Fixtures5 min read
Poka-yoke, or error-proofing, means designing a process so that mistakes are either impossible or immediately visible. In a welding fixture, it is the difference between catching a mis-loaded part at loading and finding it at final inspection.
Common error-proofing techniques
- Asymmetric locators so a part can only be loaded the right way round
- Part-presence sensors that block the cycle start if a component is missing
- Clamp-position sensing to confirm every clamp is closed
- Interlocks between the fixture and the robot or welding power source
- Tower lights and HMI messages that show the operator exactly what is wrong
Why it pays back quickly
One missing bracket welded into a frame can mean scrapping the whole assembly. Sensors and smart locators cost very little compared with that scrap, and they protect your customer from receiving a defective part.
Design it in from day one
Error-proofing is far easier to build into a new fixture than to retrofit. During design reviews we map every way a part could be mis-loaded and add a physical or electrical check for each.
