What is the reason for the tool falling off in high-speed CNC vertical lathe? - Exhibition

1. Mechanical structure problem
The gap between the screw and the nut is too large
The ball screw pair of the CNC vertical lathe has a wear gap due to long-term use, which causes the tool holder to move or sink when moving in the vertical direction (Z axis). For example, a 16m CNC vertical lathe has a screw nut gap of 0.26mm, which causes the "carrying knife" phenomenon on the machining plane (0.2mm error for every 300mm).

Imbalance of the ram transmission mechanism
The matching gap between the square ram of the CNC vertical lathe and the static pressure plate and the inlay is too large (>0.04mm) or the guide rail is poorly lubricated, causing the tool holder to slide down under the action of gravity.

Excessive friction resistance
The sliding friction structure (such as the balance hammer mechanism) of the old CNC vertical lathe is not sensitive enough to offset the weight of the tool holder, causing the tool to fall off. For example, the KNA-110 vertical lathe imported in 1958 solved this problem by changing to rolling friction.

2. Failure of the clamping system

Failure of the spindle clamping device

Disc spring fragmentation or fatigue: The disc spring assembly of the CNC vertical lathe spindle inner hole is damaged, resulting in insufficient tool clamping force. In the case, the tool still dropped repeatedly after the disc spring was replaced, and the disc spring material and preload force need to be checked.

Hydraulic system leakage or insufficient pressure: The seal ring of the CNC vertical lathe balance cylinder is worn or the oil circuit is inhaled, causing the tool holder hydraulic balance to fail, increasing the risk of sliding.

Tool installation problem

The CNC vertical lathe blade extends too long or the bottom surface of the tool groove is uneven, which weakens the clamping rigidity and is easy to break and drop the tool during intermittent cutting.

3. Mismatch between tool and cutting parameters
Abnormal tool wear or chipping
When cutting high-hardness materials (such as QT700 ductile iron), the linear speed is too high and the feed rate is too large, which causes the blade to chip and cause the tool to fall off.

Insufficient cooling and vibration control
Insufficient cooling or machine resonance during intermittent cutting accelerates tool wear and affects clamping stability.

The problem of tool dropping in CNC vertical lathes is rarely caused by a single factor. It is recommended to combine the three aspects of CNC vertical lathe mechanical precision calibration, electrical signal redundancy and cutting process optimization for simultaneous rectification, and establish a fault tree (FTA) model to systematically manage risk points.

If you need a CNC vertical lathe, please contact us as soon as possible. We will help you choose the right equipment according to your processing needs. Contact us now!