The history of centering equipment: from the early straightening of straightedge, feeler gauge and dial indicator to 1967 Martin Hamar of Hamarlaser Instrument Company in the United States created the first laser straightening instrument by using some parts of Perkin Elmer. Today, the accuracy of the latest laser centering instrument can reach 0.5 micron, and other functions such as Bluetooth transmission, wireless RF transmission, ZIGBEE wireless transmission and so on. At the same time, various companies have developed corresponding centering application software to process the data measured by centering, so a centering measurement system has been developed, which can measure points, lines and surfaces. The relative positions of these geometric elements, such as straightness and concentricity of a line, parallelism and verticality of two lines (tracks); Flatness of one surface, verticality and parallelism of two surfaces, etc. The most advanced equipment has been able to measure the relationship between three surfaces at the same time.

The laser collimation system consists of laser (straight line or plane), receiving target, data display and operation software.

Laser transmitters are divided into plane laser, line laser, rotating laser, 2-axis and 3-axis rotating laser, etc.

The receiving target is usually a bed sensor with PSD (position sensing detector).

Or CCD (charge coupled device).

According to different applications, there are many kinds of calculation software, such as Couple 5 and Couple 6 from Hamarlaser Instruments, Plane5 for geometric centering, spindle8 for spindle centering, geometric machine tool alignment software for machining center, and Read 8 Read8 and bore 8 for hole centering.