Evaluation System for Developing Products with Improved Part Reusability

在循环型制造系统中，内环物流在减少环境影响、降低材料和能源消耗方面更为有效。从这个意义上说，零件再利用是一种很有前途的策略，特别是对于生命周期较短的办公自动化家电。然而，为了便于部件重用，部件的设计应该使它们可以在多代产品中通用。本研究从设计变更因素、模块化因素和寿命因素三个方面探讨了零件可重用性的评价方法。通过对自动售货机设计变更记录的分析，将自动售货机设计变更的因素主要分为质量改进和成本降低两个方面。由于质量要求引起的设计变更是必不可少的，但为了降低成本而采取的替代措施是可以避免的。QFD用于分析设计变更项目及其因素之间的关系，以识别不一定在多个产品世代中更改的部件。从提高可分解性和可重用性方面对模块化进行了讨论。开发了基于设计规范约束网络的模块化方案生成和评价的计算机程序。在部件寿命评估方面，提出了一种基于维修记录评估各部件所需寿命和部件物理寿命的评估程序。应用动态仿真系统对零件的劣化极限进行分析。

In circular type manufacturing systems, inner loop material circulation is more effective in terms of reduction of environmental impact and material and energy consumption. In this sense, part reuse is promising strategy especially for office automation appliances, which have short life cycles. For facilitating part reuse, however, parts should be so designed that they can be common in products of multiple generations. In this study, the evaluation methods of part reusability are discussed in three aspects : factors of design changes, modularization, and life span. Based on the analysis of records of design change of vending machines, the factors of design changes are mainly categorized into quality improvement and cost down. Design changes caused by quality requirement are indispensable, but those for cost down could be avoided by adopting alternative measures. QFD is applied for analyzing relationships between items of design changes and their factors for identifying parts, which are not necessarily changed for multiple product generations. Modularization is discussed in terms of improvement of disassimilability and reusability. A computer program has been developed for generating and evaluating alternatives of modularization based on constraint network of design specifications. Regarding evaluation of part lives, an evaluation procedure is proposed in which a required life for each part as well as physical life of parts is evaluated based on maintenance records. A dynamic simulation system is applied for analyzing limit of part deterioration.