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View from the Valley of the Sun: Raining on roll-to-roll processing's parade |
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Feb 07, 2007 at 04:10 PM |
While the vast majority of the flexible display/microelectronics sector chants its mantra of roll-to-roll or web-based manufacturing, not everyone is sold on the concept.
Toru Sakai of Philips Electronics is one of the unconvinced. During his Flex conference presentation on the impact of R2R methods on flexible TFT backplane manufacturing, Sakai used classic chipmaking manufacturability metrics such as work in progress (WIP), throughput (TH), cycle time (CT), mean time between failure (MTBF), and the like to build a case against the consensus approach.
He compared CT, WIP, and TH for R2R and cassette-to-cassette approaches, showing the consequences of excessive WIP and how WIP can be reduced by integration. His model's assumptions then demonstrated an inherent unreliability of R2R integrated systems that feature the various process units connected in a series. Sakai also cited the low system availability of such equipment, leading to what he called the "high cost of nonquality." He continued to pick apart R2R, pointing to low equipment efficiency and the difficulties of system reliability improvements.
He concluded that excessive WIP associated with R2R leads to long cycle times, large risk of obsolescence, and little diversity in product types and volumes. Based on his findings, he suggested the development of concurrent technologies for cassette-to-cassette methodologies as the path to industrialize manufacturing processes for flex backplanes.
The metrics Sakai employed were nothing new, bringing back memories of dozens and dozens of equipment and manufacturing effectiveness and productivity papers I've read or heard over the years. But with the Flex audience, there was some confusion, a little grumbling, and even a bit of outright hostility to his message.
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