You don’t have to even know as a user of your vehicle that during manufacturing there were error proofing or mistake proofing solutions applied. But imagine that in today’s fast-paced and demanding automotive industry which is a benchmark for other industries, ensuring quality and efficiency is crucial. First gate keeper is our quality management system certified according to IATF 16949. It’s aim is to reduce waste and variations in the supply chain. Therefore manufacturers continuously strive to minimize errors and defects in their processes to meet econimic goals, customer expectations and stay ahead of the competition. Two methodologies frequently employed in this pursuit are error proofing and mistake proofing. While these terms are often used interchangeably, they mean differently.
Error proofing – preventing errors at the source
Let’s start from the basis how this term is defined in new 3rd edition of APQP issued 1st March 2024:
Error proofing – a technique used to identify potential errors and either design them out of the productor process or eliminate the possibility that the error could produce a nonconformance.
In other words error proofing focuses on designing processes or systems in a way that prevents errors from occurring in the first place. It involves implementing measures to eliminate or minimize the possibility of mistakes at every stage of production. The primary goal is to address potential sources of errors proactively, thereby reducing rework, waste, and defects.
One of the fundamental principles of error proofing is simplicity. By simplifying processes and providing clear instructions or visual clues, workers are less likely to make mistakes. For instance, incorporating foolproof mechanisms such as sensors, alarms, or physical barriers can help detect errors or prevent incorrect actions before they escalate into costly issues.
Moreover, error proofing emphasizes training and continuous improvement. Educating employees on best practices, potential pitfalls, and the importance of vigilance fosters a culture of accountability and quality consciousness within the organization. Regular reviews and feedback loops enable teams to identify areas for enhancement and refine error proofing strategies over time.
Mistake proofing – mitigating the impact of human
Again, let’s start with fundamentals how this term is defined in new 3rd edition of APQP issued 1st March 2024:
Mistake proofing– a method that allows you to identify errors after they occur. Mistake proofing should be used as a technique to control repetitive tasks or actions and prevent nonconformities from being passed on to the subsequent operations and ultimately to the customer.
While error proofing focuses on preventing errors at the source, mistake proofing emphasizes mitigating the consequences of inevitable human errors. Unlike machines, humans are prone to making mistakes due to various factors such as fatigue, distraction, or lack of attention to detail. Mistake proofing acknowledges this reality and seeks to design systems or processes that minimize the impact of human fallibility.
One of the key principles of mistake proofing is redundancy. By incorporating redundant checks or safeguards into workflows, organizations can detect and correct errors before they lead to significant disruptions or defects. This redundancy can take the form of double verification procedures, automated error detection systems, or backup systems to ensure continuity of operations.
Furthermore, mistake proofing often involves the use of fail-safe mechanisms. These mechanisms are designed to automatically trigger corrective actions or stop processes when errors are detected, preventing further escalation or damage. By proactively addressing potential failure points, organizations can enhance reliability, safety, and customer satisfaction.
Error proofing and mistake proofing in IATF 16949
First of all in IATF we will not meet this term mistake proofing. The standard operates only with error proofing. It is reasonable due to the goal of IATF 16949 to reduce waste and variations in the supply chain. However, if you are working with APQP both terms are used (especially in new 3rd edition dated 1.03.2024).
Here are the requirements which need to be met in our QMS for error proofing:
5.3.1 Organizational roles, responsibilities, and authorities – supplemental
Top management shall assign personnel with the responsibility and authority to (…) the selection of (…) error proofings (…).
8.3.3.2 Manufacturing process design input
The manufacturing process design shall include the use of error proofing methods to a degree appropriate to the magnitude of the problems and commensurate with the risks encountered.
8.3.5.1 Design and development outputs – supplemental
(…) The product design output shall include (…)
d) Results of product design error proofing such as DFSS, DFMA, and FTA
8.3.5.2 Manufacturing process design output
(…) The manufacturing process design output shall include (…)
m) results of error proofing identification and verification as appropriate;
8.5.6.1.1 Temporary change of process controls
The organization shall identify, document, and maintain a list of the process controls, including inspection, measuring, test, and error proofing devices. (…) Restart verification is documented for a defined period based on severity and confirmation that all features of the error proofing device or process are effectively reinstated.
10.2.4 Error proofing
The organization shall have a documented process to determine the use of appropriate error proofing methodologies. Details of the method used shall be documented in the process risk analysis (such as PFMEA) and test frequencies shall be documented in the control plan.
The process shall include the testing of error proofing devices for failure or simulated failure. Records shall be maintained. Challenge parts*, when used, shall be identified, controlled, verified, and calibrated where feasible. Error proofing device failures shall have a reaction plan.
* Challenge (master) part
Parts of known specifications, calibrated and traceable to standards, with expected results (pass or fail) that are used to validate the functionality of an error-proofing device or check fixtures (e.g., go / no-go gauging).
Let’s sum up
While error proofing and mistake proofing share the overarching goal of improving quality and reducing errors, they differ in their approaches and focus areas. Error proofing aims to prevent errors at their source through proactive measures and simplicity in design and execution. On the other hand, mistake proofing recognizes the inevitability of human error and seeks to minimize its impact through redundancy and fail-safe mechanisms. By integrating these complementary strategies into their operations, automotive organizations can enhance efficiency, reliability, and competitiveness in an increasingly complex and dynamic environment.
Do you want to know more?
We invite you to our trainings:
Error & Mistake Proofing – Effective management against errors
IATF 16949:2016 with ISO 9001:2015
APQP according to AIAG 3rd eddition
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For people who want to know more:
Knowledge must have a solid foundation in order to avoid information noise. Therefore, the article was based on the following literature:
IATF 16949: 2016 Requirements for quality management systems in serial production and the production of spare parts in the automotive industry, 1st edition, 2016
APQP AIAG, 3rd edition, 2024
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