Mistake Proofing and

Standardization The fourth step in 5S adopts the best practices for equipment and machinery layout, and the design of equipment and work practices for productivity, mistake-proofing and continual improvement. Workers at all levels have opportunities for input into the standardization procedure. Comments are sought on the design of the work methods to maximize efficiency as well as to minimize risks. 

Improve. Here, implementation of creative solutions— ways to do things better, cheaper, and/or faster—that address the problems identified dming the analysis phase takes place. Often, other lean methods such as cellular manufactming, 5S, mistake-proofing, and total productive maintenance are identified as potential solutions. Statistical methods are again used to assess improvement. 

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. 

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. 

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. 

Good proofreading involves far more than a simple run of the spell check and grammar check functions on your computer. In fact, those programs are far from Goof-Proof, and therefore a reliance on them alone to find your errors is a mistake. 

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. 

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. 

Process has been continuously improved in effectiveness, efficiency, and cycle time over the past 2yr. It is appropriately fail-safe and mistake proof. 

A control plan is the sum of the procedures and equipment used to ensure that the internal requirements are met. It includes control charts, sampling plans, 100% inspection, feed-forward/feedback mechanisms, and mistake-proofing tech-niques/devices. Some items may be performed by equipment like automatic controllers, and some are performed by operators and checkers. There may not be a single document called a control plan. Instead, these controls might be spread across a number of documents including a statistical process control plan, an inspection plan, an operator manual, and various other standard operating procedure and specifications. 

Before mistake proofing can be applied, potential mistakes must first be identified. FMEA can be used for this purpose. It identifies different failure modes along with their potential causes and consequences. For each potential failure mode, a risk evaluation is performed based on the likelihood of a defect to occur, the likelihood of it being detected, and the severity of its consequences. One of the columns in an FMEA is titled Control Plan. This column must be filled out before performing the risk assessment. Both the likelihood of occurrence and likelihood of detection are affected by the controls that are currently in place. 

Designed experiments play a key role in items 3 and 4. They also identify worst-case conditions for OQ testing and result in an understanding that allows more complex control plans to be established. However, designed experiments are not enough. They must be carefully coordinated with other tools like FMEA, mistake proofing, customer research tools, measurement system analysis, capability studies, acceptance... 

There must be a continuous improvement initiative, a constant seeking of error reduction, the goal of which is to mistake-proof systems and processes. 

Poka-Yoke. Steps to making products correctly the first time through error and mistake-proofing. (A common and popular example of mistake-proofing is the design of the VHS videotape player. A videotape will only fully enter a VCR and play if it is placed correctly into the opening.)... 

Error and mistake proofing By product or process design changes, error proofing eliminates the possibility of producing a defect. Mistake proofing includes ways to spot errors that do occur so they can be corrected before a defective product is sent to Chrysler. 

Mistake-Proofing the Design of Health Care Processes is illustrated with numerous examples and explains how to apply the industrial engineering concept of mistake-proofing to processes in hospitals, clinics, and physicians offices (AHRQ Publication No. 07-0020). 

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