Also new from Hardinge is its FlexC Collet Systems that are flexible, sealed collet heads that interchange in seconds and are available with spindle mounts for all brands of CNC lathes. Pull-back through-hole, pull-back stationary stop and push-to-close dead-length styles are available for main and sub-spindle CNC lathe applications. With these systems, shops can purchase one spindle mount and interchange collet heads from job to job. The collet heads are fully interchangeable with competitor’s models. Hardinge guarantees accuracy within 0.0004 in. (0.010 mm) TIR for A and D models collet system, and 0.0008 in. (0.020 mm) TIR for style DL.
The changeover concept is simple using a manual wrench to compress the collet for quick removal or replacement in seconds. A typical FlexC collet head has a gripping range of 0.020 in. (0.5 mm) above and below its nominal size to allow variation in bar stock without having to change the collet. There is no collet shank, therefore, the collet segments remain parallel to the stock even when there are variations in the stock size. Parallel clamping minimizes stock pushback and requires less drawbar force to achieve the same gripping capability as conventional collets.
The company said the vulcanization process joins the collet segments together as a one-piece unit with a permanent bond. Vulcanized rubber has elasticity for repeated opening and closing over the life of the collet that makes it igood for a quick-change product. It will not become brittle and is resistant to coolant. Because of the sealed design, it prevents chips from entering the collet system.
Hardinge guarantees collet head concentricity of 0.0002 in. (0.005 mm) TIR for round smooth after the segments are joined in the vulcanization process.
An emergency collet can be kept on hand for just-in-time machining when the proper size hardened collet is not immediately available. The taper and collet seat of an emergency collet are hardened while the inside diameter and the face of the collet head are soft. A face boring ring holds the collet in nominal position for boring to size. Emergency collets are reusable. Standard collets are stocked in round smooth, round serrated and hex shape. Square sizes are made to order. Special applications, such as stepped holes, special shapes and off-center, can be custom-made from stock blanks. FlexC Collet Systems soon will be available for multispindle lathes.