Microscope common faults and troubleshooting methods
1 Working principle of image measurement method
Put the object to be measured into the light path of the lighting device, pass through the light source and the optical system, and then image it in the main lens. It coincides with the Pozier engraved line in the main lens as a positioning standard, and observe the formed image with a microscope to complete various measurements. Task.
2 Some elements to be mastered in image measurement method
(1) Focal panjang
The focal length is the main factor that directly affects the measurement accuracy, so the focal length problem is the primary problem to be solved by the image method. As a surveyor, one must be proficient in the rules of focusing, especially the clarity of the original focus.
① First adjust the diopter of the eyepiece, turn the diopter adjustment ring on the eyepiece until the engraved line on the reticle can be seen clearly, the measuring personnel must re-adjust the diopter when changing the eyepiece.
②Focus the microscope on the viewing surface, move the central microscope through the focusing handwheel, and get a clear outline image of the object in the field of view of the eyepiece. If it is not clear, turn the fine handwheel to adjust until it is clear. When measuring, make the reticle, reticle and object image on the same focal plane, and observe the reticle, reticle and object image clearly in the field of view of the eyepiece at the same time.
(2) Aperture diameter
But for some non-standard geometric shapes, you can choose the size of the aperture diameter at will and measure it.
(3) Perpendicularity between the working surface and the positioning datum
For tebal-tepi test pieces that need to be measured by instruments, although there is no verticality requirement on the drawing, the verticality of the working surface and the positioning surface must also be ensured. This will not only ensure the true quality of the test piece, but also shorten the entire time period Processing time (including measuring time), such as ignoring the inspection of verticality and not according to the specific needs of production, will do more harm than good.
(4) Penjajaran
The so-called alignment is to overlap the edge of the image outline of the tested part with the engraved line of the rice character, which is generally called aiming and aligning. The accuracy of the instrument itself is constant, so the measurement uncertainty depends to a large extent on the correct alignment method and correct readings.
There are two commonly used alignment methods:
①Gap alignment method means that there is a certain gap between the reticle and the edge of the image outline during alignment. Because the outline is a black image, the engraved line is also black, and a certain gap is easy to observe, and it will juga reduce the fatigue of the eyes. This method is suitable for angle measurement. If the length measurement uses the gap alignment method% 2c it will never be possible. to the correct value.
② Overlapping alignment method refers to using the dotted line of the cross-shaped line to align the line, so that the cross-shaped line and the edge of the image overlap each other, so that the amount of the pressed line can be seen, and it is easy to read. This method is suitable for length measurement. As a good measurer, one should form a good habit of crimping one-half of the line (that is, in the middle of the line). Also equal.
(5) Other elements
There are still many factors that affect the measurement accuracy in the image measurement method, such as thermal deformation caused by the light source, natural light and reflected light from objects such as walls, especially the deformed light produced by the mutual interference of two or more light surfaces at the same time. It is very large, as as the system error of the instrument itself.
