Job Management System - LogicJMS

Once the boundaries are defined, the process flow diagram (or process flowchart) is a valuable tool for understanding the process using graphic elements to represent tasks, flows, and storage. The following is a flow diagram for a simple process having three sequential activities:

Process Flow Diagram

The symbols in a process flow diagram are defined as follows:

• Rectangles: represent tasks

• Arrows: represent flows. Flows include the flow of material and the flow of information. The flow of information may include production orders and instructions. The information flow may take the form of a slip of paper that follows the material, or it may be routed separately, possibly ahead of the material in order to ready the equipment. Material flow usually is represented by a solid line and information flow by a dashed line.

• Inverted triangles: represent storage (inventory). Storage bins commonly are used to represent raw material inventory, work in process inventory, and finished goods inventory.

• Circles: represent storage of information (not shown in the above diagram).

In a process flow diagram, tasks drawn one after the other in series are performed sequentially. Tasks drawn in parallel are performed simultaneously.

In the above diagram, raw material is held in a storage bin at the beginning of the process. After the last task, the output also is stored in a storage bin.

When constructing a flow diagram, care should be taken to avoid pitfalls that might cause the flow diagram not to represent reality. For example, if the diagram is constructed using information obtained from employees, the employees may be reluctant to disclose rework loops and other potentially embarrassing aspects of the process. Similarly, if there are illogical aspects of the process flow, employees may tend to portray it as it should be and not as it is. Even if they portray the process as they perceive it, their perception may differ from the actual process. For example, they may leave out important activities that they deem to be insignificant.