The classification of the nc machine tools
The classification of the nc machine tool release date: 2019 - 06 - Author: small make up click: a. Classified by process USES metal cutting class CNC metal cutting machine tool nc machine tool is to point to to the car, milling, planing, grinding, boring, drilling and other machining of CNC machine tools, it is divided into two classes. ( 1) Ordinary ordinary numerical control machine tools and common machine tool technology of nc machine tools, divided into CNC lathe, CNC milling machine, CNC planer, CNC grinding machine, CNC boring machine, CNC drilling machine, etc. ( 2) This kind of nc machine tool CNC machining center is on the basis of general nc machine tools equipped with a knife library and automatic tool change device, constitute a CNC machine with automatic tool change device. The emergence of CNC machining center broke a traditional concept of only a single type of work the machine, execute an installation location, finish machining, avoid the error caused by multiple installation. 2. Metal forming metal forming numerical control machine tool type nc machine tool is to point to can finish the crowded, pressure, impact, such as molding process of nc machine tools, including CNC pipe bending machine, CNC sheet metal bending machine, CNC combination punching machine, numerical control press, etc. This kind of machine starting late, but is now developing quickly. 3. Special machining CNC special machining nc machine tools including CNC edm machine, CNC wedm, CNC flame cutting machine, CNC laser cutting machine, etc. 4. Other types of CNC machine tools other types of nc machine tools are mainly three coordinate measuring instrument, CNC numerical control instrument on the knife, nc plotter, etc. two According to control movement trajectory classification 1. Position control of CNC machine tool position control numerical control machine tool requires only obtain accurate location, processing the coordinates because of nc machine tools is the tool or workpiece began to reach the designated position, and it is not processed in the process of movement, so from one location to another location trajectory do not need to strictly control. Nc drilling machine, CNC jig boring machine and CNC punch press and so on all use position control. 2. Linear control of nc machine tool control, also known as linear parallel control, its characteristic is in addition to control the displacement of the end position, also can realize the parallel axis linear cutting processing, and can be set straight cutting feed speed, its mobile route is parallel with the machine tool coordinate, coordinate axes simultaneous control only one, normally only processing rectangle, steps form such as straight line profile parts. In lathe turning ladder shaft, for example, on the milling machine milling steps. Commonly used linear control of nc machine tools have a CNC lathe, CNC milling machine, etc. 3. Profile control of CNC machine tool profile control CNC machine to two or more axes simultaneous control, not only can control the machine moving parts starting point and end point coordinates, and can control the processing speed and displacement of each point in the process, the numerical control device general requirements have straight line and arc interpolation function, the spindle speed control function and relatively complete auxiliary functions. This kind of machine tool used for machining surface. CAM and complex shape parts such as blade. The outline of commonly used control of nc machine tool with CNC milling machine, CNC lathe, CNC grinding machine, machining center, etc. 3. According to the servo system control mode classification 1. Open loop control open-loop control of CNC machine tool nc machine tools in general by the control circuit, stepper motor, gear box and the silk and nut vice, etc, no detection device, the open-loop control system after the issue of the command signal no feedback, so the open loop control. Open loop control of servo system using stepper motor. Open loop control is characterized by simple structure, convenient debugging, easy maintenance, low cost, but its control precision is not high. At present domestic to develop economical nc machine tool, widely used open-loop nc system. 2. Closed-loop control CNC machine installed on the workbench detecting element will be actual displacement feedback to the computer table, comparing with the location of the required instruction, with comparison of difference, until the difference to eliminate, so that the machining accuracy is greatly increased. Closed loop control is characterized by high machining accuracy, moving speed, this kind of nc machine tools using dc servo motor or ac servo motor as driving element. The control circuit of the motor is more complex, the detecting element is expensive, debugging and maintenance is more complex, high cost. 3. Half closed loop control of CNC machine tools, it is not a direct detection worktable displacement but are associated with servo motor corner detecting element, such as photoelectric encoder to measure the Angle of the servo motor, calculated the actual displacement of the workbench, feedback to compare location in the computer, with comparison of difference to control, because is not contained within the feedback loop workbench, therefore calls half closed loop control. A half closed loop control precision is closed loop control is poor, but has good stability, low cost, commissioning, maintenance is also easier for the open-loop control and closed-loop control the characteristics of both.