Gears are toothed mechanical parts that can mesh with each other and are extremely versatile in mechanical transmission and in the entire mechanical field. Modern gear technology has reached: gear module O.004 ~ 100 mm; gear diameter from 1 mm to 150 meters; transmission power up to 100,000 kilowatts; speed up to hundreds of thousands of revolutions per minute; m/s.

At present, there are only about 300 gear manufacturing plants in China's gear industry that have metering rooms that are basically equipped with instruments. In total, there are more than 200 coordinate measuring instruments. Most of these instruments are imported from abroad. There are more than 1,000 various types of mechanical (mechanical, optoelectronic, and numerical control) gear measuring instruments, including more than 30 gear measuring centers. The manufacturers of these instruments include foreign companies such as MAAG, Klingelnberg, Hofler, Carl Mahr, and MM, and Taylor Hobsom and Carl Mahr. Zeiss, SIP and other companies have more than 500 types of measuring instruments such as roundness meter, length measuring instrument, optical indexing head, roughness meter, projector, and Wangongxian.

There are few precision measuring instruments in some of the remaining 200 gear manufacturing plants. In addition to the thousands of energy tools, some factories do not have a measuring instrument.

Among the measuring instruments, there are about 10 sets of assembly test instruments and worm gear pay inspection instruments, and no more than 50 sets of gearbox assembly test benches and drive axle test benches nationwide. Many factories do not have necessary instruments such as noise meters and torsional vibration instruments. In the gear manufacturing process, strict inspection and control of product parts, components, and assembly quality are required. Therefore, advanced and applicable measurement technologies and instruments are necessary conditions.

Gears, worms, screws and other transmission parts must be supported by cast iron, aluminum alloy or welded box with high precision and complex structure. These boxes have a large number of precision holes and planes that need to measure dimensional accuracy and mutual position accuracy. Therefore, each gear factory should be equipped with different specifications and accuracy of the three coordinate measuring instrument.

In all kinds of machinery factories, regardless of whether the gear transmissions are manufactured or purchased, gears, threads, and spline measuring instruments should be equipped. Otherwise, the manufacturing quality of the transmission parts cannot be controlled. At present, gears, threads, and spline measuring instruments, such as the Chengdu Institute of Tools and the Harbin Institute of Precision Measuring Instruments, can basically meet the requirements. Even the gear measuring center, gear tool measuring center, gear pair and worm gear checker, and laser dynamic screw measuring instrument are available. However, for users with high technical requirements and abundant financial resources, they may also consider introducing foreign gear measuring centers.