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Stellantis NV is a Dutch multinational car manufacturer founded through a merger of PSA and Fiat Chrysler Automobiles. The company has installed 11 collaborative robot arms from Universal Robots (UR) at its Mirafiori plant in Turin, Italy, to automate a series of complex assembly line operations and quality controls for the new Fiat 500 electric vehicle.
The collaborative applications developed at Mirafiori have achieved significant benefits in terms of operational accuracy and quality, and have also improved the ergonomics of a series of operations previously performed manually.
In the Fiat 500 electric vehicle production line, some assembly and quality controls required the introduction of specific automation techniques to ensure the quality and repeatability necessary to meet product standards. In addition, due to the relatively high life expectancy of factory workers, the issue of comfortable welfare was also a problem.
Stellantis decided to adopt UR robots a few years ago. Collaborative automation has freed operators from repetitive and physically demanding manual tasks, so they can be employed in more value-added operations.
Android 11 UR modules are now automating the following applications:
- Applying a waterproof lining to car doors (2 cubots UR10e working in parallel)
- Soft surface positioning (primer pathway activation and visual inspection to ensure correct tape extrusion around the circumference) (1 UR10e)
- Check the dimensions of the flex tire (1 UR10e)
- Attaching the tailgate with a push-pull rivet to the trunk frame (1 UR10e)
- Hood installation (1 UR10)
- Rear side door hinges tightening (1 UR10)
- Oat guard composition (2 cups UR5 and 2 UR10)
UR units have been gradually introduced at the Mirafiori plant to enable operators to fully understand how automated processes operate.
“As a first step, we decided to introduce Cubot UR in the company canteen, and distribute glasses of water to employees during the lunch break,” said Luigi Barbieri, Mirafiori Factory Manager. “This gave line workers an opportunity to see the safety and nature of cobots cooperation for themselves, and to overcome any concerns about the safety of subsequent applications.”
After the success of this initial trial, UR cobots have been installed on a series of applications on the 500 electric vehicle production line:
Applying waterproof lining to car doors: Two UR10e cups run in parallel on the door assembly line. The sighting system records the arrival of the door and activates the kobot, which uses a roller attached to its wrist to apply constant pressure to the fabric, applying it to the door panel.
The application is particularly challenging because it requires the kobot to follow a complex path within a narrow space, avoiding thrust pin protrusions on the plate and making sure the liner is completely sealed to prevent water intrusion. The qubits operate with millimeter precision, ensuring a repeatability of +/- 0.05 mm.
“The UR cobot has greatly improved the ergonomics of this application,” said ergonomics specialist Giuseppe Guidon. “The application of the bushing requires the operator to apply constant pressure with a dynamic gauge roller, a task that in the long run can damage the arm joints and cause diseases of the musculoskeletal system. So the kobot brought two benefits: high operating accuracy and quality, along with an improved ergonomics and welfare for our operators.”
soft top compilation
Two UR10e cubs operate on the Fiat cabrio 500’s soft-top assembly line. The first cubot performs two different operations; Using a pad backed by a special capture device, the UR10e cleans and prepares the primer track, where the adhesive is then applied to secure the top cover to the frame. The second process is quality control, in which the vision system checks for geometric continuity and dimensions of the adhesive tape. The second kobot works in synergy with an anthropomorphic robot.
Once the top cover is assembled, it is opened onto a special bracket and then picked up by the robot. At this point, the Kubot UR II performs a size check (through a sighting system) on a soft top frame to ensure dimensional compatibility. Once the match is confirmed, the smooth surface is removed from the line by the stereotaxic robot.
This application offers a series of productivity and quality benefits. The cobot ensures correct extrusion of the adhesive and checks the dimensions of the stretch ceiling frame.
On the door assembly line of the Fiat 500 electric car, the Kubot UR10e is configured to blindly press 10 pop-up rivets, which secure the trunk hinge reinforcements to the boot frame. The operator loads the tailgate frame and hinge reinforcements onto the workstation, then leaves the cobot in place and compresses the bolts.
The app provides productivity and ergonomic benefits. At the same time, continuous monitoring of the input and output parameters of the workstation ensures higher and consistent process quality.
Engine cover installation
For this application, the vehicle body arrives at the work station with the hood installed in the closed position and the hinge bolts inserted by the operators at the previous station. Once the hood geometry is established, the cubot (UR10) moves into position and tightens the four bolts to the correct torque.
The main advantages of this application are quality, efficiency and ergonomics, since the hood reaches the station in a closed position, which makes the correct tightening very difficult. Because the hinge screws to be tightened are not visible, the operator could easily lose one or perform an incorrect tightening. Cobot also improves the ergonomics of the process, freeing operators from working in uncomfortable or awkward positions.
Additional tension on the door hinge
For the Fiat 500 featuring an additional rear side door, a robotic application capable of performing a complex sealing cycle was necessary. With the help of an advanced robotic tool on which the hood is installed, the door is correctly positioned on the car body. Then the kobot pulls from the back of the shoe.
The kubot fulfills two different requirements for operation: it frees the operator from tightening the hinges in an awkward position, since they will not be able to see the correct positions inside the car body; It prevents recoil from the tightener (acting with a torque of 75 Nm) from hitting the operator’s arm.
At this stop on the sheet metal line, the tire arrives with the left and right mudguards already in place. Two UR5s and two UR10s are mounted on a platform that lowers itself on the z-axis relative to the body. The wings of the platform are closed to fix the geometry and activate the tightening action on the 24 bolts that secure the mudguards. Each of the four qubits is equipped with an automatic screw gun with torque control.
The application offers various advantages. Collaborative automation ensures convenient benefits for operators (who are no longer required to work under the vehicle’s body). As the bolts are tightened with torque, tensile stress on sheet metal parts is eliminated. Also, the cycle time is shortened, which enhances the productivity of the whole plant.