Tesla Inc (TSLA.O) has combined a range of innovations in a technological breakthrough that could change the way it makes electric cars and help Elon Musk achieve his goal of halving production costs, according to Reuters. The company was the first to use a large press with a clamping pressure of 6,000 to 9,000 tons to manufacture the front and rear structures of Model Y through the “super casting” process, thus significantly cutting production costs.
Integrated die-casting technology will replace the most time-consuming and cumbersome stamping and welding links in traditional automobile manufacturing. Ultra-large die-casting machines with a tonnage of 6000T and above will be used to directly die-cast several aluminum alloy parts that originally needed to be assembled into complete large parts. , marking the arrival of disruptive innovation in automobile manufacturing technology.
One-piece die-casting
According to the 2019 Automobile Lightweight Conference, if the weight of pure electric vehicles is reduced by 10%, the average cruising range will increase by 5%-8%. Therefore, improving the cruising range of new energy vehicles through lightweight solutions has become a hot technology route. It is reported that Tesla has quietly made breakthroughs in reducing the weight of the vehicle. The focus is on how to design and test giant molds for large components for large-scale high-pressure casting production, and how to lighten the vehicle body by manufacturing hollow subframes with internal ribs. weight and improve crashworthiness. Among them, 3D printing sand molds may reshape the automobile manufacturing industry.
Tesla has been exploring the use of integrated die-casting to reduce manufacturing complexity, cost and body weight. Previously, in July 2019, Tesla announced a new patent “Multi-directional body integrated molding casting machine and related casting methods for automobile frames”, which realizes the casting of different components by moving different convex molds to the casting area in the center of the casting machine. Casting, most of the frame casting work is completed on one machine. This is the first time that one-piece die-casting has appeared in the public eye.
According to Tesla Battery Day 2020, Tesla plans to promote the design of the integrated structure of the car body. The integrated die-cast lower body assembly and the battery pack are better integrated, which can achieve an overall weight reduction of 10% and increase the cruising range by 14%. The effect of improving efficiency and reducing cost is obvious.
Traditional automobile body manufacturing uses sheet metal stamping + welding processes. A body is composed of more than 500 parts, and there are a total of 4,000-6,000 welding points in the entire vehicle. At the Battery Day in September 2020, Tesla announced that Model Y will use an integrated die-cast rear floor assembly, which can reduce 79 parts compared to the original, and reduce the number of solder joints from approximately 700-800 to 50. The Texas Gigafactory, which will begin delivering Model Y in April 2022, also uses an integrated die-casting process, which can reduce the number of front and rear floor parts from 171 to 2, and reduce the number of welding points by more than 1,600. In addition, Tesla plans to replace the entire lower body assembly composed of 370 parts with the front floor, CTC battery pack upper cover, middle floor, and rear floor, which is expected to further simplify the body manufacturing process.
It is reported that Tesla is cooperating with voxeljet. Of course, Tesla is not the first company to introduce the technology of binder jet 3D printing sand molds into the automotive industry. BMW adopted it a few years ago. This 3D printing technology manufactures the cast sand core of the S58 engine cylinder head to meet the needs of lightweight and thermal management performance. According to 3D Science Valley, automobiles are the largest application market for casting, and the combination of 3D printing and casting can be said to have the potential to subvert the design of automotive parts from the source of product design.
With the combination of 3D printing and casting, casting is the “source” of the “birth” of products, and its value in determining the core competitiveness of products will appear. This industry will no longer be misunderstood as “silly, big, clumsy”, but will become an enterprise. The development of core competitiveness is a manifestation of the fact that 3D printing can determine the degree of innovation of a product from the source. Many large enterprises will change the model of outsourcing casting to foundries, and instead incorporate casting into the enterprise as a core and key link. In production operations, foundries and 3D printing companies may be merged and acquired by automobile companies during this process.
However, using 3D-printed sand molds for manufacturing large parts in the automotive field is full of challenges. Compared with other casting processes, high-pressure casting has higher production efficiency, the mold can be used repeatedly, and the degree of one-time molding is high. It can produce thin-walled complex castings and high-precision, high-finish castings. However, it is inevitable to have internal pores and casting cross-sections. The structure and mechanical properties change greatly.
Through innovative 3D printing sand mold technology, we can go from model to product within 3-5 days. We can also achieve flexible and efficient production of key parts of new energy vehicles through innovative processes, fixtures, tools and full-line automation design.
