Chapter 6. Simplified Process Flow Diagram
What you will learn in this chapter, as in the previous chapter, is that it's critical to identify and examine all of the possible causes for a problem. In addition to the fishbone diagram discussed in the previous chapter, you can use the simplified process flow diagram to help identify key process input variables (KPIVs) in a process. But there's a difference between these two tools.
It is important to know where and when input variables affect a process so you can see if that makes sense with where the problem is being seen. Of special interest are positions in the process where inspection or quality sorting takes place or where process data is collected. By looking at data from these positions, you may see evidence of a change or a problem. By noting where different operations take place, you can also see where issues can arise. Simplified process flow diagrams are used primarily in the Define, Analyze, and Improve steps of the DMAIC process
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Simplified Process Flow Diagrams
Manufacturing The simplified process flow diagram will focus an investigation by identifying where and when in the process KPIVs could have affected the problem. Of special interest is where data is collected in the process.
Sales and Marketing A simplified process flow diagram will assist in identifying if the cause of low sales is region, personnel, etc. This allows the team to focus on the likely area.
Accounting and Software Development A simplified process flow diagram will help pinpoint the specific problem areas in a system or program. This simplifies the debug process. Software developers are very familiar with this process.
Receivables Identify periods when delinquent receivables are higher than normal. A simplified process flow diagram may help in designing procedures, like discounts for early payment, to minimize the problem.
Insurance Look for periods of unusual frequency of claims. A simplified process flow diagram may help identify them.
A simplified process flow diagram works well when used in conjunction with a fishbone diagram. It can further screen the KPIVs that were identified with the fishbone, minimizing where you will have to take additional samples or data.
There are software packages that enable users to fill in the blanks of standardized forms for the fishbone diagram and the process flow diagram. There are also free downloads from the Internet that have forms that tie in with Excel. However, other than for the sake of neatness, doing them by hand works just as well.