Control Engineering Online Update for July 14, 2006

July 14, 2006

Highlights
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Cepheid Inc. developed a significantly faster thermocycles test used to detect the presence of specific DNA in a test sample. While the test procedure was markedly faster than competitive tests, Cepheid’s manufacturing process for the test was not speedy. Cepheid partnered with a machine builder and assembly-line belt maker to create a cost-effective, high-capacity machine that provided very clean parts transfer.

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Belt conveyer delivers faster part cycle times

Key outcomes of successful automation include improved productivity, reduced operating costs and creation of new, innovative products. Recently, three companies collaborated to achieve those results:

Sunnyvale, CA-based Cepheid Inc.—a relatively new company applying breakthrough microfluidics and microelectronics technologies to new test systems for DNA analysis;

Stirling Engineering, Inc., in nearby San Jose, CA—designer and builder of automation equipment; and

Belt Technologies, Inc., of Agawam, MA—manufacturer of metal belts and related equipment.

Metal belts reduce contamination issues and minimize variations in surface speeds.

In a remarkable merger of microelectronics and microbiology—which Cepheid calls microDiagnostics—the company can develop proprietary products aimed at complete, cost-effective automation of complex DNA-detection procedures. Recently, Cepheid developed a significantly faster thermocycles test used to detect the presence of specific DNA in a test sample. The process can take as little as 10 minutes to complete.

While the test procedure was markedly faster than competitive tests, and faster even than the company’s previous offerings, Cepheid’s manufacturing process for the test was not speedy. Initially, the company was manually producing a disposable reaction tube—a key test component—in quantities of only 400 tubes daily. Obviously, some degree of automation was necessary to produce the annual 18 million parts required to meet expected market demand.

Reduced costs on the way Increased throughput was only half of the equation; cost savings were the other. Cepheid’s mechanical engineer, Doug Dority, elaborated: ‘After performing the financial analysis, it was clear that we could reduce the overhead on the part cost by developing a faster part cycle time. Given the number of parts we would be producing, the savings could be significant.’

After investigating several options, Cepheid turned to Stirling Engineering, Inc., which specializes in designing and building custom factory-automation conveyors. According to Greg Stirling, metal belt technology would improve flexibility and reduce cost and over-all dimensions of the assembly line. It also would provide a very clean process for Cepheid. Belt Technologies would supply the belts.

Ultimately, Cepheid engineers Dority and Ron Chang chose Stirling after evaluating competitive quotes from other machine builders who proposed rotary table concepts. Stirling’s concept was not only more cost-effective, they said, but it would also quadruple the parts capacity compared to the second-best solution. Ultimately, Stirling recommended and built an automated assembly line that incorporated 12 assembly stations and a cycle time of three seconds. A machine with eight channels met the desired production rate and would yield more than 20 million parts annually.

Stirling’s process ‘was not only fast, it provided a very clean parts transfer, as clean as any I’ve seen,’ said Dority. Cepheid had looked at various conveyor products and had a problem with the high mass of the conveyor,’ he added. ‘The obvious solution was metal belts, which provide low inertia and excellent repeatability. Plus, in the future, we could also extend the line very easily, with the belts’ flexibility.’

Betting on metal Metal belts offer advantages over similar products, as well as belts made of other materials. They have unique properties that result in superior precision control, longevity, and cost-effectiveness. In many cases, they’re preferable to other belt types, because they do not stretch so variations in surface speeds are minimized. Metal belts from Belt Technologies do not require any lubrication, offer unlimited travel lengths, and are available in various alloys.

Once Stirling completed the initial engineering design, the concept was presented to Belt Technologies’ Rich Lunden, who provided exact metal belt and pulley design specifications. Stirling subsequently incorporated Lunden’s information into the conveyor design. Belt Technologies provided drive and idler pulleys, metal belt, and timing screws used to attach the cleats.

An ISO-9001 registered company, Belt Technologies has manufactured metal belts, metal drive tapes, composite belts, pulleys, and thin metal cylinders for customer specified applications for over 30 years. The company also offers extensive in-house capabilities, including engineering and design assistance, metallurgical consulting, and high-energy beam fabrication.

‘With metal belts, contamination issues are minimized,’ Dority stated. ‘Plus, metal belts are known for their precise positioning. They proved far superior to other options.’ According to Dority, the conveyor was delivered on schedule and under budget and has been running flawlessly since its installation. The operation produces 1,800 units hourly, and is easily managed by one person.

‘Essentially, Stirling built an experimental line at the facility, with a limited budget. Cepheid saved substantial sums as a result, plus the prototype line performed well enough to become a permanent solution,’ he explained.

Dority says that the conveyor’s flexibility provides Cepheid with significant competitive leverage. ‘Cepheid is a fast-paced company producing a variety of novel products. So I might have to make adjustments to existing projects in mid-stream. Regardless of what comes down the road, metal belts provide flexibility and, just as important, the precision required.’

For more information visit: www.belttechnologies.com www.cepheid.com www.stirlingeng.com

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