermal stability, solubility and emulsifying properties of α-lactalbumin

Protein–polysaccharide conjugates often display improved techno-functional properties when compared to their individual involved biomolecules. α-Lactalbumin:acacia gum (α-la:AG) conjugates were prepared via Maillard reaction by the dry-heating method. Conjugate formation was confirmed using results of absorbance, o-phthalaldehyde test, sodium dodecyl sulfate–polyacrilamide gel electrophoresis (SDS–PAGE) and size exclusion chromatography. Techno-functional properties (emulsifying characteristics, solubility, and thermal stability) were evaluated for α-la, α-la/AG mixtures and α-la:AG conjugates. Conjugate thermal stability was improved compared to pure α-la treated at the same conditions of conjugate formation. Response surface methodology was used to establish models to predict solubility and emulsifying activity as functions of the salt concentration, pH and reaction time. α-la:AG conjugate solubility is affected in a complex manner by the three factors analyzed. Emulsifying activity index (EAI) of α-la is significantly affected by pH, while the α-la:AG EAI is affected by the three analyzed factors. Both solubility and EAI are maximized with pH 8.0, NaCl concentration of 0.3 mol L−1 and two days of Maillard reaction