In an interesting application at automotive OEM Nissan, a series of dowels and cam brackets have to be assembled to a cylinder head before the cam bolts are torqued. These tasks now benefit from a semi-automated solution, which not only improves productivity but generates quick financial payback.
The Altec system comprises two operational stations linked by a roller transfer system, plus a Kuka robot and Bosch Rexroth nut drivers. At the first station, the cylinder head is loaded manually on to a base plate, before being located and locked into position on the fixture. A guide plate is placed on to the cylinder head before six dowel pins are located and pressed home using a pneumatic hammer. Sensors located on the guide plate are used to detect that the dowels are fully inserted before the cylinder head is released.
At the second station, the cylinder head is located on a transfer table where the operator can position a guide plate to the cylinder head to allow the correct placement of the cam bracket and bolts. Sensors are used to ensure that the correct bracket is fitted for the variant being processed, and the table then transfers the cylinder head into the guarded robot cell.
Integrated within the cell is a Kuka KR16 robot, which has two spindles mounted to the wrist. The robot positions the spindles over the cylinder head before the tightening operations are initiated. Each bolt is tightened in pairs, in a pre-determined sequence, to a mid-torque point that ensures correct seating and location before being finally tightened to the final torque requirements.
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