What to expect from a rheology measurement service laboratory?
Are you looking for a rheology service laboratory for your emulsions, gels, powder, resin or other suspension?
You will find a number of them, both public and private; but beware, rheology often makes people disappointed. Here are some recommendations and points for reflection to assist you in your efforts.
Do you really want a viscosity measurement?
Becoming aware of the limitations of Brookfield-type viscosity measurement, often incapable of distinguishing between products with concrete behaviors that are nevertheless significantly different, many industrial players request viscosity measurements on a rheometer, hoping to find immediate answers to their outstanding questions.
If the challenge is to better distinguish products, it is reasonable to entertain such hopes: producing a flow curve on a rheometer is often able to unambiguously differentiate products that are indistinguishable by viscometry.
However, the common problem is that distinguishing products is not enough to understand their concrete behavioral differences. Worse: some differences in behavior may prove to be inconsistent with empirical observations. Thus, many actors find themselves with data that they do not know what to do with. Some even go so far as to conclude that “rheology doesn't work”.
Our advice: ask your future educational provider. There are many possible tests on a rheometer, useful for quantifying various rheological behaviors (viscoelastic properties, yield point, thixotropy, etc.), but also physical behaviors in the broad sense (see our article “What can a rheometer do? »), it is up to him to be able to explain to you clearly and simply the contributions of the different approaches according to your context. Obviously, for this, the analysis of the problematic context is essential.
The importance of the concrete operating context
We never look for rheological measurement without an underlying concrete problem.
In our experience, the surest way to determine the most appropriate measurement approaches for a concrete problem is to carry out the analysis of the phenomena involved in the concrete context. The couplings between materials, formulation, process, equipment, application are generally complex and highly sensitive (non-linear in more scientific language). An approximate analysis most often leads to inconclusive results from which it is difficult to extract concrete actions.
Our advice: challenge your future partner on his understanding of your problem. Many approaches in rheology - and elsewhere - fail because of a study plan designed based on an a priori and erroneous view of the relative importance of influencing factors. A quality service provider must also be a relevant interlocutor on these issues.
Going beyond rheology to address industrial issues
More than ten years of advanced practice of rheology have shown us that a considerable number of concrete problems require going beyond the strict framework of rheology, in the analysis of the problem as well as in the experimental approaches.
Whether it is a question of mobilizing approaches relating to fluid mechanics, the physics of interfaces, physico-chemistry, thermomechanical processes, tribology, it is above all the analysis of phenomena which must guide the approaches , from the design of the studies to the interpretation of the results.
Our advice: expect your future service provider to provide you with a better understanding. The interpretation of the results is often as (or even more) important than the measurement itself. Do not hesitate to challenge your future service provider on its methodology.
The importance of industrial consulting
The main frustration that disappointed users of rheology share with us concerns the ability of service providers to extract operational keys from the measurement or study process.
Adequate interpretation of the curves is one aspect of this, the ability to draw practical recommendations from them in terms of formulation, processing, control of influencing factors, predictive methods, is no less essential.
Our advice: favor the choice of an actor able to respond to the different aspects of your problem. The rheological measurement is enough if you know clearly why you need it and you are able to use it. In all other cases, it is the skills of your service provider that will help you on this path.
If you want to know more, do not hesitate to consult our various articles in the Documentation section.
We are also at your disposal to answer your questions.
Last Updated on March 9, 2023 by Vincent Billot