What is Process flow diagram in quality control?

Process Flow diagram :

It is the graphic representation of the sequence of the steps taken to produce an output. The output can be a product, service or combination of both. It is also called a flow diagram or process flow chart. Flow diagram helps us to understand the process easily how a product is manufactured. It is also the main part of APQP which to be define during Plan and Define phase. Also during PPAP submission, PFD need to be submitted.

How to solve the problem with flow diagram?

A flow diagram enables a quality team to go through a process without going to the workplace. Such understanding of the process often sorts out the potential problems, bottlenecks in the system and extra steps etc.

Flow diagram provides the team a better understanding of the process. It provides a complete understanding of the process to each member of the team easily. So the team takes part in the problem-solving process effectively after understanding the process fully.

When the proper flow diagram is prepared, the team does not need to invest time and energy to observe the process every time it has to discuss the problem. We can easily identify the problem in any process in the flow diagram and high-lite it in the diagram to increase visibility. 

Symbols used in Flow Diagram :

  1. Activity symbol : It is a rectangle, which indicate a single step in the process. Brief description of the process is written inside it.
  2. Decision symbol : It is a diamond which indicate a decision point in the process. Description of decision is written inside the symbol usually in the form of a question. Answer to the question determine the path coming out of the decision symbol.
  3. Storage symbol : It is a triangle which indicates material stored in the process. e.g. Raw material in store.
  4. Delay symbol : It is a D shape symbol which indicate delay or waiting. e.g. Material waiting of further processing
  5. Terminal symbol : It is a rectangle with rounded corners. It identify the start or end of a process.
  6. Connector : It is a circle, which indicate continuation of the flow diagram. A number inside the circle shows the link to the other flow diagram.
  7. Flow Lines : It is the lines, which indicate flow of the flow diagram.
Flow diagram

Types of Process Flow Diagram :

1. High-Level Flow Diagram:  The flow diagram which shows the broad flow of the process. The blocks in the high-level flow diagram usually represent the main function. For example, Orders received from customers, manufacturing of a product etc.

2. Detailed Flow Diagram:  The flow diagram which describes the detail of the blocks of a high-level flow diagram. For example in the case of orders received from customers are as mail received, check for the order, check other details etc.

3. Matrix Flow Diagram:  The flow diagram shows the main activities and processes together with the department in which the process is taking place. 

How to interpret Flow diagram :

Flow diagram helps in understanding the process: A flow diagram is a very useful tool to gain a better understanding of the process.

Flow diagram analysis provides opportunities to make changes that will result in significant improvement in quality, cost and productivity.

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Application of Process Flow Diagram :

Flow diagram
  • To define the project
  • To identify the root cause
  • To design the solutions
  • To implement the solutions
  • To hold the gains

How to construct the process flow diagram:

Group discussion and the free exchange of information are required while constructing a flow diagram. The following steps should be followed for the construction of any type of flow diagram :

  1. Discuss how you need to use the flow diagram.
  2. Decide about the desired result.
  3. Define the boundaries of the process.
  4. Document each step in the sequence from the start to the last step.
  5. When you encounter a decision, select one branch and continue flow diagramming.
  6. If you have doubt about a segment of the process, make a note and continue.
  7. Repeat step no 4,5,6 until you reach the last step in the process.
  8. Go back and make the flow diagram for the other branch from the decision symbol.
  9. Review the flow diagram for any missing points.
  10. When you are confident that the flow diagram is OK and complete, analyze it.

Process Flow Diagram Format:

Process Flow Diagram Format

Download the PFD Format template:

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2 Responses

  1. Inzmam says:

    Well explained thanks for this content

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