Grinding is not like other machining such as turning and milling as the operational force of grinding is a different issue concerned this topic. As a result, spindle is one of the critical components of modern grinders, and grinding spindles are designed in a wide variety of forms which is basically based on the driving mechanisms.
Common inventories of spindles
For lathe and milling machines, there are mainly belt driven, motorized, gear driven, direct driven, built in, etc. Compared with other driving mechanisms, direct drive spindles are designed with stronger torque power, faster and more accurate activation, while is with larger area coverage. Therefore, when it’s about grinding, direct drive spindle is most like to be the option. Normally, a machine tool could contain several spindles, such as the headstock and tailstock spindles on a bench lathe machine, and the primary spindle is usually is the biggest one and the longest length if it is on the grinder.
For that reason, if the references to the spindle without further qualification imply that the targeted subject is the primary spindle. Some machine tools that specialize in mass-volume quantitative production have a group of 5, 7, or even more primary spindles. These are called multi-spindle machines such as gang drills and screw machines. Although a bench type machine tool may have more than one spindle (the primary one and the one installed inside the tailstock), it is not called a multi-spindle machine and this applies to bench-type grinders as well regardless of the size.
Grinder spindles driven by DD motors
Grinder spindles driven byDD spindles are usually designed with larger machine base shell so that they can accommodate with the larger and longer spindle body, which eventually offer greater machining strength onto the work pieces.
Some spindles are specifically designed for certain models or machine tool types, such as turning spindles, milling spindles, drilling spindles, and so on. Only with an appropriate installation of the spindle, can machine tools able to perform the designed capacity. Aside the direct drive motors, examples of spindles include a wide variety of other designs. On a grinding-turning machine, the spindle is the heart component of the headstock case. On the other hand, in rotating-grinding woodworking machinery, the spindle is the part component on which shaped milling cutters are equipped for cutting features, such as profiles of rebates, beads, and curves into moldings and similar grinding and milling works. Although the role may be different, the DD motors are the same common ground.
DD motor in other applications
Identically, in rotating-cutter metalworking machine tools such as milling machines, tapping centers, and drill presses, the spindle is the shaft to which the tool is attached to the machinery as just one part of the big picture via a chuck. Varieties of spindles include grinding spindles, electric spindles, machine tool spindles, low-speed spindles, and high speed spindles. If, for example, a grinder is equipped with belt-driven spindle, the torque then is largely weakened. For belt-driven spindle, it is consisted of spindle and bearing shafts held within the spindle housing, and the belt-driven spindle is powered by an external motor rather than an in-built, or did a shaft-driven connect via a belt-pulley system.
With this design, the pulley is not as stable as the direct drive mechanism and thus the belt materials become one of the key variables concerning the machinery operation. Furthermore, the external motor that drives the belt-driven spindle may range from 13,000 RPM to 17,000 RPM. The average RPM limitation confines the performance of the belt-driven spindles just like the torque issues so that normally high end lathes, though the most practical match is belt-driven, but are installed with the in-built spindles for advanced torque force and speedy drinding.
If, for example, compared with the built-in spindle, which is most well known for its fast speed performance on lathe and milling machines, the most excellent capacity of the direct drive spindle is the torque that it can make, which is far more powerful than other spindle types. As a result, most direct drive spindles are capable of processing the heavy duty grinding tasks with prominent precision even if the machinery has been working for a long period of time.