Magnetic Pulse Welding: Ready for Prime Time?

Development of magnetic pulse welding systems have been relegated to research & development groups at major OEM and Tier 1 suppliers (see: Marriage of Metals and Magnets), but Hirotec America (www.hirotecamerica.com) says it is ready to move the technology from the lab onto the production line with its C3 (clean, cost-effective cold welding) technology. The supplier has developed proprietary coils; additionally, it has partnered with Pulsar Ltd. (www.pulsar.co.il) to utilize the company’s MP-Weld systems to improve throughput and part quality. Magnetic pulse welding is a “cold” process; the materials are not melted. It utilizes electrical current which is passed through an inductor coil to create magnetic forces strong enough to accelerate the outer material toward the inner, creating a seamless weld. Providing the materials have high conductive qualities, the magnetic pulse process can be used to join dissimilar materials, including stainless steel and aluminum. “The ability to join dissimilar materials could help automakers reduce the weight of certain components, which could help when it comes to meeting CAFE standards,” says Michael Blakely, Hirotec America’s operations manager.

“I have heard people say that this process costs about a dollar per pulse, but that’s based on very old technology. Our coil is warranted for 50,000 pulses and can be used for as many as 75,000 and it costs about $2,000—or about four cents per pulse,” Blakely says. While the equipment needed to install a C3 magnetic pulse welding station is significantly more than gas metal arc welding, the process does not require filler materials or gas emission removal systems. What’s more, materials deformity is reduced while part quality is improved. Hirotec’s system is being utilized on an HVAC receiver drive application and manufacturing cycle times have been cut from 26 sec. on a two-pass system to less then 1 sec. on a single pulse cell, while rework rates have been slashed from 20% to nearly zero.

Magnetic pulse does have its limitations, especially when it comes to thicker grade materials, especially high-grade stainless steel. Using the technology on parts with complex forms also poses problems, since the electrical current does not flow evenly throughout larger dies. Still, Hirotec sees a number of unique application possibilities in the future, including development of a hybrid door beam made from aluminum that could be magnetically attached to the steel door structure, reducing weight. “We’re working with the research and manufacturing departments at some OEMs right now,” Blakely says, hinting Hirotec’s process may make inroads on several ’09-’11 vehicles.—KMK