The inspection, inspection, certification, and testing methods of drawing instrument rulers mainly cover appearance inspection, dimensional accuracy inspection, flatness inspection, scale error inspection, and other aspects. The following is a detailed summary of these inspection methods:

1. Appearance inspection
Inspection content:
The surface of the ruler should be smooth, without damage, rust, or stains.
The scale lines of the ruler should be clear and uniform, without blur or breakage.
The material of the ruler should meet the relevant standards, such as hardwood, aluminum alloy steel, etc.
The ruler should have a nameplate, including the instrument name, model specifications, factory number, factory date, manufacturer, and other information.
Inspection method:
Use a visual method to check the surface quality, scale line clarity, and material of the ruler.
Check the nameplate information of the ruler against the relevant standards to see if it is complete and accurate.
2. Dimensional accuracy inspection
Inspection content:
The full length of the ruler should meet the size range specified in the relevant standards.
The scale spacing of the ruler should be accurate and meet the accuracy requirements specified in the standards.
Test method:
Use measuring tools such as steel tape measure or vernier caliper to measure the full length of the ruler multiple times, and take the average value as the test result.
Use tools such as vernier caliper or microscope to measure the scale spacing of the ruler one by one and compare it with the standard value.
3. Flatness test
Test content:
The working surface (i.e. measuring surface) of the ruler should be flat, without warping or depression.
Test method:
Place the ruler against a non-deformed glass plate or flat reference, and use tools such as a feeler gauge to check the full length of the ruler.
Record the maximum gap that the feeler gauge can be inserted into as the flatness test result.
4. Scale error test
Test content:
The scale lines of the ruler should accurately indicate the corresponding length value without deviation.
Test method:
Use a vernier caliper or higher precision measuring tools to measure specific scale lines on the ruler one by one.
Compare the measurement results with the standard value and calculate the scale error.
5. Other testing items
Material testing:
Analyze the chemical composition or physical properties of the ruler to ensure that it meets the requirements of relevant standards.
Durability testing:
Test the ruler for long-term use or simulate the use in harsh environments to evaluate its durability and stability.
Certification and testing:
Send the ruler to a third-party testing agency with relevant qualifications for certification and testing to obtain the corresponding certification certificate and test report.
6. Testing precautions
Testing environment:
The testing work should be carried out indoors, and the ambient temperature and humidity should comply with the provisions of relevant standards.
The testing site should be clean, vibration-free, pollution-free, and free of corrosive gases.
Testing personnel:
The testing personnel should have relevant professional knowledge and operating skills, and be familiar with the testing standards and testing methods.
The testing personnel should operate strictly in accordance with the testing procedures to ensure the accuracy and reliability of the test results.
Testing records:
Accurately record all data and information during the testing process, including test results, measuring tools, testing environment, etc.
Testing records should be clear, complete, and traceable.
In summary, the inspection, testing, certification, and testing methods of drawing instrument rulers are a complex and systematic process that needs to be operated in accordance with relevant standards and procedures. Through scientific testing methods and strict testing processes, it can be ensured that the quality and performance of rulers meet relevant requirements, providing reliable protection for drawing and measurement work.