Eight Disciplines (8Ds) Problem Solving is a method developed at Ford Motor Company used to approach and to resolve problems, typically employed by engineers or other professionals. Focused on product and process improvement, its purpose is to identify, correct, and eliminate recurring problems. It establishes a permanent corrective action based on statistical analysis of the problem and on the origin of the problem by determining the root causes. Although it originally comprised eight stages, or 'disciplines', it was later augmented by an initial planning stage. 8D follows the logic of the PDCA cycle. The disciplines are:
Contents
- Ford Motor Companys Team Oriented Problem Solving
- Usage
- Benefits
- Disadvantages
- Problem Solving Tools
- Background of common corrective actions to dispose of nonconforming items
- Military usage
- Relationship Between 8D and FMEA
- References
8Ds has become a standard in the automotive, assembly, and other industries that require a thorough structured problem-solving process using a team approach.
Ford Motor Company's Team Oriented Problem Solving
The executives of the Powertrain Organization (transmissions, chassis, engines) wanted a methodology where teams (design engineering, manufacturing engineering, and production) could work on recurring chronic problems. In 1986, the assignment was given to develop a manual and a subsequent course that would achieve a new approach to solving identified engineering design and manufacturing problems. The manual for this methodology was documented and defined in Team Oriented Problem Solving (TOPS), first published in 1987. The manual and subsequent course material were piloted at Ford World Headquarters in Dearborn, Michigan. Ford refers to their current variant as G8D (Global 8D). The Ford 8Ds manual is extensive and covers chapter by chapter how to go about addressing, quantifying, and resolving engineering issues. It begins with a cross-functional team and concludes with a successful demonstrated resolution of the problem. Containment actions may or may not be needed based on where the problem occurred in the life cycle of the product.
Usage
Many disciplines are typically involved in the "8Ds" methodology. The tools used can be found in textbooks and reference materials used by quality assurance professionals. For example, an "Is/Is Not" worksheet is a common tool employed at D2, and Ishikawa, or "fishbone," diagrams and "5-why analysis" are common tools employed at step D4. In the late 1990s, Ford developed a revised version of the 8D process that they call "Global 8D" (G8D), which is the current global standard for Ford and many other companies in the automotive supply chain. The major revisions to the process are as follows:
Recently, the 8D process has been employed significantly outside the auto industry. As part of lean initiatives and continuous-improvement processes it is employed extensively in the food manufacturing, health care, and high-tech manufacturing industries.
Benefits
The benefits of the 8D methodology include effective approaches to finding a root cause, developing proper actions to eliminate root causes, and implementing the permanent corrective action. The system also helps to explore the control systems that allowed the problem to escape. The Escape Point is studied for the purpose of improving the ability of the Control System to detect the failure or cause when and if it should occur again. Finally the Prevention Loop explores the systems that permitted the condition that allowed the Failure and Cause Mechanism to exist in the first place.
Disadvantages
Requires training in the 8D problem-solving process as well as appropriate data collection and analysis tools such as Pareto charts, Fishbone Diagrams, and process maps.
Problem Solving Tools
The following tools can be used within 8D:
Background of common corrective actions to dispose of nonconforming items
The 8D methodology was first described in a Ford manual in 1987. The manual describes the eight-step methodology to address chronic product and process problems. The 8Ds included several concepts of effective problem solving, including taking corrective actions and containing nonconforming items. These two steps have been very common in most manufacturing facilities, including government and military installations. In 1974, the U.S. Department of Defense (DOD) released “MIL-STD 1520 Corrective Action and Disposition System for Nonconforming Material”. This 13 page standard defines establishing some corrective actions and then taking containment actions on nonconforming material or items. It is focused on inspection for defects and disposing of them. The basic idea of corrective actions and containment of defectives was officially abolished in 1995, but these concepts were also common to Ford Motor Company, a major supplier to the government in World War II. Corrective actions and containment of poor quality parts were part of the manual and course for the automotive industry and are well known to many companies. Ford's 60 page manual covers details associated with each step in their 8D problem solving manual and the actions to take to deal with identified problems.
Military usage
The US Government standardized a procedure during the Second World War to address nonconforming material in Military Standard 1520, Corrective Action and Disposition System for Nonconforming Material. This military standard focused on nonconforming material and the disposition of the material.
Relationship Between 8D and FMEA
FMEA (Failure Mode and Effect Analysis) is a tool generally used in the planning of product or process design. The relationships between 8D and FMEA are outlined below:
- The problem statements and descriptions are sometimes linked between both documents. An 8D can utilize pre-brainstormed information from a FMEA to assist in looking for potential problems.
- Possible causes in a FMEA can immediately be used to jump start 8D Fishbone or Ishikawa diagrams. Brainstorming information that is already known is not a good use of time or resources.
- Data and brainstorming collected during an 8D can be placed into a FMEA for future planning of new product or process quality. This allows a FMEA to consider actual failures, occurring as failure modes and causes, becoming more effective and complete.
- The design or process controls in a FMEA can be used in verifying the root cause and Permanent Corrective Action in an 8D.
The FMEA and 8D should reconcile each failure and cause by cross documenting failure modes, problem statements and possible causes. Each FMEA can be used as a database of possible causes of failure as an 8D is developed.