One day in late 2018, in Palo Alto, Musk sat at his desk at Tesla's engineering headquarters, playing with a toy model of a Model S that looked like a miniature version of the real car. When Musk took it apart, it was found that there was even a suspension system inside, but the entire underbody of the car was die-cast into a single piece of metal. At the team meeting that day, Musk took out the toy car and put it on the white conference table, and he asked: Why can't we do this?
The above paragraph is quite dramatic, as if it comes from the plot of a domestic Internet cool article, which is actually contained in "Elon Musk's Biography" published last year, written by the famous American biographer Walter Isaacson.
The description of the biography inevitably involves embellishment and exaggeration. But one thing is certain, since Tesla officially announced in September 2020, the latest Model Y models will begin to use the one-piece die-casting method to produce rear underbody assemblies, and will greatly promote the use of die-casting technology in Tesla-branded cars in the future. After a brief period of confusion and confusion, the global automotive industry began to follow suit quickly.
Suddenly, the die-casting process seems to have become the main direction of the future of automobile manufacturing technology, and Europe, Japan, the United States and even local car companies have launched die-casting technology.
The signature data of the large die-casting machine is the clamping force, that is, the die-casting machine exerts a locking force on the mold in order to overcome the opening force of the melt on the mold after the metal liquid is injected into the cavity. Generally, the larger the mold, the stronger the clamping force required. Since 2020, Idra, a subsidiary of LK Technology, developed the "Giga Press" with a clamping force of 6,000 tons specifically for Tesla, OEMs at home and abroad have been competing to chase after each other and continue to place orders for more powerful die-casting equipment.
The clamping force of the die-casting machine has also crossed the 7,000 tons, 8,000 tons and 9,000 tons all the way, and the tide has risen to the 9,100 tons of "steel monster" used by Xiaomi Automobile to produce large assemblies for the SU7 model chassis. Even earlier this year, Xpeng announced that its 12,000-ton die-casting machine had been installed and production had started.
However, the industry trend driven by Tesla suddenly changed at the beginning of May.
When the headline "Tesla Even Gives Up On Next-Gen Gigacasting" appeared in the U.S. media during Labor Day, many people must have felt blindfolded. Because just at Tesla's investor day on March 1 last year, the more radical "Unboxed Assembly Process" (Unboxed Assembly Process) was announced, announcing that it would further reduce production costs by 50% and reduce factory space by 40%. At the root of this is the integrated die casting process version 2.0, which produces larger integrated castings.
So, what happened to cause the "world" to begin to change so dramatically so quickly?
Die casting machine "arms race"
Combining more than 70 parts into one can reduce the total weight of the "rear floor" by 30% and reduce the manufacturing cost of the vehicle by 40% – this is how Tesla explained the benefits of the process when it officially announced in September 2020 that the Model Y would use one-piece die-casting technology to produce the rear floor assembly.
As early as 2019, when Tesla announced the latest Model Y model, Tesla continued to reveal to its investors and even the outside world through various light and dark channels that it would "pioneer the use of one-piece die-casting design" on this important model.
There is no doubt that higher production capacity and lower cost have been the pursuit of the automotive industry and even the global manufacturing industry from beginning to end. So in order to achieve this, Tesla even sacrificed the commonality of the Model Y and Model 3. Even though the former is based on the chassis of the latter, a sister model was developed.
But even so, the whole process is still difficult from the perspective of today.
From the end of 2019, when the news was first released to the outside world (the actual trial production should be earlier than this), it was tossed until the first half of 2021, and the cycle of technical research exceeded one year, and the deployment of large-scale die-casting equipment, the whole process flow, and even the pass rate and production capacity problems were finally solved. Previously, it was reported that in the early stage of trial production of die castings, the pass rate was even lower than forty percent.
If it weren't for this process, Tesla's current most competitive model, the Model Y, could actually be delivered in 2019, instead of a year's delay after the official announcement. As for the ramp-up of production capacity, there is no need to delay until the beginning of 2022.
Finally, at that time, after receiving the blessing of China's local pure electric vehicle industry chain, Tesla had the world's top strength on the pure electric vehicle track, a big cut ahead of all its opponents. So in the end, I was able to complete the whole process without danger.
The success of the Model Y has also made all companies interested in automobile manufacturing seem to see the dawn of new technologies. The "competition" for die casting equipment mentioned above also roughly began at the end of 2022.
According to professional estimates, in order to achieve integrated die-casting of the entire body of a compact vehicle, the clamping force of the die-casting machine needs to be at least 16,000 tons, and the 12,000-ton equipment that Xpeng Motors commissioned at the beginning of this year is particularly sufficient.
Of course, this is not a big deal in front of today's Chinese equipment manufacturing industry, after all, in December last year, there was news that Nezha Automobile signed a strategic cooperation agreement with LK Group, planning to jointly develop die-casting equipment with more than 20,000 tons of lock grinding force. Once delivered, the machine will theoretically be able to process chassis components in a single pass for medium-sized vehicles.
And at what cost?
In fact, the integrated die-casting technology seems to be able to greatly save the production cost of car companies, but its initial investment is very high. In addition to the corresponding development costs, as well as the huge investment in the purchase of large die-casting machines, enterprises also have to bear the cost of developing and purchasing die-casting molds and supporting the corresponding smelting furnaces.
And die casting itself is only the beginning of the whole process. After the rough blank is taken out of the die-casting equipment, special cooling equipment, pick-up and transfer devices, as well as corresponding trimming machinery and even special spraying processes are required for subsequent process matching.
In fact, this is to develop a whole new set of processes and get the corresponding production line.
Even so, integrated die casting is still not comparable to traditional processes in many aspects. Even Tesla has always continued the traditional style of "American rough cars", and its castings often make people feel indescribable.
Tesla has officially displayed a set of Model Y rear body panel assembly parts produced by die-casting in a "generous" manner, and compared them with similar parts of the Model 3 made by welding process. After reading it, it can only be said that it is a profound understanding of what it means to "no comparison, no harm".
The first is that the accuracy of castings cannot be compared with stamping parts at all. The error of the former often reaches the millimeter level, while the modern automobile stamping process can control the error in the range of 10 wires.
In addition, the casting process is often characterized by the presence of air bubbles, which can lead to a vulnerable area of the casting once they are concentrated in one area. In order to effectively detect such defects, the factory can only sacrifice X-rays for flaw detection. But this means that it is very cumbersome and cumbersome to build a special room for testing in the workshop.
In addition, in order to increase the strength of the casting, heat treatment is usually carried out after the casting is completed. However, in this way, thermal expansion and cold contraction are inevitable, which is bound to make the problem of poor accuracy of castings more serious. To this end, Tesla has specially developed a special aluminum alloy without heat treatment, which can reach a certain strength after casting without heat treatment. However, although this can improve the yield rate, it is only a "certain strength" after all......
So at this point, you should understand what Tesla's engineers have been tossing about for more than a year. Whether the use of die-casting technology is a problem for Musk or not is a problem, but in order to realize this "dream", the engineering team is indeed tossed enough, and many times it is forced to make a lot of technical compromises.
For example, in the above heat-free problem, in order to ensure that the strength of the casting has enough redundancy, the compromise is to put more materials, which leads to a considerable part of the cake drawn on weight reduction at the beginning.
So is it not necessary to do die castings well? Not necessarily.
For example, in July last year, when I attended the 70th anniversary of the founding of FAW Group, I saw the body floor assembly processed by an 8,000-ton die-casting machine. It can almost achieve the level of similar assembly parts that are welded and processed.
In addition, Zhao Chunlin, vice president of ZEEKR, once complained about the quality of Tesla's castings on his personal social media account. The complaint is very ruthless, but after showing off the comparison picture, it is obvious that he is just telling the truth.
Of course, whether it is FAW Group or ZEEKR brand, there is no car whose monthly output can be compared with Tesla's Model Y for the time being. Considering the characteristics of die-casting technology itself, Tesla should actually find a relatively most reasonable and economical quality control standard point while meeting the basic technical indicators through a large number of production practices.
There are defects, but they can be used normally and will not affect safety. So among Tesla owners, there is also self-deprecation like "the car I bought is flawed, so it is a genuine Tesla".
As the backlog of orders gradually ran out and the overall earnings expectation deteriorated, Musk announced in April that Tesla would lay off 10% of its global workforce. Some executives were also "persuaded to retire" or even directly dismissed, and many of them had followed them for ten years.
Caresoft Global, an American automotive data and consulting company, believes that Tesla is facing short-term financial pressure. The temporary suspension of the expansion of the use of integrated die-casting process will avoid investing too much money in the short term that is difficult to recover in the short term. Because in order to realize the casting of the chassis parts of the whole vehicle, Tesla needs to be equipped with a super die-casting machine of at least 20,000 tons. One can imagine how much money would be needed to purchase additional equipment. What's more, many of the technical problems faced by the overall die casting have not yet been solved.
What's more, consumers have gradually recovered from the boom in the past few years, and have even gradually realized that integrated die-casting technology will not provide you with better cars, and its only value is to reduce the production cost of car companies. However, the key thing is that under the intertwining of many factors, it is difficult for Tesla to significantly reduce the price of its car again......
In addition, the problem of aging models is also becoming a concern for Tesla. After all, the Model 3 is already an old car that was released 8 years ago, and even the Model Y has been released for more than 5 years, and only the former underwent a mid-term facelift last year, with the main change being the change of headlights. It's understandable that consumers are getting tired of it.
Since the Shanghai Lingang Gigafactory was put into use in 2019, Tesla's first curve has crossed its peak. So, the most important result of Musk's visit to China at the end of last month, the F-SD system (Full-Self Driving) was approved to land in China, can it pull a second curve for the global leader in new energy vehicles?
We can, wait and see!