Corrosion resistant and lightweight, aluminum is ideal for hauling goods cross country. Trailers made from aluminum may cost more than steel ones, but users can haul more weight in them and spend less on maintenance. Since 2009, demand for lightweight trailers has nearly tripled.

In Huntsville, Tennessee, Great Dane Trailers wanted to tap into that market with a new all-aluminum trailer and boost production of parts for the combination steel-and-aluminum model.

Senior Manufacturing Engineer Howard Reeve says conditions called for new equipment. “People like them because they don’t rust, and they weigh less. So you can carry more weight on them. We’re trying to have greater market penetration in aluminum trailers, so we needed more capacity. Sales wanted greater capacity to fill orders by large customers.”

Soaring demand

Despite high-profile aluminum use in passenger vehicles, such as Ford’s F-150 or Chevrolet’s Bolt EV electric car, the fastest-growing user of the lightweight metal in ground transportation has come from the commercial side. Since 2009, aluminum shipments to trailer and semitrailer producers have grown at a 19.7% compound annual growth rate (CAGR) – far exceeding the 14.8% CAGR posted by cars and light trucks and the 13.5% CAGR noted for all ground transportation by the Aluminum Association trade group.

The plant had been using an aluminum milling machine designed to make screen doors to machine parts for the combination trailers, and a small volume of all-aluminum parts. However, Great Dane engineers had been looking for the proper machine for a long time. The milling machine was the tool they had, not the tool they needed, and Reeve says that the old, high-maintenance machine caused lots of problems.

Programmable logic controllers (PLCs) used a German-language operating system that employees didn’t understand. When the PLCs failed, replacing them required weeks to receive shipments. To avoid lengthy downtime, Great Dane had to stock several spares.

“It was a milling machine that never really fit the application,” Reeve says. The machine was intended for precise metal cutting, so it moved slowly. Front and rear cross members don’t need 20µm tolerances, they needed fast cutting times, he adds. “When you have tight tolerances, things fit better and last longer, but you need to set your tolerances to the part you’re making. It’s typically too expensive to have things milled in the trailer industry.”

New equipment

After meeting with C.R. Onsrud officials at a trade show, Reeve sent the machine maker several aluminum test pieces and asked for sample cuts. C.R. Onsrud Regional Sales Manager Ken Stissel says Great Dane had been considering a 4-axis machine for side milling and drilling of aluminum parts.

“After understanding the application and volumes, I was able to explain and justify the use of a 5-axis spindle. It would provide much more flexibility, less maintenance, and faster cutting,” Stissel says.

He adds that C.R. Onsrud engineers learned so much about the commercial truck and trailer market through projects with customers such as Great Dane that the tool maker developed its X-Series 5-axis CNC machine for that market.

Although it doesn’t use the X-Series, the 5-axis router that C.R. Onsrud supplied to Great Dane is faster than the milling machine it replaced, Reeve says.

After moving all of the parts that had been produced on the milling machine to the C.R. Onsrud router, Great Dane increased the number of parts produced per shift and still had capacity to insource parts it had sent to job shops in the region, paying off its equipment investments more quickly.

“We’re able to get very good products made on the new machine,” Reeve says, adding that the router isn’t as precise as the milling machine had been, but it’s the right tool for the job. As one plant manager noted, Great Dane makes trailers, not watches. “The biggest opportunity for the new equipment is insourcing parts that we were purchasing from machine shops.”

Partner relationship

A big factor in the success of the project, Reeve adds, is the similarity of the companies. Both are more than 100 years old, meaning they’ve learned to adapt to changing markets while maintaining reputations for quality and innovation. Location was important as well. Great Dane Trailer engineers and manufacturing managers from the Tennessee plant visited C.R. Onsrud’s North Carolina factory to see how the tools are made.

“I’ve never seen a cleaner production facility,” Reeve says.

Stissel says C.R. Onsrud engineers worked with Great Dane to identify as many opportunities as possible to move production from aging, expensive equipment to modern machines.

“I learned that Great Dane was looking for another machine to cut aluminum plate. I then showed them our twin table machine that would allow them to cut extrusions on one table and aluminum plate on the other table with little to no setup or changeover,” Stissel explains. “The machine has the flexibility to run extrusion or plate on either table. Great Dane liked the ability for them to run parts on one table while setting up the next job or part on the other table, without sacrificing downtime.”

Reeve says buying the router was justified by the reduced costs for the parts due to the machine’s higher speed. The lower price tag for the router helped with the justification, and he says if he factored in downtime reductions, cost savings would be higher.

C.R. Onsrud Inc.

www.cronsrud.com

Great Dane Trailers

www.greatdanetrailers.com

About the author: Robert Schoenberger is the editor of TMV and can be reached at 216.393.0271 or rschoenberger@gie.net.