- This case study is filed under:
Automated Assembly: a Large Scale Application
Faverges (France) - For 25 years, ALSTOM SERVICES S.A. Systems and Services is one of the main European automated assembly experts with increasing participation in the international market. This company, located very close to the international airport of LYON SATOLAS, has already shipped several cells with Stäubli robots to major automotive and electromechanical/electronics industrial companies. The cell that is presented here has been designed by the Automated Assembly Department.
The product and the application
Stators assembled by the three RX130 L robots are the fixed part of alternators that are supplied to local power plants. They are made by stacking thousands of magnetic steel sheets (electric sheets) that are arranged in torus. Each electric sheet ties in with a variable dimensions area (up to 1m x 1m roughly), according to the stator pattern. Once the stator is assembled, it is a cylindrical set of :
- Outside diameter : 1.5 to 3 m
- Height : 1.5 to 5m
- Gross weight (including implements) : up to 240 metric tons.
Electric sheet stacking accomplished by the robots is done on a hydraulic elevating platform, of 7 meters stroke, located in a pit, keeping the work area at roughly 1.2 meters above the floor level. Electric sheets ( supplied on a wooden pallet) are unstacked and rejoged mechanically before being assembled by three RX130 L robots. Three robots are needed in order to cover the entire torus surface and to ensure the required production cycle of an electric sheet fixed every 1.25 seconds. Thus, a complete stator assembly can take several days. As the stator is being assembled, the hydraulic platform's downward movement is synchronized to the robot's work cycle.
Compared to the previous assembly procedures the customer was using, this in-stallation allows:
- Deletion of intermediate handling when assembling the stator
- Suppression of stacking mistakes. Width verification is done automatically by the robots with correction if necessary.
- A high precision cell (+/- 0.2 mm radius) that not only deletes all manual rework operations but improves the finished alternator's efficiency as well,
- Preparation of specific electric sheet bundles (edges) during tooling set up and heavy handling operations,
- Switching from one stator model to another by:
-setting up appropriate tooling
-robot program selection
- Reducing down time and increasing market reactivity
RX robot choice
Sheet loading on the elevating platform is done with a rounded movement in order to avoid air concentration (buffer) and thus sheet sliding which would jeopardize the required precision. These movements require the use of a 6-axis robot:
- The application requires both very high speed and very high precision.
- Easy programming and flexibility of the cell allow a constant adaptation to the assembly of specific stators dedicated to each customer (total dimensions, sheet number, sheet specifications).
The three robots are mounted on horizontal tracks to allow finished stator extraction and new tool settings on the elevating platform, with regards to safety regulations.
STÄUBLI is a 100+ year old, 2,400-employee Company with annual revenues of over 700 million Swiss Francs, headquartered in Switzerland. The STÄUBLI Group commitment to customer satisfaction is proven by worldwide office locations offering a 'first class' level of services such as training and maintenance.
In its production facility located in the heart of the French Alps a few miles south of Geneva (Switzerland), STÄUBLI's Robotics Division invests 12 % of its revenues in Research and Development. An innovation and quality strategy lead STÄUBLI to be awarded ISO 9001 for its three activities: textile, connectors and robotics.
For additional information, please contact
Stäubli Corporation - Robotics Division
201 Parkway West
Duncan, SC 29334