Three points for attention in the operation of universal tool microscope
1. Pay attention to the focusing sequence of eyepiece and objective lens.
Many people use the objective lens to focus at the beginning of measurement, and then use the "meter" line in the eyepiece for alignment measurement after adjusting the focal length of the object. If the "meter" line is not clear enough, the eyepiece will be focused. In fact, this order is wrong, because it will cause a certain virtual shadow in the image of the measured object after focusing. The correct method is to clear the "meter" line in the eyepiece first, and then focus on the object, so as to ensure that the "meter" line and the image of the object are clear.
2. Pay attention to burrs and scratches on the surface of the measured part before measurement.
Some burrs and nicks may occur in the process of processing, use and transportation of the measured part. These defects are not easy to be detected, but in the measurement, it is easy to cause alignment errors of the universal tool microscope or the measurement surface is not in the same focal plane, thus forming a certain local virtual shadow, thus affecting the accuracy of the measurement results. Therefore, these surface burrs and nicks must be thoroughly eliminated.
3. Pay attention to the correct installation of the tested part.
Generally, there are two installation forms of the tested part on the universal tool microscope: (1) Placement of the flat test part. For plane measuring parts, it is important to pay attention to the fact that the measured surface of the measured part should be in the same focal plane, otherwise it is easy to form a local virtual shadow. For parts with chamfers on the measured surface, so that the chamfers face down, otherwise it is easy to cause unclear focusing and inaccurate measurement. (2) Installation of shaft test pieces. Axis-like test pieces generally rely on the central hole for positioning. Before installation, it is necessary to clean the hole, especially to eliminate the sediment and burr in it, otherwise the axis of the tested piece will be different from the center line of the instrument, which will lead to greater measurement error. This situation is often encountered in daily measurement. * A good way is to check the runout error of the outer diameter of the shaft to be measured with the horizontal line of the "meter" line in the instrument reticle after installation, so as to judge whether the measured part is installed correctly.
