Collet Workholding Concentricity from 0.0001" to 0.00015"

Article originally appeared in Cutting Tool Engineering March 2014 / Volume 66 / Issue 3

In the world of micromachining, precision is relative—the smaller the work, the greater the need for accuracy in all aspects of the process. End users must optimize the entire micromanufacturing system to be efficient, competitive and successful.

Traditional techniques for achieving precision may work well for macro-scale parts, but can be subtly awkward or downright clumsy when applied to smaller work. Workholding is a classic example of this, noted Matt Saccomanno, a principal who handles product design, engineering and R&D for Masa Tool Inc.

He added that a collet is often the best workholding method because it firmly grips the workpiece and is highly accurate in a production setting. 

However, the collet system installed by the machine builder accommodates the largest workpiece the machine was designed for, such as a Swiss-style machine with a 20mm capacity.

Microconic workholding system consists of (clockwise, starting at 12 o’clock) a cartridge, collet, hex key wrench and collet wrench with graduations for adjusting the collet closure.

The Microconic system can be installed in the subspindle of a Swiss-style CNC lathe.

Although collets for smaller bores to hold smaller workpieces are available, the rest of the system (collet body, spindle nose and closing mechanism) is sized for 20mm, creating problems when chucking smaller parts, according to Saccomanno.

Therefore, Masa Tool developed the Microconic collet system specifically for holding workpieces from 10mm (0.39 ") to 0.75mm (0.03 ") in any machine that has a collet-type chuck. The system consists of two major components: the cartridge, which transforms the work spindle for miniature workholding, and the “right-sized” collet, which fits in the cartridge. 

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