在做材料的力学性能试验时,对试件在试验前后的几何数据的测试是必不可少的,特别是在科研中对测试精度的要求很高,而现在使用的划线装置,多是五十年代苏联的划线机,陈旧而笨重、功能较少。就是这样的装置也只是一些比较老的大学才有,而一般学校在给学生做实验时,多是采用笔尺划标距,卡尺测量的方法,这种方法一是不准确,二是不注意很容易抹 In the mechanical properties of the material to be tested, the test of the specimen geometry data before and after the test is essential, especially in the research requirements of the high accuracy of the test, and now the use of crossed devices, mostly five The Soviet Union in the decade of marking machines, old and heavy, less functional. Is such a device only some of the older universities have, and in general schools to experiment with students, mostly using pen ruler and caliper measurement method, this method is not accurate one, and second, do not pay attention Very easy to wipe