Air conditioner producer Trane, a unit of Ingersoll Rand, drives lean manufacturing principles deep into its operations, touching every process, every pair of eyes and every pair of hands on the manufacturing floor. The company says that, on average, a Trane air conditioning unit is installed every minute of every day. And, transporting manufacturing components and parts to the right workstation at the right time has driven the company to find customized material handling aids to keep the air conditioner production line flowing like cool air on a hot day.

“We are using lean projects to tighten up and take advantage of efficiencies in our manufacturing operations,” explains Bruce Pate, an industrial engineer in Trane's largest facility in Tyler, Texas. The Tyler plant for Trane Residential Systems employs 2,000 people and manufactures condensing units for air conditioners.

Pate says he and his colleagues have put material handling on the manufacturing floor under the microscope. “We knew we could improve the flow of materials in our manufacturing process, so we pulled together a lean event to dig into the issues,” he says.

During their continuous improvement (kaizen) events, the cross-functional teams of salaried and hourly employees attacked the problem by identifying ways of saving floor space, combining jobs and streamlining the movement of components and parts. Pate says his teams continually identify ways to smooth out inefficiencies in the plant's five assembly lines that sometimes experience material shortages and interruptions.

“We've created a central supermarket of components and parts, with a highly efficient ordering and replenishment system,” Pate notes. “We figured out that, with a components supermarket, we could save time, avoid delays and transport exactly the right pieces to the right line at exactly the right time.”

And, that's no small feat for a facility churning out 5,000 air conditioning units per day.

Ergonomically Correct

The Trane lean teams also faced another task — how to get those thousands of types and lengths of tubing, suction discharges, parts and components to each manufacturing station.

Fortunately, Trane managers anticipated the challenge and invited material handling experts from two firms to participate in a lean event to assist with design and implementation of the cart needed to transport materials on the manufacturing floor in Tyler. One of them was Ryan Metzdorf from material handling equipment manufacturer Valley Craft. The fact that Metzdorf was invited to the lean event exemplifies Trane's partnership approach with its suppliers.

“Our team evaluated the unique needs of each line, including ergonomic assessment and load requirements,” Pate points out. “When we got through, we had a concept for a customized cart that could carry enough product to the lines that would keep them supplied in an ergonomically correct method and in a timely manner.”

Valley Craft was chosen to manufacture the carts, through its Ovation custom manufacturing service. Trane requirements were conveyed to the Ovation team in Minnesota, which produced conceptual sketches and 3-D images of the proposed carts. Interaction between the Trane and Ovation teams led to prototypes that were studied and fine tuned, and finally to production of the carts using Ovation's own lean manufacturing process.

“The first cart made was for a coupled route where the carts stay attached to a tugger. The supply train stops at scheduled times, and the carts are unloaded into the flow racks that go to the operator at each line,” Pate explains. These quad-steer carts travel in the exact path as the tugger for safety; they don't veer off to where people or materials might be hit.

“The next lean cart built was for a decoupled route, where we needed a cart that's easy to maneuver when not being tugged because the carts are uncoupled and left with materials on them,” he adds.

These decoupled carts have six wheels with tall, rigid wheels in the middle. All four corner wheels swivel. The result is that the carts track easily and are safe and convenient to maneuver by hand.

Efficient Movement

Trane now has a variety of carts that dispense tubing, wiring, flow controls, switches and other materials throughout the plant to various lines from the central supermarket, as well as completed assemblies from one line to another.

“We're efficiently moving components without starving any of the lines,” Pate says.

A key factor in the relationship is constant contact between Trane and Valley Craft/Ovation engineers, with plenty of idea exchange and “a lot of give and take,” Pate explains, adding that communication is essential because “they work with me to find the solution.”

Valley Craft's Metzdorf says the feeling is mutual. “We have a common goal of customer input and feedback into our process for customized, one-of-a-kind material handling solutions,” he says. Pate said Trane and Valley Craft engineers are now engaged in designing a new cart that's unlike anything else out on the market.

Pate is justifiably proud of his plant's lean event team results. The plant has more than 100 lean events per year, and he can point to the returns in money, time and reduced downtime as a result of his team's customized material handling solutions.

Bob Rumpza is a freelance writer in Eden Prairie, Minn.