How to operate a metallographic microscope
(1) Connect the light source plug to the power transformer, and then connect the transformer to the indoor 220V power supply to use. The lighting system has been calibrated at the factory.
(2) Every time the light bulb is replaced, the lamp holder must be adjusted repeatedly. After the light bulb is plugged into the lamp holder, place the color filter glass on the aperture light bar, then rotate the lamp holder and adjust it back and forth so that the light source illuminates the color filter glass evenly and brightly. In this way, the light bulb has been adjusted correctly. At this time, Turn the eccentric ring of the lamp holder at an angle to secure the lamp holder in the chassis. There are red dots on the lamp holder and eccentric ring. When removing, just put the red dots opposite each other.
(3) In principle, each objective lens must be installed before observation. When attaching or removing the objective lens, the stage must be raised to avoid touching the lens. If you choose a certain magnification, you can refer to the total magnification table to select eyepieces and objectives.
(4) When the sample is placed on the stage, the surface to be observed is placed back on the stage. If it is a small sample, a spring pressure piece can be used to compress it.
(5) When using a low-magnification objective lens to observe and adjust the focus, be careful to avoid collision between the lens and the specimen. You can look at the objective lens from the side and move the stage as low as possible until the lens is almost in contact with the specimen (but must not be in contact), and then View through the eyepiece. At this time, you should first use the coarse adjustment handwheel to adjust until the object image is first visible, and then use the fine adjustment handwheel to adjust until the object image is very clear. Do not use excessive force to avoid damaging the lens and affecting object image observation. When using a high-magnification objective lens for observation or using an oil immersion objective lens, you must first pay attention to the limit marking line. Be sure to keep the marking line on the bracket between the two marking lines outside the gear box, so that there is an appropriate lifting margin for micro-movement. When turning the coarse handwheel, carefully lower the stage slowly. When the object image outline appears in the eyepiece field of view, immediately switch to the fine handwheel to correctly focus until the object image is clearest.
(6) Before using the oil immersion objective lens, raise the stage, dip a smooth and clean stick into a drop of fir oil, and drop it on the front lens of the objective lens. At this time, avoid the stick from hitting the lens and not dripping. Apply too much oil, otherwise the lens will be damaged or stained.
(7) In order to match various objective lenses with different numerical apertures, adjustable aperture diaphragms and field diaphragms are set up. The purpose is to obtain good object images and microphotography contrast. When using an objective lens with a certain numerical aperture, first focus the specimen correctly, and then adjust the field diaphragm. At this time, the field of view is gradually blocked from the eyepiece field, and then slowly adjust to open the diaphragm hole. Open until the shielding part is just right when the field of view appears. Its function is to block the light source outside the field of view of the specimen to eliminate the diffuse astigmatism reflected on the surface. In order to use different objective lenses and adapt to the brightness requirements of different types of specimens, an adjustable aperture diaphragm is set up. Turn the aperture diaphragm ring to make the object image clear, bright and well-defined. There are graduations engraved on the diaphragm to indicate the aperture size.
