The calibration of the automatic two-piece bottle and can detector should be based on industry standards and equipment characteristics, ensuring measurement accuracy through standard comparison, repeatability testing, and uncertainty evaluation. At the same time, attention should be paid to key aspects such as environmental control, equipment status identification, and data traceability. The following are the specific verification and calibration steps and key points:
1、 Verification and Calibration Basis and Standards
Industry standards and specifications, such as GB/T9106.1-2019 "Two piece cans for packaging containers - Part 1: Aluminum cans with easy to open lids", provide clear requirements for sealing testing, stipulating that the sample should not leak after being held at a test pressure of 610kPa for 1 minute. This type of standard provides a technical benchmark for verification and calibration.
Equipment calibration specifications: For specialized equipment such as bottle and container vertical axis deviation measuring instruments, it is necessary to follow calibration specifications such as JJF (Lu) 128-2022, and clarify the measurement characteristics requirements such as indication error and measurement repeatability of the indicator.
2、 Verification and calibration steps
Appearance and functional inspection:
Check if the appearance of the equipment is intact and if all components (such as sensors, fixtures, display screens, etc.) are functioning properly.
Confirm whether the equipment is in a horizontal state to avoid measurement errors caused by tilting.
Standard equipment preparation:
Choose standard instruments that meet the accuracy requirements, such as high-precision pressure sensors (for sealing testing), specialized cylindrical angle gauges (for vertical axis deviation measurement), etc.
Ensure that the standard is within its calibration validity period and has a valid traceability certificate.
Calibration project implementation:
Calibration of indication error of indicator: By comparing the indication values of the standard and equipment, adjust the equipment indication value to be consistent with the standard. For example, using a standard pressure source to calibrate the sealing tester.
Measurement repeatability test: Repeat the measurement of the same sample under the same conditions, calculate the coefficient of variation of the measurement results, and evaluate the measurement stability of the equipment.
Calibration of indication error: By measuring samples of different sizes or shapes, comparing the difference between the measured values of the equipment and the true values (or standard values), the indication error is determined.
Uncertainty assessment:
Based on calibration data, analyze the sources of measurement uncertainty (such as standard errors, environmental temperature fluctuations, equipment repeatability, etc.).
Calculate the composite uncertainty and provide the extended uncertainty (e.g. U=0.5 μ m, k=2) to ensure that the device uncertainty does not exceed one-third of the uncertainty of the detection result.
3、 Precautions for verification and calibration
Environmental condition control:
The temperature of the calibration laboratory should be controlled at (20 ± 5) ℃, and the relative humidity should not exceed 75%.
Avoid calibration in environments with high humidity or large temperature fluctuations to avoid affecting the performance of optical systems and electronic devices.
Equipment status identification:
According to the calibration results, label the equipment with "qualified", "approved for use" or "discontinued" labels.
The qualified label indicates that the equipment meets the testing requirements and can be used normally; The approval mark indicates that the device is restricted from use (such as only for a certain scope); The stop sign indicates that the device does not meet the requirements and needs to be immediately stopped from use.
Data traceability and correction:
If there is a correction value for calibration (such as "100 ℃+0.3 ℃"), it is necessary to determine whether the correction value needs to be used. If the deviation affects the detection results, a "correction value" column should be added to the original record and the correction information should be posted on the instrument.
If the equipment does not meet the requirements, it should be immediately stopped from use, and the testing data previously done with the equipment should be traced to determine if there is a risk. If necessary, the report should be retrieved.