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Teaching Sensors the POKA-YOKE

Product News Tuesday, June 6, 2006: SoftNoze USA Inc

TEACHING SENSORS THE POKA-YOKE

Frankfort, NY, June 2, 2006- What sounds like a childhood dance to many, is actually a trend driving sensor usage in the industrial automation industry. Helping this movement is the newly expanded ProxPlunger™ & WeldSwitch™ product lines from SoftNoze.

Not to be confused with kids, or wedding parties, doing a silly dance called the “Hokey Pokey”; Poka-Yoke (pronounced "poka-YO-kay”) is an error-checking process often accomplished using automation sensors. The basic principle of Poka-Yoke is to create devices that make it impossible, or at least very difficult, for workers to make errors that cause the production of bad products.

As explained by Brett Truett, Chief Engineer for SoftNoze, “A welding cell equipped with Poka-Yoke devices prevents mismatched parts from accidentally being joined. For example, in a cell equipped to produce a variety of different style mufflers, Poka-Yoke devices confirm that the parts loaded by workers are correct. If the parts are not correct, the control system will prevent the welding cycle from being initiated.” Truett concludes, “SoftNoze’s ProxPlungers™ and WeldSwitches™ are ideal for part detection in these applications.”

ProxPlunger™ and WeldSwitch™ devices are prox-based limit switches. The devices use spring-loaded pins and buttons to interface with production parts to detect whether a part is in fact in place, correctly orientated and is the correct part to be processed at the time; painted, welded, assembled, etc. According to George Zachary, a Product Engineer with SoftNoze, “Some part detection applications are still best accomplished with mechanical actuated devices. Our products are highly modular, so whereas many Poka-Yoke designers have made their own devices, they can now purchase a full array of components, off the shelf.”

ProxPlungers™ are general purpose and are of steel construction. The WeldSwitch™ family uses copper and copper-steel alloy construction for applications in hostile welding environments. Both families are available in standard and right-angle designs, where the later design places a 12mm prox sensor at a right angle to the pin’s central axis, making the device more compact. Models are readily available from stock and custom pins and buttons readily quoted.