Job Shop Gets a Square Deal with Metal-Cored Wire

Specifically, the shop has been able to incorporate shorter lead times and learn how to operate the business at a lower capacity (typically, 60 to 80 percent), which acts as a fail-safe against unexpected demand. It also allows time for preventive maintenance and upgrades to the facility, all while keeping the company productive and profitable. “It’s important for us to stay as lean as we can,” explains Baatz. “If we run our shop at 100 percent capacity and have an unexpected request from a customer, we’d end up with late parts. We could easily lose a customer that way.”

Because the company is also on constant deadline, it has come to rely on another important facet of QRM: reducing non-value-added activities — tasks that don’t contribute directly to the company’s throughput. Three years ago, Morgan challenged Baatz to reduce the post-weld grinding portion of the company’s welding operations (a major non-value-added activity) and with it, the cost for purchasing grinding wheels. Recalling his discussion with a customer about metal-cored wire and its benefits, Baatz decided to try the technology as a means to address this challenge and keep improving the company’s operations. It worked, and then some.

JUSTIFYING AND IMPLEMENTING METAL-CORED WIRES
According to Baatz, the first step in trialing the shop’s welding operations with metal-cored wire involved a time study of the product in the manual welding cells. Because metal-cored wire costs slightly more per pound, he explains, it was critical that the company have a firm grasp on how the product could improve its welding operations in order to justify the conversion. They compared the results after the trial to the solid wire they had been using.

“We had to substantiate cost value versus time,” says Baatz. “We knew if we could find the cost value for the company that it’d be worth it.” By working with Hobart Brothers and Caminiti to trial and test the wire, Baatz quickly realized the value of the metal-cored technology. Not only did the trial show the potential for faster welding, but it also produced welds with less spatter than the solid wire the company was using previously, thereby reducing the need for post-weld grinding, as Morgan had requested.

The reason? Metal-cored wire’s unique physical and chemical attributes. Metal-cored uses the spray transfer process, which deposits tiny filler metal droplets in the weld puddle and generates little to no spatter. It also offers other benefits that Baatz saw right away. Because metal-cored wire consists of a hollow metal sheath filled with metallic powders, alloys and arc stabilizers, the current travels through the outside metal sheath. The result is a broad, cone-shaped arc that provides companies like Square Deal Machining with a wider penetration profile compared to the more finger-like penetration of solid wire. This arc shape also creates a wide, consistent bead profile that bridges gaps easily and accurately without burn-through.

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“We liked how broad the weld bead is,” states Baatz.  “It gives us good weld penetration, which helps our welders, especially new ones, make quality welds with proper fusion.” Caminiti adds, “We all really thought metal-cored wire was a good way for our shop to keep improving itself. We were confident it would provide Carl and his team with the quality they needed and make it easier to train his welders on the manual side of the operation.”

The trial of the wire also showed that it could provide the company with greater travel speeds and higher deposition rates. Combined, the benefits the company saw during the manual welding trial justified a conversion to Baatz and Morgan. The process of changing many of the remaining manual cells, along with the robotic welding cells, began.