Thursday, October 16, 2008

Error Proofing vs. Process Control

I recently had a discussion about the differences between error proofing and process control. Later I was looking for documented answers and realized that error proofing itself is described by several terms with slight shades of meaning. There is also mistake proofing, mistake prevention and mistake detection, fool proofing (now seen as a derogatory phrase but what was its definition?), and Shideo Shingo's description as related in an Elsmar Cove discussion.
Poka Yoke roughly translates as mistake proofing and is typically applied to the PROCESS to prevent the cause of the mistake, shut the process down if the mistake occurs, or trigger an alarm if the mistake occurs. This was originally called Misu Yoke, or fool proofing, but was quickly changed, when Japanese sensibilities were offended by the term fool (anyone can make a mistake).Shingo uses the term Error Proofing to refer to actions applied to the DESIGN to prevent errors from occurring. This could include the addition of design features to prevent misassembly defects such as reversed, upside-down, etc. This could include making the part asymmetrical so it can only be assembled one way, or making it perfectly symmetrical so it does not matter how it is assembled.

More to come

1 comment:

Anonymous said...

Good discussion. I think error proofing implies the whole system, including process controls.