CNC lathe is one of the widely used CNC machine tools. It is mainly used for cutting the inner and outer cylindrical surface of shaft parts or disc parts, the inner and outer conical surface of arbitrary cone angle, the complex rotary inner and outer curved surface, cylinder, taper thread, etc., and can be used for grooving, drilling, reaming, reaming and boring, etc.
The parts are processed automatically according to the NC program. According to the instruction code and program format specified by the CNC lathe customized manufacturer, the machining process route, process parameters, tool motion path, displacement, cutting parameters and auxiliary functions of the parts are compiled into a processing program sheet, and then the contents of the program list are recorded on the control medium, and then input into the numerical control device of the numerical control machine tool to command Machine tool processing parts.
The semi closed-loop control system is that angular displacement and angular velocity detection devices are installed at the end of the motor shaft or screw rod. The comparator fed back to the numerical control device through the position detection feedback device is compared with the input command, and the moving parts are controlled by the difference value. It is characterized by convenient debugging, good system stability and compact structure, but the error in the mechanical transmission chain cannot be corrected or eliminated. At present, the ball screw carrying nut mechanism has good precision and precision retention, and adopts reliable mechanism to eliminate reverse movement clearance, which can meet the majority of CNC machine tool users, so it is widely used and becomes the preferred control mode.
The closed-loop control system is to install a linear or rotary detection device at the corresponding position of the moving parts of the machine tool. The displacement or angular displacement measured directly is fed back to the comparator of the numerical control device, and compared with the displacement of the input command, the moving part is controlled by the difference value. The advantage is that all links of the mechanical transmission chain are included in the closed loop, and the accuracy depends on the accuracy of the detection device, which is more than that of the semi closed loop system. The disadvantages are high price and strict requirements for mechanism and transmission chain, otherwise it will cause oscillation and reduce the stability of the system.
Open loop control system is a control mode without position detection and feedback device. It is characterized by simple structure and low price, but it is difficult to realize the rapid control of moving parts. It is widely used in the drive control of small equipment with low torque, high precision and medium speed, especially in microelectronics production equipment.
On 2018-08-08 11:45:46
