This instrument is composed of five parts: long-range sensor (Renishaw XL80 laser head), micrometer sensor (WS16-Z0.6-LP), CNC motion system, measuring bracket, and host computer. This instrument can achieve absolute or comparative measurement of precision parts within 2 meters, and the accuracy can meet the comparison measurement of three-level gauge blocks above 150 mm, or the absolute measurement of four-level gauge blocks. The innovation of this instrument is that it breaks through the mechanical structure mode of the traditional length measuring machine for a hundred years, leading to two advantages: 1. The weight limit of the instrument on the measured object is greatly expanded. 2. The main guide rail can be designed into a whole body with equal cross-section, and the temperature deformation is not restricted by other parts, which greatly simplifies the main guide rail's response to temperature changes. In addition, the realization of CNC semi-automatic measurement technology on the length measuring machine can not only improve the quality and efficiency of the measurement work, but also help realize the constant temperature sealing of the instrument, improve the adaptability of the instrument to the laboratory environment temperature, and save energy. At present, only a handful of manufacturers in the world have the technology to realize CNC semi-automatic measurement on length measuring machines.
The numerical control system of this instrument realizes the computer control of five kinds of motions of the tested part, such as translational movement along X-axis and Y-axis, rotation around X-axis and Y-axis, and expansion and contraction of sensor contacts. In this way, the universal adjustment and positioning of the measured part in the measurement operation, the transposition operation of the 6 measuring points on the surface of the standard gauge block and the measured block are all automated. The upper computer software of the instrument is compiled in C++ language and runs under the Chinese Windows environment. It also has the functions of animation simulation and dynamic digital display. Under the control of the software, the computer instantly displays the movement and status of the various parts of the instrument, and automatically prompts the operator for each step of the operation, and directly stores the data sampled by the sensor on the gauge block into the computer. The required standard gauge block data is pre-stored in the computer, and the software automatically adds the sampled data to the standard gauge block data. After the verification, the verification records and certificates are automatically compiled, and the operation automation degree is high, so the work efficiency can be greatly improved.