• Regarding Compensation of Wear in a Series of Measurement with One Tool Only
• “Carry-Over-“ or “Spill-Over-Effect“

Regarding Compensation of Wear in a Series of Measurement with One Tool Only
(download pdf file)

When we conduct a comparison measurement of three media/lubricants with three cuts/measurements each, the tool will be called into action 18 times (3 x 3 x 2 = 18). Even though with 18 cuts/measurements we not nearly reach the end of tool-life it still is a fact that between the first cut and cut/measurement no 18 a certain wear of the measurement tool takes place, which may falsify the measurement results. In order to avoid such false measurements we either can use a new tool for each medium/lubricant or we employ the TTT-method, which has the ability to fully compensate this wear with one measurement tool only.

As usual with a new measurement tool we conduct three run-ins.

We then start with medium A (three cuts), we continue with medium B (three cuts) and finish the first series of measurement with medium C (three cuts). These series of measurements we denote with A-a / B-a / C-a and create the sum.cuts for each medium.

So as to compensate the natural wear that has taken place up to now, we conduct a second measurement where we do not conduct the following comparative measurements according to A-B-C but rather in converse order; we continue with medium C (three cuts), we follow up with medium B (three cuts) and finally come to an end of the measurement series with medium A (three cuts) and get the summarized sum.cut for each medium (C-b / B-b / A-b).

In so doing we managed to proportionally dispense the wear of the tool, due to rising torques, and are up to undistorted measurement results.

In this context we ask you to kindly regard our fact sheet concerning the so called “Carry-over-Effect” to avoid measurement results.

“Carry-Over-“ or “Spill-Over-Effect“
(download pdf file)

Involved is the mechanism of action, when surface-active additives form so-called reaction layers like iron sulfides, pyrite (FeS). These layers may change the crystalline surface-structure of the tool; they may change the electronic situation locally and enlarge its surface. Attention should be paid to the fact then that in the moment of functioning the additives do not sit on top of the surface – as often is read in books – but rather become the surface themselves. Therefore it sometimes may not be possible to remove these residues from
the tool by “chemical-cleaning” with agents like gasoline, acetone and air drying.

In order not to falsify the results of a measurement series and the results of the measurement series of media/lubricants to be compared with, we are challenged
to optimize our TTTmethodology adjusting it to new findings.

Resultant we recommend conducting two additional measurements for each series, discarding* the first two measurements, not adding them to the creation of a sum-cut.
This is the only way to remove all residues from the tool by mechanical friction (mechanical-cleaning) thus avoiding influence and distortion by Carry-Over resp. Spill-Over.

The addition of three “cleaning-cuts” for each medium to the TTTmethodology is indeed the only viable way which in the light of serious consideration may cover various advantages.

Firstly, by mechanical cleaning we avoid falsification of measurements, secondly, with analysis we gain additional parameters of evaluation and insights into the properties and efficiency of additives. And thirdly we can convert this perception in practical experience and at the same time prove factual knowledge by cause and effect.

By this procedure we prevent a possible Carry-Over-Effect which may distort / falsify the
next measured formulation.

* With “discarding” is meant, not to include these cuts into the measurements of the medium. We however recommend storing these cuts in an extra file