Thread Content
The diameter of the outer circle of a circular object is called the outer diameter. In engineering, the outer diameter is often an important indicator of quality issues; therefore, measuring it is a very important process. In fact, throughout history there have been many methods for measuring outer diameter, and today more convenient and user-friendly testing equipment has been developed. Most traditional measurement methods are contact-based, including calipers, vernier calipers, micrometers, resistance methods, and weighing methods. Optical methods are also used, such as optical microscopy, interference method, scanning method, projection magnification method, comparison method, etc. Most of the above testing methods can generally meet production requirements, but when it comes to measuring high-precision instruments, their shortcomings become apparent: slow testing speeds, low production efficiency, and high labor intensity, which fail to keep up with the demands of modern automated production. Moreover, contact-based measurement can very easily cause secondary damage to the rolled products. Measurement results are prone to errors. Currently, laser scanning and CCD photoelectric measurement methods are commonly used both domestically and internationally for such measurements. Among them, the laser scanning measurement method offers higher precision, but it is more suitable for static, high-precision measurements. When used for dynamic measurements, the movement of the rolled material being measured causes the diffraction fringes to shift rapidly, leading to inaccuracies; it is also difficult to obtain measurement results quickly. Additionally, this method has disadvantages such as a complex structure, high cost, and vulnerable rotating components. The CCD photometric measurement method employs a high-precision measurement technique with a pixel resolution of 4.7 μm, allowing for non-destructive measurement of the rolled material being tested. It has low production costs and can achieve ultra-high precision levels of up to 0.003 mm. It can meet the measurement requirements of various rolled products. Meanwhile, the use of dual probes with adjustable spacing expands the measurement range for such products, making it particularly suitable for inspecting large-diameter rolled products. The photoelectric diameter meter has a longer service life and is also highly suitable for dynamic testing. To ensure higher quality of the products being manufactured, it is equipped with a PID control system that integrates online testing, monitoring and alarm functions, as well as closed-loop control and digital display. This testing approach simplifies the production process and significantly improves both quality and efficiency. To summarize, for different applications, the appropriate measuring equipment is chosen: for test objects such as wires, cables, and hoses that are in good condition, photoelectric and laser diameter meters are used to accurately determine the outer diameter ； Ultra-fine filaments are measured using a laser diffraction diameter meter, offering high precision ； For ultra-large diameter pipes, fixed-spacing dual-probe diameter measuring instruments or dual-probe large-diameter measuring instruments with adjustable spacing are used; they represent a boon for the inspection of large-diameter rolled products, with accuracy sufficient to meet the requirements of such inspections ； For production in harsh environments such as steel rolling (high temperatures, water mist, dust, etc.), steel rolling diameter meters are used, along with analysis software ； Random inspections can use vernier calipers and similar tools. There are corresponding diameter measuring instruments for use in different situations; using such instruments not only relieves the workload on workers but also ensures quality.