I have participated in some paper machine trials that failed badly but taught some valuable lessons.
In the early 1990s, when everyone wanted recycled content, we added some supposedly "clean" pressroom clippings from a magazine run into the machine chest of a newsprint machine.
We ended up with staples all over the paper machine! This taught us the importance of screens and cleaners for recycled pulp (and never trusting recycled streams to be free of contaminants).
Another time, in attempting to meet a brightness target, we ran high levels of calcined clay. It took a few days until it was discovered that the highly abrasive clay was wearing out some of the equipment. We learned to set an upper limit on its use.
As pointed out by 19th century American educator Amos Bronson Alcott, "Our... best lessons are not learned through success, but through misadventure."
I learned another valuable lesson when I was a summer student. We had spent a few days building an elaborate plastic device held together with silicone caulking, and I was told to dry it in an oven at 100°. Fifteen minutes later, I opened the oven door and found the device warped out of shape, useless. It turned out my instructions were meant to be in degrees Fahrenheit rather than Celsius. This illustrates the need for clear communication whenever doing something new.
Any budding scientist is taught about the scientific method. This method teaches us to make observations in order to develop a hypothesis about how things work, and then use that understanding to predict future behaviour. Well-designed experiments can test these hypotheses. We can then develop improvements based on that understanding.
In the pure sciences, the scientific method works well and is relatively easy to apply. But add in human behaviour, emotions and strong opinions, and things can go wrong. Double-blind studies have to be used in evaluating medicines to avoid the placebo effect, and supposedly scientifically-designed surveys can be biased by the way the questions are posed.
Paper machines are very complex systems and it's often hard to be in control of the papermaking process. My colleagues and I working in research and development used to joke about how papermakers solve any problem: look for the last change made and reverse it! When that change was part of an experiment we were running, you can understand our frustration. The design of experiments (trials) in the paper industry needs both good planning and good communication. We had to educate the papermakers about a few things, for example:
a) changing results are expected when changing the recipe, and usually many changes are required to arrive at the optimum dosage;
b) the change in results may be within experimental variation - wait a little longer before rushing to judgment and reacting;
c) the papermaking system may self-adjust to the change over time, as the white water is recycled.
Of course, papermaking trials are expensive, especially if they result in off-spec paper that has to be rejected. The risks can be minimized by doing extensive lab trials to understand the expected effects, developing clear trial objectives, communicating those objectives with everyone involved or affected, making frequent measurements before, during and after the trial, and developing contingency plans in case of unexpected results.
In these days of striving for lower costs and higher efficiency, continuous improvement of processes is important. With high levels of employee turnover due to retirements, it's important to remind new employees that there's a lot of science involved in the pulp and paper industry, and the scientific method is still a key tool for process improvement.
Martin Fairbank has worked in the forest products industry for 31 years,
including many years for a pulp and paper producer and two years with
Natural Resources Canada. With a Ph.D. in chemistry and experience in
process improvement, product development, energy management and lean
manufacturing, Martin currently works as an independent consultant,
based in Montreal. He is also an author, having recently published
Resolute Roots, a history of Resolute Forest Products and its
predecessors over the last 200 years.
Martin Fairbank Consulting
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