Safety & Operational Precautions for Universal Tool Microscopes
1. Focusing sequence of eyepiece and objective lens
Many people like to use the objective lens to focus at the beginning of the measurement. After adjusting the focal length of the object, they use the "meter" line in the eyepiece to align and measure. If they feel that the "meter" line is not clear enough at this time, they will focus the eyepiece. In fact, this order is incorrect because it will cause some ghosting in the image of the object being measured after being focused earlier. The correct method is to first adjust the "meter" line in the eyepiece clearly, and then focus on the object to ensure that both the "meter" line and the image of the object are clear.
2. Burrs and scratches on the surface of the tested part before measurement
During the processing, use, and transportation of the test piece, some burrs and scratches may occur. These defects are not easy to detect, but they can easily cause alignment errors in the Wan Gong display or result in the measurement surface not being on the same focal plane, forming certain local shadows and affecting the accuracy of the measurement results. Therefore, it is necessary to thoroughly remove these surface burrs and scratches.
3. Correctly install the tested component
There are generally two installation forms for the test piece on a universal tool microscope: (1) placement of flat test pieces. The tested surface of the tested part should be on the same focal plane, otherwise it is easy to form local ghosting. For parts with chamfers on the tested surface, it is best to make the chamfer face downwards, otherwise it may cause unclear focusing and inaccurate measurement. (2) Installation of axis measuring components. Axial measuring components generally rely on the center hole for positioning, so it is necessary to clean the * * hole thoroughly before installation, especially to eliminate any mud, sand, and burrs. Otherwise, it may cause the axis of the measured component to be different from the center line of the instrument, resulting in significant measurement errors. *After installation, check the runout error of the outer diameter of the measured shaft using the horizontal line of the "meter" line in the instrument dividing board, in order to determine whether the measured part is installed properly.
4. When measuring threaded parts, pay attention to the inclination direction of the column of the multimeter display
When measuring the thread pitch diameter and tooth half angle, in order to make the image clear, the column of the universal tool microscope is generally tilted to the left or right by a helix angle, and the tilt direction of the column should be consistent with the helix direction of the measured part. When the helix angle is large, it is easy to determine whether the inclination direction of the column is consistent with the helix direction of the workpiece by observing the clarity of the image. However, when the helix angle of the workpiece is less than 1 °, the impact on the image is small and difficult to judge with the naked eye. This often causes the inclination direction of the column to be opposite to the helix angle direction of the workpiece, resulting in inconsistent tooth profile half angles on the left and right sides of the measured workpiece, which poses great difficulties for workpiece processing. So before measurement, it is necessary to correctly determine the inclination direction of the column based on the spiral direction indicated in the workpiece drawing data.
