Every job is a series of tasks and activities performed sequentially. Make an error in any work task and it remains behind to potentially become a future failure.
The reliability of a completed job—i.e. its chance of being completed successfully—depends on how accurately each task is done.
Slide 29 – Every Job is a Series of Tasks and Activities Performed Sequentially where Errors, Mistakes and Misunderstandings Can Happen All the Time
The technician in the picture on the above slide is repairing bearings. The job requires various tasks and activities to be performed in sequence. Ideally, he has a comprehensive and clear procedure to follow in which each task, and its sub-activities, are listed and explained. From the procedure we can draw a Reliability Block Diagram of doing the whole job. Because every job is a series of tasks and activities performed sequentially we can estimate the reliability of the completed job from the reliability of completing each task. The job reliability equation to use is shown under the work task flow diagram.
The slide shows a simple five task job. Each task is completed one after the other. The job is only done 100% correctly if each task is itself done 100% right. Because the job is a series of tasks and activities performed sequentially, the job is right if, and only if, each task is first done right.
A Job is a Series of Tasks, What’s Your Chance of Getting Them All Right?
The reliability of a task is the chance that it will be completed correctly. When work tasks are not done right an error or defect is left behind. Each error or defect caused by a task mistake makes the task reliability fall from 100% to a lesser value. If a task reliability is 90%, then for every 10 times the task is done once it will be done wrong. We know from the risk equation shown at the bottom of the slide that unless task reliability is 100%, the error in the task will cause risks in the future. Once a defect is left behind in a job it sits there waiting to become a future problem or failure.
Because work is a series of tasks and activities performed sequentially everyone who does work can produce errors, mistakes, defects, and failures in every task and activity they do. No job is certain of being successful until every task is known to be done right.
The slide makes the point we must control the quality of individual work tasks, so they are always completed right, if you want to ensure the job is 100% successfully done.
This slide is a companion to the new Industrial and Manufacturing Wellness book. The book has extensive information, all the necessary templates, and useful examples of how to design and build your own Plant Wellness Way enterprise asset life cycle management system-of-reliability. Get the book from its publisher, Industrial Press, and Amazon Books.
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