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Lightweight Vehicle Structures: The Catalyst Of Change In Automotive Welding Technology

Aluminum is quickly dominating the DNA structure of some of the world’s most popular vehicles.

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Aluminum: performance enhancing, safe and environmentally friendly. It’s no surprise that it is quickly becoming a preferred metal among automakers around the world. From mass-produced sedans to luxury sports cars, aluminum is quickly dominating the DNA structure of some of the world’s most popular vehicles. But how does the use of this “new” metal affect the manufacturers and suppliers of these vehicles?

According to independent studies and research done by the Aluminum Transportation Group (ATG), aluminum is now second only to steel as the “most used material in vehicle production” and saves the equivalent of 44 million tons of CO2 emissions per fleet. It is clear that aluminum is transforming both the environment we live in and the landscape of technology and production in the automotive manufacturing industry.

Redesigning, Restructuring and Resizing

The increase in production of lightweight vehicles is causing manufacturers and suppliers to make significant changes to their welding processes. From the design to the technology, resistance welding guns are undergoing various structural changes to make them suitable for the assembly of aluminum alloy vehicles.

The current resistance spot welding techniques, normally applied to steel, now need to be transferred directly to aluminum alloy. However, more than double the secondary amperage is needed to weld aluminum due to its composition. This  causes manufacturers to reconsider design methods that have been the industry standard for many years.

Resistance welding components were increased in size for rigidity in order to increase the water flow for cooling purposes and to decrease deflection from mechanical and electro-magnetic field forces. Transformers, which supply power, also increased in size to the meet the higher amperage requirement of roughly 40,000 amps.

The actual welding contact surface, or electrode styles, underwent change as well. Common electrodes used for welding steel traditionally have small, flat contact surfaces. However, these are now being redesigned to have large, rough surfaces to help break through the oxidation on the surface of aluminum. This process must accommodate a higher frequency of tip dressing, up to 2.5 times more than standard steel.

As you can see, most of the gun design changes required to weld aluminum resulted in an increase in size, which means an increase in weight — something equipment manufacturers are trying to avoid.

Achieving the Right Balance: Light Yet Robust

Automakers, manufacturers and suppliers alike are all striving to achieve the same goal: Find materials that are light enough to provide better efficiency yet robust enough to provide the proper amount of safety and durability. Aluminum might be the favorite metal these days, but full aluminum body structures are most likely not here to stay.

It is expected that car manufacturers will act strategically moving forward by experimenting with the combinations of materials used to build vehicle bodies. High-strength steel, magnesium and carbon fiber are just a few of the potential power players, giving those of us in the automotive manufacturing industry an opportunity to redesign and improve our current welding equipment. We must be prepared to efficiently adapt to these changing materials and structures, while simultaneously providing high-quality products to aid in the manufacturing process.

The key here is to remain nimble and flexible enough to be able to adapt to new technologies, new materials and new manufacturing processes. The automotive world is ever-changing and constantly pushing the boundaries to create better, more efficient vehicles. And we, the “makers,” have to push alongside them to set the standards from the inside out.

About the Author: Jeff Beach is the General Manager with Detroit-based Milco Manufacturing. He is a third generation partner with over 20 years of experience in the resistance welding industry.

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