The Psychology of Quality and More
The Flow Process Chart
In analysing processes, particular actions along the way are often significant, especially if you are looking to eliminate sources of waste (or muda, as the Japanese call it) such as having documents piling up in in-trays or materials being moved from pillar to post.
How it works
The Flow process Chart is a simple half-text, half-picture method of showing the steps in a process, using symbols to indicate the type of action being taken and text to give details of the action. The chart can selectively be used to show what happens to selected people, materials or equipment.
Parts of a Flow Process Chart
A particularly useful feature of the chart is that it can be drawn up as the process is happening. Thus you can follow a part around a factory floor, for example, noting how and when it is machined, stored, moved, etc.
The table below shows many of the symbols that may be found in Flow Process Charts.
How to do it
1. Identify the process to be charted and the objective for charting it.
2. Identify the symbol set to be used.
3. Record the steps of the process as it happens, starting at the top of the page, with symbols on the left overlaying a vertical line with appropriate notes about what is happening to the right. Try to record significant activities which are generally of approximately equal size (unless the problem is at the detail level, do not try to capture too much detail).
You can also make the diagram more useful by such tricks as numbering the different action types in sequence (for example so you can see how many times the item under examination was moved) and changing the direction of movement arrows to show input or output activity. You can also put the time taken in each activity to the left of the symbol.
Using the Flow Process Chart
4. If you are watching the process as it happens, you may want to repeat the analysis several times to ensure you have captured the normal chain of events.
5. Analyse the final chart, for example totalling times taken in non-value-adding activities such as storage, movement and inspection.
Next time: Mind Maps
This article first appeared in Quality World, the journal of the Institute for Quality Assurance
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