Centralized control and comprehensive documentation of assembly processes
In Focus: The Customer’s Requirements
“As a component manufacturer, we need a solution that seamlessly connects assembly lines, inspection systems, and IT systems, and ensures unique identification and full traceability of all assemblies. At the same time, multi-stage assembly inspection must be guaranteed, and production processes must remain flexibly controllable in order to reliably meet quality requirements and regulatory documentation obligations.”
(Project Manager in the Automotive Industry)
Here’s how we implemented it
A central control PC was implemented for a German automaker to control, coordinate, and document an assembly line. The facility assembles control units for electric vehicle battery systems. The solution handles the line’s overarching process control and connects the individual assembly stations to the customer’s IT systems.
Future-proof control system integration through platform-independent architecture
The system consists of a total of ten assembly and testing workstations, whose station controllers are based on the Siemens S7-1500. Communication between the master PC and the stations takes place via a TCP/IP-based, telegram-oriented interface. This communication architecture is deliberately designed to be platform-independent, so that, in addition to Siemens controllers, other PLC systems can also be integrated—even within the same facility. This ensures that the system architecture remains flexible and independent of specific control platforms.
External interfaces for real-time data exchange and traceability
Process data, status information, and test results are transmitted, processed, and centrally documented in real time via these interfaces. In addition to direct telegram communication, further data is integrated via file and FTP interfaces. This allows external systems—such as test benches, measurement systems, or specialized equipment—that provide their results in file format to be connected as well.
The customer’s proprietary documentation system plays a central role within the overall architecture; it is used to ensure compliance with regulatory requirements and to provide full traceability. Individual components are registered in the system via their unique serial numbers as early as the assembly process.
Intelligent Inspection and Validation of Complex Assembly Processes
The required assembly check is performed in several stages. First, the master PC performs an internal plausibility check that takes into account, for example, the component type, assembly status, and previously documented process steps. In addition, an external verification is performed via an API interface to the customer’s own system, which checks whether the respective component is approved for the specific assembly and may be installed in this combination.
The master PC is responsible for the overall validation of all production steps. It verifies whether all necessary process steps, assembly operations, and inspection results have been carried out completely and correctly. Only when all conditions have been met does the system release the assembly.
The finished assembly is then transferred to the customer’s own documentation system as a fully documented data set. In addition to the assembly’s serial number, all relevant assembly and inspection results are also included. Only after successful documentation may the assembly leave the assembly line as an “OK” part.
Integration of Interfaces for Logistics & Shipping
In addition, an interface to an internal logistics and shipping system was implemented. Once assembly and packaging are complete, the finished assemblies are automatically transferred to this system. As part of this process, logistics information is transmitted, and the necessary shipping documents are generated.
Smart Workpiece Flow Through Flexible Routing
The physical routing of the assemblies through the system is handled by a circulating transfer system with a ring configuration. In this specific project, the routing of the assemblies was implemented in the station PLCs based on their respective processing status. Based on the current processing status, the controllers determine whether a workpiece carrier is processed at the respective station or moves on to the next station. In principle, however, this routing logic can also be provided centrally by the master PC system, which allows for the implementation of more complex production strategies or dynamic line control.
Unique Assembly Identification and Traceability
To ensure that assemblies can be uniquely identified within the system, the workpiece carriers are equipped with a unique identifier, such as a barcode or an RFID chip. This allows each assembly to be uniquely identified regardless of sequence, cycle times, or possible loops in the ring. This concept enables robust process control even with buffer sections, multiple cycles, or variable processing times, and ensures that all process and inspection data can be correctly assigned to the respective assembly at all times.
Modular and Flexible Process Design
A key concept of the solution is the process-oriented modeling of assembly sequences. The system logic is not based on a fixed, product-specific structure, but rather on a freely configurable sequence of standardized process steps. As a result, assembly, inspection, and documentation steps can be flexibly defined, combined, and adapted. This architecture makes it possible to integrate new product variants or even completely different assembly processes without having to change the underlying software structure.
Secure Access Management for Operators
A chip-based authorization system was also integrated to control user access. Employees can use it to authenticate themselves at individual workstations, allowing roles, qualifications, and process approvals to be clearly assigned and documented.
The ROTH Solution at a Glance
- Flexible Control of Complex Assembly Processes
Process-oriented logic for mapping variable assembly, inspection, and documentation workflows. - Expandable and future-proof system architecture
Modular design for easy expansions and adaptations to new products and processes. - Platform-independent communication
Compatible with various control and IT systems through standardized interfaces. - Deep integration with production and IT systems
Seamless integration with PLCs, test benches, documentation, logistics, and quality systems. - Compliance with high-quality and documentation requirements
Seamless traceability and secure process approvals for regulated production environments. - Efficient Networking of Systems and Production Lines
Flexible integration of individual stations into a comprehensive production platform.
