Requirements for spindle components of CNC machine tools

The spindle component of a CNC machine tool is one of the important key components of the machine tool. The spindle component includes the spindle, the support (bearing) of the spindle, the transmission parts installed on the spindle, seals, and corresponding fasteners. It drives the workpiece or tool to perform the cutting motion of the machine tool, directly affecting the machining quality of the machine tool. Therefore, the spindle components of CNC machine tools should not only meet the requirements of high precision during precision machining, but also have the ability to efficiently cut during rough machining. At the same time, the spindle components of CNC machine tools should have higher dynamic and static stiffness and the ability to resist thermal deformation.

Requirements for spindle components of CNC machine tools:

(1) High enough stiffness. During the operation of CNC machine tools, high-speed and powerful cutting is usually used, which requires the spindle components to have high stiffness. Otherwise, the spindle will produce significant elastic deformation under external forces, causing vibration and affecting the accuracy and surface roughness of the machined parts.

(2) High rotational accuracy. The same rotation accuracy of CNC machine tool spindle components refers to the radial and axial runout measured with a micrometer on the positioning surface of the workpiece, fixture or tool installed at the front end of the spindle at low speed and no load. Its height directly affects the geometric accuracy and surface quality of the processed parts. Therefore, the spindle components of CNC machine tools must have high rotational accuracy.

(3) Good seismic resistance. The seismic resistance of the spindle components of CNC machine tools refers to the ability of the spindle components to resist vibration and maintain balanced operation in CNC machining. If a CNC machine tool vibrates, it will affect the surface quality of the workpiece, tool durability, and the lifespan of the spindle bearings, as well as generate noise that affects the working environment.

(4) Strong thermal stability. The thermal stability of spindle components refers to their ability to resist deformation and positional changes caused by heating. During operation, CNC machine tools may generate heat due to friction, oil stirring, or other reasons, resulting in imbalanced temperature of the spindle components and distortion of their shape and position, thereby affecting machining accuracy.

(5) Long precision retention. The accuracy retention of spindle components refers to the ability of the spindle to maintain its original manufacturing accuracy for a long time. CNC machine equipment is expensive, and in order to accelerate the investment recovery of CNC machine equipment, it is necessary to maintain a high operating rate of CNC machine tools. At the same time, it is hoped to extend the service life and reduce the number of repairs, which requires that the spindle components of CNC machine tools must have good accuracy retention.

(6) Reliable and accurate positioning. The structure of the spindle components of CNC machine tools should ensure reliable radial and axial positioning accuracy to ensure reliable clamping of workpieces or tools, accurate positioning, and reduce the impact of clamping errors and positioning errors on machining quality.

(7) Other requirements. For CNC machine tools that require automatic tool changing, the spindle components often require functions such as automatic tool loading and unloading, chip blowing, and spindle directional stop to meet the requirements of improving the automation level and shortening auxiliary time of CNC machine tools.