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For metal cutting machinery, a rotational shaft clamped with tooling unit is the key to machining, and a spindle is a rotational axis of the machine, which usually designed with a shaft at its center. The shaft itself is named a spindle, but also, in the market slang, the referring term (phrase) is often used metonymically to point at the entire rotating unit, including not only the shaft itself, but also its bearings and anything around (or attached to) to it (such as chuck, cylinder, etc.).
In this point of view, a built-in spindle is one of the top-classed one that is self-motorized due to its electric-driven nature and is designed with the power unit close with the spindle case box. A machine tool may be installed with several different spindles, such as the headstock and tailstock spindles on a bench lathe, or primary spindle and secondary spindle on machining centers. The main spindle is usually the biggest one installed at the primary machining unit. In the market, references to "the spindle" without further qualification indicate the main spindle for sure.
For machining centers with high-speed requirements, motorized spindles are of great help in the overall processing. In the metal processing industry, the main shaft is the rotating shaft of the machine, which is usually designed to be centered on the shaft. The shaft itself is called the main shaft, but in market colloquial terms, this term is often metonymically used to refer to the entire rotating unit, including not only the shaft itself, but also its bearings and anything around it.
From this perspective, the motorized spindle is one of the top spindles. Due to its electric driving characteristics, it is automatically electric and its power unit is designed close to the headstock box. In addition to the machining center, multiple different spindles can also be installed on the machine tool, such as the spindle box and tailstock spindle on a table lathe, or the spindle and counter spindle on the machining center.
In actual use, some machine tools dedicated to mass production models have four, five or even more than six spindle groups, some of which can also be motorized spindles. These are called multi-spindle machine tools. For example, row drills and many screw machines are multi-axis machines that can be processed simultaneously. However, although a table lathe has multiple spindles, it is not called a multi-spindle machine. If it is on a lathe, the spindle is the center of the spindle box. In addition, in the rotary cutting metal processing machine tool, the spindle unit is a shaft to which a processing tool is mounted.
Regarding the speed of the motorized spindle, the RPM and range classification are ambiguous throughout the application and on all continents. Generally, high-speed motorized spindles are strictly used in machining centers, such as profiling, and their speeds are about 20,000 to 30,000, and even some are 40,000 RPM.
Compared with the higher ROM speed, the rotation speed of other types of spindles is relatively low. For example, the belt-driven spindle consists of a spindle fixed in the spindle box and the bearing shaft. The belt-driven spindle is passed by The external motor connected to the pulley system, in this case, the RPM is usually about 12,000 RPM; at the same time, regarding the external motor source, this design can be changed to produce higher "torque", but the maximum speed range is only 12,000 RPM to 15,000 RPM.
However, the advantage of this type of spindle is that the speed switching is flexible and cost-effective. At the same time, the disadvantage of the external motor source is the limited maximum speed, which will eventually limit the mechanical application and the roughing and other machining processes.
Therefore, this is the main reason why motorized spindles are so popular in most top machining centers (such as vertical machining centers and horizontal machining centers with multi-axis arrangements). The center is used as the main equipment type for processing 3C products, aerospace components, aircraft parts, automobile engine cases and other complex single-piece workpieces with hardened materials.
For those spindles with built-in structures (also called electric spindles), the main application is not heavy-duty machining here, but mainly high-end machining. For example, electronic consumables processing, workpiece finishing, direct cutting of aviation propellers, engine cylinder processing, car chassis processing, gearbox joint grinding, and other detailed processing steps.
Regarding these applications, most manufacturers require common features that are quick and flexible during processing. Therefore, this key determines most of the application fields of motorized spindle (or, electric spindles) to be developed in the high-speed rotation processing model.
In addition, compared with other spindle models, the motorized spindle can achieve good processing quality due to its high-speed RPM and rapid switching between models. That is to say, even if the torque performance of the direct drive spindle cannot be compared with the direct drive spindle, because the direct drive spindle has high torque, but considering its overall performance, it is much more stable and stronger than the belt drive spindle model.
For example, a traditional CNC lathe may be equipped with a belt-driven spindle, but the requirements for machining are higher, such as a turning and milling center with a power turret. Since the workpiece is fixed on the chuck and clamped by the workpiece, a motorized spindle is usually used.
The toughness of the cylinder may be higher, so if the main shaft is driven by a belt, the teeth on the belt are likely to encounter gear errors, leading to undesirable results.
As long as the demand for smooth metal surfaces and stable mechanical operations in a short period of time in the global industrial field continues to increase, the utilization rate and adaptability of such electric spindles will continue to increase.
In the future, it is expected that one day, a high-speed electric spindle will produce a high torque output for the shaft that can be transferred to the shank and eventually the tool for cutting the workpiece, because more and more work is now done, these parts are made of hardened materials Yes, these materials are difficult to handle with low torque. Therefore, it is likely that high-speed and high-torque electric spindles were invented to meet market demands.
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