Review of Problem Solving for Manufacturing Processes, Part 3
We continued our discussion on problem-solving skills in Part 2 by breaking down the “Logical Pathway to Problem Solving.” This sequence of 11 steps produces consistent, reliable results in manufacturing enterprises:
- Identify the problem.
- Describe and define the problem.
- List the symptoms.
- List the known changes.
- Analyze the problem.
- Hypothesize possible causes.
- Test possible causes.
- Take action(s) on the cause(s).
- Test and implement the solution.
- Implement appropriate controls.
- Celebrate, recognize success, and document.
In Part 3, we detailed the first three elements of this 11-step process. In Part 4, we will examine the next four elements, from listing the known changes to testing possible causes. Again, much of what I’m presenting is taken directly from my first book written in 2001,  Process Problem Solving—A Guide for Maintenance and Operation’s Teams.
List the known changes
In Manufacturing Processes—Production and Business, Part 1, I explained that problems are the direct result of changes that have occurred prior to the new, decreased performance level. Even though there is a cause and effect, the change(s) responsible for the performance drop could have occurred at any time prior to the problem arising. For this reason, all changes must be listed and investigated.
Unfortunately, process variables change quickly in many organizations, and the personnel involved often overlook the importance of documenting changes. If you are now investigating a problem without the benefit of consistent documentation, you may be forced to reconstruct the changes by interviewing the process owners. Problem solving ultimately relies on documenting all changes made in the process, including actions taken to repair or improve processes, changes in equipment settings, and variances in raw material lots. If your company does not document exhaustively, then you must insist on this process improvement.
Analyze the problem
After you have developed a complete problem description that details all of the symptoms and changes, you can begin to analyze the problem. Effective analysis attempts to relate the change in performance to symptoms, differences, changes, and times. In other words, your goal is to determine the differences between what the problem is and what it is not, where the problem is and is not, and when the problem occurs and does not.
With an understanding of these four puzzle pieces—symptoms, differences, changes, and times—you are ready to form hypotheses for possible causes. Approach this step with the anticipation that your problem may have one or more root causes.
Hypothesize possible causes
Following your analysis, the next step is to create a list of realistic potential causes. This is not a list of guesses, but a logical and systematic review of the information you have collected. If you need more data to develop this list and make it more useable, then continue to collect the information you will need. Involve as many knowledgeable contributors as possible. A logically developed list reduces the likelihood of reliance on intuition and hunches.
With your list in hand, ask your collaborators how the observed differences in what, where, and when could have caused the problem. Remember, problems represent the outcome of a series of multiple cause and effect relationships.
Test possible causes
Next, distill your list into a shorter rundown of the most probable causes by testing each possible cause against a pre-determined set of test criteria. Using “if-then” statements, one can develop these test criteria quite simply. For example, “If I increase the voltage, then x (x=some predictable event) should happen.” Each possible cause must be looked at individually and only the survivors will be considered among the most probable causes. Your final list will be tested using more rigorous criteria to further zero in on the root cause(s).
Coming in the next post
We will continue our progression through the logical pathway for solving problems by looking at the last four steps. As always, if you have any questions or comments about any of my posts, please leave a message and I will respond.
Until next time,
 Process Problem Solving—A Guide for Maintenance and Operation’s Teams, 2001, Productivity Press
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