I. Preparation Before Calibration
1. Equipment Inspection
Confirm that the instrument is undamaged, all components are securely connected, and the power supply is stable (220V is required for motor-driven models).
2. Environmental Requirements
Calibration should be performed in a constant temperature and humidity environment (recommended temperature 20±2℃, humidity 65±4%) to avoid environmental fluctuations affecting accuracy.
3. Preparation of Standard Tools
Precision balance (for weighing the friction head mass)
Standard weights (for verifying the applied force)
Vernier caliper or micrometer (for measuring the stroke and friction head dimensions)
Tachometer or speedometer (for detecting friction speed)
High-precision timer (for calibration time control)
II. Calibration Steps for Key Components
1. Friction Head Calibration
Mass and Dimensions: Use a precision balance to measure the mass of the friction head to ensure it meets the standard requirements (usually 500g±10g). Check that its diameter is Φ16mm (circular) or 19×25mm (rectangular). Hardness Testing: A dedicated hardness tester is used to test the surface hardness of the friction head to prevent uneven pressure distribution due to wear.
2. Pressure Calibration (Core): The vertical pressure on the friction head should be 9N ± 0.5N (approximately 918g force).
Use standard weights for comparison through the loading system. If the deviation exceeds the allowable range, the spring or pressure adjustment mechanism needs to be adjusted.
3. Stroke Length Calibration: The standard reciprocating stroke is 100mm ± 1mm (some instruments support 104mm).
Measure the friction head movement distance using measuring tools and adjust the connection position of the drive arm and crank to correct the stroke.
4. Friction Speed Calibration: The standard speed is 60 times/min (cpm), some devices are 40~43cpm.
Measure the actual operating frequency using a tachometer, compare it with the set value, and adjust the motor control system.
5. Counter and Time Control Calibration: Use an electronic counter with a known number of cycles or a high-precision stopwatch to verify the instrument's counting accuracy.
For models with automatic alarm functions (such as G238BB), confirm that they can accurately stop and alarm after the set number of cycles.
6. Calibration of Color Evaluation Auxiliary Equipment
If a colorimeter or color difference meter is equipped, it needs to be calibrated regularly using a standard white board to ensure objective and accurate staining rating.
Gray cards should be stored in a cool, dry place away from light to prevent aging from affecting visual judgment.
III. Calibration Cycle and Records
It is recommended to calibrate at least once a year; high-frequency users can perform calibration every 6 months.
A calibration report should be issued after each calibration, including: calibration date, personnel, method, results, adjustment measures, and conclusions, and properly archived for future reference.
