Error Proofing and Standardized Work Instructions

Error-proofing

While we would like to think otherwise, all humans involved in the manufacturing process make errors leading to product defects.  While it isn’t possible to eliminate all errors from tasks performed by humans, the Poka-Yoke philosophy introduce by Shigeo Shingo ⁽²⁾ is focused on “error-proofing” processes using methods to avoid simple human error.

While there are any number of successful methods and guides that have been devised for preventing human error, one important tool that has been shown to help mitigate a number of different causes of mistakes (errors made by novice employees, errors made due to process changes, errors made due to forgetfulness and infrequency of task performance) is Standardized Work Instructions (SWIs). SWIs are instructions designed to ensure that processes are consistent, timely and repeatable. SWIs, especially Visual Work Instructions, support consistent optimal processing by every operator and, provide a convenient way for supervisors to check the operators’ actions. Without the SWI, the operators and their supervisors must rely on collective memory to continue performing a process in an optimal fashion.  ⁽³⁾

Often the SWI are printed and posted near the operator’s work station. The goals and actual results of using SWI are improvements in: ⁽³⁾

• Quality of the finished product
• Consistency of the finished product
• Throughput of the process
• Safety of the operator

Work Instructions & Quality

Work Instructions are also used as a key tool in developing the product and standard processes from concept to production, control and quality planning  For compliance and consistent Quality, accurate, available Work Instructions are a critical part of implementing  Error Proofing, Mistake Proofing, and Fail Safe techniques, often used to meet QS-9000 requirements and Quality Improvement initiatives.   Work Instructions with the proper versioning and approval control, become significant in diagnosing problems down to root cause analysis during FMEA (Failure Mode and Effects Analysis), corrective action and preventative activities.

Writing Work Instructions

Finally, Standardized Work Instructions should be designed to create  the manufacturing process of record for customer, quality and regulatory compliance needs.  They shouldn’t be written behind a desk by an engineer who has never seen the manufacturing floor or process. ⁽⁴⁾ Rather, the most effective instructions come from documenting the current manufacturing process on line with a wider focus and input from Quality.

Standard Work

Using functionally-specific software like LockStep or Sequence Enterprise allows appropriate manufacturing content to be captured and deployed 90% faster.  Both LockStep and Sequence were designed exclusively to simplify shop floor knowledge capture and transform that knowledge into effective work instructions.   If you are thinking about getting started with Standardized Work or are struggling with your current method of controlling your Standardized Work documents, we would welcome the opportunity to talk with you about how either LockStep or Sequence Enterprise can greatly reduce the time required for creation, revision management and deployment. To learn more, simply send us an email ( This e-mail address is being protected from spambots. You need JavaScript enabled to view it ) or fill out the request more information form and let us know how we can help.

References­­­­­­­­­­­­

1. Poka-Yoke, Nikkon Kogyo Shimbun, Productivity Press, 1988.
2. Zero Quality Control: Source Inspection and the Poka-Yoke System, Shigeo Shingo, Productivity Press, 1986.
3. http://trainingwithinindustry.blogspot.com/2010/03/dont-write-work-instructions.html
4. http://world-class-manufacturing.com/Lean/swi.html