The third and last Mercedes-Benz (also known as Daimler) is its newest and comparatively smallest plant, in Rastatt. I have been to Rastatt many times, but this blog post is based on public information and on information from the guided tour. It is in my view the best-performing plant of Mercedes-Benz, and among the top automotive plants in Germany (albeit behind BMW and Porsche). Read on…
Disclaimer: The following is based on my personal observations and opinions and may not be accurate or correct. It is based on publicly available information and what I observed during public tours, and when I observed it. The observations may differ at a different time and place.
Introduction to Mercedes-Benz Rastatt
The Mercedes-Benz Rastatt plant is the third car plant of the company, after Sindelfingen and Bremen. Production started in 1992 and the plant currently employs 6100 people, plus suppliers. The comparatively new plant is a greenfield location, with lots of space for possible expansions.
The plant produces A-Class, B-Class, GLA (compact SUV), and EQA (fully electric) cars. Combustion engines, hybrids, and electric cars are all produced on the same line. The plant produces 206,000 cars per year (2023), down from 300,000 in 2014. 20% of cars are picked up by the customer, 65% are delivered by truck, and 15% by train. The press shop is located in Kuppenheim (8km away), while the body shop, paint, and final assembly are in Rastatt. Gearboxes are from Mercedes-Benz Gaggenau (20km away).
Like all Mercedes-Benz plants in Germany, logistics was outsourced two years ago, and all forklift drivers are no longer from Mercedes-Benz. No direct work-related communication is allowed, and if a manufacturing operator needs to tell something to the forklift operator, they need to contact the manufacturing support, which will contact the logistic support, which will contact the logistic operator. This creates a lot of potential for losses, delays, and mix-ups, but makes logistic cheaper.
We had a brief visit to the body shop in Hall 2.1, followed by the assembly line in Hall 4. Another assembly line is in Hall 4.1. In the body shop I learned that there is 90m of glue in an average car, and 6400 spot welds. During the tour, all mobile phones had to be put in lockers.
Assembly Hall 4.1
The assembly line in Hall 4 is the larger of the two assembly lines in Rastatt. The main assembly line in Hall 4.0 has 12 segments and around 300 stations, while Hall 4.1 has only 8 segments. The cleanliness of the Hall 4.1 is acceptable, comparable to Audi and VW, with a few big cardboard boxes standing around somewhat randomly.
The car was supported by different devices in different sections. In some, it was on a moving platform, in others on a hanging device with a scissors-like mechanism. I did not see any C-frames or AGVs for moving car bodies.
The scissor hangers could reach at least 6 meters down. Oddly, for working on the underbody, the hanger track was right under the high roof, and the scissors stretched almost all the way to meet the workers 10m below. For attaching doors and so on from the side, the hanger track was much lower, and the hanger itself was nearly closed to fit the car under the low track. In this case, the space above the hanger track was used for other logistics. The hanger arrangement was not very consistent across the sections. The hanger provides flexibility but suspending it entirely from the ceiling takes up space for future overhead logistics. In any case, overhead work is limited to two hours before the employees are rotated to another location, as working overhead is quite tiring. I did not see any C-hangers that could rotate the car body for easier access to the underside.
The moving platforms also had, in some places, some side platforms with tools. The side platform moves along with the car until the end of the station, and then moves back to the beginning of the station again.
The takt time was 80 seconds. Somehow surprising, this was not confidential information as in the other two Mercedes plants. I also estimated the percentage value add of the assembly operations at 51% for the final assembly and 39% for the dashboard subassembly (see my blog post How to Estimate Value Add for Manual Work for more). The final assembly is actually above average for Germany, albeit still behind BMW and the Porsche Taycan line, and miles behind Toyota in Japan. The lead time for assembly operations was 24 hours, but this is only the actual work, and does not include the cars waiting in the inventories between. The dashboard subassembly lead time was 30 minutes. The lines also had an andon system, called the Q-Stop for quality stop.
The assembly of the dashboard was done entirely by a robot, which lifted the dashboard into the car, positioned it, and tightened the screws. When the robot arm moved back out, it also dropped three bags (with cables) on the floor of the car. These will be installed by operators later. I found this a quite neat idea to do the installation and the pre-placement of the cables in one single operation!
By the way, the assembly of the dashboard is called the “digital marriage” (Digitale Hochzeit), in reference to the normal marriage (Hochzeit) where the drivetrain and the car body are merged. This makes sense, as the digital side of the car and the user interface will become more important as cars become more digital.
One quirky observation: While we were touring the plant, they also had a new type of car body on the line as part of the ramp-up, surrounded by lots of engineers in pink high-visibility vests that tested the assembly operations. As this was highly confidential, our tour was accompanied by three people from the product protection department (Produktschutz), telling us when we could move ahead, where we could not stop, and where we had to wait. As a guest I do respect that, and I did not look in the direction of the super-secret car body. Moreover, I am very interested in how to make a car, but I have little concern about their appearance, and barely can see the difference between a Mercedes and a BMW anyway.
My next post is my last visit of a Mercedes-Benz plant, their heavy-duty truck plant in Wörth. This is the largest heavy-duty truck plant in the world, and—as far as truck plants go—actually quite good. Now, go out, find out which other plant can improve your improve yours, and organize your industry!
PS: Many thanks to Mercedes-Benz for offering tours through their plants to the public!