General Motors Boosts Corrosion Prevention at New Assembly Plant

A new quality audit station in the body shop uses robotic laser scanners to produce a detailed color map of body assemblies for tolerance analysis. Image courtesy of Chevrolet.

General Motors (GM) is investing more than $1.4 billion into a 1.6 million ft2 (148,644.9 m2) expansion of its assembly plant in Arlington, Texas, USA, to improve the production efficiency and build quality of Chevrolet’s Tahoe and Suburban lines of sport utility vehicles (SUVs).

Among several measures, the Arlington plant expansion is aimed at enhancing the corrosion resistance of each automobile.1

The investment includes a new, 1 million ft2 (92.903 m2) body shop and a 600,000 ft2 (55,741.8 m2) expansion of the paint shop, along with new, high-precision camera- and laser-based inspection systems that offer more sophisticated quality checks.

Body Shop

According to GM, the body shop comprises the largest phase of the plant's expansion and upgrades. “GM uses the latest in assembly and quality-assurance technologies to assemble the Tahoe and Suburban bodies with exceptional precision,” the company says in its news release.1

New features of the body shop include:

• All-new robots—1,450 of them—including new six-axis robotic systems, which nearly doubles the number from the previous body shop;

• Automated vision-system-based dimensional and parts placement stations with cameras and lasers to locate body components for assembly and ensure dimensional accuracy prior to welding for proper gaps and flushness;

• Non-contact inspection systems to accommodate temperature fluctuations and other variables in the plant;

•Cameras and laser scanners to locate points in body panels that must be pierced for fasteners, contributing to more precise panel alignment during assembly; and

•A laser-based quality audit system that uses robot-mounted Leica scanners to quickly produce color maps of assembled bodies to ensure dimensional accuracy.

The body shop’s upgraded systems support the new body structure of the SUVs, which features an integrated front-end assembly that is welded to the rest of the body, rather than bolted on later in the assembly process. This improves the visual quality with improved flushness of the front-end body panels with the rest of the body, according to GM.

“The new body shop is ground zero for the quality built into the new SUVs,” says Mike Stevens, launch manager for Tahoe and Suburban. “It’s a stronger, more precise foundation on which the vehicles are assembled. With the all-new inspection technologies incorporated, we’ve taken quality control to an even higher level.”

Paint Shop

After leaving the body shop, the bare body assemblies are sent through the upgraded paint shop. The shop employs many new procedures and revised processes after the upgrade, including:

• A new “thin film” pretreatment process, which preps the steel and aluminum bodywork to accept paint. According to GM, this is a more environmentally friendly process than the previous method, which used more caustic material to etch the metal.

• After the thin-film process, the bodies are rinsed before being immersed in another tank for electro-deposition coating, commonly called Elpo or E-dip. This helps seal the metal for corrosion protection.

• The bodies move next to the underbody sealing station, which uses robots to precisely and consistently apply liquid material to the seams and body-panel overlaps on the bottom of the body assembly. This new procedure is designed to enhance corrosion resistance.

• A more environmentally friendly waterborne topcoat system replaces the solvent-based materials previously used in the paint shop. It also requires less time and less material than solvent-based paints, GM explains.

• Finally, vision-system cameras are used to verify various color and paint finish-quality characteristics.

A new quality audit station in the body shop uses robotic laser scanners to produce a detailed color map of body assemblies for tolerance analysis. Image courtesy of Chevrolet.

Because the front fenders and hood of each vehicle are now painted in line with the rest of the body, the integrated front-end assembly has a smoother overall appearance, according to GM.

“We are now able to perform a single, continuous paint application across the body,” says Benito Garcia, paint shop project lead. “The more consistent color spray-out creates a more consistent finish, from front to rear. It’s a big win for the paint-finish quality.”

Next Steps

The plant's enhancements are also supported by a new, nearby supplier park, which includes two industrial manufacturing and warehouse facilities. According to GM, this should enable a quicker turnaround for vehicle parts.

The changes will be incorporated into the automotive manufacturer's 2021 models, which will go on sale in mid-2020.

“This strategic expansion brings the latest in manufacturing and inspection technologies, while adding procedures designed to improve the quality and durability of the Tahoe and Suburban,” says Bill Kulhanek, plant executive director at the Arlington assembly facility.


1 “Latest Manufacturing Technologies Drive Production at GM's Updated Arlington Assembly Plant,” Chevrolet Pressroom, Dec. 10, 2019, (Jan. 20, 2020).

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