Hybrid assembly of door panels for premium vehicles
At its assembly plant in Turnov (Czech Republic), Grupo Antolin has automated the process of screwing together door panels for the Audi Q2. Two SCARAs assemble approximately 1,800 panels a day with their high degree of flexibility and speed of the hybrid assembly, concept; they are able to cope with the many available versions.
Audi’s requirement for just-in-time delivery of its door panels without the need for interim storage placed very high demands in terms of flexibility on the assembly process. Grupo Antolin came up with the idea of combining a highly flexible automated screwdriving station with a manual workstation for special screws that were not suitable for automated feed.
The next step was to identify robots capable of performing the specified task. The system engineers opted for two TS60s from the Stäubli SCARA range. These robots are ultrafast, which was an essential requirement for 20 screwdriving operations on a single panel. They are able to achieve a very high repeat accuracy of ± 0.01 mm during positioning, this is an essential precondition for consistency in the firmness of the screw fixings.
Division of labor between human and robot
The innovative concept of a “division of labor” between human and robot was fully implemented in the design of the plant. The individual components of the door panel are mounted on a rotary table, the position of which is established by means of safety sensors. On one side of the turntable, the TS60 uses between 18 and 20 screws (depending on the model variant) to assemble a complete door module. On the other side, a manual worker equipped with a pneumatic bolt gun inserts two additional screws, each of a special design.
The assembly line consists of two identical cells for right and left door panels. The production process is based on the principle of the “digital twin”. Each part is identifiable from an individual QR code that contains information about the respective configuration of the door trim. The operators log in with a chip card at their workplace, the robots then relay the data from each individual screwdriving process to the central control unit. This enables each assembly step to be documented.
Guaranteed compliance with the strictest quality specifications
The quality demands imposed by Audi do not end there. The next step on the assembly line is an additional visual inspection, which includes matching up the finished panel with the information stored in the QR code. This ensures that the right part is delivered to Audi in the correct configuration and with top quality assured. Tested as part of the final inspection are all of the electronic components and features, there are – up to 20 different sets of cables which are concealed inside the trim (depending on customer specification).
Once the door panels have passed the quality checks, they are boxed up into sets of four per individual vehicle. In total, around 450 such sets leave the Antolin plant in Turnov every working day. The assembly stations with their Stäubli SCARA robots have certainly proved their worth in the opinion of senior management at Antolin. They are cost-effective and flexible and the screw driving process achieves a high level of quantity and reliability.