浅谈如何正确选择测量基准

Brief Discussion on How to Correctly Choose Datum Reference

在零件精确测量中,要想获得正确的测量结果,正确地选择测量基准建立零件坐标系与选用精确测量机同样重要。目前常规零件大都标注设计基准,在数控测量时一般优选设计基准作为测量基准来建立零件坐标系,以实现快捷、准确、有效的检测。而由于飞机设计采用的是整机设计基准,因此,目前实际测量大多数国产飞机零件时,只能依据加工基准作为测量基准来建立零件坐标系,若不考虑工艺所提供的基准是否合理而盲目测量,会影响测量结果的准确性和可靠性,严重时会造成零件的误判。本文以典型梁框零件为例,通过对零件图纸、使用性能及装配特点的分析,论证了不同的测量基准对测量结果的影响,阐述了在测量过程中正确选择测量基准的重要性。

In order to accurately and precisely measure parts,it is as important as the selection of precision measuring machines to choose correct datum reference to establish the coordinate system of the workpieces. At present,most of the conventional parts are marked on the basis of design,and the general optimization design reference is used as the datum reference to establish the part coordinate system in order to realize the fast,accurate and effective detection.However,aircraft design adopts the reference of the whole machine design,when measuring most domestic aircraft parts,only the machining datum is used as the reference to build the part coordinate system. If not considering whether the reference provided is reasonable,the measurement may have a low accuracy and reliability,which may result in serious miscalculation of parts. This paper,by choosing the typical beam frame part as an example,demonstrates the effect of different datum references on the measurement by analyzing drawings,performance,and assembly characteristics. The paper describes the importance of correct datum reference choice in the measurement process.