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How To Chart (Map) Your Process

A Step-By-Step Tutorial 

Process Mapping is also known as Process Charting or Flow Charting. It is one of the oldest, simplest and most valuable techniques for streamlining work. It is also subtle and requires experienced facilitators for best results. some of the benefits of Process Charting (Mapping) are:

A process map visually depicts the sequence of events to build a product or produce an outcome. It may include additional information such as cycle time, inventory, and equipment information.

Several systems of conventions exist. At Strategos, we find that the original system invented by Frank Gilbreth in the early 1900's is still the most useful.

The Gilbreth approach is highly visual and discriminates between waste and value-added activity. It is also simple, intuitive and easily used by untrained groups. An experienced facilitator, however, is required.

The figure below shows a Process Map example and instructions for its construction. In most situations only the circle symbol (Operation) adds value.

  1. Follow one product or a narrow product group.
  2. Place the dominant component on the right.
  3. Show other components and subassemblies on the left.
  4. Describe each event concisely.
  5. Add additional information as required.
  6. Merge items on the chart only when the physical items are merged.


General Hints

Identify The Product

Process maps and charts show the sequence of events that act on a product. Therefore, we must carefully identify the product and ask "What is being done to the product."

In manufacturing processes, the product is physical and easily identified. For service and office processes it is easy to confuse activity with the product.

Information Flows

A common criticism of Process Mapping is that it does not represent information flows. And, many Process Maps do not show information flows, but they can show them and often should.

To map information, consider it as packet such as a work order or a database record. Or, a component necessary to complete the event.  Chart information sequence with dashed lines.

The Team

When mapping the current state, assemble a broad based team from all areas and several levels. It should include workers because they know the details of what really happens. It should include engineers and support people because they have a broad view of the process and know what is supposed to happen.

Drawing the Working Map

During a mapping session the entire team should see the entire map. And, each individual be able to focus on any detail that sparks a thought.

Draw the map on large paper sheets. This may cover several walls in an average conference room. Later the map can be redrawn with computer tools for distribution.


Using Symbols

Rules of Thumb

These rules of thumb apply to a factory-level maps. You may want to modify them for more detailed maps.

Storage & Delay--
Process Chart-Storage Process Chart-Delay
Process Chart-handling and delaysHandling & Transport
Process Chart-transport
Process Chart-Handling
When In Doubt...
 
Value Added

Occasionally, it is unclear whether an event adds value. Here are three useful tests:

Controversy

The following process events often bring controversy:

Inspection--
Process Chart-inspect
Curing/Drying--
process
Transport--
transport

Setups and Batches

Batch processes and setups frequently confuse mapping teams. When this happens, return to the question "What is happening to the product?"

Setups
Batching

Detail Levels

Process maps can depict many levels of detail. Like a Mandelbrot set, every event can expand to reveal more and more detail, as shown in the figure. Determining an appropriate level for the map is vital. With too much detail, the map becomes too large to see or print; too little and important elements are lost.

The best level depends on your purpose. Here are some guidelines:

Workflow & Group Technology-- The objectives here are to simplify movement between departments or develop part families. Operation events normally correspond to operations in the process specification or routings. Often, each operation is in a separate department. When charting at this level, be sure to include all moves, set downs and delays between departments as well as any moves from a departmental staging area to the process equipment.

Workcell Design may require a finer breakdown of the events. Once the product families and cells are selected, only those events within the cell or immediately subsequent and prior need be depicted.

Workstation Design-- At this level, events are quite detailed. In most situations, a process map is not the best way to analyze workstations, although variations such as right-left hand charts are often useful.

Most beginners make their first charts with too little detail and often overlook non-value added events.

In theory, process mapping could be extended to sub-micro maps that show micro-motions. Or, It could extend to global value-chain processes. But, usually, other tools are more suitable for these situations.

The maps below show two levels of detail. The upper map shows individual elements within a workcell such as Head Subassembly and Body-Coil Subassembly. It also shows the moves and delays between these elements within the cell. 

The lower map explodes the Head Subassembly operation into smaller elements. Even this map could conceivably be exploded into micro-motions, but there is not much point in doing so.

At an even higher level than shown below, all assembly operations would compress into the single element, "Assemble Pump." Such a map would work well in sorting out product families.

The first map, below, would be appropriate for workcell design while the second map would help workstation design.


Setting Boundaries

Process maps are most useful at a micro or macro level. Micro level charts show small steps such as "Assemble Cover" and "Adjust Tension." Their boundaries are usually the physical boundaries of a workcell or department.

Macro-level maps show the process on a larger scale and often have boundaries corresponding to the boundaries of the factory. Macro-level maps consolidate small process events into a single larger event such as "Assemble Product."

A road map of Missouri also shows parts of Iowa, Kansas, Illinois and Arkansas. Apply this idea to your process map also. Start a bit upstream from the perceived area of interest and move downstream a bit beyond your area of interest.

For example, if you are concerned with the entire factory, start at the supplier's dock or inbound truck. Include the customer or the outbound truck.

If the project is a workcell design, start with the upstream workcenter or area. In this way, you capture moves in and out. You may discover that factors outside your perceived area of interest have major effects.

Complex Assembly Example

The example below shows an assembly process for commercial dishwashers. Notice how the subassemblies stand out. This particular map was very useful in laying out the assembly area. It was easy to see where subassembly areas should be located with respect to the assembly line. Such process maps can be very large and complex but this reflects the true complexity of the process. It was tempting to take short cuts on the process map. This would have simplified the map but not the process.

Example of Information Charting

In this example, information processes in sales caused many order delays. These information sequences show as dashed lines on the left side of the map. The final product is a roll of automotive pin-striping tape. It starts as a large roll of vinyl sheet

While the manufacturing cycle was longer than the customer order cycle, a finished goods stock allowed immediate delivery once the order was processed. However this long manufacturing cycle created excess inventory and many stockouts.

Both the manufacturing and order cycle times went down by almost 80% with large savings in inventory, labor and increased customer service.

ZoomIn

Present State

Present State Information flow Process map
ZoomIn

Future State

Future State Information Flow Process Chart

 

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Value Stream & Process Mapping

The Strategos Guide To Value Stream and Process Mapping goes  beyond symbols and arrows. In over 163 pages it tells the reader how to do it and what to do with it.

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