High speed CNC drilling and milling machines are widely used in the field of precision machining, and the vibration control during the machining process directly affects the machining accuracy of parts, tool life, and equipment stability. When the vibration amplitude exceeds the allowable range, it can cause problems such as ripples, dimensional deviations, and even damage to equipment components on the machined surface. Therefore, accurately diagnosing the root cause of excessive vibration and taking effective measures to eliminate it is the key to ensuring machining quality.

The root cause of excessive vibration faults needs to be comprehensively analyzed from three aspects: mechanical system, cutting parameters, and control system. In terms of mechanical systems, spindle unit imbalance is a common cause, as spindle bearing wear, excessive clearance, or insufficient rotor dynamic balancing accuracy can generate periodic excitation forces during high-speed rotation; If there is wear or improper pre tightening force on the ball screw and guide rail pair of the feed system, it will cause impact vibration during the motion process; The clamping rigidity between the fixture and the workpiece is insufficient, and it is also prone to elastic vibration under cutting force. Unreasonable selection of cutting parameters can also cause vibration, imbalance in the matching of cutting speed, feed rate, and back cutting amount, which may lead to sudden changes in cutting force and trigger system resonance. Improper parameter settings in the control system, such as excessively high servo gain, can cause the feed system to overreact and generate high-frequency vibrations.

Fault diagnosis should follow the principle of "simple before complex, mechanical before control". Firstly, through intuitive observation and preliminary positioning detection, vibration signals of key parts such as the spindle and feed shaft are collected using a vibration detector, and the vibration frequency characteristics are determined by combining frequency spectrum analysis; Check whether the fixture is firmly clamped, whether the workpiece is deformed, and whether there is any jamming or abnormal noise when manually turning the spindle. Subsequently, targeted verification was carried out by replacing the standard test bar to test the dynamic balance state of the spindle, adjusting the pre tension force of the feed system and observing the vibration changes. By changing the cutting parameters, resonance points were tested to gradually narrow down the scope of the fault.

The elimination of faults requires corresponding measures to be taken based on the diagnostic results. In terms of mechanical systems, perform dynamic balance correction on the spindle, replace worn bearings, and adjust clearances; Repair or replace worn screws and guide rails, and recalibrate the preload force; Adopting fixtures with stronger rigidity and optimizing the clamping method to enhance rigidity. Optimization of cutting parameters can be achieved by reducing cutting speed to avoid resonance intervals, increasing feed rate reasonably, or reducing back cutting amount to reduce cutting force fluctuations. At the control system level, by debugging software to reduce servo gain, optimize acceleration and deceleration curves, and reduce motion impact. In addition, regular precision calibration and lubrication maintenance of equipment can reduce the occurrence of vibration faults from the source.

The vibration control of high-speed CNC drilling and milling machines is a system engineering that requires comprehensive control based on mechanical characteristics, cutting processes, and control parameters. By scientifically diagnosing and locating the root cause, targeted elimination measures can be taken to effectively improve equipment stability and processing quality.