The feed drive of CNC machining machine tools has higher requirements for position accuracy (precision), fast response performance, and speed adjustment range. In the numerical control processing, the control system issues instructions to make the tool perform various movements that meet the requirements, and the shape and size of the workpiece are expressed in the form of numbers and letters, and the processing required by the processing technology. It generally refers to the process of processing parts on CNC machine tools. In order to improve the degree of production automation, shorten the programming time and reduce the cost of CNC machining, a series of advanced CNC machining technologies have been developed and used in the aerospace industry. CNC machining CNC is also called computer gong, CNCCH or numerical control machine tool. It is actually a kind of name in Hong Kong, which greatly reduces the number of tooling. CNC machining parts with complex shapes does not require complicated tooling. CNC machining is a new type of processing technology, the main work It is to compile the processing program, that is, to convert the original manual work to computer programming. If you want to change the shape and size of the part, you only need to modify the part processing program, which is suitable for new product development and modification. There are three main types of motors for CNC machining machine tools to achieve feed transmission: stepper motors, DC servo motors and AC servo motors. At present, stepping motors are only used in economical CNC machine tools (attributes: automated machine tools), DC servo motors are being extensively used in our country, and AC servo motors as ideal transmission components are gradually replacing (step by step). One substance replaces another substance (mostly the strong replaces the position of the weak)) DC servo motor. When the feed system of the CNC machine tool adopts different transmission elements, the transmission structure is different. There are three main forms of connection between the motor and the lead screw, as shown in Figure 69.
1. Gear transmission mode
For the connection form of the motor and the lead screw, the CNC machining machine tool generally adopts a gear transmission pair in the feed transmission device to achieve a certain speed reduction ratio requirement. Since gears may not meet the requirements of the ideal tooth surface during manufacturing, there is always a certain error. A pair of meshing gears must have a certain tooth side clearance to work normally, but the tooth side clearance will cause reverse transmission clearance. For a closed-loop system, the side clearance will affect the stability of the system (explanation: stable and stable; no change) (The stability of). Therefore, the gear transmission pair often adopts an anti-backlash mechanism (organization) to minimize the tooth backlash.
2. Synchronous pulley transmission form
The structure of this connection form is relatively simple. In the numerical control processing, the control system issues instructions to make the tool perform various movements that meet the requirements, and the shape and size of the workpiece are expressed in the form of numbers and letters, and the processing required by the processing technology. It generally refers to the process of processing parts on CNC machine tools. In order to improve the degree of production automation, shorten the programming time and reduce the cost of CNC machining, a series of advanced CNC machining technologies have been developed and used in the aerospace industry. Synchronous belt transmission combines the advantages of belt transmission and chain transmission, which can avoid vibration and noise caused by gear transmission, but it can only be applied to occasions with low torque characteristics. The requirements for center distance during installation are strict. The manufacturing process of belt and pulley complex.
3. Coupling transmission form
Usually the motor shaft and the screw are connected by a cone-ring keyless connection or a high-precision (precision) cross coupling (Coupling), so that the feed transmission system has a higher transmission accuracy (precision) and transmission rigidity. And greatly simplify the transmission structure. This type of connection is commonly used in the feed drive of machining centers and numerically controlled machine tools (attributes: automated machine tools) with high precision (precision).
