Original Date: 02/09/1998
Revision Date: 04/22/2003
Information : Poka-yoke: Mistake-Proofing the Process
UE applies Poka-yoke (mistake-proofing) principles to prevent and detect defects in its manufacturing processes. The procedure typically incorporates straightforward, simple tooling fixtures to ensure that various assemblies can only be assembled in the correct manner.
Poka-yoke prevents or detects problems before additional value is added to the parts, and eliminates subsequent inspection steps to determine if the parts were correctly assembled. The process includes a series of questions on a defect such as:
What was wrong? When was it discovered?
What were the standard elements involved in making the part or assembly?
What mistakes or errors were made?
Why were the mistakes made?
This information is used to generate ideas on possible solutions to the problem. For its assembly fixtures, UE uses Poka-yoke devices such as limit switches, assembly templates or counters, and strategically placed pins or sensors on fixtures. Visual aids, detailed equipment set-up sheets, and in-process final assembly checks also aid the Poka-yoke process to ensure that the part was correctly assembled before it leaves the workstation.
UE’s fixtures continue to go through the Poka-yoke process as assembly problems are noted. In addition, employees continue to identify other workcells where similar fixturing can be used to eliminate assembly problems.
For more information see the
Point of Contact for this survey.