High Speed Spindles

What is a high speed spindle?
High speed spindles have today emerged as the most important component of any kind of high machining process. For all kind of machining tasks, whether in the CNC, tool, machining center and other process components, the use of high speed spindles always optimizes productivity. For all manufacturers in this fast growing world, using high speed spindles has become a "rule" in keeping ahead of competitors. High speed spindles are considered to be the most critical elements of high speed machine tools and usually very expensive.


Major components of a high speed spindle
All spindles are not necessarily high speed spindles. Certain specific points are to be taken into consideration for the design of a high speed spindle because the performance of a high speed spindle is different and better than a conventional spindle. The major components that are to be considered for a high speed spindle design include:

• Spindle Drive: This can be either belt driven or motor driven. While the belt driven spindle is run by a tangential belt system, the motorized spindle is driven by an external or internal motor installed in to the system. This is determined by evaluating the requirements of the machine tool, considering the requirement of the the maximum speed, power and stiffness.
  
  
• Spindle Bearings: This includes the evaluation of the type, quantity, mounting, and lubrication method used in the bearings.
  
  
• Spindle Motor: Belt-Type, Motor-Spindle, Capacity and Size
  
  
• Spindle Shaft: This includes tool retention drawbar and tooling system used
  
  
• Spindle Housing: Evaluate the size, mounting style and capacity of the housing.

Functions of high speed spindles
Numerous industries use high speed spindles to

• Deliver high speed
• Maximize application performance
• Deliver high power
• Shorter through time
• Better accuracy
• Reliability for high performance machine tools
• Used for all applications like
  • Micro machining
  • Engraving
  • Drilling
  • Milling
  • Grinding
  • Boring

Difference between a high speed spindle and a conventional machine tool spindle
High speed spindles are more or less designed with the motor directly flanged to the spindle shaft. On the other hand conventional spindles are mostly gear or belt driven. While the maximum rotational speed of belt or gear driven spindles is some where about 12000 to 15000 RPM and at speed higher than this the spindle tends to induce vibrations, which usually result in poor surface finish. For this reason, machine tool spindle spindles mostly use a directly flanged motor and thereby achieving more higher speed, torque and power compared to a standard spindle.

Types of retro fit high speed spindles
Some advantages of high speed spindles can be attained in high speed machining by retrofitting a high speed spindle to an existing machine. The high speed spindle can be chosen according to the needs of the application. The various options are as follows:

Replacement spindle: The existing machine tool spindle is replaced by a high speed spindle .


Fixed Centerline Spindle :An independently powered machine tool spindle mounts in the original spindle. At times, the high speed spindle can be removed allowing the original spindle take slower, heavier cuts.


Secondary Spindle: An independent high speed spindle is fixed alongside the main spindle. This makes the original spindle available for slower, heavier cuts.