The customer is a famous domestic yoke machining enterprise. The customer used to machine yokes by sequential machining mode. There were not only many equipments but also many operators on the site. Customers used indexing chucks starting three years before. In the beginning，there was only one set in use, and now there are  more than 20 sets on site.The number of machines operated by worker has also changed from 2 to 4. Due to the extensive application of indexing chuck, the single machine output and single person output of customer have been increased by more than 30%, and the defect rate of products is lower than before. Now, the customer is planning to purchase joint manipulator. One manipulator operates three devices, and one person manageing 12 devices can be realized ultimately.