Abstract

The automotive industry is undergoing radical and disruptive changes to meet the net zero emission target by 2050, which dictates the need for holistic approach, encompassing sustainable product design life cycles, optimized manufacturing, and assembly processes. This has fueled the growth of more sustainable vehicles such as Hybrid, Battery, and Fuel Cell Electric Vehicles. Numerous studies have shown that aluminum usage in passenger vehicles has been growing for decades in the form of sheet metals, extrusions, and castings. Historically, castings have been the predominant product form mainly used in powertrains. But now with the need for lightweight, sustainable, and long range/fuel efficient Electric Vehicles, the usage of aluminum is extending to car body and chassis. New technologies are emerging and one of them is Giga-Casting, which is a process of making large and complicated casting structures in a high-pressure die-casting machine that injects molten aluminum into casting molds.

Note: Giga-Castings are also known as Mega-Castings, Large-Castings, Hyper- Castings & Large Integrated die Castings.

Chronological events of Giga Casting Development

Elon Musk “With our giant casting machines, we are literally trying to make full-size cars in the same way that toy cars are made”.

Introduction

Giga-Casting is transforming the automotive industry. Significant investments by global legacy OEMs and EV start-ups have developed the Giga-Casting process. These large cast structural components can integrate many different stamped sheet-metal parts into a single ultra-large casting.

As the world shifts towards electric vehicles and manufacturing optimization becomes more important, Giga-Casting will play an important role in shaping how cars are manufactured in the future. The global automotive industries have taken note of its advantages in terms of production speed, cost-effectiveness, and environmental impact. With all the benefits, they have certain limitations, as these massive Giga-Castings carry huge initial startup costs, may have distortion issues in the metal, alter collision- repair capabilities, and require extensive end-of-line inspection scanning.

Advancement of car body structure development

Reconfigurable Giga-Casting design

Giga-Castings are complex integral structural parts in the design of BIW. Designing complex casting parts involves several iterations to achieve optimized design solution. It is imperative to design them in a way that ensures their resilience subjected to various load cases. Designing complex casting parts involves several iterations in design parameters to evolve to optimized solutions. Giga-Casting with a ground up approach consumes significant design and development time. At the core, the approach is to use reconfigurable and parametric design framework which can be suitably modified to suit different vehicle body configurations for faster design and development time.

Parametric Design

The casting design framework is modelled parametrically to suit diverse sizes of passenger cars across various OEMs vehicle designs. The design of underbody giga- castings, despite variations among manufacturers, follows a standardized workflow,
facilitating the development of a generic design configuration. Independent generic frameworks are created for front and rear end Giga Cast design. These frameworks are reconfigurable, allowing rapid adjustments to accommodate diverse part geometries. Vehicle body structures of varied sizes varying from compact cars, luxury sedans to SUVs can be built with changes in key dimensions. Identifying key parameters influencing the performance of Giga-Casting is crucial and will significantly impact the structural behavior. Key dimensional changes of the parameters as shown in below image can be modified to suit Giga Cast part design for a variety of wheelbase and front track options.

Courtesy – Tesla Front underbody Giga-Casting

Modular approach

Incorporating modular elements empowers designers to effectively modify the template without the need for excessive design changes. The modularity not only simplifies the design process but also facilitates rapid configuration, reducing development time significantly. Designed with efficiency in mind, the framework incorporates quick-change mechanisms, allowing designers to make modifications swiftly.

Virtual Validation

Advance simulations play a transformative role to enhance vehicle body stiffness, reduce weight and enhance structural integrity to meet static/dynamic stiffness, NVH and crash requirements. Furthermore, use of Topology optimisation eliminates any unnecessary features or material, reducing both waste and cost.

Artificial Intelligence/Machine learning

The usage of AI/ML based product development methodologies. The process starts with training the ML Algorithm with simulation/ testing results as input. The trained model will predict the results for user requested data as shown in the fig below.

Extended reality

Taking it ahead through the effective use of Augmented Reality (AR), Virtual Reality (VR), and Extended Reality (XR), engineers and designers can interact with 3D models of products during the development stage. This innovative approach fosters enhanced collaboration among team members while simultaneously allowing for hands-on evaluation and design validation.

Summary and Conclusion

Early Giga Casting adoption offers a crucial edge over traditional methods. It lets you build lighter, stronger, and more efficient cars that resonate with environmentally conscious consumers. The solution proposed use of parametric and modular design approach, complemented by Virtual validation, Topology Optimization & usage of AI/ML mode and Extended Reality capabilities to offer highly optimized solutions in terms of lightweight design, resulting in reduced per-piece costs and shorter process cycles for part manufacturing.

Author – Vehicle Engineering & Design Team

References

1. Ducker 2022 Mega-Casting Trends for Automotive Manufacturers, Bertrand Rakoto.
URL: https://www.duckercarlisle.com/wp-content/uploads/2022/11/Mega-Casting-Whitepaper-May-2022-1.pdf

2. Akayuki Yao, Kazuhiro Noguchi, Sep 2023, Japan’s Aisin to adopt Tesla-style ‘gigacasting’ for EV parts,
URL: https://asia.nikkei.com/Business/Automobiles/Japan-s-Aisin-to-adopt-Tesla-style-gigacasting-for-EV-parts

3. Douglas A. Bolduc, Feb 2022, Volvo plans switch to Tesla technique to improve next-generation EVs,
URL: https://www.autonews.com/manufacturing/volvo-plans-switch-tesla-technique-improve-next-generation-evs