The following Article can be found on the 2004 August Issue of Product Design and Development.

Custom Conveying

There's a shift taking place in the material handling world. In order to boost productivity and reduce fabrication time, companies are switching to 3D CAD to figure out manufacturing lines. They want to make sure the equipment they install fits — without a mismatch. The results have included surprisingly fast turnaround times.

By Bart Eisenberg, Technical Editor

Wearing a hard hat and ear plugs, David Gadberry inspects his company's handiwork on the line of a Southern California Miller Brewing plant, where thousands of beer bottles move forward like so many cars on an LA freeway. It is Gadberry's engineering team at nearby Can Lines Inc. that designed the custom conveyors that do much of the moving. Empty bottles are filled, filled bottles are capped, capped bottles are inserted into six-packs, which are packed into cases, which are arranged for stacking onto pallets. Aside from a few workers on forklifts, the operation seems to run itself. To demonstrate, Gadberry reaches into the line and tips over a filled bottle. It catches on a railing, which shunts it to a basin. The bottle shatters and is gone with no human intervention required.

Admittedly, this is not rocket science. And that's the point. Can Lines is a prime example of how 3D CAD is bringing productivity gains to industries where the goal is fast turnaround rather than complex design. The company has reduced the design-build time for its material handling systems by about 30 percent so far, and more gains are expected. "We always thought of solid modeling more as a tool for designing a product over months or even years," says Gadberry. "We didn't think it would work for an industry that's as quick-paced as ours — where a single line may need to be designed and delivered in less than a month."

The source of Can Lines's productivity gain can be found in a shift in resources from fabrication to design. In the past, a 12-week project typically required about 10 days to engineer with the remaining time spent laying out the sheet metal, figuring out the dimensions and hole placement, and then cutting, de-burring, and punching. Fabricators worked from rough 2D drawings. "We relied more on the experience of our shop fabricators to interpret and fill in the missing pieces of the drawing," says Gadberry. "The drawings were rough because they took so long to draw." The company realized it could model all the pieces of a conveyor in 3D and see the interferences before it was built. That represented a big improvement over the past, where mistakes went overlooked until the equipment was assembled in the shop, or worse, installed in the field.
 

Engineering Staff Increased

With 3D, Can Lines's engineering group actually takes more time, but costly fabrication time has dropped by about 50 percent. Can Lines has nearly doubled its engineering staff to fill its 10 CAD seats, while employing about 35 percent fewer people in the shop. Gadberry now wades through resumes to find 3D CAD experience, figuring he can teach recruits about the intricacies of designing custom conveyors, palletizers and depalletizers, rack-and-pinion elevators, can orienters, and up-enders. The company has even gotten good enough to outsource its engineering skills to other companies, whose projects don't have a conveyor in sight.

Most conveyors are formed out of sheet metal, which is laser cut using data output converted from the CAD program, then punched, and bent into shape. Computer control reduces scrap by more efficient mapping of the shapes onto the material.

Kanwar Anand of KETIV Technologies in Fullerton, CA, the CAD software reseller used by Can Lines, says his firm has seen an increase in manufacturing design companies converting to 3D. "These customers are not in the forefront of technology — they aren't making high-end consumer products or medical equipment. They are not concerned about aesthetic considerations. But they install a lot of equipment on site, and that's not the place you want to find a mismatch." In the past, says Anand, the benefits of 3D in manufacturing were outweighed by the steep learning curve and the high cost of hardware. These days, both the cost and the curve have shrunk.

Still, a company's early 3D work requires considerable faith. At the bottling plant, Gadberry shows a visitor Can Lines's first 3D project — an elevated circular inspection platform. The project seems pretty rudimentary now, but at the time, the engineering team held its collective breath during installation, waiting to see if the dimensions and clearances shown on the screen actually had some basis in reality. They did.

Can Lines took about three months to convert to 3D CAD and another three months to become proficient. Gadberry says that was longer than the four weeks promised by the reseller, but it was understandable because they were working around deadlines. "For us, the change required a whole different thought process. With 2D, you're thinking about making lines and holes. With 3D, you're thinking about making a solid part — a flange — or extruding a hole through something, and you're controlling it by your dimensions. Now our guys hate to even draw in 2D. They find it very cumbersome although plant line layouts, which are overhead views, still use it."

Cutthroat Competition

The Can Lines name is something of a misnomer. The company's equipment moves more than just cans. It handles bottles, paper towels, tortillas, and numerous other products. Customers include Pepsi-Cola Bottling, Anheuser-Busch, and Nabisco. Fast turnaround is required because of cutthroat competition in the food and beverage industry, where a succession of new products and packaging is the norm. Each new retooling means squeezing new equipment within the fixed space of what was there before. To make that work on the average project, about 20 percent of the conveyor equipment is custom made.

"Our niche is that we can design and build anything in a matter of three or four weeks," says Gadberry. "That's why we've been able to stay union and keep really skilled people." The third-generation family-owned business operates out of an industrial area of Los Angeles, one of the more expensive places in the country to do business. It must compete nationally against companies from Canada and the Midwest.

3D CAD lets designers at Can Lines better plan the details of conveyor systems.

In keeping costs down, Can Lines makes good use of its 3D CAD package's sheet metal capability. Most conveyors are formed out of sheet metal, which is laser cut using data output converted from the CAD package, then punched, and bent into shape. Computer control has reduced scrap by more efficient mapping of the shapes onto the material. The operator loads the machine with sheets and returns when the cuts are done.

"A limitation of 2D CAD is that it doesn't readily allow for bend radiuses so that getting it right often required drawing the spec a second time," says Gadberry. "By contrast, the 3D package creates flat patterns that are automatically transformed into your shape. So whatever change you make in the shape, the corresponding flat pattern changes automatically. That means you draw something once and that's it." Also, 3D CAD makes it easier to derive variations from an existing design. A 10-foot conveyor shelf can be easily modified into a 6-foot version because the 2D flat-pattern sketch is connected to the solid model.

Can Lines has been sending design images to its customers in a compressed format that facilitates sending by e-mail. Customers view the results using a free downloadable viewer. "People can view your drawings and your models without having access to the underlying data." The rotatable color images are easier to see than the conventional 2D view, speeding the approval cycle.

Gadberry says the standard for creating a floor layout remains the 2D drawing. A floor layout is a line drawing on 3-foot x 6-foot paper that takes some 40 hours to complete. Even so, 3D is encroaching on the process. Some drawing components begin as solid models that are then converted.

Some Can Lines customers would like to see 3D play an even larger role. One company sent 3D views of its existing line for producing rolled taquitos. "The advantage was that they could see all the interferences," says Gadberry. Because most food conveyor lines run at least partly overhead and go up and down like a slow-motion roller coaster, 3D gives a more complete sense of the layout. It's viewable from any angle.

"Several of our customers have asked if we could put their whole conveyor line into 3D. We said 'sure, if you want to pay for it.' The problem with conversion is that it's not automatic — it would mean putting in the engineering time to interpret the 2D image." But in time, says Gadberry, 2D will disappear, and the images that describe a manufacturing line will better model the real thing.

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