1. Open loop control of CNC machine tools
The control system of this kind of CNC machine tool has no position detecting element, and the servo driving parts are usually reactive stepping motor or hybrid servo stepping motor. After the power amplification of the drive circuit, the CNC system drives the stepper motor to rotate an angle, and then drives the screw to rotate through the gear reducer, which is converted into the linear displacement of the moving parts through the screw nut mechanism. The moving speed and displacement of moving parts are determined by the frequency and number of input pulses. The information flow of this kind of CNC machine tool is unidirectional, that is, after the feed pulse is sent out, the actual movement value is no longer fed back, so it is called open-loop control CNC machine tool.
The CNC machine tool with open-loop control system has simple structure and low cost. However, the system does not monitor the actual displacement of the moving parts and can not correct the error. Therefore, the step out of step, step angle error, gear and screw transmission error will affect the accuracy of the machined parts. The open-loop control system is only suitable for small and medium-sized CNC machine tools, especially for simple and economical CNC machine tools.
2. Aluminum profile cutting saw
Aluminum profile cutting saw is directly installed with a linear displacement detection device on the moving parts of the machine tool, which directly detects the actual displacement of the worktable, feeds back the measured actual displacement value to the numerical control device, compares it with the input command displacement value, and controls the machine tool with the difference value, so that the moving parts move according to the actual displacement, Finally, the precise movement and positioning of the moving parts are realized.
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