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Monday, September 29, 2014

A story from the testing lab: Scott-bond

One time I was visiting a customer facility with a Technidyne sales person. We were discussing their biggest challenges and opportunities in the future. While we were there, we had a conversation with the Technical Director. He seemed very distracted. Finally, he asked if we knew anything about Scott Bond testing. {Internal bond strength (Scott-type) according to TAPPI T569 measures the energy required to rapidly delaminate a sheet-type specimen.}

We are certainly not experts on Scott Bond, but we thought we would try to help. We went to the test lab and watched as paper samples came down from the machine floor for testing.  The samples were prepared and tested for a variety of properties as we talked to the Technical Director. He explained that in the last week, the Scott Bond test values were always lower at then end of the first shift each day.  This was resulting in increased chemical and mechanical costs in the pulping process to get the bond strength back up to the specification.  The Director, also, had retrained all the testers and were confident that everyone was using the same sample preparation and testing procedure.  We watched the tester prepare the samples and then test them on the Scott Bond instrument.

We asked that the tester continue to prepare and test samples while we watched. Finally, it struck us. We asked the tester to wash his hands and prepare the next sample WITHOUT getting some potato chips out of the bag and eating them before he handled the sample and tape.  When we said this, everyone stopped for a moment. The tester proceeded to wash his hands as we asked and then prepared the sample and tested it. The values jumped back up to the expected values that were received before noon that day and every other day.

No one could believe how simple the solution to the problem was. The operator, after eating lunch, would bring his potato chips from the lunch room and eat some before each test sequence. The grease from the chips reduced the tack of the tape to the samples.  This resulted in lower internal bond numbers after lunch each day.

Simple audits of your testing practices and operator processes can result in more efficient testing and more reliable data....do it.