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Thame Workholding delivers productivity with Samchully quick jaw change chucks
Thame Workholding delivers productivity with Samchully quick jaw change chucks

Thame Workholding delivers productivity with Samchully quick jaw change chucks

Added to MTDCNC by Thame Workholding on 22 May 2013

The Samchully quick jaw change power chucks supplied by Thame Workholding make it possible to change jaws in less than one minute. For companies producing short runs of components the savings in setup time are significant and will pay for the investment extremely quickly.

Compared with a standard 3 jaw power chuck, where the jaws can take around 10 minutes to change, Samchully quick jaw change chucks use a wedge-bar mechanism which allows each jaw to be removed with a single turn of an operating key. This disengages the wedge-bar from the master jaw allowing the jaw to be removed and replaced extremely easily. In addition to the time saved in the actual jaw changing operation, the accuracy possible with the system makes reboring of the soft jaws unnecessary. For a workshop carrying out three jaw changes each day the savings can amount to over 300 hours per chuck in a year.

Samchully uses the wedge-bar technology in its quick jaw change chucks as it has some important advantages over the commonly used wedge-hook system in standard power chucks. The latter uses a mechanism which directly actuates the master jaw and cannot achieve the accuracy of the wedge-bar system. Wedge-hook is normally capable of TIR 0.025 mm while, with properly bored soft jaws, a Samchully quick jaw change chuck, up to 300mm, can achieve TIR between .005 and .01 mm.

As well as improved accuracy the wedge-bar system helps to compensate for centrifugal force at high rotational speeds. With the wedge-hook system counterweights are required to offset loss of grip due to centrifugal force. When the spindle stops, these weights have moved to their fullest extent, so cause a sudden spike or hysteresis in the grip load which can be 25% more than the static grip load. For thin wall and delicate components this sudden increase in pressure can damage or distort the part. On the Samchully wedge-bar chucks there is no need for counterweights as the loss of grip is much less. On a 200mm chuck running at 5,000 rpm it will only lose 30% of the static grip compared with 50% on a wedge-hook chuck. In addition, the hysteresis is only 5%.

These factors make the Samchully quick jaw change power chucks an ideal choice for achieving higher metal removal rates at higher speeds, further adding to their cost saving characteristics.

Maurice Day, Director at Thame Workholding, says, 'Samchully chucks are fitted as standard equipment on leading machine tools including Doosan (Daewoo) Haas and Hyundai-Kia which is a measure of their outstanding quality. Companies specialising in small batches of parts can achieve significant cost savings and improvements in productivity and flexibility by investing in Samchully quick jaw change technology.'

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