Measuring technology of tool microscope
1. Working principle of image measurement method
Place the object under test into the light path of the illumination device, and after passing through the light source and optical system, image it in the main lens. It coincides with the meter mark line in the main lens as the positioning standard. Observe the formed image with a microscope to complete various measurement tasks.
2. Several elements that need to be mastered in image measurement method
(1) Focal length
Focal length is the main factor that directly affects measurement accuracy, so the focal length issue is the primary problem to be solved in imaging methods. As a surveyor, it is important to master the rules of focusing, especially the clarity of the original focus.
① Firstly, adjust the visual acuity of the eyepiece by rotating the visual acuity adjustment ring on the eyepiece until the markings on the reticle can be seen clearly. The measuring personnel must readjust the visual acuity before replacing the eyepiece.
② Focus the microscope onto the viewing surface, move the central microscope with the focusing handwheel, and obtain a clear object contour image in the eyepiece field of view. If it is not clear, rotate the micro adjustment handwheel until it is clear. When measuring, the reticle, reticle, and object image should be placed on the same focal plane, and clear reticle, reticle, and object image should be observed simultaneously in the field of view of the eyepiece.
(2) Aperture diameter
When the measured object is a smooth cylinder or threaded part, the diameter of the illumination aperture must be selected correctly to minimize measurement errors. The adjustment of aperture diameter can be achieved by rotating the rolling flower ring at the lighting fixture base, and reading the diameter of the shading plate from the dial of the shading plate. The aperture diameter can be selected according to the relevant table.
But for some non-standard geometric shapes, the aperture diameter can be freely selected for measurement.
(3) Verticality between the working face and the positioning reference
For thick edge measuring parts that require instrument measurement, although there is no requirement for verticality on the drawing, it is still necessary to ensure the verticality of the working and positioning surfaces. This not only ensures the true quality of the measuring parts, but also shortens the entire processing time (including measurement time) of the measuring parts. If the verticality inspection is ignored and not based on the specific needs of production, the disadvantages outweigh the advantages.
