Process Mapping Tips

Level of Detail

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 below.

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.

Determining the best level and following it consistently is something of an art and talent. It develops with practice. 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.

Rules of Thumb

Storage & Delay--

• When a product is in an official storage location with a record, use the Storage symbol.

• If the product is set aside casually to wait for a fork truck, for example, use the Delay symbol.

• Set a time, say five minutes, below which a Delay will not be shown.

Handling & Transport

• If the product moves more than three paces, use the Transport symbol.

• If the product is sorted, rearranged or moved less than three paces, use the Handling Symbol.

• If a delay is more than five minutes for a macro-level map, show it. Otherwise consider it as part of an adjacent event. Use a 30-second limit for micro-level maps.

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

Information Flows

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

To map information, consider information as packet such as a work order or a database record. Think of it as a component necessary to complete a subsequent event. You can chart information with dashed lines as in this example

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.

During the mapping session the entire team needs to see the entire map. At the same time each individual must be able to focus on any detail that sparks a thought.

Draw the map on butcher paper large enough for everyone to see. This may require several walls in an average conference room. Later the map can be redrawn with computer tools for distribution. (Example)

Setups and Batches

Batch processes and setups frequently confuse mapping teams. When this happens, return to the question "What is happening to the product?" During a setup, nothing happens to the product. It simply waits for the completion of the setup.

The setup is a separate process and can be studied as such. It has nothing to do with product other than causing a delay.

In addition, batches always have a delay before and after an operation while the remainder of the batch is processed. Moves often have delays when they wait for material handlers. This map detail shows a typical batch operation with setup.

 Ideal State Map

An "Ideal State Map" is useful and easy to construct. An ideal

 process has no waste so we simply take the "Current State" map and eliminate non-value adding events, as shown.

Real processes seldom approach this ideal state. However, the ideal state map helps us to focus on the value added events. It provides a benchmark.

See "A Mental Model" for another view of this ideal process.

Future State Map

With current and ideal state maps, a team has a deep and common knowledge of the process. Their next task is to identify improvements and illustrate them with a "Future State" map.

A future state map bridges the gulf between the current and ideal states. It incorporates the realities of technical limits, budgets and time.

Developing a future state map is often surprisingly easy. The primary tools are Brainstorming and what Alan Mogensen, Work Simplification pioneer, called "The Questioning Attitude."

Measuring the Results

Once complete, the team can measure results in several ways. The simplest is to count the symbols and construct a frequency percent histogram as shown below.

Processes that have not been studied and refined generally show 10%-20% added value. Future state processes typically show 20%-40% added value and eliminate half of the wasteful events.

This is a crude but effective metric. Elapsed time, labor hours or cost might also be used.

Software

Many software packages are available for mapping. Most are specialized drawing programs. They can serve to cleanup and document the resulting map.

ProPlanner is a software package that helps manage the entire industrial engineering process. It can generate Value Stream and Process Maps from the process database found in MRP and ERP systems. However, these maps rarely include all the non-value adding events.

More on Process Mapping

The How-To of Process Mapping
Facilitating A Mapping Team
Process Mapping Example
Information Flow Example
Future State Process

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