lean manufacturing

Posts Tagged ‘error-proofing’

Error Proofing are methods that help operators avoid mistakes in their work caused by choosing the wrong part, leaving out a part, installing a part backwards, etc. Also called mistake-proofing, poka-yoke (errorproofing) and baka-yoke (fool-proofing). Common examples of error-proofing include:
• Product designs with physical shapes that make it impossible to install parts in any but the correct orientation.
• Photocells above parts containers to prevent a product from moving to the next stage if the operator’s hands have not broken the light to obtain necessary parts.
• A more complex parts monitoring system, again using photocells, but with additional logic to make sure the right combination of parts was selected for the specific product being assembled.
See: Inspection, Jidoka.

Automatic Line Stop
Ensuring that a production process stops whenever a problem or defect occurs or rather is detected.
For an automated line this usually involves the installation of sensors and switches that automatically stop the line when an abnormality is detected via the quality control equipment. For a manual line a fixed-position stop system often is installed. This permits operators to pull an overhead cord or push a button that stops the process at the end of a work cycle if the problem encountered cannot be fixed during the cycle.
These examples illustrate the lean principle of jidoka, which prevents defects from going to the next phase of production and avoids the waste of making a series of more defective items. Mass producers, by contrast, will try to keep lines running to achieve high equipment utilization, even when known defects occur repetitively and require rework at the end of the process.

Adapted from the lean glossary and  lexicon