Basic Studies On Accuracy Management System for Shipbuilding

装配行业中最重要的问题之一是产品的精确度管理。精度管理与产品质量、制造效率、成本等密切相关。精度管理在未来的制造系统中将发挥越来越重要的作用。在这项研究中，我们提出了基于产品模型的计算机辅助精度管理系统。精度管理有两种重要方法。一种方式是“精度规划”，另一种方式是“精度测量”。前者是生产设计阶段的精确度管理，从产品精确度的角度制定生产计划。后者是实际装配阶段的精度管理，用来评估已建成产品的精度，对于精度规划来说，对装配阶段的变形进行估计是非常重要的。我们提出了易于估计产品焊接变形的模型。为了估计有限元线性分析中的变形，引入了焊接等效刚度和等效载荷(即等效收缩力矩和等效弯矩)的概念。根据装配程序，可以很容易地理解产品的变形形状。利用它们可以得到每个生产阶段的初始零件的理想形状和中间产品的理想形状。为了测量精度，我们提出了两种类型的产品计算机模型。这是一个理想的形状模型和一个实际测量的形状模型。当对理想形状模型上的特殊点进行测量时，实现的系统将这些测量值描述在被测模型中。在此基础上，明确了两种形状模型的差异性评价函数。第一个功能是设置位置。第二个函数是将坐标的差值解释为形状精度信息。通过计算机内部公差带的概念来评估两种形状的差异。

One of the most significant issues in assembly industries is accuracy management of products. Accuracy management is deeply related with product quality, manufacturing efficiency, costs and so on. Accuracy management will be more and more important in the future manufacturing systems. In this research we propose computer aided accuracy management systems based on the concept of a product model.There are two significant ways for accuracy management. One way is "accuracy planning", and the other way is "accuracy measurement". The former is accuracy management in production design stage to make production plans in the view of accuracy of products.. The latter is accuracy management in real assembling stage to evaluate accuracy of built products.For accuracy planning, it is important to estimate deformation in assembling stages. We propose models to estimate easily weld deformation of products. The concepts of equivalent stiffness and equivalent loading (that is equivalent shrinkage force and equivalent bending moment) of a welding are introduces to estimate deformation for FEM linear analysis. According to assembling procedure, deformed shapes of products are easily understood. By using them ideal shape of initial parts and an ideal shape of intermediate products in each production stage can be gotteen.For accuracy measurement we propose two types of computer models of products. Those are an ideal shaped model and a real measured shaped model. When a measurement is carried for special points on ideal shaped model, the implemented system describes these measured values in measured model. Furthermore we make clear the function for difference evaluation between two types of shaped models. The first function is setting a position. And the second function is interpretation of difference of coordinates into shape accuracy inrotmation. Differences of two shapes are evaluated by the concept of a tolerance zone inside of a computer.