The Grand Tour of German Automotive—Porsche Assembly Lines

In my previous post I looked at Porsche and the Porsche plants in Zuffenhausen near Stuttgart and the plant in Leipzig. In this post I will go deeper and look at three final assembly lines in these two plants. In Zuffenhausen I visited two final assembly lines, the 911 and 718, as well as the fully electric Taycan assembly line. In Leipzig, they have only one assembly line where they produce the Panamera and the Macan. Let’s go through them from the oldest (forty-year-old line for the 911 Zuffenhausen) to the intermediate (twenty-year-old line in Leipzig) to the latest (five-year old line for the Taycan in Zuffenhausen). Let’s go!

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.

911 & 718 Cayman Final Assembly Zuffenhausen

This assembly line, producing all kinds of 911 models as well as the 718, is now forty years old but still doing well. Like all Porsche locations, it was exceptionally clean, comparable only to BMW.

The workers work in groups of 15 people. They rotate their jobs roughly every hour to avoid boredom. When the workers had a break, it seems that they were able to work ahead by 3 minutes, and start roughly 3 minutes after the break ended, extending their break by 6 minutes. Compared to other plants I have seen in Germany, this is actually not too much.

A large number of car bodies buffered the assembly line from the preceding paint shop. To handle the different models and different workloads, they do a lot of mixed model sequencing. For example, the Cabrios need no rear windows at all, whereas the Targa has a devilish tricky rear window.

Most of the 137 stations are based on a moving platform, with production located on two floors. They produce at a takt of roughly three minutes per car. Compared to the other (newer) lines there is less automaton. While I did not see the entire line, I remember robots only for the window installation. Material carts were either on the platform or moving along with it. I always like to estimate of the percentage of the time the worker adds value. At this line, I measured a value added time of 40%, which puts this line in the middle of the field in Germany (the newer line in Leipzig is better, and the newest line for the Taycan is best).

Curiously, the final quality check for dents in the metal was done with bare hands. While checks by hand are the standard in industry, most of them use gloves. The guide claimed that this gives the quality control more information. And another nugget of information: the Porsche logos that are attached to the center of the wheels are often not mounted in the plant, but only at the destination. Porsche learned by experience that a bored crew of a car transporter loves to collect Porsche emblems as souvenirs. To avoid these losses, the emblems are now shipped separately.

Panamera and (Also Electric) Macan Final Assembly Leipzig

The single assembly line in the greenfield plant Leipzig is much more aligned with the material flow. On a single floor the twenty-year-old line makes around 600 cars per day in three shifts at a takt of two minutes per car. Their overall lead time is around two days. Besides the moving platform and a hanging rail like for the 911 in Zuffenhausen, they now also have a hanging rail that can rotate the car (called a C-hanger) for more ergonomic work on the underside of the car.  Still, there is some overhead work.

Teams of 8–12 people per team leader work on the stations. I found it interesting that every team member can have a 15-minute break per shift whenever he wants. Normally, people walking away whenever they want clashes with the concept of an assembly line, but the team leader will cover the break. I find this a nice idea, as it gives the workers flexibility for a call of nature, an urgent phone call, or whatever they need. Generally, Porsche seems to take care of its people. The shop floor was also sparkling clean, and the team corners were among the nicest I have seen in automotive, with leather and wooden seats.

A lot of material is delivered just in time (JIT) and just in sequence (JIS). For example, for the wheels, the supplier gets the sequence information four hours beforehand, and there were indeed very few wheels between the (un-)loading dock and the adjacent tire assembly station. Albeit, with four hours’ notice, you still need an inventory, it is just at the supplier location. The line also has the now common andon system to call for help and to stop the line. During breaks, the illumination on the line is also dimmed or turned off.

In terms of value adding time, the engine and transmission line had 39% value add, and the final assembly had 47% value add, which is quite good (behind the Porsche Taycan line and the BMW plants).

Taycan (Electric) Final Assembly Zuffenhausen

The latest Porsche assembly line is for the fully electric Taycan. This line started production only in 2020. While still using two floors due to the space constraint in Zuffenhausen, this is the most modern line, using not only moving platforms, hanging rails, and rotating hanging rails, but also AGVs to move the cars along the stations. It felt more automated than the other lines with more robots, albeit an automotive final assembly is still a largely manual job. Twenty of the stations on the line were with cars on AGVs, albeit only 16 AGVs seem to be used when I visited. The AGVs follow a 2cm wide strip of QR-codes on the floor for orientation. Additional AGVs supply material to the line, navigating by reflectors in corners.

The line is by far the most efficient line I have seen at Porsche, with 56% of the time being value adding. Only BMW in Munich and Leipzig had a better value adding share in Germany. This is despite a rather slow takt of 4:18 minutes per car when I visited (it was supposed to be faster normally).

They also have an andon cord, where a yellow cord calls for help and a blue cord stops the line. A light signal was counting down from twenty rings to zero during the takt so the workers could see how much time was left. Around sixteen of the light rings were green, followed by two orange and two red. Confusingly, they had the same design elsewhere as stack light.

One legal constraint for the line was that as soon as the battery was added, only specially trained high-voltage technicians were allowed to work on the car. And, due to the expansion into electric vehicles, such technicians are in short supply. If you want to work for Porsche and have a certificate as a Hochvolttechniker, now is your chance!

Overall, I found Porsche the cleanest plants along with BMW in Munich and Leipzig. I liked their organization, and especially the newest Taycan line was very well organized and the most efficient line after BMW in Munich and Leipzig. The technical progress with the lines was also visible, with mostly only a moving platform on the forty-year-old line for the 911, C-hooks to rotate the cars at the twenty-year-old line in Leipzig, and finally AGVs at the four-year-old Taycan line. I am wondering, if the age is also a factor for the percentage value add, which rises from ok-isch 40 % for the 911 to very good 47% in Leipzig to second best after BMW with 56% for the Taycan (all numbers my estimates, only). I am sure having Porsche leadership will be good for the rest of Volkswagen, even if they don’t always like it. In my next post, I will continue with the plants of Audi, before closing this series with Volkswagen branded plants. Now, go out, lead your own plant toward a leaner and better future, and organize your industry!

PS: Many thanks to Porsche for offering tours through their plants to the public!