The electric car manufacturer Tesla registered a patent for mega-casting in 2018.With this new production method, it should be possible in the future to produce a body in one production step in aluminum die-casting without subsequent heat treatment.The approach is contrary to the established body construction.What does mega-casting mean for the automotive industry?A team of experts from the WZL machine tool laboratory at RWTH Aachen University examined the opportunities and risks of mega-casting in a SWOT analysis.Figure 1. Classification of the "Mega-Casting" body construction method and its concepts with exemplary OEMs and models within the framework of established body construction methods (own contribution).Framework and partial representations based on Birkert et al.[3], Stellantis [14], Land Rover [15], Tesla [5].‧Graphic: WZLIssue 9-2022, p. 580, DOI 10.37544/1436-4980-2022-09-52Abstract: The electric car manufacturer Tesla granted a patent for Mega-Casting in 2018. This new manufacturing method should make it possible in the future to produce a car body in one process using aluminum high pressure die casting (HPDC).The approach is contrary to the established body shop.What does mega-casting mean for the automotive and supplier industry?A team of experts from the Laboratory for Machine Tools and Production Engineering (WZL) at RWTH Aachen University has examined the opportunities and risks of Mega-Casting in a SWOT analysis.In the course of electromobility, the established automobile manufacturers, also known as Original Equipment Manufacturers (OEM), have to realign their production and face up to competition with new market participants.New and established market participants have the opportunity to completely rethink their corporate structures and to take new manufacturing processes into account.With regard to the body, the self-supporting shell construction made of steel is the most common body construction, but for years there has been an increasing use of aluminum die-cast components in structural mixed construction, since the number of parts can be reduced here without using more material [2 , p. 15].In addition, complex geometries and shapes can be created using cast components, for example in the spring strut support [3, p. 6].With mega-casting, Tesla wants to herald the next step in large-format aluminum die-cast components.In the future, body components, for example the front end or even entire bodies, are to be manufactured in one piece.With patent applications, Tesla has shown the vision of rethinking vehicle production [1, p. 1;4, p. 3].This article shows how mega-casting is to be classified in the overall picture of the established body construction methods, which mega-casting concepts are conceivable and which product and production-side opportunities and risks can exist with mega-casting.Historically, the first body construction was the so-called frame construction, which was still based on the wooden chassis of the carriage.The further development for the first motor vehicles was the ladder or tubular frame made of steel or aluminum, on which sheet metal components for the outer skin could be mounted.In Figure 1, this type of construction can be assigned to the structural and material mixed construction, for example in the form of today's "Al space frame" (for example the Audi A8, which has been built in this way since 1994) [3, pp. 8-14].With the self-supporting shell construction, deep-drawn sheet metal components are joined together in a complex structure and thus form a load-bearing overall structure.The body takes on tasks such as connecting the outer skin components, the static and dynamic behavior of the body and crash properties.The classic shell construction can be divided into steel (e.g. VW Golf) and aluminum (Honda Acura NSX from the 1990s) (Figure 1).Mixed construction is the third basic body construction method. It can be used either as a combination of steel and lightweight materials (e.g. aluminium) as a material mixed construction (example Audi A6), or as a structural mixed construction in which the shell construction is combined with other body constructions (example frame construction ) is combined (e.g. Jaguar F-Type) [3, pp. 8-14].Due to the currently extensive developments in the aluminum die-cast-dominated body construction, the focus will be placed on this below.Tesla's patent on Mega-Casting describes the invention of streamlined production of fully die-cast vehicle bodies.By using a specially developed die-casting machine with five-sided tool guidance, the production time should be reduced and operating, production and tool costs reduced [1, p. 1].With the die-casting machine "Gigapress" from the Italian manufacturer Idra, the patent idea was partially implemented in practice for the first time and is intended to set a new standard for future body construction methods.If Tesla has its way, in the short term the body will consist of three large-format aluminum die-cast components: the front, middle and rear end [5, min 46:56-48:54] and will in future be made from a single cast [1, p. 1 ].There is also another Tesla patent that includes an aluminum alloy for the specific needs of mega-casting.This should have improved properties in the areas of strength, ductility and castability for high-performance applications without the need for subsequent heat treatment [4, p. 3].Another Tesla patent describes how the crash energy can be absorbed and dissipated in the areas of the mega-casting components [6, p. 3].However, the use of die-cast aluminum in car bodies is by no means new.Structural components made of die-cast aluminum were used for the first time in 1994 in the Audi A8 [3, p. 9] or, for example, in the damper console of the Mercedes-Benz S-Class in 2013 [7, p. 55-61].The new body construction method "Mega-Casting" can be classified as a further development of the structural hybrid construction method in Figure 1 due to the more intensive use of aluminum die-casting.According to recent news, Mega-Casting was used by Tesla in a structural battery pack in addition to the front and rear of the Tesla Model Y at the Gigafactory in Texas [8], hence this model in Figure 1 in the top half of the Mega-Casting Concepts is classified.Volkswagen (VW) wants to use the mega-casting for the e-mobility project "VW Trinity" [9].Volvo has also announced that it will use mega-casting primarily in the rear end of e-cars, but without specifically naming which models are involved [10].Mercedes Benz (MB) has indicated the use of mega-casting (MB calls it bionic-cast) in the rear of the EQXX [11, p. 2].Chinese OEMs are aware of the use of mega-casting at XPeng (also called Xiaopeng Motors), Nio [12] and Human Horizons (HiPhi model), and there are speculations about the use of mega-casting at Xiaomi and Li Auto.At Nio, a mega-casting component is to be used in the rear section of the underbody in the ET5 [12, 13].In principle, all mega-casting concepts can be assigned to structural hybrid construction (compare 5 in the middle of Figure 1), since they all combine large-format aluminum die-cast components with conventional shell construction.A key feature of the respective mega-casting concepts is the overall proportion of die-cast aluminum and thus the successive replacement of the respective other body construction.To classify the car body construction methods, several concepts were identified as part of the investigations at the WZL and summarized in Figure 2: the 1+3 piece, the 2+2 piece, the 3+1 piece, the 1+1 piece and the 1 (+0) piece.Figure 2. Classification of the mega-casting body construction method into five concepts with an increasing proportion of the use of die-cast aluminum (1+3 piece to 1 (+0) piece).Graphic: WZLThe digits of the concept designation indicate the relationship between the use of mega-casting (first digit) and the supplementary body construction, e.g. the shell construction (second digit) in the assembly stages of the body.A distinction is made here between the front end (VW), the middle end (MW), the rear end (HW), the undercarriage (UW) and the superstructure (AB).With the 1+3 piece, either the VW or the HW is manufactured and with the 2+2 piece, both are manufactured using mega casting, with the MW and the AB connecting the mega casting components in a classic shell construction [5, min 46:56 -48:54].In the case of the 3+1 piece, the MW/structure battery pack housing is also produced using mega-casting, while the AB continues to be produced using the monocoque construction.Likewise, with the 1+1 piece, the AB is made in a shell construction, while the UW (incl. VW, MW and HW) is made from a single aluminum die-cast component.With the 1 (+0) piece, the entire body is to be cast in mega casting.Since Tesla published patents, more and more companies have been dealing with mega-casting (Figure 3) and consider the new body construction method to be a serious alternative to conventional vehicle production.Figure 3. Types of companies and examples in the field of mega-casting in the automotive process chain and supplier pyramid (TIER).Graphic: WZLIn addition to the OEMs already mentioned, the die casting machine manufacturers Idra Group Ltd.(“Gigapress”) [16], Bühler AG (“Carat 920”) [17] and LK Group (“Dreampress 9000T”) [18] on their websites with cold-chamber die-casting machines for mega-casting.For example, the Handtmann Group [19], a supplier of system components for the automotive industry, bought a Bühler machine.Idra shows on its website that 23 Gigapress have already been sold [20].In addition, supplier companies such as Fuchs Petrolub SE [21] are already working on lubricants, or the company Magma [22] on a virtual process chain for mega-casting.In the area of ​​joining technology, Atlas Copco addresses mechanical joining with rivet connections, which could be used for joining mega-castings [23].As a new body construction method, mega-casting has a potential impact on product and production design, from the press shop to body construction and assembly.But what exactly can this influence look like?The authors of this post have examined the opportunities and risks of mega-casting.For this purpose, six SWOT analyzes were carried out in the "Mega-Casting" project team of the machine tool laboratory WZL of the RWTH Aachen University after an exchange with experts [24].Each of the six members of the project team carried out the SWOT analysis independently and the results were then consolidated in Figure 4.The classification was based on the product "body" and the production "vehicle production" from the OEM's point of view.Figure 4. Product and production-side SWOT analysis of mega-casting in vehicle production.Graphic: WZLA weight of around 260 kg can be assumed for bodies based on the conventional hybrid construction of a mid-range car [25].Wall thicknesses of at least 0.7 mm are necessary, whereas 2 mm to 3 mm was assumed for die-cast components [26].This roughly corresponds to a factor of three.The density ratio also differs by a factor of three from steel to aluminum [19], which roughly balances out the potential for lightweight construction and can therefore be evaluated neutrally in a first approximation.Due to the greater minimum wall thickness and the change in structure to an open-shell design, new challenges in the area of ​​operational and crash strength are imminent [6].At the same time, a reduction in product complexity can be expected, since the small parts in the body are reduced by large-format die-cast components.The large and complex die-casting tools presumably at least reduce the number of variants of the die-cast body assemblies.In the case of the “body” product, the reduction in the number of components is seen as an opportunity, since it is associated with the complexity and number of joining operations to complete the body.By using a new, patented aluminum alloy, the product can do without heat treatment [4].In addition, functions could be integrated into the body, such as battery storage or connection points that were previously implemented using welded studs.The risks include a limited variety of variants and the change management of the product due to the complex tools.Process advantages in mega-casting or aluminum alloys in turn result in the opportunity to make better use of the potential for lightweight construction.In addition, higher value retention could be achieved more easily through recycling in the life cycle, since the variety of materials and the many complexly joined individual components is reduced compared to a classic mixed construction (see Figure 1) and local recycling of defective mega-casting components is already possible in the casting plant is established.Risks or weaknesses include crash performance, since the design options are limited in terms of material (aluminium) and die-casting process (e.g. wall thickness or draft angles).Furthermore, inadequate repair solutions in the event of damage due to the lower deformability and the lack of the possibility of replacing defective areas of the large-format die-cast components are to be assessed as disadvantages.When considering electric vehicles, for example, the functional integration of the battery storage follows.In addition, the manufacture of battery pack housings could be modified to cast larger, more complex battery pack housings or to produce several smaller ones in one run.When considering the production "vehicle production", the first part of the process chain changes in relation to the press shop, body shop and post-processing.First of all, the resource and logistics management has to be adjusted, since the advantage arises primarily when the entire body is manufactured at an OEM location.As a result, significantly higher quantities of aluminum are required locally and this results in higher logistical procurement costs.Since the body consists of one or more large-format aluminum die-cast components, the number of joining operations is significantly reduced.Joining aluminum is more challenging than joining steel, for example.In addition, there must be accessibility to the joints that are still required, even with large individual components such as a rear end, so that as few interfering contours as possible have to be taken into account in the design process.However, the handling (e.g. when removing it from the die-casting machine) and the post-processing also change with the size of the component.This includes manufacturing processes with high precision, for example for trimming the components and introducing functional surfaces and connection points.In the area of ​​vehicle final assembly, on the other hand, there should not be any major changes, but new assembly sequences are conceivable here, such as the pre-assembly of part of the interior equipment on the battery pack.When considering the design process, change management becomes significantly more complex due to the large and complex tools and the early determination of welding studs, which previously could be modified in body construction, for example, as connection points.Thus, the development and toolmaking can be seen as a significant challenge in mega-casting.One of the strengths and opportunities is the reduction of complex automation and process technology in body construction, which goes hand in hand with the reduction in components.In addition, an increase in added value at the OEM and reduced space, cycle times and investment costs with the "green field approach" are counted among the opportunities.Decreasing or changed logistics, the change in competences at suppliers and OEMs and the objective of achieving corrosion resistance of the components with as little effort as possible were rated as risks.In terms of mechanical engineering, the large die-casting machines required for mega-casting could reach their physical limits, but this has often been overtaken in the past.Other weaknesses and risks are the lack of know-how about mega-casting components, the dependence on "one" technology, company and the raw material aluminum.In addition, there is a risk of a shift in competence and complexity due to the change from press shop and body construction processes that have been established for several decades to a highly complex die casting process.This, in turn, also creates opportunities: On the one hand, mega-casting is a highly complex die-casting process that requires highly qualified personnel and can therefore create jobs in high-wage countries like Germany.On the other hand, sufficient component quality must be achieved in combination with a low scrap rate.Mega-Casting is a new body construction method that can differentiate itself from established construction methods in terms of production and the use of materials.Since Tesla filed patent applications in 2018 and the constant practical application, other OEMs and suppliers have also increasingly been dealing with mega-casting, including Volvo and Volkswagen, which have published concrete plans for this.In the future, mega-casting has the potential to play a crucial role in vehicle production.A SWOT analysis shows: By constructing the body as a single component, a reduction in cycle time and complexity can probably be achieved.At the same time, however, mega-casting also creates new challenges in terms of crash performance and repair solutions.For the production process, concepts for production, machines and resource management must be further developed.In addition, die-casting machines for such large components (e.g. 1(+0)-piece concept) must be developed with high qualitative reliability.In order to develop the necessary concepts, we are in close contact with experts from research and industry to identify the potential and enable mega-casting.Specifically, a consortium study and an online survey on trends in vehicle production with a focus on mega-casting is currently planned.The impact analysis on the supplier industry has also been completed and will be published promptly.* This article is a technical paper that has been peer-reviewed and approved by experts in the field.Falko Fiedler, M.Sc., IWE Prof. Dr.-Ing.Dipl.-Wirt.Ing. Günther Schuh Dr.-Ing.Georg Bergweiler Leonhard Dworog, B.Sc.Machine tool laboratory WZL of the RWTH Aachen University Campus-Boulevard 30, 52074 Aachen Tel. +49 160 91794274 f.fiedler@wzl.rwth-aachen.de www.wzl.rwth-aachen.de www.anlauffabrik-aachen.deDie-cast aluminum bodyFlexible automation with virtual agentsCookies are also used on this site.We can use it to evaluate page usage in order to display usage-based editorial content and advertising.This is important for us, because our offer is financed by advertising.Use of the site is considered consent to the use of cookies.Further information