Error-proofing refers to the implementation of fail-safe mechanisms to prevent a process from producing defects. This activity is also know by the Japanese term poka-yoke, from poka (inadvertent errors) and yokeru (to avoid)
In essence, error-proofing becomes a method 100% inspection at the source rather than down the line, after additional value has been added (wasted). Achieving extremely high levels of process capability requires this type of focus on prevention rather than detection.
Examples From Industry:
A sensor connected to the electric nut-runner in an automobile assembly plant triggers a horn if a suspension assembly is moved to the next operation before a bolt is properly tightened.
Color-coding of components that otherwise look similar. Bins of parts that are electronically connected to the bill of materials through a bar code scanner, so that only the proper bin door opens for a given product.
Bar-code scanning at the check-out lane to eliminate errors and increase speed
Computer controlled inspection of a vehicle’s electrical system that senses any disconnected modules and electronically “locks out” the shipping documents so the vehicle must be properly repaired and verified by computer retest before it can be shipped to a customer.
Fuse box lock-out procedures so that power cannot be turned on before an electrical repair is complete and all personnel are out of harm’s way.
Guide pins on emblems on the back of a car to guarantee proper alignment.
At the simplest level are WARNINGS that provide quick feedback of a potential problem, like a smoke-alarm or the warning lights on your car instrument panel.
Automatic SHUTDOWN controls force the problem to be corrected before resuming production, such as the vehicle electrical test mentioned above.
AUTOCORRECTION controls provide an integrated test-feedback-repair loop, such as the spell-checker in a word processing program.
If you are considering the first steps in applying error-proofing principles contact us and we’ll reduce the possible errors that can be generated by an operation in your company.