Milwaukee, Wisconsin - It looks like a cross between a tank, a tractor and a crane. When demand for this enormous electric mining shovel more than doubled in two years, size became an issue for maker Bucyrus.

In Lewis Carroll’s Alice in Wonderland, the heroine drinks from a bottle that shrinks her to a tiny size. You get the same feeling standing in front of the electric mining shovel unit at U.S. manufacturer Bucyrus’ main shop south of Milwaukee, Wisconsin.

Let’s put things in perspective. The assembled unit weighs nearly 1,500 tons — as much as five double-decker Airbus 380 planes. The bucket reaches a height of 60 feet when it stretches out to scoop rocks. It’s as tall as a seven-story building, and its 130-ton payload capacity is as big as that of two fully loaded trailer trucks.

Bucyrus Machining: Big is Better

Big is beautiful here. Since its founding in 1880 in Ohio, Bucyrus has been large-scale by every possible definition. Almost all the parts for the company’s different mining machines, including shafts, gears, sheaves, pulleys and frame components, are produced at the main shop.

A walk around the facilities in the complex reveals an array  of giant steel parts, not always easy for the untrained eye to identify. One of the biggest is a swing rack, a giant gear wheel that sits horizontally under the shovel’s body and makes the unit turn. “It’s our biggest part and one of three main parts we had to craft more efficiently,” says John Matysiak, manufacturing engineer at Bucyrus.

When it comes to the company’s electric mining shovel, we are really talking about massive scales. A single part for such a piece of equipment could measure up to 18 feet in diameter.

The electric mining shovel is powered by an electric motor, one of the few parts that are not made in-house. It works as well for open-pit gold and copper mining in the Australian heat as for oil sand operations in the northern Canadian cold. But the gigantic scale of the machines can present a challenge when it comes to mobility.

“Some of these parts weigh around 110,000 kilos [240,000 pounds],” Matysiak says. “It means we can’t possibly ship our whole units to the customer assembled. We do some sub-assembly right here, but sometimes the mines are at very remote locations. We have to ship everything in parts.”

Machining Logistics

Just creating the three biggest parts included several steps at different locations around the complex. “We had to move the parts so many times when machining them,” Matysiak says. “We had to do turning at one place and then use a crane to put the part on one of our internal railway carts to get it to another facility for gear cutting. Sometimes a part traveled several miles before [it was] finished.”

This logistical problem was highlighted by a study that pointed to a future capacity squeeze. In 2005, when Bucyrus announced the first phase of its multimillion-dollar expansion of its South Milwaukee manufacturing facility, the company believed that demand for electric mining shovels would increase significantly in the coming years because of growing global demand for coal, copper, iron ore, oil sands and other commodities.

“Previously we made eight to 10 units a year,” Matysiak says. “We were told that over a two-year period that number would go up to 24.” The current capacity for electric mining shovels is just over 30.

Bucyrus also manufacturers blasthole drills, used to drill holes and plant explosives in harder types of rocks. Occasionally it also receives an order for a dragline, a huge crane-like shovel. As orders increased, it became clear that the existing process wasn’t fast enough to meet the demand.

The company took a close look at the capacity constraints on three key components — the swing rack, hoist drum and hoist drum gear — all very large and manufactured in the same time-consuming process that required shipment to various departments for completion.

Bucyrus found what it was looking for in a twin-column, live-tooled 16-foot table 200 HP VTC from Italian manufacturer Pietro Carnaghi, which can turn, drill, bore, tap and mill in one setup. This instantly reduced the number of setups on any given part, saving significant time and money.

Sandvik Coromant was chosen to find the most efficient tooling solution for the machine, involving both the Italian and American Sandvik Coromant organizations.

Bucyrus also reduced lead time, according to Matysiak. Additional savings came through reduced lead time and transportation costs as well as improved quality of the components.

For Sandvik Coromant, not only is it the first time it has been involved in a start-up project with Bucyrus, but it also marks a success for its “Right from the Start” campaign on an international level, involving many different levels of Sandvik Coromant in two countries.

Technical Insight

Big Business

The 16-foot table Pietro Carnaghi machine can turn, drill, bore, tap and mill in one setup.

With demand ramping up fast, Bucyrus had only one option: to get a new and efficient machine center.

The objectives were clear.  A study showed that Bucyrus’ weakest point was in the big turning facility. The company needed a new machine center, but it also wanted:

• A more cost-efficient cutting process
• A machine that would help reduce handling and transportation of large parts
• A machine that would fit in the large turning facility.

“Not many manufacturers could meet those demands,” says John Matysiak, manufacturing engineer at Bucyrus.

Italian machine tool builder Pietro Carnaghi could. At the same time, Bucyrus faced tooling options, and Sandvik Coromant was involved from the start to find the most efficient solution.

“We hadn’t worked with Sandvik Coromant before, but we knew they were capable when it came to turning,” Matysiak says.

The order to Pietro Carnaghi included turn keys for the three main parts: the swing rack, which enables pivoting for the shovel body; the hoist drum, which hoists the cable for the shovel; and the hoist gear, which turns the drum.

The machine was to be fitted with Coromant Capto C8 clamping units from Sandvik Coromant for all the OD and ID tool blocks. Sandvik Coromant Italy prepared process layouts, time studies and tool lists. Bucyrus received this information from Pietro Carnaghi and contacted Sandvik Coromant US for input. To deal with process and tool selection issues, Sandvik Coromant US worked as a mediator between Pietro Carnaghi, Sandvik Coromant Italy and Bucyrus. The Sandvik Coromant US group out of Pontiac, Michigan, was also involved.

Sandvik Coromant Tools

The finalized list of required tools, including Coromant Capto C8 clamping units, CoroDrill 880 drills, Duobore and CoroBore boring tools and a variety of milling cutters, was approved by the customer and by Pietro Carnaghi. When the machine was shipped, Sandvik Coromant US provided daily support to Pietro Carnaghi and Bucyrus through all the required run-off parts. Numerous changes had to be made to tool type, insert grade and geometry and processes in “real” time in order to achieve the aggressive run-off schedule.

“The people at Pietro Carnaghi had only seen two-dimensional drawings of the parts. Sometimes you have to see a part in real life to fully understand how to craft it,” says Lyle Schmaus, sales engineer at Sandvik Coromant.

“Lyle and Sandvik Coromant were with us from the start and gave us real-time support in the early stages,” says Matysiak. “Lyle spent about five weeks here.”

The Pietro Carnaghi machine was installed in 2009 and became fully operational in mid-2010.

“It’s even on over-capacity,” says programmer Neil Cramer. “It’s working so well that all the engineers have started putting everything in here, not only the three original main parts.” According to the numbers, Bucyrus has made all the right choices.

Says Matysiak: “We were aiming for a 25 percent cost reduction. On average we’re at 44 percent, which is very exciting. In transportation we’re down 66 percent and in lead time 19 percent. That equals many, many days.”

Originally published in Metalworking World 2.2011, a business magazine published by Sandvik Coromant.

Text: Henrik Ek, Geoff Mortimore
Photo: Martin Adolfsson