Understanding Grinder Spindles: Mechanisms, Drives, and Applications

 

Grinder Spindle

Grinding is different from other machining, in this topic we will focus on the application of grinding spindle. The spindle is one of the key components of modern grinding machines, and the spindle of the grinding machine is designed in various forms according to its driving mechanism.

 

Common Inventories of Spindles

There are several types of lathe and milling machine spindles, including belt driven, motorized, gear driven, and direct driven. Compared with other drive mechanisms, the direct driven spindle can provide greater torque, faster, more accurate activation, and a larger processing area.

Therefore, for grinding purpose, it is most desirable to choose a direct driven spindle as for grinding spindles’ usages. A machine tool can contain multiple spindles, such as the headstock and tailstock spindles on a bench lathe machine, and if it is on a grinding machine, the primary spindle is usually the largest and longest spindle. Grinding spindles can be composed of different types.

Therefore, if the grinding spindles are referenced without further limitation, it means that the target object is the primary spindle. Machine tools dedicated to mass production often have 5, 7 or more spindles.

They are called multi-spindle machine tools, such as gang drills and screw machines. Although a bench type machine tool may have multiple spindles (the primary one and the one installed inside the tailstock), it is not called a multi-spindle machine.

 

Grinder Spindles Driven by Direct Drive Motors

Grinding machines equipped with direct driven spindles are usually designed with larger machine base so that they can accommodate larger and longer spindle, thus providing greater machining strength for the work piece.

Some spindles are designed for specific functions, such as turning spindles, milling spindles, drilling spindles, etc. Only when the spindle is properly installed can the machine tool exert its design capabilities.

In addition to direct drive motors, the spindle also includes a variety of other designs. On the grinding and turning machine, the spindle is the heart of the headstock. In rotary grinding woodworking machinery, the spindle is used to connect shaped milling cutter for curve cutting or similar grinding and milling processing. Although spindle functions may vary, they are usually equipped with DD motors.

 

DD Motor in Other Applications

Similarly, in rotary cutting metalworking machine tools such as milling machines, tapping centers, and drilling machines, the spindle is the shaft that attaches the tool to the machine through a chuck.

The types of spindles include grinding spindles, electric spindles, machine tool spindles, low-speed spindles, and high-speed spindles. If the grinder is equipped with a belt driven spindle, the torque will be greatly reduced. The belt driven spindle is connected by an external motor or did a shaft-driven connect via a belt-pulley system.

A belt driven spindle using a pulley is not as stable as a direct drive mechanism, and the belt material is often one of the key variables in mechanical operation. In addition, the external motor of the belt driven spindle can provide a speed range of about 13,000 RPM to 17,000 RPM. Speed limits the performance of the belt driven spindle.

Therefore, high-end lathes usually prefer to install a built-in spindle to provide higher torque and speed. The situation also applies to the grinding spindles.

Compared with the high-speed built-in spindle, the best performance of the direct driven spindle is its powerful torque. Even if the machine has been working for a long time, most direct driven spindles can handle heavy grinding tasks with remarkable accuracy.