工程制图课程教学中组合体尺寸标注的三基法

复杂组合体由于其尺寸繁多和标注方法冗杂而难以高效、精确标注,尤以定位尺寸最为凸出。三基法基于形体分解而得,其主体思想是通过确定基准体、基准线和基准点继而求得组合体中各形体对于基准体的定位尺寸。通过理论分析与实例讲解证明了该方法在尺寸标注过程中具有独特的优势,为高效、精确标注尺寸注入了新的内涵。

Three-Basis Method of Combination Dimension Mark in Engineering Drawing Course Teaching

Because of its multi-size and marking miscellaneous, the dimension mark of complex combination is difficult, especially for the location dimension. Based on shape-breakdown system, the basic idea of three-basis method is to obtain the location dimension of other bodies relative to the datum body in the combination by defining the datum body, datum lines and datum points. The special advantage of this method on dimension mark has been proved through theoretical analysis and examples interpret. Moreover, it gives a new connotation in dimensioning the combination efficiently and exactly.