The Power of Plasma: How Thermal Innovations are Impacting Lightweight Vehicle Manufacturing

Vehicle manufacturers need to drop a few pounds. Many times, it’s more than a few. After all, a vehicle’s overall weight can affect everything: its fuel efficiency, its emissions, and even its overall performance. And with emission reduction regulations becoming increasingly stricter across the globe, every pound goes a long way in helping automakers reach their targets.

It’s simple physics that a lighter vehicle requires less energy to move; even lightening a car by 100 kilograms can result in fuel cost savings of $1,040 over 200,000 kilometers. That’s less gasoline, less money, and fewer carbon emissions making their way into the atmosphere.

However, vehicle manufacturers need to reduce that weight without sacrificing strength and durability. And that presents a problem. Lighter materials can make welding and joining more difficult if they’re prone to warping or may not handle the heat as well as heavier materials. In other words, manufacturing lighter vehicles isn’t as simple as swapping out metals.

Let’s explore how today’s vehicle manufacturers are innovating the connections in sheet metal and what it might mean for the future.

The Challenges Auto Engineers Face When Connecting Sheet Metal

Variable Surface Conditions & Thicknesses

The increased use of aluminum in car bodies means that lightweight vehicle manufacturing needs to address the individual quirks of this metal. And, for example, with castings, the part’s thickness can vary depending on where you’re looking. If you were to open a cross-section of a complex part like this, you’d see an inconsistency that makes high-quality joining more difficult. And it can make it more difficult to know the parameters for your joint.

Cleanliness of Parts

You can’t properly weld dirty metals together. Good, clean parts are critical: contaminants like dirt, rust, or grease can lead to weak joints and adhesion. Without a properly clean weld, any gains you make in the vehicle’s lightweight features won’t measure up to the losses in strength and quality – same goes for gluing and soldering. If debris gets in the way, it can affect the weld pool, resulting in poor joining of the materials. Weak connections lead to a poorer reaction to stress, making the vehicles less reliable and prone to defects.

Access to Parts

Then there’s the problem of reach. Can professionals even access the parts during the manufacturing process? Do they have double or single-sided access? Even if you can get the double-sided access you need, it can throw metaphorical wrenches and add both time and cost, complicating the entire assembly.

Access limitations to target locations play a crucial role in selecting the most suitable manufacturing technology for a given application. Restricted space reduces the available technology options, potentially leading to higher costs and lengthy redesign periods if only one method proves viable. In such cases, single-sided solutions offer a significant advantage by maximizing accessibility and design flexibility.

Some Materials Are Difficult to Work With

Let’s say you’re working with high-strength and press-hardened steels. These metals may have additional durability and strength, but that durability and strength have consequences. They’re more resistant to cutting and stamping.

As a consequence, the toughness of these metals makes joining them more challenging. You can do it, but you may need specialized tools and techniques. Once again, it’s a problem that can add time and cost to the manufacturing process.

Ensuring Water and Gas Tightness

A good seal is watertight and gastight. This is critical for vehicle performance and basic vehicle safety, especially in the fuel system and electrical compartments. If you don’t properly join the metals, you’re asking for leaks and corrosion—and that’s not something any manufacturer wants to do.

Lack of Knowledge for Connecting or Fixing Materials

If only creating lightweight vehicles was as simple as swapping out materials. But as vehicle materials evolve, engineers can sometimes feel left behind. They may not know the latest techniques for joining new and advanced materials like lighter-weight alloys and composites.

That isn’t to say engineers will always be a step behind manufacturing innovations. But once again, any lack of experience with new materials can cost time, money, and energy in manufacturing. Engineers may have to spend training time getting up to speed.

The Math of Connection Strength

Vibration. Shock. Impact. The wear and tear of everyday use on the road. Every day a driver uses a vehicle, these dynamic forces put pressure on the vehicle’s connections. If you don’t build strong enough connections to handle these dynamic forces, it’s going to compromise vehicle performance. It may even put the basic safety of the vehicle at risk.

One challenge here is that engineers have to consider the force a connection can carry. This isn’t just a matter of calculating the maximum force, but how the connection’s durability may last under chronic stress.

Joining Dissimilar Materials

Steel, aluminum, and carbon composites aren’t always peanut butter and jelly. These different materials have different thermal, mechanical, and physical properties. A reliable joint has to take these different properties into account if it’s going to be strong enough for lightweight vehicle manufacturing.

Aluminum Can Be Difficult to Work With

Aluminum has plenty of positive attributes. It’s more affordable than other metals. It’s lightweight. However, it can sometimes be difficult to form and join with other metals. Tougher grades of aluminum—or aluminum parts that have complex shapes—will introduce all sorts of variables into the lightweight vehicle manufacturing equation.

The inconsistent surface conditions of aluminum necessitate additional treatments, including washing and passivation, before welding. These extra steps extend production time, add complexity to the manufacturing process, and reduce the anticipated cost savings associated with choosing aluminum materials.

Given all of these challenges, what are some ways to make lightweight vehicle manufacturing much more efficient?

Thermal Innovations and Their Impact on Lightweight Vehicle Manufacturing

SEF plasma-based solutions can address and even resolve a number of these issues. If a technique can safely and effectively bond lightweight materials, it makes it possible to build a reliable and durable product without heavier construction. SEF joining innovations can help overcome many of the challenges listed above.

But it also helps to get specific about how this is possible. Let’s look at a few thermal innovations and explore their impact on lightweight vehicle manufacturing:

• Tucker Plasma Riveting (TPR) integrates plasma technology with traditional self-pierce riveting (SPR), expanding the capabilities of SPR beyond its current limits. This innovation enables the joining of even stronger ultra-high-strength steel (UHSS) top-layer stacks with reduced force and makes it possible to assemble previously unachievable material combinations using SPR.
  As a result, lightweight sheet metals, including aluminum and mixed materials, can continue being joined without pre-drilling holes, now at tensile strengths up to 2,000MPa and thicknesses of 2mm. This not only reduces the setting force with no punch stroke but results in lower noise emissions and a more equipment-to-material-friendly process, ultimately enhancing durability and longevity.
• Tucker Plasma Joining (TPJ) is another plasma-based joining technique that offers a single-sided access solution. This technology employs “plasma pins” to penetrate the sheet metal, ensuring superior structural performance. By using plasma to locally soften the top sheet, TPJ enables the joining of steels with tensile strengths of up to 2,000 MPa without the need for a pre-drilled hole. This method creates strong and reliable bonds, even when joining dissimilar materials, enhancing the versatility and effectiveness of the process.
• Tucker CleanJet for Stud Welding also uses plasma, but largely to prepare the metal surfaces before stud welding. A plasma powered cleaning process, attached to the stud weld head is run just prior to the stud welding process to ensure an ideally clean surface. This delivers the same clean condition every time to guarantee a stable stud weld process and shores up the joint quality.
• Tucker Automated Cleaning (TAC) is a surface cleaning system for the sheet metals. It preps the surface for soldering, TIG welding, or adhesive bonding. Thanks to reduced spatter due to no oil or other contaminants on the surface, it can lead to less post-weld cleaning. The fun part here? The torch is mounted on a robot that can handle linear cleaning. This method ends up working as a “standalone” solution.

How do these innovations impact lightweight vehicle manufacturing? When incorporating lightweight alloys and aluminum, ensuring strong, durable bonds and joints is essential to withstand the demands of manufacturing and long-term consumer use. While reducing the vehicle weight remains a key goal, achieving it requires a comprehensive approach that prioritizes both material integrity and structural reliability.

With thermal innovations like the above in place, a lot of those hurdles are avoided. Solutions like TPJ and TPR make it possible to join materials that were previously incompatible, expanding design possibilities for next-generation vehicles. For example, you can improve your material compatibility, or the ability to handle mixed metals. But their benefits extend far beyond improved material compatibility. Consider the following advantages:

• Optimized Surface Preparation: Properly preparing metal surfaces enhances their readiness for joining techniques such as solder, TIG welding, or adhesive bonding. Since these methods require clean surfaces for optimal performance, a more efficient and comprehensive cleaning process directly benefits lightweight vehicle manufacturing.
• Enhanced Joining Efficiency: The enhanced scope of SPR technology adds new application capabilities throughout the vehicle, pushing beyond the standard limitations that would typically require specialized rivets and dies. For example, both TPR and TPJ offer significant advantages when joining aluminum castings, for example. The heat transfer involved in these processes facilitates the deformation of aluminum without causing cracks, making them particularly effective for F-state aluminum castings, which are increasingly prevalent in Body-in-White (BIW) design.
• Cost-Effective Manufacturing: Eliminating the need for pre-drilled holes and having an expanded portfolio of technology options to choose from makes lightweight vehicle production more economically viable. Additionally, better weld quality with reduced spatter minimizes the need for expensive secondary cleaning, further lowering costs and improving efficiencies.

Good thermal innovations make lightweight vehicle manufacturing not only stronger, but more practical in a business sense. The more efficient your joining processes are, the easier it is to make manufacturing affordable.

Bringing Thermal Innovations to Lightweight Vehicle Manufacturing

New technology is changing lightweight vehicle manufacturing, and it’s not always because there are new materials being introduced. STANLEY Engineered Fastenings’ thermal innovations for enhanced cleanliness and joining can make it easier to hold two lightweight metal sheets together, which gives you more options for manufacturing at a lighter weight without incurring additional costs. That means you can produce safe, reliable, and quality vehicle parts that place less carbon demand on the engines.