Numerical Control Lathe Machining Spindle Speed Regulation Method

In order to meet the requirements of the main transmission of CNC lathe processing, CNC machine tools (attribute: automatic machine tools) often use a motor stepless speed regulation system. The method of combined speed regulation can realize the spindle speed regulation.

In numerical control processing, the control system sends out instructions to make the cutter perform various movements that meet the requirements, and expresses the processing of technical requirements and processing requirements such as the shape and size of the workpiece in the form of numbers and letters.

It generally refers to the process of processing parts on CNC machine tools. In order to improve production automation, shorten programming time and reduce CNC machining costs, a series of advanced CNC machining technologies have also been developed and used in the aerospace industry.

1. Mechanical gear shift

In the main transmission system of CNC lathe machining, the stepless speed regulation of the motor is adopted, which greatly simplifies the structure of the traditional spindle box. However, due to the limitations of the spindle motor and drive power, it is often a constant torque output at its low speed section. In order to make the spindle provide the maximum output power of the main motor in the entire speed range as much as possible, and to meet the needs of low-speed powerful cutting of CNC machine tools (attribute: automatic machine tools), 1 to 4 gear speeds and stepless speed regulation are often used The combined method is the so-called stepless stepless speed regulation. The use of mechanical gear deceleration not only amplifies the output power, but also expands the speed regulation range.
During CNC lathe machining, the spindle is automatically operated at the speed specified by the S command in the part processing procedure (procedure). Therefore, there must be two types of spindle speed command signals in the CNC system, that is, analog (definition: virtual to real things or processes) or digital signals (S code) to control the drive adjustment of the spindle motor. High-speed circuit, at the same time using the digital signal (M code) to control the mechanical gear shift automatic shifting actuator (organization). The automatic shift actuator is an electro-mechanical conversion device, commonly used hydraulic (hydraulic) fork and electromagnetic clutch (Clutch).

2. Motor speed regulation

The speed-regulating motors used for the spindle drive of CNC lathes are mainly divided into two categories: DC and AC.

(1) Speed regulation of DC motors? Generally, the range of speed regulation of CNC machine tools is large, and two methods of voltage regulation and magnetization are used for the speed regulation of DC motors. Its typical DC spindle electric machine characteristic curve is shown in Figure 61. From its characteristic curve, it can be known that the motor belongs to constant torque speed regulation below the speed n0, that is, it is realized by changing the armature voltage; above the speed n0 belongs to the constant power (How many) speed regulation, by changing the excitation current (Electron flow) to achieve. The more commonly used? FANUC DC-excited spindle electric motor? The machine uses a three-phase fully controlled thyristor (zhá) tube without circulating current reversible speed regulation system? The system can realize voltage regulation and magnetic regulation, speed regulation range 35 ? ~ 3500r / min. CNC machining generally CNC machining usually refers to computer digitally controlled precision machining, CNC machining lathe, CNC machining milling machine, CNC machining boring and milling machine, etc. The feed route for finishing is basically carried out along the contour of its parts. Therefore, the work of determining the feed route is to determine the feed route for rough machining and empty stroke.
(2) AC motor speed regulation At present, cage induction motors are used in the AC spindle drive of CNC machine tools, and the vector control (frequency conversion) speed adjustment method is widely used. With the improvement of new DC and AC spindle speed regulating motors, motor speed regulation will be widely used. However, in order to reduce costs in economic CNC machine tools (attributes: automated machine tools), mechanical gear shifts are often used Method to change the spindle speed. In numerical control processing, the control system sends out instructions to make the cutter perform various movements that meet the requirements, and expresses the processing of technical requirements and processing requirements such as the shape and size of the workpiece in the form of numbers and letters. It generally refers to the process of processing parts on CNC machine tools. In order to improve production automation, shorten programming time and reduce CNC machining costs, a series of advanced CNC machining technologies have also been developed and used in the aerospace industry.