 In days gone by, a reputable troubleshooter was an invaluable human resource in papermaking. When all attempts to eliminate the cause(s) of process upsets failed, this person could be called upon to save the day. This person might be a member of the mill staff, a supplier, or a consultant. Since process monitoring and control were not advanced to today's levels, these special persons possessed unique training or experience sometimes not available among most mill technical or operating personnel. Troubleshooters were often recognized for intuitive reasoning skills that could introduce fresh ideas into the solving of difficult problems.
Some larger mills and supplier companies recognized the value of "rapid response" groups at the corporate level. These groups included both experienced engineers and skilled practical papermakers. Their survival as "go to" groups depended on their reliability. They were also used to share information between mills and to introduce new technologies. Their reputations were often dependent upon being able to solve problems in a cost effective manner, as viewed by the respective mills or customers. While working in the industry, I recognized that International Paper had such a support group operating out of Mobile, Alabama, with a strong reputation in this regard.
Another approach to the quick solving of problems included using both a technical superintendent and a practical superintendent on paper machines, to take advantage of their complimentary skills. A few mills even elected to staff specialized manufacturing engineering groups locally, but over time many of these were eliminated due to overhead costs.
Eventually mills began to understand that effective problem solving was not limited to relying on a few skilled troubleshooters, although such personnel might remain as human resources assets if available. The new understanding began with the basic definition of troubleshooting as a logical and systematic approach to solving a problem. And although the need to solve papermaking problems quickly was of utmost importance, there had to be a better way than a "shot gun" approach to stabilizing an out-of-control process. Included below are some of the basic techniques that have been used. None of these methods is likely to succeed without a complete and accurate description of the problem symptoms.
• Check the simple things first. Don't automatically assume that the problem is so complex that it will take days of analysis to find the cause(s). Make a quick check of the key process variables to determine if something is obviously out of control. This includes checking both instrument outputs and statistical process control records.
• Rely on checklists and records. If a problem is not totally unique, it may be that a similar situation has been experienced in the past. Having quick access to the solutions previously documented may result in narrowing down the possible cause(s).
• Serial substitution involves making specific changes in each variable that is felt to affect the control of the process significantly, and then determining if the problem experienced is reproduced. (Major papermaking problems do not usually allow for either the time or cost associated with using this technique.)
• Develop a "top ten" list of most likely solutions to the problem. This involves developing input from both operating and technical personnel, and a probability is assigned to each item. Of course, the highest probability solutions are applied first in attempt to eliminate the problem. This approach uses the logic of the Pareto Analysis introduced in the 1940's, which is based on the premise that 80% of problems are caused by 20% of the key causes. The technique is a refinement of the shot gun approach, but may not reliably result in finding the specific cause(s) of the problem, even if the end result is favorable.
• Contact key vendors for ideas. Due to supplier visits in many mills and their exposure to a range of papermaking problems, it is possible that they have knowledge that could be useful in pinpointing problem causes.
• Communicate with personnel of other mills. The paper industry has always been considered a "fraternity" in many ways. In difficult problem situations, outside mill contacts may be willing to provide valuable input to help solve what they consider to be a generic industry problem.
• Conduct a root cause or cause/effect type analysis. Many papermaking problems are too complex to be solved using one of the aforementioned techniques. In addition, mills may not accept arriving at "solutions" without knowing the actual problem causes, since it is likely the situation will be repeated at some future time. In these cases, more sophisticated methods have been used successfully. Root Cause Analysis helps find the initiating or fundamental cause(s) of a problem. After the problem is accurately defined, the issue is examined from the standpoints of how it may have happened, why, and what can be done to prevent it from happening again. Physical, human, and organizational effects are taken into consideration. Accepting that there is likely no single cause for the most difficult problems, each possible cause is assigned a probability related to its influence on the effect. One of the most successful methods of this type is the Kepner-Tregoe®, analysis introduced in the 1950's. Other cause/effect methods originating in the 1960's included the Isikawa® or "fishbone" analysis, which develops many potential problem causes. Still another is the Fault Tree® analysis method, which is a cause-elimination technique based on deductive failure considerations beginning with the top failure-causing candidate. While all these methods have the disadvantage of being used "after the fact", they can be very useful in identifying areas that need improved process control.
Troubleshooting can be an exciting and rewarding part of the papermaking experience, but it is a time consuming and costly function. Consequently, the primary objective must be to eliminate as much process variation as possible, in order to minimize defects in the finished product. To accomplish this, many mills have now initiated Six Sigma quality management to the largest extent possible, which is equivalent to 3.4 defects per million opportunities. Those who are successful problem managers will not only increase their profit margins, but should also significantly decrease the need to troubleshoot process upsets frequently.
Robert Moore is a retired chemical engineer, and is an experienced technical and fictional writer. His past work experience spanned the chemical, paper and equipment manufacturing industries, including holding management positions at Voith Paper, Scapa plc, and The Mead Paper Corporation. He is also the author of humorous short stories about life in southwest Virginia, circa 1940-1960.
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