Introduced nearly a century ago, flow charts are one of the most basic mapping tools available; they are also very useful. As such, they have become ubiquitous, though the name used may vary slightly – flow diagram, process map, etc. When packaged with a PFMEA and Control Plan, it is a Process Flow Diagram (PFD). Extensions of the original flow chart have also been developed, identified with new aliases for what is, at its core, a process flow chart.
The variations need not be a distraction; a basic flow chart can be very useful to your organization. Once a basic chart is available, it can be expanded or modified to suit your needs as you learn and gain experience. The following discussion demonstrates this progression.
Development of a process flow chart is straightforward, requiring only a few simple steps.
First, you must define the process to be mapped. This is often at a higher level than a D•I•P•O•D analysis, where the flow chart provides a schematic overview of the entire process chain. For example, a flow chart may consolidate a detailed sequence that includes instructions such as “torque cover screw to 30 lb-in” in a single process step “assemble cabinet.”
Sequence all process steps in the order they must be performed. If technical requirements do not force a sequence on steps, select a preferred sequence based on other factors – facility layout, skills required, duration of tasks, etc. Organize the flow chart to standardize this preferred sequence. The sequence can be modified later, creating a new standard, if experience suggests an advantage in doing so.
Identify all decision points in the process, such as quality inspections, routing for optional content, etc. Define the alternative paths created by the decision points. An alternative path from an inspection may define a rework process, for example.
All of the required information should be gathered in the above steps. All that is left to do is add symbols and format the chart for ease of use.
Structure and Symbols
A “conventional” flow chart will progress from the top to bottom of a page or from left to write. However, this is not a strict rule; alternate paths, feedback loops, and unusual process relationships may require that you deviate from the norm.
Use of a standard set of symbols, such as those in ISO 5807:1985, is recommended; this ensures consistent use and universal understanding. As your flow charts become more sophisticated, additional symbols may be needed, but the following four will get you started:
As flow charts develop further, it may become necessary to create links across pages or to other flow charts. This can be done with the following symbols:
Highly detailed flow charts will use more symbols to convey additional information. Refer to the standard for additional symbols and guidance on their use.
Templates and software packages are available to simplify creation of flow charts. Standard symbols are stored for rapid placement in a chart, often in drag-and-drop fashion. Microsoft Visio is a well-known example, but there are many other options available, both paid and free.
Applications and Examples
The following examples are simplified generic versions of what you might find in real applications:
Process flow charts are commonly associated with discrete physical activities, such as those in the manufacturing and service examples above. However, the tool has value for other types of processes as well.
Previous entries in “The Third Degree” have used flow charts to convey information in a succinct manner by presenting it in a visual format. “Use Process Maps to Guide Product and Service Development” provides several examples of the use of flow charts to illustrate cognitive processes. A few more can be found in “Lightweight Product Design – An Introduction to the How and Why.”
There are many other processes that are more involved with information or data processing than with physical movement of material. These include order processing, billing/invoicing, financial reporting, inventory management, call center operations, and many more.
The “Troubleshoot a Problem” process is an example of one that requires a combination of physical and cognitive activities. The results of tests performed (physical activities) are used to progress along a logical path (cognitive activity) to determine the cause of the failure under investigation. The following example illustrates the process one may follow – again, greatly simplified – to determine why their car won’t start and to resolve the issue.
Our final example is a special case of the troubleshooting process; it is known as the “CYA Chart” among other names. It is self-explanatory, presented here for review:
Flow charts are useful tools for important endeavors. Is that any reason not to have a little fun with them as well?
Elements can be added to a basic flow chart to customize it and increase its value to your organization. Notes provide additional information about elements of the diagram. Decision diamonds can be augmented with checklists that delineate the decision criteria. Processes can be represented with graphics, in addition to text, for rapid identification.
Material and information flows can both be illustrated on a process flow chart to more fully define the responsibilities of participants. For example, an inspection (decision) may require that the parts inspected be transferred to the next operation (material flow) and inspection reports to be delivered to the QA department (information flow).
To quickly identify who performs each task, flow charts can be expanded into a swim lane chart. Each lane is identified by the person or group (often, functional department) responsible for performing the processes and making the decisions in that lane (e.g. column). The flow is then shown traversing lanes as responsibility for progress is transferred between parties.
A value-added flow chart is similar to a swim lane chart in that it partitions the activities. In this case, however, there are only two “lanes” and they do not identify responsibility for tasks. Instead, one lane contains value-added activities and the other contains non-value-added activities. The duration of each activity is often added to the diagram for a quick reference to the amount of time consumed by value-added and non-value-added activities in the process.
As more and more information is added to a flow chart, it becomes more like a Value Stream Map (VSM). If your flow diagrams have developed significantly beyond the basic form, it may be advantageous to transition to value stream mapping. Simpler process flow charts should be retained for quick references, while VSMs are used for detailed analysis and process improvement.
I would be remiss if failed to mention the tabular format of process flow charts. It will not be covered in detail, however, as it lacks the utility and versatility of the graphical format. A thorough discussion is, therefore, unwarranted.
Flow charts can range from very simple to very complex. Complex flow charts can often be split into multiple diagrams (a la process chain), each easier to read and understand. This can be done by referencing a completely separate flow chart document, using predefined processes, as shown in the examples. A complex chart can also be made easier to read by moving some “branches” to separate pages, referenced with off-page connectors. Particularly “busy” areas of a chart become decluttered, facilitating focus on the relevant areas of the chart.
There are no strict rules on the number of process steps, decisions, etc. to include in a single flow chart; it requires the judgment of its creator - the cartographer must determine what map will best aid the planned journey.
For additional guidance, feel free to leave a comment below, reach out via our Contact page, or send me a message directly.
For a directory of “Commercial Cartography” volumes on “The Third Degree,” see “Vol. I: An Introduction to Business Mapping.”
[Link] “Flowchart,” Wikipedia.com.
[Link] “What is a Flowchart?” American Society for Quality.
[Link] “Process Mapping,” Continuous Improvement Toolkit.
[Link] “How to Draw a Swimlane Flowchart,” Edrawsoft.
[Link] “Value-added Flow Chart,” MoreSteam.com.
[Link] Mapping Work Processes. Dianne Galloway, 1994, ASQ Quality Press.
Jody W. Phelps, MSc, PMP®, MBA
JayWink Solutions, LLC
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