May 1, 2009
Ohio-based Diamond heavy-haul found efficiency in its cutting operations through nesting software by managing remnants and reducing scrap.
Dennis Nadolsky has a lot on his shoulders. For several months the software guru has been, in essence, bringing into the 3-D CAD world some of the ideas that changed Diamond Heavy Haul from a heavy-haul trucking company into a firm that was also a successful manufacturer of superheavy-duty, oversized-load trailers. Those ideas came from Steve Engel Sr., company founder and semipro drag racer who passed away as a result of a racing accident last fall.
The family business continues on, however, as does Nadolsky"s work. The designer is converting hundreds of flat-pattern layouts, originally drawn directly into nesting software, into a 3-D CAD environment. The idea sounds a bit backward: transferring parts from nesting software to 3-D CAD? Don"t part files usually export to nesting software? At Diamond Heavy Haul, many part files do, but not all, at least not yet.
This shows that a metal fabricator"s success doesn"t hinge on following conventions. New ideas build a business foundation, and two ideas in particular have spurred Diamond"s growth and baffled competitors: its product design and business organization. In their eyes, neither the product nor the business should have worked.
But both did.
In 1986 Engel hit a crossroads. It had been six years since the entrepreneur launched his heavy-haul business, but he saw some inherent shortcomings in the trailers available at the time.
Enormous payloads, in some cases weighing 250 tons—that"s right, tons—require significant precautions. One is weight distribution, which requires the axles to be extra-wide, often taking up both lanes of the highway (see Figure 1). This isn"t avoidable when dealing with extreme tonnages, but what is avoidable, as Engel discovered, is the tedious process required to get the trailer to the shipper.
Because wheel bases take up two lanes, these trucks require special escorts and road closures—a lot of trouble for an empty truck. So historically, these trailers had to be sent in pieces on several flatbed trucks and assembled on-site at the shipper.
But what if the wheel axles (up to 38 of them for some of the superheavy-duty models) could expand and contract hydraulically? Haulers could drive to the shipper"s site with wheel axles contracted, and then leave fully loaded with the axles expanded (see Figure 2). Such a design would save hours of tedious time spent assembling trailers in plant parking lots. But considering the incredible loads, would it be possible?
Engel, it turned out, found a way.
Engel was "the brains of the operation," said General Manager Don Madl. "He was a natural-born mechanical engineer," just without the formal degree. He never went to college. As Madl put it, "His first CAD program was the garage floor and a piece of soapstone."
That is where Engel drew the dimensions for Diamond"s first trailer, after which the area was roped off like some archeological discovery. "If anybody messed up his dimensions, he was going to be in bad shape," Madl said.
With the design drawn out, Engel"s team torch-cut and welded everything and put their first hauler on the road in the mid-1980s. So how did he do it—without formal training in CAD? For that very first trailer, it seemed the garage"s concrete floor worked just fine. "Steve could see intricate designs in 3-D," Madl recalled. "It was all in his head. It was a gift."
Today the company produces a variety of trailers that include 38-axle superdual-lane haulers, those massive trailers with more than 160 tires that take advantage of hydraulic axle systems once thought to be impossible to engineer. Since Engel"s business introduced them, the units have come to be known as hydraulic expandable dual-lane transport trailers. Each wheel set has two axles side by side. Together the axles are 14 ft. contracted and 20 ft. hydraulically expanded, for carrying those heavy loads, with each axle taking up an entire lane to spread the weight. In addition, the loading platform"s width and length can be adjusted to match the exact dimension of a load.
The design hinges on weight distribution, which is why these trailers are so long, sometimes 230 ft. Anything weighing hundreds of tons would crush pavement beneath it if all its load was concentrated in an area as small as the actual load dimension. To transport such incredibly heavy stuff, the weight must first be distributed. The middle deck section carrying the load is hung, pendulumlike, between the front and back wheel sections (see Figure 1). This in effect transfers the load to the front and back wheel sections.
As sources described, if a person could actually see the loading force, it would look like a waterfall starting at the top of the trailer"s load, then cascading as it continually splits and distributes throughout the length and, for the dual-lane trailers, width as well. "This breaks it down to manageable amounts of weight per square inch of pavement," Madl explained.
All A514 I-beams that make up these trailers are custom-made, and such huge trailers require some monster metal fabrication. The shop"s equipment includes a custom plasma table with a high-definition Hypertherm torch that will cut up to 1-in. A514 plate. Also on the floor are 400- and 750-ton press brakes, custom-built rollers, submerged arc welding, as well as an innovative robotic gas metal arc welding setup. The fabrication shop encompasses 80,000 square feet. Blanks are first cut on the plasma table. Certain parts go to the brake for forming, then all travel to the submerged and gas metal arc welding cells and head to finishing and painting.
Engel"s son, Steve Engel Jr., engineering and design manager, runs and programs the company"s plasma cutting system. And like everything else at Diamond, it"s big. The machine is set up to be able to run up to seven torches positioned across a horizontal gantry that can move the length of the 11- by 85-ft. table (see Figure 3). "Say we want to cut several flanges at once," Engel said. "We can set up to run all the torches to run at one time."
The fabrication technology seems on par with other large-scale fabrication operations, but what"s unusual is what happens before parts are nested. From that first garage-floor drawing, Engel transitioned to 2-D AutoCAD®. But when the shop invested in its first plasma system and nesting software, Engel actually stopped using AutoCAD and started designing parts within the nesting program itself. In other words, he used nesting software as CAD software (see Figure 4).
"We have thousands upon thousands of parts in our nesting software," Madl said. "That"s all [Steve] had to work with, and obviously it worked well for nesting; all the parts were right there. And it was just so second nature to him. He did all his complex stress analyses manually, with a calculator. He was so far ahead, that it was no big deal for him to draw [these parts] out on the nesting program, be able to check his clearances, and make it work like a 3-D program just by intersecting lines and rotating assemblies."
Madl chuckled. "Of course, it wasn"t really designed to do that. But it was all he had."
Before Engel"s death in September, the company had already decided to bring in 3-D CAD to speed product design and development. "I knew we needed a better way to unlock the stuff that was in his head," Madl said.
When Engel died, it became all the more important to "unlock" those designs. So in January Nadolsky, a SolidWorks® veteran, was brought on to tackle a job unlike any he had seen: Transfer parts drawn in a nesting software environment and put them together in a 3-D CAD environment (see Figure 5).
"There are a lot of parts," Nadolsky said. "It will take me significant time to do all of them. You look at these parts made [in the nesting software], and you"re just amazed."
Nadolsky"s time will be worth it. When a design change is made in SolidWorks, for instance, the file can be exported to the SigmaNEST nesting software, which automatically separates the part elements, nests them—utilizing common-line cutting to increase material utilization—and sends a new program to the plasma cutting system.
Remnant management has been a big step forward for Diamond too. "In our business, you can"t help but have remnants," Madl said. "We buy most everything in 96- by 480-in. plates, and our parts have a lot of rounded contours. Previously there was no inventory side to the software." Now the latest version of SigmaNEST saves that remnant for a future job.
"The program gives you a number to retrieve these remnants too," Engel added. "So if you cut sheet one, its remnant is labeled Sheet 1-1. We can bring that remnant up and nest additional parts."
Such remnant utilization came at a good time. Material prices have plummeted with the recession, but last year it wasn"t uncommon for Diamond to pay $2 a pound for A514 plate.Complementary Businesses
Diamond is a hybrid business, part heavy hauler, part metal fabricator. It"s a combination that industry watchers thought unfeasible, Madl said. But again, Engel proved them wrong.
In retrospect, the naysayers had a point. When Diamond entered the manufacturing business and yet stayed in the heavy-haul business, the company in effect started selling equipment to its competitors. But over the years, the two businesses have complemented each other in various ways. The hauling business acts as a revenue-producing R&D testing ground for the fabrication business. Diamond tests and uses equipment options that it doesn"t sell. Also, the equipment represents only half the equation for a heavy-haul business; experienced operation crews are the other half. No matter how innovative the trailer, it doesn"t give much competitive advantage without a skilled team—including drivers and support personnel—to get the trailer from point A to point B.
The strategy seems to have paid off. During this economy, the manufacturing business is down significantly. Credit is tight. Those who bought trailers worth more than $1.5 million last year can"t get financing for a $500,000 trailer this year. As Madl explained, "The interest in the product is there, but the banks aren"t there to back the loans. The flip side is that the transportation business is booming," he said, adding that the heavy-hauling side is set to bring in between 70 and 80 percent of company revenue this year.
More important, the company operates free of debt. Diamond has seen significant growth since Engel and his wife, Tonya, launched the business, but it still employs only 42 people across the two business units. Through the years the Engels reinvested earnings in the business. Without leverage, it took time for them to grow the business. But Madl said when significant growth did happen, the company stood on a solid financial foundation.
"This was pretty much a small shop until the late 1990s, when things really started clicking," he said. "People asked Steve why he didn"t do more with financing. He told me, 'Because if I wanted to quit tomorrow, I can."" Today, he added, company finances stand firmly in the black, with cash in the bank.
In the current economic reality, that"s as good as gold.
Diamond Heavy Haul"s monstrous trailers need extremely heavy-duty fabricating equipment. And not far away from the company"s 85-ft. plasma table sits another 80-ft.-long fabrication cell: a gas metal arc welding cell in which a track-mounted robot—a FANUC using a Lincoln power source—runs along a series of small I-beams positioned on either side that together make up an extremely long welding table. Once parts are programmed in a library, the operator simply selects it, and the robot finds the part with touch-sensing and starts to weld. Some parts are "only" 6 ft. long and 6 in. wide, while others can be as big as 40-ft.-long beams.
Usually the most complex part of robotic welding, fixturing in this cell is rather straightforward. Each small I-beam, placed about a foot apart, has the same clamping system (see Figure 6). Each clamp positioning pin is assigned a specific coordinate that together make up a kind of coordinate grid, which helps simplify robot programming. On one side is a stationary vertical component to butt the part against, and on the other are clamps that use the same type of hydraulic cylinder found in log splitters.
Because these I-beam clamp systems are placed so close together, they can handle a variety of part geometries. "We can clamp contours and put 2,500 pounds of pressure to hold parts in place," said Diamond"s Don Madl.
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