Automotive Assembly – Gigacasting: The Next Big Idea in Automotive Manufacturing?

Traditionally, automobiles contain hundreds of structural metal parts that people never see. Whether it’s full front or rear underbodies, shock-tower modules or floor structures, they act as the “skeleton” of cars and trucks. Multiple components are riveted and welded together to form a safe, reliable framework and is covered with body panels.

However, automakers such as Ford, General Motors, Honda, Hyundai, Rivian, Tesla, Toyota and Volvo are rethinking that process. They are investing in new technology that enables them to produce large castings.

Tier One suppliers, such as Aisin and Ryobi, are also bullish on gigacasting. The goal is to consolidate parts, reduce complexity and eliminate weight.

A Big Idea

Gigacasting—also referred to as hypercasting, megacasting and unicasting—uses high-pressure aluminum die-casting to produce very large, single-piece structural components. It appeals to automotive engineers who are struggling to address the unique lightweighting challenges posed by electric vehicles.

Several companies make gigacasting equipment, including Bühler, IDRA and LK Machinery.

“Megacasting is an evolutionary step in die-casting,” says Michael Cinelli, head of product management and marketing at Bühler Group. “It uses the same fundamental physics, but applied at a dramatically larger scale, and with higher structural and quality requirements.

“It leverages ultra-large die-casting machines that generate between 6,000 and 9,000 tons of locking force,” explains Cinelli. “Megacasting relies on optimized alloys, advanced thermal management and integrated process control.”

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Bühler unveiled its first ultra-large press in 2020 as automakers around the world began demanding more efficient production processes to meet the requirements of next-generation vehicles. Since then, the company has sold more than 50 Carat series machines to a variety of OEMs and suppliers.

Designed specifically for gigacasting applications, the huge presses feature die locking forces up to 92,000 kilonewtons. For instance, the Carat 920 machine can inject more than 200 kilograms of liquid aluminum into a die within milliseconds.

“This approach simplifies manufacturing, reduces vehicle weight and improves structural performance,” claims Cinelli. “With fewer joining processes and less material waste, megacasting also supports more sustainable production. It is suitable for both traditional and electric vehicle architectures.”

Gigacasting (right) reduces assembly complexity. Illustration courtesy Tesla Inc.

According to Cinelli, gigacasting’s rise reflects a convergence of trends in the auto industry, such as maturing technology, market pressure and a more capable supply ecosystem. “The barriers were significant for years, and only recently have they been cleared, largely within the past five,” he points out.

“In short, megacasting required simultaneous progress in presses, tooling, alloys, simulation, and a compelling economic and architectural driver,” says Cinelli. “Those pieces only aligned recently, triggered by EV-focused manufacturing strategies and proven early implementations, enabling rapid adoption after decades of technical interest.”

“Several factors have only recently converged to make gigacasting feasible at scale,” adds Leonard Ling, senior analyst and automotive knowledge manager at Ducker Carlisle Worldwide LLC. “The introduction of ultra-large presses, combined with advances in high-strength, heat-treat-free aluminum alloys, now allows for large, dimensionally stable castings.

“EV architectures offer more flexibility in underbody design and benefit significantly from reduced weight and simplified assembly,” notes Ling. “In contrast, traditional ICE platforms and legacy tooling investments made such large integrated castings uneconomical in the past.

“Gigacasting delivers meaningful structural and cost advantages,” claims Ling. “It can dramatically reduce part counts, welds and assembly operations, while improving dimensional accuracy. Fewer joints and more uniform load paths enhance stiffness and crash performance.

“For EV manufacturers, simplification means faster platform development, lower capital intensity and weight savings that translate directly into extended range,” says Ling. “The process also supports local manufacturing, as large castings are often produced adjacent to final assembly plants, cutting logistics costs and emissions.”

New Production Philosophy

In North America, Tesla has been the only high-volume adopter of large, high-pressure die-casting, using it on the Model 3, Model Y and Cybertruck.

“Ford and GM are moving in that direction and have sourced giga-press equipment, but remain in early deployment phases,” explains Ling. “European automakers are more cautious. Volvo is the clear front-runner, investing heavily in megacast rear floors for its next-generation EVs, while most German OEMs are still running pilots.

“Asian automakers, particularly in China, are advancing the fastest,” Ling points out. “BYD, Geely/Zeekr, Li, NIO and XPeng, among others, already use gigacast front or rear modules and battery housings in production, with some experimenting with casting nearly the entire underbody.”

Megacasting disrupts decades of a “we always do it this way” mindset in the auto industry.

“For legacy automakers, integrating gigacasting into existing plants remains a hurdle, requiring reconfiguration of body shops and balancing new investment with existing stamping capacity,” says Ling. “Beyond the press itself, gigacasting depends on a complete casting ecosystem. That includes large melting and holding furnaces, vacuum systems to control porosity and tight temperature management throughout the process.

“Heavy automation handles ladling, part extraction and trimming, along with localized heat treatment or quenching where needed,” explains Ling. “Quality assurance is equally critical. High-end X-ray or CT scanners, ultrasonic inspection, dimensional measurement cells and straightening systems are all required to monitor and correct defects or distortion in these massive structural parts.”

While it is technically feasible to convert traditional automotive body shops to gigacasting, it’s far from a plug-and-play process.

“A conventional body shop built around hundreds of stamped panels and weld points must be re-engineered to accommodate a handful of very large castings instead,” says Ling. “That means new fixtures, updated joining methods, such as bonding or hybrid welding, and reconfigured conveyors and handling systems for heavier parts.

“Complete revalidation of crash and corrosion performance is also necessary,” notes Ling. “In addition, repair networks need retraining.

“In practice, OEMs can adapt portions of an existing body shop, but full integration of gigacasting usually aligns better with a new EV platform or major retooling effort rather than a retrofit,” warns Ling.

Automakers and suppliers are investing in high-pressure machines that enable them to mass-produce large castings. Photo courtesy Bühler Group

Parts Consolidation

One of the biggest advantages of gigacasting is its ability to consolidate parts and eliminate time-consuming assembly processes. That enables engineers to replace complex stampings with single, cast structures by combining geometry, functions and interfaces.

“Engineers can integrate multiple sheet metal stampings into one net-shape component,” says Bühler’s Cinelli. “Cast-in ribs, bosses and flanges replicate stiffness and joining features previously created by separate brackets and reinforcements. Overlapping panels, hem flanges and spot-weld seams can be eliminated by using continuous wall sections and local thickening.”

Functional features that previously needed add-on parts can be embedded, such as:

• Mounting points—cast threaded bosses or machined pads for suspension, seats, batteries, crash rails and power train mounts.
• Joining features—lap/plug-weld zones, adhesive channels and self-piercing rivet landings, reducing separate reinforcements.
• Cable and pipe management—cast clips, channels and through-holes for wiring harnesses, brake lines and coolant lines.
• NVH features—stiffening beads, rib lattices and tuned thickness transitions can be used instead of separate braces.

In addition, engineers can consolidate crash structures and load paths. Design ribs, crush initiators and energy-management features can be integrated directly into castings to replace multiple boxed sections and add-on crash brackets. Shock towers, subframe attachments and load transfer nodes can be combined into a single underbody and front or rear module.

Subassemblies can be reduced through interface integration. Floor pans, crossmembers, rocker reinforcements, and rear rails can be combined into one casting, minimizing fixture sets and welding sequences. With cast-in datum features for body alignment, fewer locator brackets and machining fixtures are needed.

According to Cinelli, engineers can leverage localized thickness and tailor topology. “Variable wall thicknesses, gussets and lattice ribs can be used to place material only where needed—replacing stacked stampings used for stiffness,” he points out.

“Conformal cooling and precise filling allow thin walls in low-load regions, avoiding extra patch panels,” adds Cinelli. “Fasteners and sealers can also be minimized, because continuous-cast walls remove many lap joints, reducing seam sealers and mastic pads.”

This sport utility vehicle made in China features gigacast subassemblies. Photo courtesy XPeng Inc.

Gigacasting Applications

Tesla Inc. pioneered automotive gigacasting several years ago. The automaker used the technology to produce front and rear underbodies on the Model Y sport utility vehicle, sharply cutting part counts and welds.

Tesla engineers adopted large megacastings to produce a three-piece chassis that consists of a structural battery pack sandwiched between front and rear castings. The massive components eliminated more than 350 stamped steel parts, including brackets. Megacasting also enabled Tesla to reduce the size of its body shop.

“The front casting includes the left and right shock towers, the wheel arch, the crush can for the front bumper, and the left and right door hinge pillars,” says Cory Steuben, director of cost engineering at Lucid Motors who previously participated in several tear downs of Tesla vehicles when he served as president of Munro & Associates. “The rear casting is even longer.

“Castings are like stones,” explains Steuben. “They provide amazing structural rigidity, because they don’t flex like many types of stamped steel subassemblies. They are attached to the rest of the vehicle with threaded fasteners and structural adhesives.”

Tesla engineers pioneered gigacasting technology. Photo courtesy Munro & Associates

Engineers at other automakers have also been intrigued by the potential of megacasting. They see it as a key enabler in the quest to produce a $25,000 EV for the mass-market.

Rivian Automotive Inc., for instance, has announced that its next-generation R2 platform will employ large structural castings for the underbody. In fact, by using the technology throughout the vehicle’s body structure, the automaker expects to eliminate 50 metal stampings and get rid of more than 300 joints.

Ford Motor Co. plans to use gigacasting as part of the Universal EV Production System that it’s in the process of installing at the retooled Louisville Assembly Plant. The technology will form the backbone of its Universal EV Platform, which will feature a structural battery pack sandwiched between a front and rear structure.

“Large single-piece aluminum unicastings [will] replace dozens of smaller parts, enabling the front and rear of the vehicle to be assembled separately,” says Jim Farley, president and CEO of Ford. Farley predicts the new process will reduce parts by 20 percent vs. a typical vehicle, with 25 percent fewer fasteners, 40 percent fewer workstations and 15 percent faster assembly time.

Honda Motor Co. engineers are also bullish on the potential of gigacasting. The automaker recently installed six Bühler Carat 610 presses at its engine plant in Anna, OH. The machines are producing two-part battery enclosures that will serve as the main frame structure for the floor of next-generation Honda and Acura EVs. The front and rear sections are joined together using friction stir welding.

In addition, Honda is conducting extensive research at its technical center in Tochigi, Japan. Engineers are experimenting with different casting conditions and parameters, such as temperature, pressure, speed and cooling rate.

Large front and rear castings may be used in more vehicles in the near future. Illustration courtesy XPeng Inc.

Numerous Challenges

Despite lots of hype and promise, gigacasting has several disadvantages over traditional automotive production processes. Some of the biggest hurdles, for instance, involve finding materials that can be formed and joined reliably.

Other challenges include keeping large thin-walled parts dimensionally stable, maintaining consistent casting quality and using tooling that holds up while still allowing quick changeovers.

“Casting has been around forever, but defects and stress concentrations are always a challenge,” warns Dilip Banerjee, Ph.D., a research engineer who specializes in mechanical performance at the Center for Automotive Lightweighting at the National Institute of Standards and Technology. “Die-cast parts must also be able to absorb the energy of impacts that can occur during vehicle crashes.”

Crashworthiness depends on smart designs. Specifically, how cast ribs, joining zones and alloys are engineered for ductility in as-cast form.

“Uniform cooling is critical, because during solidification the composition can change,” explains Banerjee. “Microstructures are prone to porosity caused by bubbles or voids, which can lead to ductility problems. High-quality, pore-free castings are essential to avoid thermal destruction.”

“Gigacasting brings new challenges in equipment cost, die durability, quality control and repairability,” adds Ducker Carlisle’s Ling. “Machines above 6,000 tons require significant infrastructure investment and extremely precise process control to avoid porosity, distortion or cracking.

“Tooling and dies are expensive, each costing several million dollars and requiring frequent maintenance,” says Ling. “That means that gigacasting is more economical for high-volume vehicle programs where costs can be amortized across large production runs.”

Gigacasting presses enable automotive engineers to consolidate parts, reduce complexity and eliminate weight. Photo courtesy Bühler Group

Ling believes that broader adoption in the auto industry will depend on continued progress in several areas, including:

• – Capital investment. “Giga presses, auxiliary systems and facility modifications represent multimillion-dollar commitments, still a barrier for many automakers and Tier One suppliers,” says Ling..
• – Material development. “Current alloys often carry licensing costs and patent limits,” explains Ling. “Many OEMs are developing proprietary alloys that balance strength and ductility without post-casting heat treatment.”
• – Production flexibility. “Gigacasting equipment is specialized for a limited number of large parts, which can constrain flexibility across multiple vehicle platforms,” notes Ling.
• – Process reliability. “Improving die-life management, dimensional control and nondestructive inspection remains key to consistent mass production,” Ling points out.
• – Sustainability. “While gigacasting minimizes material waste, it is energy-intensive, warns Ling. “Closed-loop recycling systems for complex aluminum alloys will be essential to making the process truly sustainable.”
• – Market dynamics. “If EV growth slows or shifts geographically, OEMs may hesitate to commit to capital-intensive infrastructure,” says Ling.

“For legacy automakers, integrating gigacasting into existing plants remains a hurdle, requiring reconfiguration of body shops and balancing new investment with existing stamping capacity,” concludes Ling.