Tesla is a technology company in the eyes of many people. From autonomous driving to battery management technology, there is always something unique. In fact, Tesla also dares to invest in manufacturing. For example, its all-aluminum body and steel-aluminum hybrid body are not inferior to the old car companies in technology, and the models it produces have therefore become frequent visitors to the top evaluation lists of institutions such as IIHS and E-NCAP.
Recently, a topic about Tesla manufacturing technology in the industry is very hot: Tesla model? Y body will be converted into casting design, from 70 pieces to 1 piece.
The idea of this technology is very surprising. I believe that friends who have read our article "Returning to work is imminent, and there are still many invisible difficulties for automobile manufacturers" know that the production pressure of the main engine factory is very high because of the new pneumonia epidemic.
Regarding the problem that the automation rate of BIW manufacturing industry cannot be further improved, this article says:
Because the stamping and painting workshop does not involve assembly and the automation rate is high, the demand for personnel is relatively small. However, there are many people in the car body and assembly workshop. Let's take the body production line of a joint venture as an example. Although the welding automation rate is as high as 99.9%, there are still hundreds of people in each class.
Does that mean that the OEM is exaggerating publicity? In fact, the key lies in the statement of "welding automation rate", which measures whether the body solder joint is completed manually or by machine, and does not include the automation degree of loading and unloading, maintenance and quality inspection. At present, the degree of automation in most factories is not high.
We say that German Industry 4.0 and Made in China 2025 are essentially the same-pursuing a high degree of automation. However, due to the manufacturing characteristics, it is impossible for the automobile main engine factory to achieve the comprehensive automation rate of 100%. However, if Tesla can really realize this technology, it will really help to improve the automation rate. From Tesla's point of view, this will reduce construction time, operating costs, manufacturing costs, factory floor space, processing costs and the number of equipment.
Body-in-white refers to the welded but unpainted body. Usually it does not include moving parts such as four doors and two covers, but there are four doors and two covers when they leave the welding workshop.
How does Tesla achieve an integrated body?
Actually, Tesla model? The news that Y body-in-white turned to aluminum casting design broke out last year, when Musk said: When we have a large casting machine, the body will be reduced from 70 parts to 65,438+0 parts.
What are the "70 parts" that Musk did not explicitly mention? As we all know, the key assembly components involved in body-in-white are as follows.
In the whole welding process, the welding of parts is generally considered first, and then the sub-assembly and assembly are considered.
The characteristics of BIW in the welding process are obvious timing. In order to facilitate assembly, the car body is usually divided into several assemblies, and each assembly is divided into several sub-assemblies, which are composed of several parts. The above picture is a simple car body workshop manufacturing flow chart, and it can be seen that there are many main splicing parts. Therefore, it would be great if a huge new machine can be designed to produce the frame as a whole.
According to Tesla's patent information, we saw the schematic diagram of the multi-directional casting machine for the frame as shown in the following figure. Its left and right sides are symmetrical, that is, the casting of the left and right side walls is completed; The fore and aft casting machines are responsible for casting the fore and aft cabins.
It is mentioned in the description of Tesla patent that some features and subcombinations are useful and can be used without reference to other features and subcombinations. Generally speaking, we protect not only the whole design idea, but also some functions under this design idea can be used independently and should be protected.
In fact, some parts have been cast, such as Cadillac CT6, which creates a stiffening rib system, which can keep the structural integrity of the chassis while minimizing the use of materials. And in the process of simplifying key parts, the original 227 steel parts can be integrated into 3 1 cast aluminum parts.
Cadillac CT6 is a steel-aluminum hybrid body. Made of 1 1 different materials and high-strength steel and aluminum, the number of parts is reduced by 20%.
The picture above shows the aluminum casting with honeycomb structure.
Models? Y-body to casting design?
Models? Y has been put into production in fremont Tesla factory in June 5438 +2020 10, several months ahead of schedule. As planned, model? 3 and model? The total output of Y is 400,000 vehicles/year (in 20 19, Tesla produced 30,2301models here? 3)。
We know models? Y is based on the model? Developed, it is unlikely that there will be a breakthrough manufacturing technology in a short time. Did we see that model from the production drawing of Tesla fremont factory? Y does not adopt the integrated molding process described in the patent. For example, this part of the external wall, the following figure is obviously a traditional external wall panel, not a multi-layer sheet metal formed at one time.
Can you look at the model? 3. The blue part belongs to the outer panel. What is the model? Y is similar.
So you can see, say model? Y is now using an integrated framework, which is more accurate. It can indeed reduce the number of parts of the floor to a certain extent, and because it is not a cover, it will not significantly increase the maintenance cost. Of course, we can't say that this is a concept of stealing. As mentioned above, this is really a good technology (just not as surprising as the patent shows).
Models? Y's body-in-white is not a typical load-bearing vehicle structure, and it has a frame that obviously strengthens the bearing and collision ability.
The spot welds of the car body can be clearly seen, and the layout of the pallet sled is obviously a traditional manufacturing method.
Compared with the traditional production line, there is no obvious difference.
In the traditional production line, a large number of resistance spot welding processes will be used to splice the car body.
Is it possible to have a complete body?
The aluminum alloy casting process used in Tesla's patent can really reduce the difficulty of assembly process of parts, shorten the manufacturing line at the same time, and alleviate the trouble that Tesla's production capacity has been rising, but it will greatly increase the difficulty of maintainability. Friends who can afford Tesla may say: I'm just willing to pay for its technology.
Of course, this is just a joke. For a long time to come, it will be very difficult to realize the aluminum alloy integrated fuselage technology.
However, it does not mean that the integrated molding process does not exist, such as the all-plastic process, in which high molecular materials are used instead of steel, and large-scale hollow plastic products with complex surfaces are prepared by rotational molding process at one time.
At present, this technology is mainly used in low-speed vehicles. Its method is to add raw material particles into a specific mold, and the mold will rotate and heat continuously along the axis. Under the action of gravity and heat energy, the plastic in the mold will be evenly coated and melted and attached to the whole surface of the mold cavity, molded into the required shape, and then cooled, shaped and demoulded to obtain an integrated molded product.
However, due to the insufficient impact strength of plastic products, even if the built-in steel mesh structure or glass fiber and other reinforcement materials are added to enhance the structural strength of the car body, it is still far from the traditional car body strength level.
Ashton tubercle
We increasingly feel that a lengthy process chain will affect the improvement of automation rate. We always talk about the integration of parts, but the technology of body-in-white has not changed much in recent years. Tesla, Cadillac and other companies have given us a good demonstration by shortening the process chain through casting process. However, there is still a long way to go from the ideal integrated body. It is hoped that leading enterprises will not exaggerate existing achievements and lead technological development.
Figure? |? From the network
This article comes from car home, the author of the car manufacturer, and does not represent car home's position.