Assembly line operations at Dutch automobile manufacturer

On the door assembly line for the FIAT 500 electric cabrio car, a UR10e cobot has been configured to press-set 10 blind pop rivets, which secure the boot hinge reinforcements to the boot frame. The operator loads the tailgate frame and hinge reinforcements on to the workstation, then leaves the cobot to position and press-set the rivets. The application provides productivity and ergonomic benefits. At the same time, constant monitoring of the workstation input and output parameters ensures higher and consistent process quality.

For the hood mounting application, the car body reaches the workstation with the hood mounted in a closed position and the hinge screws inserted by the operators on the previous station. Once the hood geometry has been established, the cobot (a UR10) moves into position and tightens the 4 screws to the correct torque. The main advantages of this application are quality, efficiency and ergonomics, given that the hood reaches the station in a closed position, making correct tightening extremely difficult. Since the hinge screws to be tightened are not visible, the operator could easily miss one or make an incorrect tightening. The cobot also improves the ergonomics of the operation, freeing the operators from working in uncomfortable or awkward positions.

For the FIAT 500 model featuring an extra rear side door, an automated application capable of performing a complex tightening cycle was required. With the assistance of an advanced automated tool on which the cobot is installed, the door is positioned correctly on the vehicle body. The cobot then performs the tightening operations, from the rear of the boot. The cobot meets two different process requirements: it frees the operator from tightening the hinges in an awkward posture, where they would be unable to see the correct positions inside the car body; and it prevents the kickback from the tightening tool (which operates with a 75 Nm torque) hitting the arm of the operator.

In this station on the sheet metal line, the frame arrives with the right and left mudguards already in position. Two UR5 and two UR10s cobots are installed on a platform that lowers itself on the z axis in relation to the body. The wings of the platform close to fix the geometry and activate the tightening operation on the 24 screws that fasten the mudguards. Each of the 4 cobots is fitted with an automatic screw gun with torque control.

The application offers various advantages. Collaborative automation guarantees ergonomic benefits for the operators (who are no longer required to work below the vehicle body). Since the screws are torque tightened, tensile stress on the sheet metal parts is eliminated. Also, the cycle time is shortened, boosting the productivity of the whole station.