12 calibration steps for metallographic microscopy
1. Adjust the direction of the metallographic microscope and the light source so that the light source is aligned with the flat collecting mirror of the metallographic microscope, but at least 10 inches away.
2. Adjust the light so that the filament can be clearly focused on the flat collector.
3. Adjust the mirror so that light is transmitted from the center of the spotlight to the spotlight below the stage.
4. Place a glass slide on the stage and align the focusing lens downwards with the slide specimen, focusing in order from low to high magnification.
5. Clearly focus on the slide specimen. It may be necessary to slightly increase the spotlight in order to obtain sufficient illumination.
6. Turn down the aperture on the light source. Carefully rotate the spotlight group under the stage up (or down) until the reduced aperture is focused on the same plane as the glass slide. At this stage, do not focus on the metallographic microscope itself (i.e. do not adjust the rotation above the stage).
7. If your metallographic microscope has the function of focusing the spotlight, you can move the image by reducing the aperture and adjusting the spotlight to the center of the field of view (most research metallographic microscopes you can use must do this to move the aperture to the center of the field of view).
8. Open the aperture ring until the polygonal aperture ring is just enough to fill the field of view.
9. If possible, remove one eyepiece. Turn down the iris aperture of the spotlight under the stage and look into the tube to observe the receiving lens. At this point, the light should appear symmetrical. In the study of metallographic microscopes, we can adjust any errors at this stage.
10. Turn on or off the iris aperture on the spotlight under the stage, so that only 2/3 of the lens field of view is illuminated. Replace the eyepiece. At this point, the system calibration is completed, and the metallographic microscope is ready for microscopic examination of glass slides.
When using low magnification, medium magnification, and oil lenses, some compromises must be made. In the metallographic microscope you are using, this compromise is to adjust the height of the focusing lens. You must adjust the light intensity by moving the spotlight below the correct height. Think about it, what would you sacrifice when making this compromise move?
12. Do not control the light intensity by moving the spotlight, adjusting the iris aperture on the spotlight under the stage, or strengthening or weakening the light. The ideal control method is to use a neutral filter (i.e. a gray filter).
