The calibration of the civil air defense roughness tester must strictly follow environmental conditions, standard requirements, appearance and functional inspection, indication error calibration, sampling and evaluation length specifications, operation details control, regular maintenance and calibration standards to ensure accurate and reliable measurement results and provide data support for the quality of civil air defense engineering. The specific explanation is as follows:
1、 Environmental conditions
Temperature and humidity: The calibration should be conducted at a temperature of
(20±5)
∘
C
Conducted in an environment with a relative humidity not exceeding 80%. Such environmental conditions help reduce the impact of temperature and humidity changes on measurement results, ensuring measurement accuracy.
Shock and dust prevention: The instrument should be placed on a stable table, away from vibration sources, and kept in a clean environment to prevent dust from affecting the accuracy of the probe. Vibration and dust may interfere with the measurement results, so strict control is required.
2、 Standardization and auxiliary equipment
Roughness standard template: A high-precision roughness standard template should be prepared, whose roughness value should cover the measurement range of the tested instrument, and the uncertainty should meet the corresponding requirements. These standard templates are used to calibrate instruments and ensure the accuracy of measurement results.
Calibration tools: such as measuring blocks, used for geometric parameter calibration of instruments. These tools help to precisely adjust the instrument to achieve optimal measurement conditions.
3、 Appearance and normal operation inspection
Appearance inspection: The appearance of the instrument should have no obvious damage or deformation, and all components should be firmly connected. The operation buttons and knobs should be flexible and reliable. This helps ensure that the instrument does not malfunction during normal use.
Function check: After connecting the power, the instrument should be able to start normally, the display screen should be clear, and there should be no missing or garbled characters. Each function key operation should be able to achieve the corresponding function. This helps confirm whether the instrument is in normal working condition.
4、 Calibration of indication error
Calibration steps: Select a standard template with appropriate roughness values, place it on the instrument measuring table, and measure according to the instrument operation manual. Compare the measured values with the standard template values and calculate the indication error.
Calibration requirement: The indication error must be within the error range specified by the instrument. If the indication error exceeds the range, it may be necessary to recalibrate or repair the instrument.
5、 Specification for Sampling Length and Evaluation Length
Sampling length selection: Select the appropriate sampling length based on the roughness level of the tested surface and measurement requirements. For example, for rough surfaces, it may be necessary to choose a longer sampling length; For precision surfaces, it may be necessary to choose a shorter sampling length.
Determination of evaluation length: The evaluation length is usually selected as 1-5 times the sampling length based on the length of the measured surface. This helps to more comprehensively evaluate the roughness of the tested surface.
6、 Control of operational details
Probe usage: The probe should be in vertical contact with the measured surface to avoid measurement errors caused by tilting. Meanwhile, the probe pressure must comply with the instrument settings, as excessive pressure may scratch the surface of soft materials or damage the probe.
Measurement speed: When measuring, the sensor should be moved at a constant speed to avoid acceleration or deceleration that may cause the stylus to jump. This helps ensure the stability of the measurement results.
Repeated measurement: It is recommended to measure the same location three times and take the average to improve reliability. This helps to reduce the impact of accidental errors on measurement results.
7、 Regular maintenance and calibration
Daily maintenance: Clean all components of the instrument, including computers, printers, etc., after each use. At the same time, check the working components such as the transmission screw and guide rail, remove burrs and dirt, and add lubricating oil.
Regular calibration: It is recommended to send it to a professional organization for calibration every 3 months or after frequent use. This helps ensure that the instrument is in optimal measurement condition for a long time.