Modelo para avaliação econômica comparativa entre alternativas de sistemas de fixação com elementos roscados An approach model to a comparative economic assessment of alternatives for threaded fastening systems

As demandas junto aos diferentes setores de manufatura têm crescido em termos de qualidade e prazos. Todavia, estas demandas sofrem forte impacto de etapas anteriores, mais notadamente, do estágio de desenvolvimento do produto. Nesta fase, importantes decisões são tomadas, sendo que, em muitos casos, estas são fortemente influenciadas pela experiência ou preferência das pessoas envolvidas na atividade. Outra constatação bastante evidente é a de que, na maioria das vezes, produtos dependem de processos de montagem, que podem assumir diferentes configurações (e.g., uniões fixas ou móveis; reversíveis ou irreversíveis; entre outras). Considerando, principalmente as pressões ambientais, as uniões do tipo "desmontáveis" assumem papel fundamental no desenvolvimento de produtos. Estas podem ser de diferentes tipos, sendo que sua escolha ocorre na etapa de projeto. Assim, o objetivo deste artigo é apresentar o desenvolvimento de um modelo para facilitar a tomada de decisão quanto ao emprego de sistemas de fixação desmontáveis, considerando aspectos econômicos envolvidos nos processos examinados. Os dados de entrada e estruturação do modelo são representativos da realidade industrial, de parâmetros oriundos de literatura e de dados obtidos a partir de experimentos em ambiente controlado. O modelo contempla as considerações de custos nas etapas de: i) aquisição e estocagem; ii) manufatura; iii) montagem; e iv) manutenção; que são etapas principais do ciclo de vida do componente. O conjunto de equações que dá sustentação ao modelo é apresentado em anexo. Um teste preliminar do uso do modelo ilustra que este é capaz de capturar as diferenças de custos entre os sistemas de fixação considerados para determinada montagem, a partir de parâmetros definidos nas etapas iniciais de projeto.<br>The demands for quality and delivery time have been growing in the majority of manufacturing sectors. However, these demands are strongly dependent on previous stages decisions, mostly those related to the product development process. Several of these decisions are influenced by the experience or personal preferences from the design team. Additionally, most products depend on the assembly processes, which can assume different configurations (e.g. permanent (riveting) or non-permanent (fastening) joining solutions). From the environment point of view, the reversible systems perform a fundamental role during the product development process. The choice for a fastening system occurs during the design stage. Thus, this paper aims at the development of a model that supports the decision making process when choosing reversible fastening systems, based on the economic aspects of the manufacturing/assembling process examined. The entry data and model structure are well adhered to the industrial reality, theoretical parameters, and data from the experiments. The model considers the costs factors originated from: i/ purchasing and storage; ii/ manufacturing; iii/ assembling; and iv/ maintenance; which are the main stages of a component life cycle. The set of equations that support the model is also presented. A preliminary model test illustrates its capabilities for capturing the cost differences amongst fastening systems for a specific assembly, from parameters defined at early stages of the design process

Software Process Improvement in Inter-departmental Development of Software-Intensive Automotive Systems – A Case Study

This paper presents a software process improvement (SPI) initiative conducted at two automotive companies, focusing on the inter-departmental interplay between manufacturing and product development, which are central players in automotive development. In such a complex environment with multiple departments with varying challenges⎯the planning of improvement possibilities was considered as mission critical to get support for changes in the companies. This paper reports the results of the SPI efforts following the process assessment, namely specifically the improvement planning step, which is often overlooked in empirical reports. We also thoroughly describe and report on lessons learned from employing our tailored planning method involving 41 professionals. We found that requirements engineering, early manufacturing involvement and roles and responsibilities were prioritized as main challenges to address. Furthermore, our and the involved professionals' experiences of the used SPI (planning) method, showed that it was useful, giving valuable decision support for the planning of the improvement