Use Case: DEPRAG Screwdriving Technology for Energy Master Assembly at BMW
With the BMW i3, BMW launched its first series-production model developed from the outset as an electric vehicle in 2013. With its sixth generation (Gen6), the automaker continues to expand its battery-electric vehicle portfolio. This also increases the demands placed on the production of key components: assembly lines must reliably handle a wide range of assembly tasks. At the same time, process quality, system availability, and secure integration into the production environment must be ensured.
One of these key components is the Energy Master: the central control unit of the high-voltage system. It manages energy and data flows and controls the power supply for the electric motor and the vehicle electrical system. It therefore plays a key role in ensuring the safe and intelligent operation of the overall system.
The Energy Master is manufactured at the BMW Group Plant Landshut. From there, assembly plants worldwide are supplied with the control unit. A comprehensive DEPRAG system solution is used for the screwdriving operations on the two production lines: more than 100 active screwdriving controllers, application-specific built-in screwdrivers and tools, automated tool changes, and centralized monitoring with the DEPRAG Cockpit.
Two lines and a wide range of screwdriving tasks
Two production lines are in use for the assembly of the Energy Master for battery-electric vehicles. The first line is already in series production. In the approximately 120-meter-long overall system, more than 100 DEPRAG screwdriving controllers control and monitor the different screwdriving operations on both lines. Reliable execution of each individual screw joint is therefore only part of the challenge. All systems must also work together seamlessly across the entire line.
Four requirements were at the heart of the screwdriving technology design:
Variety of fasteners: The lines process up to 14 different fasteners using the corresponding tools.
IT security and system integration: The screwdriving controllers must meet the project-specific IT requirements and integrate into the higher-level production environment.
Uniform system architecture: The screwdriving technology must be based on a common technical platform across both production lines while still adapting to the respective screwdriving task.
Centralized process transparency: The data and status of all screwdriving controllers must be clearly recorded and analyzed.
What was needed was therefore not a collection of independent screwdriving stations, but an integrated system concept.
Screwdriving system DEPRAG Plus as a standardized platform
The technical foundation is the DEPRAG Plus screwdriving system. It combines the AST12 sequence controller with application-specific DEPRAG built-in screwdrivers and the required screwdriving tools.
The AST12 controls the defined screwdriving sequence, processes the signals from the screwdriving system, and provides operating, interface, and documentation functions. Suitable screwdriving programs can be stored for each application. Standardized interfaces connect the screwdriving technology to the higher-level system controller.
IT security was a key selection criterion. The controllers used had to meet both regulatory cybersecurity requirements and the security requirements defined specifically for the project. In addition, integration into the specified system architecture had to be ensured. The AST12 met these requirements and was therefore used as the standardized control platform.
The common platform simplifies the operation of the numerous stations. Operating concepts, interfaces, and the basic structure of the screwdriving programs remain consistent across the lines. At the same time, process parameters can be individually adapted to the respective screwdriving operation, for example in terms of torque, angle, or speed.
Learn more about the DEPRAG Plus screwdriving system
DEPRAG Tool Changer: flexibly processing different fasteners
A particular challenge is the variety of fasteners. Up to 14 different variants must be tightened using the corresponding tools.
Using a separate screwdriving spindle for each tool variant would require significantly more space, equipment, and additional handling components. This is why the automated DEPRAG Tool Changer tool changing system is used.
The Tool Changer provides the required tool for each screwdriving process. This allows one screwdriving system to process different fasteners with various internal or external drive profiles. The tools are stored in dedicated tool stations within the line.
The tool change is fully integrated into the automated process:
1. The screwdriving system moves to the designated tool station.
2. The previously used tool is deposited.
3. The tool required for the next screwdriving operation is picked up.
4. The screwdriving process starts with the corresponding stored program.
No manual intervention is required. This makes it possible to flexibly process different fasteners without having to provide a separate screwdriving system for each variant.
During the tool change, the screwdriver picks up the tool directly. A separate search movement for the coupling process is not required. This reduces the number of necessary movements and allows the tool change to be efficiently integrated into the automated process.
Learn more about the Tool Changer
DEPRAG Cockpit: centralized overview of more than 100 screwdriving controllers
The more screwdriving stations an assembly line includes, the more important a centralized process overview becomes. Monitoring each controller individually and exclusively on site would be neither clear nor efficient in day-to-day production with more than 100 active systems.
The DEPRAG Cockpit brings together the relevant information from the connected screwdriving controllers on a central platform. This makes it possible to monitor the screwdriving technology across lines and stations.
The software provides, among other things:
centralized monitoring of the connected screwdriving controllers,
visualization and analysis of screwdriving results and screwdriving curves,
analysis of system and error messages,
identification of recurring deviations and trends,
as well as structured documentation of all screwdriving processes and connected devices.
For Energy Master assembly, this means that instead of numerous separate individual views, a consolidated overview of the entire screwdriving system is available.
This makes it possible to assign irregularities more quickly to a specific line, station, or controller. At the same time, process managers can analyze screwdriving results across the system and identify recurring trends at an early stage.
Learn more about the DEPRAG Cockpit
An integrated system solution for complex assembly tasks
The particular added value of this project lies not in a single component, but in the coordinated interaction of the systems. Built-in screwdrivers, tools, sequence controllers, tool changes, interfaces, and software were combined into an integrated solution tailored to the requirements of the assembly lines.
The result is not a rigid standard solution. Instead, it creates a reusable system platform that can be individually adapted wherever the specific screwdriving task requires it.
At the same time, this application shows that in complex series-production lines, the performance of an individual screwdriving spindle alone is not what matters. The key is an overall architecture that takes different fasteners, process data, interfaces, and IT requirements into account as a whole.
The DEPRAG Plus screwdriving system provides a standardized control platform. The Tool Changer provides the flexibility required for the different fasteners. The DEPRAG Cockpit provides transparency across all connected screwdriving controllers.
The result is a screwdriving solution that provides a common technical foundation across both production lines while remaining flexible enough to adapt to different screwdriving tasks.
Plan your screwdriving technology as an integrated system
All requirements relating to IT security, interfaces, or process documentation should be considered together from the very beginning when designing an assembly line.
DEPRAG analyzes the specific screwdriving task and coordinates the required components and software solutions. The result is an integrated system that can be reliably incorporated into new or existing assembly lines.
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