Mistake Proofing

Can the equipment or process be simplified, be made mistake proof, or at least mistake tolerant, by applying ergonomic/hu-man factors principles ... 

During process hazards reviews (such as HAZOP), inherent safety concepts are also considered. Mistake proofing the design should receive attention and each safety critical device (last line of defense) and safety critical procedure should be examined to see if there is a way to eliminate the need for the device or procedure. 

Is FMEA and mistake-proofing applied to each product and process and are the results used to effect beneficial changes to these products and processes ... 

The standard requires suppliers to utilize appropriate mistake-proofing methods during the planning of processes, facilities equipment, and tooling. 

Mistake-proofing is a preventive action and like FMEA is addressed in Part 2 Chapter 14. 

Mistake-proofing using the results of failure modes analysis... 

The object of the studies is to compute the indices and then take action to reduce common cause variation by preventive maintenance, mistake-proofing, operator training, revision to procedures and instructions, etc. 

The standard requires the supplier to use mistake-proofing in corrective and preventive action process. 

Mistake-proofing can be accomplished by product design features in order that the possibility of incorrect assembly, operation, or handling is avoided. In such cases the requirements for mistake-proofing need to form part of the design input requirements for the part. 

In both cases the Design FMEA and Process FMEA should be analyzed to reveal features that present a certain risk which can be contained by redesign with mistake-proofing features. 

Your first objective with axiomatic design is to make your design as independent as possible with reference to functionai requirements. After this you wouid make it as robust as possible, as per the information axiom, using such techniques as Robust Design (Technique 38), Design FMEA (Technique 40), and Mistake Proofing (Technique 49). 

While the purpose of Design Scorecards is to prevent problems, defects, and errors through superior design, they also enable better problem detection after a new solution (design) is implemented. If you are in detect-and-fix mode, any number of process-optimization techniques may help, such as Process Behavior Charts (Technique 52), Cause Effect Matrix (Technique 54), Mistake Proofing (Technique 49), and Design of Experiments (Technique 50). 

Use DFMEA during your preliminary, initial, and detail design reviews to uncover any potential failure modes. Then your first priority is to prevent these modes by improving the design itself (see Mistake Proofing, Technique 49). If you can t mistake-proof your solution (as in the foot-on-brake example), your next priority is to detect a failure mode before it occurs and prompt the user to take action. The oil warning light in a vehicle is an example of this approach. 

After processes are documented, they have to become as fast, efficient, and flawless as possible. This means you optimize the processes that generate all the value for your new solution. Several techniques will help you do this, but you should start with Measurement Systems Analysis, because it ensures the validity of any data you use in optimization studies (see the Design of Experiments, and Conjoint Analysis techniques). Then use Work Cell Design and Mistake Proofing to optimize the layout of people, machines, materials, and other factors in an office or factory. 

In the realm of innovation, mistake proofing helps you combat the possibility that your product or service doesn t function properly due to unforeseen events, equipment failure, and other factors. Mistake proofing also makes it easier for employees to perform their work correctly and ensures immediate recognition and repair when a mistake is made. 

Mistake proofing can be as straightforward as a checklist or warning label, or as complex as a computerized system that regulates a nuclear power plant. Regardless of the situation, you should strive to apply the maximum level of mistake proofing that is both affordable and feasible for your innovation. 

The Mistake Proofingtechnique can be leveraged early in the innovation process to help you scope your opportunity and generate ideas. For instance, a new feature in some automobiles makes the car brake automatically if it senses that you re about to hit the vehicle in front of you. The mistake-proofing strategy of preventing accidents was leveraged early on when the job to be done was identified. 

Scenario Producers of home security systems must take care to mistake-proof their offerings. After all, if the system is confusing to use or fails to perform as designed, it could lead to a costly or even a dangerous situation. In this example, we ll look at a few areas that, if neglected, could lead to potential errors in a home alarm system. 

Use a Cause Effect Diagram (Technique 53) to determine the root cause for each potential error. This is a critical step in mistake proofing that is often missed because too many people confuse errors with defects. For example, motion sensor failure is a defect motion sensor zone set incorrectly is an error. You can only truly solve a problem at the error level, so make sure you understand the difference. 

Safety and risk considerations are often at the center of mistake proofing. Imagine the risk associated with unveiling new investment software, or with implementing a new surgical procedure. Both the financial and health care industries have a host of mistake-proofing measures in place to avoid costly errors and litigation. 

For example, we could prevent a homeowner from forgetting to activate the front-door security alarm by automatically arming the system. Of course, this would introduce problems when the homeowner wanted to enter or leave. Perhaps this problem could be solved by installing a fingerprint-sensitive doorknob that allows authorized individuals to enter and leave at will without setting off the alarm. Even so, you would still have to consider how to mistake-proof this solution. 

The final step is to actually create and test your mistake-proofing solution. You can do this before you move on, or as part of a prototyping or piloting process. 

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