Applied knowledge of CNC machine

In CNC machine tools, the electric spindle usually adopts frequency conversion speed adjustment method. Currently, there are three main control methods. Normal variable frequency drive and control, vector control drive and direct torque control.

The common frequency conversion is scalar drive and control, the drive control characteristic is constant torque drive, the output is proportional to the speed. The normal dynamic performance of frequency conversion control is not ideal, the control performance is not good at low speed, the output power is not stable enough, and there is no C axis function. However, the price is low, the structure is simple, and it is generally used for grinding machines and general high-speed milling machines.

Vector control technology mimics the control of a DC motor, orients with a rotor magnetic field, uses a vector transformation method to drive and control, and has excellent dynamic performance. With vector control drive, the torque value at start is large, and the electric spindle itself has a simple structure and low inertia, so the start acceleration is large and the allowable limit speed can be reached immediately after start. There are two types of drives, open loop and closed loop. The latter can provide position and velocity feedback. This not only improves dynamic performance, but also provides C-axis functionality. The former has low dynamic performance and lacks the C-axis function , But the price is cheap.

Direct torque control is another new type of high performance AC speed regulation technology developed after the vector control technology. Its new control concept and simple and clear system structure make it more suitable for driving high speed electric spindles, even high speed electric spindles. The requirements for high speed, wide speed range, dynamic characteristics, and static characteristics for high-speed instantaneous stop are technologies that are attracting attention in the field of AC power transmission.

Scope of application

Woodworking industry

Furniture decoration, musical instrument industry, wooden handicraft industry, large area flat panel carving, solid wood furniture, mahogany furniture, solid art murals, MDF paint free doors, composite doors, cabinet windows, bedside tables , Screen engraving, etc.