Mistake Proofing

1. Mistake Proofing • LEVEL I DEVICES (e.g.: Bridge Over Railroad Tracks) • –Physical devices that prevent the error at the source. • •Designing errors out up front through thorough quality planning. • •One way fits, required actions in order to operate equipment, etc. • •LEVEL II DEVICES (e.g.: Railroad Crossing Flashing Lights and Bar Across Road) • –Warning devices like Control Charts, buzzers, lights, alarms that require a human response. • •Control Chart • –Helps to determine if the variation within the measured output is strictly due to the system (common causes) or if something out of the ordinary (special causes) has occurred. • –Do we need management’s involvement to help solve this problem or can the Operator handle it locally? • •LEVEL III DEVICES (e.g.: Railroad Crossing Signs) • –Helps prevent a defect from going onto the next operation (i.e.: kick-out device on a gage checking bushing diameters). • –May prevent an unsafe condition from happening even though an unsafe act has already occurred (i.e., oil drip pan beneath a machine).

2. Mistake Proofing PHYSICAL DEVICES LEVEL 1 WARNING DEVICES LEVEL 2 MISTAKE-PROOFING TYPE LEVEL 3 INSTRUCTIONS HIGH LOW MEDIUM MISTAKE-PROOFING EFFECTIVENESS