Magna Automotive's questions and answers about lightweight chassis are all here

The lightweighting of automobiles plays an indispensable role in the overall energy conservation and emission reduction of vehicles. As the body and chassis structural parts account for half of the total vehicle weight, their lightweight design must be the top priority of the entire vehicle lightweighting.

Recently, in the "Black Technology is Coming" live event, Magna's technical experts Xu Ziqing and Kong Lingbo led us to learn more about Magna's lightweight solutions for body and chassis. Due to the time limit of the live broadcast, many questions were not answered during the live broadcast. Now, it's time for fans to benefit! The editor has sorted out popular technical issues for everyone, and will take you to deeply analyze the mysteries of body and chassis.

Get a sneak peek

Since electric vehicle battery packs are relatively heavy, CTC technology is now being promoted. How does Magna ensure the safety of the battery pack while reducing the weight of the vehicle body? What is the solution?

Kong: CTC, in short, is to integrate the battery housing with the lower body structural parts such as the body floor and door sill beam, so as to remove the redundant structure of the current independent battery housing to achieve lightweight and obtain a larger battery carrying space. Therefore, CTC achieves lightweighting through a design path. Its first premise is to ensure product performance such as collision safety, strength, and stiffness. Magna has many years of research in the design of CTC battery housings and has corresponding mature technical solutions. In addition, our lightweight materials, hot-formed ultra-high-strength steel, and high-pressure cast aluminum and other technologies can further achieve weight reduction effects. Magna's various steel and aluminum forming technologies, as well as corresponding connection technologies, such as laser welding, FDS, SPR, and stir friction welding, are widely used in lightweight battery housings.

Xu: We have very strict requirements for quality control. For example, we have corresponding online quality control for gluing and welding: 100% online sealing test and detection. There is also AR detection technology to ensure that we provide customers with high-quality delivery.

What lightweight technologies does Cosma have for chassis subframes?

Xu: Two lightweight technologies have been mentioned in the live broadcast, one is the high-pressure cast aluminum subframe, and the other is the carbon fiber one-piece subframe. In terms of materials, subframe products are mainly divided into steel and aluminum. Steel parts mainly have structures using hydraulic pipes and traditional stamping parts welding structures; aluminum subframes have low-pressure cast one-piece structures, high-pressure cast one-piece structures, and aluminum profiles plus low-pressure cast aluminum welded structures. Magna has very rich design and manufacturing experience in these fields. In addition, we will conduct very comprehensive performance structure optimization based on customers' target requirements for product performance and weight, and provide lightweight products with competitive advantages.

What are the advantages of the five-cavity unit bumper and the traditional Japanese/English type?

Hole: As a patented product of Magna, the five-cavity bumper has the advantage of better bending resistance under the same cross-sectional size. While meeting the customer's collision requirements, this design can achieve a 15% weight reduction effect compared to the Japanese-shaped/Mesh-shaped bumper. At the same time, it takes up less space and is more design-friendly. Magna's five-cavity bumper has been mass-produced in multiple projects in North America, and we are very much looking forward to more and more applications in China. In addition to the five-cavity bumper, Magna also has other hot-formed bumpers, roll-formed bumpers, ultra-high-strength steel bumpers, various designs, and various technical applications.

What technical advantages does Magna have in door knocker products?

Kong: As early as 2014, Magna developed the industry's first door ring for customers in North America. After nearly a decade of development, we also have multiple thermoformed door ring mass production projects in China, including laser-welded door rings of different thicknesses and materials, as well as door rings using a single thermoformed material combined with local soft zone technology and patch plate technology. At the same time, we are also developing double door ring products, which have higher parts integration, greater weight reduction effect, and better safety performance.

Xu: The feasibility study and sample verification of Magna's integrated double door ring design have been completed in North America, and we are ready for mass production.

What are Magna’s main product application cases in high-pressure aluminum casting?

Kong: Compared with the complex body assembly of traditional stamping and welding, high-pressure cast aluminum is a very good lightweight solution. High-pressure cast aluminum has been widely used in body parts such as shock towers, longitudinal beams, fenders, and inner panels. At present, we also use high-pressure cast aluminum to reduce weight in subframes and battery housings, and these have corresponding mass production cases.

Magna's high-pressure aluminum die-casting machine is equipped with our patented vacuum system, High-Q-Cast, which can achieve thinner wall thickness and higher quality parts. In China, we have achieved mass production of high-pressure aluminum die-casting projects in 2015, and have rich experience in product design, process simulation, mold design, etc.

From Magna's perspective, how much room is there for lightweighting the body and chassis? What are the most critical issues to be solved in order to achieve greater lightweighting?

Xu: The ways to achieve lightweight body and chassis include materials, processes, and design. Magna has many years of experience in these areas and is still innovating. The mature engineering team can perform well in product design, process simulation optimization, mold design, etc. Of course, we will integrate market demand and discuss with customers to explore the best lightweight solution.

Based on our years of engineering experience, the timing of supplier involvement in a project is very critical. If we can participate as early as possible, we can provide customers with more lightweight design and optimized design ideas.

What are Magna’s thoughts and plans for integrated die casting?

Kong: Magna has been conducting research on large integrated die-casting. For example, we have heat-treatment-free die-casting materials and corresponding process technology reserves. At the same time, we have also developed a two-piece structure to replace the one-piece rear floor, which has the advantages of lower cost, better quality and better dimensional performance. We are also continuously discussing with customers to promote the layout of large integrated die-casting.

How much more expensive is aluminum than steel in some applications?

Kong: For example, Magna has high-pressure cast aluminum one-piece subframes and low-pressure cast aluminum one-piece subframes. Compared with traditional steel subframes, the cost of a single part will indeed increase to a certain extent, but the benefits generated are multi-faceted. It can not only achieve energy conservation and emission reduction of the entire vehicle and increase the driving range, but also greatly reduce the number of parts, welding points, and welding space because it becomes a single piece. The dimensional accuracy of the single piece will also be higher, and the design will be more flexible. Overall, the economic benefits of aluminum subframes will be better.

Will the integrated double door knocker technology be brought to China?

Xu: The feasibility verification and sample verification of the integrated double door ring have been completed. From a technical point of view, there is no difficulty in introducing it to China. We strongly recommend that customers contact us in the early stage of the double door ring project development, so that the design can adapt to the development process of the double door ring and adapt to the size of the existing hot forming heating furnace, press requirements, etc.

Current collision safety regulations have strict requirements for new energy vehicles. What challenges does this pose to the design of the vehicle chassis structure?

Xu: With the development of new energy vehicles, we have found that there is a trend that chassis parts, especially the front subframe, have more and more functions in a collision. Even the subframe has to bear a part of the energy absorption function, which is not conducive to the weight reduction of the subframe design. In addition, as the motors and related peripheral parts of new energy vehicles are becoming more and more complex, the design space left for chassis parts is also becoming more and more complex. All these have greatly increased the difficulty of chassis part design.

面对重重挑战，我们深耕底盘结构领域，并不断在产品和工艺上进行创新，持续为客户提供优质的底盘设计解决方案。目前我们已成功设计开发了多个新能源车型的前后副车架，并通过多种钢铝成型轻量化技术的应用达到显著的减重效果。

How does the integrated door knocker achieve cost reduction and weight reduction?

Hole: Traditional door rings are complex and large assemblies formed by welding multiple stamping parts such as the A-pillar assembly, B-pillar assembly, threshold beam assembly, hinge column assembly, etc. Thermoformed one-piece door rings can significantly reduce the number of parts, welding points, mold sets, welding stations and corresponding land occupation, thereby reducing costs and weight. In addition, the one-piece door ring can also improve the body rigidity and collision safety performance.

Are all the technologies mentioned in the live broadcast already installed in cars? Are they more suitable for some high-end models at present?