Recommendations for machine spindles for different machine types

Choosing the interface of a CNC machine tool is very important, as it can affect the efficiency and performance of machine processing.

How you choose a machine tool spindle interface is very important because it determines the limits on metal cutting efficiency. When asked which machine tool spindle interface is best, no one can immediately answer which interface is the best choice. This is because the choice of machine tool spindle depends on the part being machined and the process being performed.

Requirements of the machine spindle

The machine spindle interface needs to be quickly interchangeable in non-machining conditions and the connection between the machine spindle and the interface needs to be robust. It is therefore important to select tool interfaces with good bending rigidity and torque transmission.

• Bending rigidity: essential for a stable cutting process under high tool cutting loads.
• Precise tool center position: Repeatability is particularly important for reliable turning processes.

What kind of interface can withstand high bending moments and radial cutting forces?

• Flanges: Flange face contact increases the stability of the spindle motor system and reduces the leverage of cutting forces.
• Clamping force: The higher the force clamping the interface, the stronger and less likely it is to be broken.
• Cross-sectional area: Reducing the tool diameter will reduce the rigidity of the tool compared to the flange contact diameter.
• Torque transfer: Turning with large-diameter tools requires ensuring that the interface can withstand torque, otherwise machining accuracy will be compromised.

History of machine tool spindle interfaces

As machine tools have evolved, so have machine tool spindle interfaces. Some of the key milestones that have influenced this can be seen in the CNC controls that have enabled automatic tool changing and tool storage, which has also led to the development of the 7/24 taper shank.

Different types of machine tool spindle recommendations

For machining centers (rotary applications only), a flange face contact spindle interface is usually recommended. This is because it provides good enough stability for most rotary applications in machining centers. For multifunctional machines (stationary and rotary applications), an interface should be selected that meets the torque and flexural rigidity requirements of multitasking machines for turning and rotary applications.