The encyclopedia · Engineering & Operations · Technical decision · 2007-2008
Yaskawa let an RFID tag tell a robot how to build each inverter
Yaskawa's DrivE Center factory tagged each of 500 inverter types so robots and screens knew what to do, cutting work-in-progress to a third.
Yaskawa Electric
the move
Yaskawa had about 14% of the global general-purpose inverter market and demand was surging on energy-saving investment. Its Yukuhashi plant had to raise output without adding the skilled labour that variety normally demands.
The DrivE Center, which began full operation in September 2007, runs a flexible automated assembly line. Each work-in-progress part carries an RFID tag, so when it reaches a robot the reader tells the machine which of roughly 500 inverter variants it is building and the 6-axis MOTOMAN performs the matching weld or solder.
Because the robots are smaller than human arms, Yaskawa used 6-axis machines; the first generated a takt time of 2-3 minutes but refinement cut it to 45 seconds. For the human steps that remain, the RFID tag opens the correct electronic instruction and a 2D barcode on each parts box confirms the right component. Fourteen AGVs carry about 90% of internal volume.
why it works
- RFID made each variant identifiable as it moved, so one line could build 500 products rather than one line per product.
- Robots responding to a tag could automate the skill-dependent step of soldering a particular unit.
- Electronic work instructions + barcoded parts boxes catch operator errors on the steps that stay manual.
- AGV transport removed the misrouting and lag that had inflated work-in-process inventory.
what transfers
When variety is too high for people to memorize, carry the recipe on the product itself. The tag makes every machine and worker correct without retraining for each new model.
what came after
By summer 2008 work-in-progress inventory had fallen to about one third, and the plant produced around 1.67 million units in the fiscal year, up about 70% over four years — while the company aimed to double output by 2011 without adding people. The system won the 2008 Nihon Keizai Monozukuri Grand Prize and its approach became the standard Yaskawa model exported to its overseas plants.
references
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