Aluminum has a reputation, in the welding industry, for being difficult to work with. Most times, to get a quality weld with solid penetration takes a lot of time in rework. Spencer Manufacturing can tell you a thing or two about this: The family-owned company designs and builds 20 to 25 customized fire trucks per year for municipalities across the US. It has clients as far away as Alaska and as close as their backyard in southwestern Michigan. Every vehicle is designed to fit the customer’s individual specifications. On a fire truck, nearly every square inch has to be functional, by housing firefighting gear and controls. Spencer has customized items as small as tool brackets up to changing the configuration of access so that no one has to step up onto the truck in order to reach for ladders and gear.
Beginning with a 3-D digital model, the frame is configured to the proper specification. Each piece of extruded aluminum tubing is cut and welded in-house. Next, the sidewalls are attached. This step presents the weld radius that has caused so much time in rework: where the sidewalls attach to the frame. On a flat surface, any pits in the weld could be filled in and painted over but, here, any type of filler would flake off with usage and weather. This edge has to be solid metal.
With the MIG equipment Spencer previously used, the actual welding took only minutes compared to the hours of grinding, routering and sanding to get a solid, paintable corner. “One truck, two walls, used to take 16 hours,” said Grant Spencer, head of the company.
Even with all this work, the company wasn’t highly confident about each of those welds. With the Fronius TPS 320i Compact welding system, however, Spencer has been able to reduce the time on this one application by 75 percent.
Spencer Manufacturing began working with the TPS 320i Compact just a few months ago. For this application the company is using primarily Synchropulse, a pulsed gas metal arc welding (GMAW) process.
The most significant time savings was in the reduction of rework. The TPS/i has spatter-free ignition and an intelligent arc that adjusts during welding according to set parameters. Overall there is less spatter, proper penetration and a good bead profile. The resulting seam is solid and requires little to prep for primer and paint. “With the new process, we can do both walls in four hours,” Grant pointed out.
Another advantage came from the smart design of on-torch controls. Spencer found these to be incredibly helpful when moving in and out of the framework. “With competing weld systems you have to move around to see your machine. Having the controls right on the torch saves time. No need to look at or mess with the machine.” The on-torch controls give the user the ability to change weld settings such as hot start, tac and crater fill. These features are especially handy for welding aluminum in order to get through the oxide layer and end the bead cleanly. The Fronius TPS/i also offers assistance to novice welders by using waveform control to make the process easier. This concept makes the welding system more versatile, allowing one machine to weld aluminum, steel or any other metal.
Spencer Manufacturing plans to exploit this versatility at its sister company, Haven Harvesters, which builds blueberry harvesters from both steel and aluminum. Haven works out of the same location – which is at the center of the blueberry capital of the world. The Harvesters have to be designed to endure rough field environments while handling the delicate berries. Steel holds up well in farming conditions, but it rusts and it’s heavy, which means sometimes equipment gets stuck in muddy fields. Aluminum harvesters have been tried before, but when they’re built in the same design as steel ones, they sometimes get ripped apart in the field.
But the Spencer family understands aluminum, “Aluminum flexes more and you have to allow for that,” Grant Spencer says. Haven expects to manufacture five harvesters this year.
With this additional work, saving 12 hours per fire truck was a muchneeded fix. Grant Spencer estimates they’ll be able to build an extra one to two trucks each year. “This means the fire-and-rescue vehicles will be on the road helping people sooner, and more communities can be served.”
“It’s one of those tools that, once you have it, you don’t know how you made it without it.”
Weld shop supervisor at Spencer Manufacturing speaking about their Fronius TPS 320i with Synchropulse.