Micro Vickers hardness testerIt is a precision instrument used to measure the hardness of micro areas of materials, widely used in scientific research and quality control in fields such as metals, ceramics, semiconductors, thin films, coatings, and composite materials. Its working principle is based on the Vickers hardness testing method, which involves pressing a diamond regular pyramid indenter into the surface of the specimen under a specific load, holding it for a certain period of time, and then removing the load. The diagonal length of the indentation is measured through an optical system, and the Vickers hardness value (HV) is calculated. Due to its small indentation and high accuracy, it is particularly suitable for hardness analysis of thin layers, small parts, or materials with uneven microstructure.
Micro Vickers hardness testers are typically equipped with high magnification optical microscopes, precision stages, automatic loading systems, and image analysis software. The testing load range is generally from 1 gf to 2000 gf (gram force), and some high-D models can achieve smaller micro scale loading to meet the research needs of nanoscale materials. The instrument has good repeatability and accuracy, and can effectively reflect the local mechanical properties of materials. It is an indispensable tool in metallographic analysis, failure analysis, process optimization and other work.
Micro Vickers hardness testerOperation guide:
1、 Preparation before operation
Sample preparation
Ensure that the surface of the sample is clean, smooth, and free of oil stains, oxidation layers, or scratches. For irregular samples, fixtures need to be used for fixation.
The sample size must meet the equipment requirements. The maximum height allowed for the sample is usually 70mm, and the maximum distance from the center of the indenter to the machine wall is 95mm.
Equipment inspection
Check if the power cord and plug are intact to avoid poor contact or damage.
Confirm that the equipment accessories are complete, including the host, cross test bench, micrometer eyepiece, weights (if any), CCD camera (optional), etc.
Environmental Requirements
The operating environment should be free from strong vibrations, strong magnetic field interference, stable temperature, and avoid direct sunlight.
2、 Equipment installation and debugging
Main assembly
Place the hardness tester host on a sturdy workbench, remove the upper cover and shock-absorbing screws.
Install weights (if the device requires manual loading): Open the weight cover and install the weights onto the weight shaft in sequence, ensuring that the pins are fixed in the V-shaped groove.
Install the cross test bench: fix it on the lifting screw and tighten it with an internal hexagonal screw.
Install the micrometer eyepiece: Insert it into the eyepiece hole of the host to ensure proper installation.
Light source and imaging adjustment
Turn on the power switch, and the indicator light and light source light will turn on.
Adjust the light source intensity through the control panel to ensure moderate brightness in the field of view.
Rotate the microscope focus knob to make the image clear. If the image is blurry or half clear and half blurry, adjust the center position of the light bulb.
Switching between indenter and objective lens
Rotate the objective lens and pressure head conversion handle to place the 40x objective lens in the front position of the main body (measurement state) or the 10x objective lens (observation state).
Ensure that the gap between the tip of the indenter and the focusing plane is approximately 0.4-0.5mm to avoid damage from indenter collisions when measuring irregular samples.
3、 Parameter settings
Experimental force selection
Rotate the test force change handwheel, select the appropriate load (such as 0.098N, 0.246N, 0.49N, etc.), and rotate slowly to prevent impact.
Test force selection criteria: The sample thickness should be at least 1.5 times the average length of the indentation diagonal, and there should be no visible deformation on the back after the test.
Guarantee time setting
Enter the test force delay holding time (usually 5-60 seconds) through the operation panel, and adjust it by pressing the "+" or "-" keys.
Measurement mode selection
Choose the Vickers (HV) or Knoop (HK) hardness testing method according to the requirements (if supported by the equipment).
Choose between single or continuous measurement mode.
4、 Hardness testing process
Sample positioning
Place the sample on the cross test bench and rotate the rotating wheel to raise the test bench.
Close the eyes to the micrometer eyepiece for observation. When the sample is 2-3mm away from the lower end of the objective lens, slowly rise until the image is clear, completing the focusing.
Loading and Maintenance
Press the "START" button on the operation panel, and the device will automatically load the test force, with the loading indicator light on.
During the loading stage, the delay indicator light is on and the LCD screen countdown displays the remaining time.
Delay ends, the device automatically uninstalls, and the uninstallation indicator light is on. Do not rotate the pressure head measurement conversion handle before unloading is completed to avoid affecting accuracy.
Indentation measurement
Switch the handle so that the 40x objective lens is in front, and measure the diagonal length of the indentation in the micrometer lens:
Rotate the right drum of the micrometer eyepiece clockwise to bring the two lines close to the critical state of no light gap, and press the "CL" key to reset.
Rotate the left drum to align the left marking with one corner of the indentation, then rotate the right drum to align the right marking with the other corner. Press the measurement button to input data, and the LCD screen will display the diagonal length (D1).
Rotate the eyepiece 90 degrees and repeat the above steps to measure the other diagonal (D2).
The device automatically calculates the hardness value and displays it (HV or HK).
Result recording and repeated testing
Record the hardness value and test parameters (test force, holding time, indentation size).
At least 3 independent measurements should be taken for each sample, and the average value should be taken as the final result.
If the measurement results are not satisfactory, the test can be repeated or the reset button can be pressed to retest (the micrometer eyepiece marking needs to be reset to zero).
5、 Post operation processing
data output
When the LCD screen displays measurement times N ≥ 1, press the print button to output the test results (s test results will not be printed).
To connect to a computer, transfer data through a CCD camera and data cable, and analyze using specialized software.
Device reset
Turn off the power and remove the sample.
Clean the surface of the equipment, especially the lens and pressure head, to avoid dust accumulation.
Shift the objective lens and pressure head to a safe position to prevent collision.
maintenance
Daily cleaning: Wipe the equipment with a clean soft cloth after each use.
Regular calibration: Use standard hardness blocks to calibrate at least once a year.
Lubrication and maintenance: Add an appropriate amount of lubricating oil to the parts that need to be lubricated according to the instructions.
Software updates: Pay attention to software update information released by manufacturers and regularly upgrade control software.