用AutoCAD标注符合国标的表面粗糙度

在零件图上，标注表面粗糙度是必不可少的。但是AutoCAD绘图软件没有标注表面粗糙度的功能。若要用AutoCAD来绘制零件图，用户必须自行解决表面粗糙度的标注问题。然而笔者经常看到有的用AutoCAD来标注的表面轻轻度代号不符合国家标准。笔者介绍了在AutoCAD中用带有属性的图决，把表面粗糙度数值定义为可变属性进行插入来标注表面粗糙度的方法。尤为重要的是为了使表面粗糙度标注完全符合国家标准，笔者定义了两个图决Ral和Ra2。

The Method for Marking Surface-Roughness Conforming to National Standard with AutoCAD

It is necessary to mark surface-roughness in the part drawing. But there is not the function of marking surface-roughness in AutoCAD. If the user wants to draw the part drawing with AutoCAD, he must resolve the problem of marking surface-roughness by himself. However,the author often sees that some marks of marking with AutoCAD do not conform the marking to national standard. This paper introduces the method of marking surface-roughness. It is done by inserting to defining the data of surface-roughness as changeable attribute through the blocks with attribute which in AutoCAD. Most important of all, the author defined two blocks-Ra1 and Ra2 in order to conform the marking completely to national standard.