As an important research tool in the field of materials science, the standard operation and meticulous maintenance of the upright metallographic microscope are crucial for ensuring observation quality and equipment lifespan. Below is a detailed description of the operation process, core skills, and daily maintenance:
1、 Preparation before operation: Collaborative regulation of environment and equipment
1. Environmental control
-The operator needs to clean and dry their hands to avoid stains or moisture from contacting the optical components; The workbench must be kept clean, dry, and away from vibration sources and corrosive gases. The laboratory humidity should be controlled below 60%, and dehumidification equipment should be installed if necessary to prevent lens mold.
2. Hardware inspection and installation
-Light source and circuit: Before connecting the power supply, it is necessary to use a transformer to reduce the voltage (usually 6-8V). It is strictly prohibited to directly connect to 220V mains power, especially when using tungsten filament lamps, be alert to the risk of overvoltage and burnout. Modern models often use LED cold light sources, but it is still necessary to check the insulation of the circuit.
-Optical component assembly: Select the matching objective lens and eyepiece combination according to the preset magnification, gently rotate and install in place to avoid thread slippage.
2、 Sample preparation and loading: key steps for precise positioning
1. Sample pretreatment
-The surface of the sample to be observed must be dry, and the etched sample should have an extended blowing time to prevent residual acid from corroding the objective lens. It is recommended to use nitrogen blowing to avoid residual water stains.
2. Calibration of the stage
-Adjust the center of the stage to coincide with the optical axis of the objective lens, and place the sample facing upwards at the center position. If using transmissive lighting, it is necessary to ensure that the light penetrates the sample; The reflection mode relies on surface diffuse reflection imaging. When moving the stage, the movement should be gentle to prevent the displacement of precision mechanical structures.
3、 Microscopic observation: the entire process from rough to refined
Step by step focusing and brightness adjustment
-Rotate the coarse focusing handwheel to lower the stage so that the sample is close to the objective lens but not in contact. Slowly lift the stage until a blurry image appears in the eyepiece, switch to the fine adjustment knob for fine focusing until the image is clear and sharp. Brightness adjustment should be gradually increased or decreased to avoid flickering and damaging the light bulb or causing visual fatigue.
2. Optical path optimization and mode switching
-Enable bright field, dark field, polarization, or Norman's differential interference contrast function according to requirements. For example, polarization mode can be used to enhance contrast when observing grain boundaries; Switch to DIC (Differential Interference Phase Difference) module to enhance the sense of depth when analyzing minor defects. Dynamically adjust the amount of incoming light in conjunction with the aperture stop and field stop to filter out stray light interference.
4、 End operation and subsequent disposal
1. Shutdown process
-After the experiment, adjust the light source to the darkest and turn off the power, then cover it with a dust cover. If using halogen lamps, wait for them to cool down before covering the cover to prevent high temperature accumulation from causing fire hazards.
2. Deep cleaning and storage
-Remove the objective lens and eyepiece, check for dust contamination. If there is contamination, gently wipe it clean with lens paper in a timely manner, and then store it in a dryer to prevent moisture and mold. The microscope should also be covered with a dust cover at all times.