Problem-Solving—the Old-Fashioned Way

These techniques can be effective in addressing any type of problem.

Columns From: 1/20/2014 Modern Machine Shop,

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Wayne Chaneski

Example of a fishbone diagram.

Problems surface in all companies. Often the longer it takes to solve these problems, the greater the impact. While the team approach to problem-solving has proven time and again to be the most effective, the techniques employed to identify and address the causes of the problems can significantly affect the outcome. Interestingly, two techniques commonly employed for problem-solving are not new, but do have a pretty good track record.

The first problem-solving technique, and the one that I have found to be most useful, is the cause and effect diagram, more commonly known as the “fishbone diagram.” This technique can be used for virtually any type of problem. It starts with a description of the problem recorded on a horizontal line in the center of what will ultimately become a detail-filled diagram. Next, possible causes of the problem are listed on radial lines originating from the horizontal line (first-level causes). Possible causes of these causes (second-level causes) are then listed on lines originating from the other radial lines. This continues until there is confidence that the “root causes,” or the true reasons that problems occur, are identified. In the example in Figure 1, the problem of an obvious quality defect has eight possible causes. For the sake of brevity, only one of these causes is explored to the fullest, resulting in two root causes that need to be addressed with either corrective actions (such as retraining, introduction of checklists or implementation of quality at the source techniques) or countermeasures (physical or systemic changes to equipment, documents, tooling, etc.) that reduce the likelihood of recurrence.

Like any tool, a cause and effect diagram is just a means to an end. Often the real benefit of employing this technique is the value gained from the interaction of the participants, who learn from each other as they focus on the shared goal of solving a problem in which they all have a stake.

The second commonly used problem-solving technique is the “Five Whys.” Although simpler in application than the cause and effect diagram, the Five Whys can also be highly effective in finding the cause of problems. In practice, the Five Whys process starts with all participants being asked for reasons why a specific problem occurred. Each reason given is recorded and a follow-up Why question is asked. These responses are also recorded, and the process continues until a most likely cause is determined. Generally, a viable reason for the problem is discovered during the fifth round of Why questioning.

For example, let’s say the quantity of parts recorded on a completed work order did not match the actual quantity produced. One Why path could start with the operator writing the wrong quantity on the work order. From there, the Five Whys could produce the following:
1. Why did the operator write the wrong quantity on the work order?
Answer: The counter on the machine was wrong.
2. Why was the counter on the machine wrong?
Answer: The counter was not cleared after the previous job.
3. Why was counter not cleared after the job?
Answer: The operator rushed the machine setup and did not clear the counter.
4. Why was the operator rushed?
Answer: He was told the job was “hot” and had to get out today.
5. Why did the operator not clear the counter on the hot job?
Answer: He did not follow the proper sequence of setup steps for this job.

Using the Five Whys enables us to view the causes of problems as learning opportunities. As such, in this example, the corrective action should focus on assuring all steps involved in a setup are followed, regardless of the urgency of the job. Rather than simply blaming the operator for the oversight, the introduction or refinement of a checklist could provide a visual reminder of the need to clear the counter at the start of each job. Alternatively, perhaps a physical interlocking of the counter to the machine’s control panel would reduce the chance of a recurrence of this cause.

Another benefit of using the Five Whys is that it enables us to see past any preconceived notions brought about by our own experience. Working alone on this problem, we may never have considered a Why path related to an inaccurate counter reading, as our individual focus may have been on how the parts went missing. Using the Five Why approach with a team increases the chance that a counter-related cause could be revealed.

As you can see, cause and effect and Five Why techniques are worth considering when the need for problem-solving arises in your company.

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