Welding Advancements and Requirements
It’s no secret that vehicle materials have changed, and materials such as high-strength steel, ultra-high-strength steel and aluminum are being used more among several auto manufacturers to meet mandated fuel efficiency standards. But those materials are also driving numerous issues that technicians can’t afford to overlook, says Steve Marks, industry technical support manager at I-CAR.
Although the industry is currently focused on steel and aluminum, Marks says vehicles with dissimilar materials (aluminum, steel and carbon fiber) that need to be joined together will become increasingly challenging.
“Technicians are going to have to get knowledgeable at a variety of materials. And not only understanding the materials themselves, but also understanding the precautions and requirements when they start joining these dissimilar materials together. Almost every car company has a higher-end premium vehicle where portions of it will be steel and portions will be aluminum. That’s starting to be common,” he says. “We’re going to be training more and more to the aspect of hygiene while working on a structure. You need to keep everything clean and be aware of what you are mixing with what.”
Marks has spent much of his career working intensively with aluminum and steel welding training for I-CAR’s OEM programs. He breaks down the equipment and training your shop needs to have for modern welding.
Advancements in Welding
Vehicle materials are changing dramatically, and Marks says there are three materials your shop’s technicians need to be aware of and trained on to weld:
Steel. In the past, steel was mostly welded with a MAG welder to do plug welds or continuous welds. Marks says that, increasingly, today’s vehicles using ultra-high-strength steel also require resistance spot welding, MIG brazing, and more specifically, MIG brazing done as slot welds or open butt joints.
Aluminum. Even for those experienced in welding steels, welding aluminum alloys can present a challenge, says Marks, as higher thermal conductivity and lower melting point of aluminum alloys can easily lead to burn through unless welders follow prescribed procedures. Welding aluminum requires both special welders unique to aluminum repair—namely a MIG welder—and the the skill to weld precisely.
Silicon bronze. Marks considers silicon bronze the least understood welding process, mainly because it has numerous variables to it. While you can do the silicon bronze process in pulse, transfer and short circuit, Marks says in general, OEMs require silicon bronze be done in pulse. The reason techs need to pay attention and practice the MIG process with silicon bronze is that the process to do an open butt joint or slot weld is notably different than steel or aluminum welding.
Given those three materials, Marks says that the modern shop needs to have the following two pieces of equipment for welding today: an MIG welder capable of pulse, and the correct squeeze-type resistance spot welder. Collision repair organizations should consider the need for specific welding equipment against the OEM requirements given for the vehicle being repaired, he says. For instance, if vehicles being repaired have advanced materials, it is likely that the latest welding equipment will be needed in the facility to repair the vehicle as per the repair instructions.
MIG welder. There are many MIG welders on the market with an array of options, features, and levels of welding capability. If you are considering becoming an authorized collision repair facility for a specific vehicle maker network, Marks says the OEM will direct you on the specific machine, or machine specifications with which you will need to comply. In general, however, Marks says that it is best to go with a machine capable of pulse synergic welding.
From there, he says there are two main paths you could go down: Purchasing a welding machine that is capable of welding multiple materials or one that is always set up for aluminum and can simply be plugged in and used. The advantage to the latter, he says, is that you don’t have to switch the machine over.
“Typically many OEMs require a specific repair area for aluminum anyway, and they don’t like these machines to be taken from the clean room and then run out in the shop and back and forth,” he says. “Whether or not you’re in an OEM program, it makes a lot more sense to leave the machine set up for aluminum.”
If not, he says the other option is to buy a machine with multiple torches that works with multiple material types (steel, aluminum, silicon bronze). He says those are ideal for efficiency because it’s “a plug and play” and the machine does not need to changed over frequently throughout the day.
When it comes to concerns of the machine overheating, some machines have optional water-cooling systems that can be added to more effectively dissipate heat with continuous use. One downside to a water-cooling system is higher cost, Marks says, and possibly a more bulky torch and cable due to the water lines running through the torch and cable.
Another key decision is determining which wire feeding system and torch assembly best suits your shop. The most common OEM requirement is for 1.2mm electrode wire, which Marks says is to reduce the feeding problems that can happen with softer wires. There are also push-pull guns to provide more reliable electrode wire feeding that incorporate a set of drive rolls in the torch assembly that pull the wire in tandem with the drive rolls that push the wire to the torch. Because this system is more efficient, the torch cable can be made much longer than when only a push system is used. This provide improved mobility for the technician around the workspace.
Resistance spot welder. Whether or not it’s for a specific OEM, Marks says that the general direction on resistance spot welding equipment is higher power and more squeeze force.
“With today’s high and ultra-high-strength-steel, there will be more OEMs that will have specific areas of the car where they will require squeeze type resistance spot welding only,” he says. “With that requirement, we are talking about welding structural parts. So we need to make sure the joining is done perfectly and it has to be strong. We’re talking about a safety issue.”
Marks recommends looking for machines capable of putting out an increased amount of squeeze force and a considerable amount of higher amperage output. In general, those machines hitting OEM requirements are three-phase, 220-volt machines.
Addressing Electrical Concerns
One overlooked consideration when purchasing new welding equipment is getting adequate power to run the machines. Marks says that many shops are underpowered and the power grids throughout the country fluctuate dramatically. In particular, getting three-phase power with the correct amount of voltage can be a challenge.
The other common problem is the shop could be underwired. Marks says that if a shop was wired by an electrical contractor and it was wired according to code, typical electrical codes have a specific size of wire that will be used to run a set amount of amperage. Normally that’s OK, he says, but a resistance spot welder needs instant power very quickly and a high amount of amps. If the copper doesn’t have a large enough diameter or a large enough path for that large amount of electricity to go from the box to the welding machine, it will starve that machine of electrical power, especially if the plug is located farther away from the main box.
Before purchasing a new welder, Marks recommends both checking with the welder manufacturer and have an electrician come out to do some easy testing to make sure you have three-phase power and that it’s not underwired. If you do have electrical concerns, the electrician can put in heavier wiring or you can go with a single-phase powered machine.
“The important part is that you have enough power in your main box coming in from the pole,” he says. “What happens when a shop is underwired is that the machine starts running hot and it can start shutting off on you. The latest machines will shut down or give you an indication that the machine is not working correctly and you can at least stop and let the machine cool.”
Getting the Necessary Training
After purchasing new welding equipment, Marks says it’s imperative that technicians receive proper welding training, even if they’ve been welding for a number of years. That training could come from an organization like I-CAR, automakers, or welding schools, such as the Lincoln Electric program. I-CAR’S welding certifications have a five-year expiration, he says, but some OEMs require certification to be renewed sooner.
Regardless of how you obtain the training, Marks calls it one of the best training investments a shop can make. Any time a technician is performing a joining process, there’s an obvious safety issue there.
“We’re talking about holding the car together,” he says. “You’re giving the customer a vehicle that is safe.”
And, as far as efficiency, Marks says that when technicians are trained in the equipment and the techniques, they are able to understand when a MIG welder is working correctly or not, how to fix an issue when it’s not working correctly, how to keep it running correctly, when you should use specific consumables, etc.
“You’re kind of getting it all. You’re getting more efficient, you’re delivering a safe product to the customer and at the same time, you’re increasing the throughput of your shop,” he says. “It’s hard to find a downside to any of that training.”