Wednesday, 8 August 2018

Fishbone diagram

The Fishbone diagram or also known as Ishikawa diagram is a causal diagram created by Kaoru Ishikawa (1968) which shows the causes of specific events.

Ishikawa diagrams are use in the planning of a product to prevent the occurrence of defects or degradation of quality, by identifying potential causes of defects that cause certain effects. Every cause of imperfection is the source of variation. The causes are usually group into main categories to identify the sources of those variations. The main categories are usually:

  • Man: anyone involve in the process.

  • Method: how the process runs and some things to watch out for before the process goes, such as policies, procedures, rules, regulations and laws.

  • Machines: equipment, equipment, computers, tools, etc., need to do the work.

  • Material: raw material, part, paper, pen, etc ..., which is use to produce finish goods.

  • Measurements: data taken from the process use to evaluate the quality of the process.

  • Environment: environmental conditions such as location, time, temperature, and culture where the process operates.

Causes Factors

The causal factors in Ishikawa diagram or fishbone diagram are categorize and known as 6M. This Ishikawa diagram can reveal the relationships among variables that are diverse, and those causal factors will present additional facts about the process behavior.

Causal factors can be obtain by brainstorming. The categories that appear can be some of the above mention, as well as something else. To identify the causal factor can use root-cause analysis or 5 Whys (why why analysis) method.

Common Causes Categories are:

6M Concept for Manufacturing Industry:

  • Machine (technology)

  • Method (process)

  • Materials (including raw materials, consumables and information)

  • Man-power (physical workers) and Mind-power (non-physical workers)

  • Measurement / measurement (inspection)

  • Mother Nature (environmental factors)

The Fishbone diagram uses the 6M concept originally use in the Toyota Production System (TPS). The concept of 6M has been develop in such a way as to form the 8M formation. But the concept of 8M is not widely known. Some of the concepts taught stick to a simple and easy-to-understand system; do not use the term 8M. Two additional causes in manufacturing are: Management / Money Power , and Maintenance.

Fishbone Diagram 7P Concept for the Marketing Industry:

  • Product = service

  • Price

  • Place

  • Promotion

  • People / personnel

  • Process

  • Physical Evidence

Fishbone Diagram 5S Concept for Service and Service Industry:

  • Surroundings (environment)

  • Supplier

  • System (customer service system)

  • Skill

  • Safety (safety)

Questions to Ask When Creating Fishbone / Ishikawa Diagram

Man / Operator (worker)

  • Are the existing documents comprehensively understood?

  • Has the information been properly channel to all functions in the process?

  • Did the recipient of the information have understood the messages convey?

  • Has there been enough training for employees?

  • Is there too much assessment to do before starting work?

  • Are guidelines for making those assessments available?

  • Does the environment affect individual work activities?

  • Are there any disruptions occurring in the work area?

  • Are there issues related to worker fatigue?

  • Is the work efficiency of the employees acceptable?

  • Are employees accountable and reliable enough?

  • Do employees qualify?

  • Do employees have enough experience?

  • Is good employee health?

  • How much experience does the employee have in performing specific tasks?

  • Can employees do work without errors?

Machinery and Equipment

  • Are the tools and tooling use correct?

  • Is the machine use exactly to the needs of production?

  • Does the machine meet the process capability?

  • Is the file save with the correct extension in the right place?

  • Is the equipment affect by environmental conditions?

  • Is the equipment getting proper care (daily / weekly / monthly maintenance)?

  • Do software and hardware need to be update?

  • Do equipment and software have capabilities that meet the needs of use?

  • Is the machine getting proper care?

  • Is the machine well program?
    Is tooling and featuring adequate to do the job?

  • Does the machine have proper protection?

  • Is the equipment use according to their capabilities and limitations?

  • Do all controls including emergency stop buttons have been properly label and are color codes and size codes complete?

  • Are the appropriate equipment and machinery use to perform the process to be perform?

Measurement / Measurement

  • Does the gauge have a valid calibration date?

  • Is gauge feasible to measure part, process, chemical, compound, etc.?

  • Has the study of gauge capability ever been done?

  • Do the measurements between one operator and another vary significantly?

  • Does the operator find it difficult to use the available gauge? Is fix Turing gauge sufficient?

  • Does the gauge have the right measurement resolution?

  • Does the environment affect the measurement results?

  • Materials (including raw materials, consumables and information)

  • Is all the require information available and accurate?

  • Can information be verify and cross-check?

  • Is there information change recently?

  • Is the information kept up-to-date?

  • What will happen if the require information is not entirely available?

  • Is Material Safety Data Sheet (MSDS) available?

  • Is the material use well test? Are the materials available / substitute?

  • Has the process undertaken by suppliers been define and control?

  • Is there a defect in the raw material?

  • Is the material contaminate?

  • Is the material handle properly (storage, use and disposal)?


  • Can the canister, barrel, etc., have been properly labeled?

  • Have the employees been properly trained on procedures?

  • Is the testing performed statistically significant?

  • Has the data been tested to find the root cause?

  • How many words "if required" and "maximum" are found in this process?

  • Is this process done by the Integrated Product Development (IPD) team?

  • Does the IPD team implement the principles of Design for Experimental (DFE)?

  • Has a feasibility study been undertaken for this process?

  • Does the process run in accordance with Statistical Process Control (SPC)?

  • Are job instructions clearly written?

  • Have mistake-proofing techniques and tools been use?

  • Are the work instructions detail?

  • Have the existing work standards been update according to the latest revisions?

  • Has the tooling been adequately designed and control?

  • Are handling and packaging well specify?

  • Has the process change?

  • Has the design change?

  • Is the lighting and ventilation system feasible?

  • Is the Failure Mode and Effect Analysis (FMEA) ever done?

  • Has adequate sampling been done?

  • Do all security-related features have been clearly communicate to the operator?


  • Is the process affect by temperature changes in a day?

  • Is the process affect by moisture, vibration, noise, lighting, etc.?

  • Does the process run in a control environment?

  • Are employees bother by noise, uncomfortable temperatures, fluorescent lighting, etc.?


  • Is management's involvement clearly visible? Lack of management involvement results in:

  • Negligence in work.

  • Potential hazards in the work are not well prevent.

  • Employees feel depress, lack of attention.

  • Lack of process.

  • Inadequate training and education for employees.

  • Lack of employee involvement in tasks.

  • Lack of capability regarding the hazards and risks of the process.

  • The previously identify risks are not lost.

The fishbone diagram (Ishikawa diagram) is mainly use in product design in order to identify possible factors causing an overall effect. The fishbone diagram has two sides, cause and effect.

Fishbone diagram shows you the causes of the related problems graphically. Fishbone diagram consists of a rectangular box on the right hand side, where the effect which is to be examine is written. On the cause side of the diagram are the factors that influence the effect. Causes grow out of the horizontal line, which is the main body. There may be further smaller bones stressing more exact aspects of a certain cause.

Fishbone diagram is use to identify major or minor reasons for a specific problem and also to identify the root causes if any.

Although Fishbone diagram can determine the possible causes but it does not make clear the sequence or importance / magnitude or likelihood of causes.

No comments:

Post a Comment