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Working Principle of Fully Automatic CNC Milling Machine

The fully automatic CNC milling machine employs a variable-speed motor for drive, equipped with a high-power reduction system featuring soft start and soft stop for smooth operation. During processing, the upper and lower grinding discs, sun gear, and planetary gears coordinate to generate four-directional grinding motions with synchronized speeds, achieving simultaneous grinding of both upper and lower surfaces.

Automatic CNC Milling Machine Speed Control Method: The grinding process comprises three phases: initial, formal, and final. During the initial phase, the grinding wheel accelerates to rotation, with acceleration exhibiting an inflection point. The maximum acceleration value controlling the wheel speed gradually decreases from fast to slow until the wheel reaches the formal grinding speed. In the formal phase, the wheel rotates at a constant speed, while in the final phase, it decelerates. During the initial grinding phase, the acceleration of the grinding wheel speed is manually controlled to increase gradually from zero. When the wheel speed reaches half of the formal grinding speed, the acceleration of the wheel speed is reduced to zero.

By leveraging the characteristic of grinding with bonded abrasives, the density distribution of abrasives on the grinding wheel is rationally designed based on the relative motion trajectory density distribution between the workpiece and the wheel. This ensures that wear occurring during the grinding process does not compromise the surface profile accuracy of the wheel, thereby significantly improving the surface profile accuracy of the workpiece while eliminating the hassle of wheel dressing. In planar bonded abrasive grinding, the rotational motion of the grinding wheel serves as the primary motion, while the movement of the workpiece functions as the auxiliary motion.

The lower grinding disc of the milling machine is adjustable for height during workpiece loading and unloading. The pneumatic sun wheel directional control device precisely regulates the grinding accuracy and speed for both sides of the workpiece. A correction wheel is included to adjust parallelism errors between the upper and lower grinding discs. Therefore, analyzing the forces acting on the workpiece is essential to determine its stress conditions and motion characteristics. Treating the workpiece as a separate entity within the entire grinding system, establish differential equations for force equilibrium. Solving these equations yields the workpiece’s motion characteristics.