Quick-change collets offer many benefits

HQC Quick-Change Collets deliver faster changeover times than standard collets, and being more flexible than conventional master collets and pads - they offer versatility, high performance, greater process reliability, ensure longer tool life, can accommodate bar stock size variation, and provide the opportunity for increased spindle speeds. The HQC’s flexible collet head delivers true parallel gripping with the collet segments running parallel to the stock even when there are variations in the stock size. The collet head has a working range of ±40 microns. Parallel clamping minimises the potential for stock “push back” and also requires less draw bar force than conventional collets – which enable customers to use higher feeds and speeds. The Hardinge HQC Quick-Change Collet System exerts more gripping force and ensures greater concentricity control than standard collets, master collets and pads, or 3-jaw chucks. The system can be changed from one size collet to another size in less than 20 seconds. This is accomplished by using a manual or hydraulic changing wrench which compresses the collet, allowing for quick and easy removal, and quick installation of a different size collet head. In terms of multi-spindle automatics, the benefits from such fast collet changeover times are multiplied (by the number of spindles on the machine) – and the significant productivity gains (speed, machine tool utilisation etc.) that can be achieved are self evident. Because the system requires less draw bar force to adequately grip the bar, issues and problems such as closing finger and pins breaks, (common when the bar varies beyond the range of a standard solid collet or master collet with pads) are avoided. As well as increasing the productivity potential for multi-spindle automatic screw machines, HQC Quick-Change Collets will significantly increase the performance of Hardinge collet-ready CNC lathes and chuck-style lathes too. On chuck-style lathes, HQC Quick-Change Collets can replace bulky 3-jaw chucks. The reduction in weight and the unique, efficient design of the HQC System allows customers to increase spindle speeds (and therefore increase productivity/reduce cycle times etc) without any concern for the effects of centrifugal forces. In addition, HQC collet heads are designed with special replaceable inserts that form a seal while holding the collet segments together. These seals protect the spindle, collet body and draw tube from chips and coolant ingress. Unlike other quick-change collet systems, the HQC patented slot-seal system eliminates the need to return the collet to the manufacturer to have the seals changed or re-vulcanised. The seal (inserts) can be replaced quickly by the machine operator, further reducing operating costs and production interruptions. "Manufacturers thinking about adapting their existing chuck-style lathes to accept collets for high-precision work should consider the HQC® Quick-Change Collet System instead of a conventional spindle adapter (collet adaptation chuck) that uses conventional collets, said David Andrew, Hardinge’s UK sales & marketing director.