eMobility: automated final assembly of inverters
Laser welding with the highest precision
A powerful battery with a high charging capacity is the heart of an electric car. But for the vehicle to get on the road and be used dynamically and efficiently, the battery needs support that has just as much to offer as the battery itself. For example, the inverter controls the rpm and torque of the motor. Its second task is to convert the battery's direct current into alternating current for the electric motor. It is therefore an important component that requires maximum precision. PIA Automation developed a system for automated final inverter assembly for a customer in the automotive industry that supplies a major vehicle manufacturer, and installed and commissioned it in Mexico.
Special requirements for this system included a newly developed process for high-precision laser welding and the integration of manual work processes in direct interlinking with automatic processes. The 11 x 22 meter system assembles the customer inverter from 37 components, one of which is a pre-assembled module, in a automated process with a cycle time of 80 seconds. The assembly material is fed in by workers at various process stations. The system integrates the assembly techniques of joining, pressing, screwing, and laser welding. A leak test is also carried out during the production process.
Individually developed laser welding process
Together with a partner for laser optics, PIA Automation has invested a significant amount of development work in automatic laser tracking and integrated weld seam monitoring. The laser welding optics are integrated into a six-axis robot. Its camera centers itself on the respective welding sleeve and compensates production tolerances by precisely aligning the welding robot with the center of the sleeve. To monitor the weld seam, a scanning laser scans the surface before and after the welding process to determine the welding depth. “This combination is anything but an off-the-shelf product,” reports Philipp Metz, senior design engineer and project manager of the PIA inverter assembly line. "We have optimized the systems, for example the camera recognition, in such a way that we can assume our system is one of the most precise and stable in operation of its kind."
Master computer integrates PIA Industrial App Suite
An important instrument for data management and process analysis is the PIA Industrial App Suite, which is installed in the system's master computer. This software package enables users to optimize the use of their assembly systems and includes a broad portfolio of digital products, solutions, and services. The large volumes of data and the depth of data acquisition in the system for final inverter assembly allow the system performance to be monitored over long periods of time. The data helps, for example, to find and eliminate the causes of production inaccuracies or to identify optimization potential in the interaction between personnel and machine. The stability of the system processes can also be displayed in detail.
System ensures safety and cleanness
The Inverter assembly combines human labor with fully automated processes. Special precautions were therefore taken to ensure the safety of the workers and the ergonomics of the workstations. The precise coordination of operators and machine to meet the target cycle time also influenced the design of the system. As the assembled inverters are expensive, highly sensitive components, the customer required cleanliness for the production system that goes beyond the usual DIN ISO standards in the industry.
The system was handed over to the customer in Mexico ready for operation in December 2024. "Initial feedback was that our assembly line for inverter assembly achieved a very good ramp-up and significantly exceeded the customer's expectations. The fact that our system produces so stable and immediately performed after commissioning makes us a very proud company!", says Philipp Metz.
Strong in international cooperation
Since PIA Automation operates a branch in León, Mexico, our Mexican colleagues were also closely involved in the commissioning process. This proximity to the customer means that PIA can offer a fast on-site service if required, for example for system maintenance. “Projects like this demonstrate the strength of our international PIA network,” says Philipp Metz, Project Manager at PIA. "Our aim is to provide our customers with best -in-class support at every stage of the project. This makes projects like this even more satisfying: this project showed once more that international cooperation within the PIA team works very well."