Role Of High Temperature Tribometer

By Author: Vishal Khosla
Total Articles: 19
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It is hard to achieve accurate results in high temperatures. This is the reason the devices are manufactured to appreciate the temperature changes by scaling up to proximal accuracy. What this means is that the materials used to hold the samples and take the real time measurements are designed to take accurate measurements, taking out the heat factor.

Many systems have mechanical moving parts and for those with a significant load, the moving parts are normally made using techniques that increase their duty cycle. Some of the problems that have been measured are related to friction, culminating in the tolerance of heat and mechanical wear due to friction. Even with modern greasing methods, there is still some significant wear whose characteristics need to be understood for determining efficiency.

A High Temperature Tribometer is intended to determine the coefficient of friction and the consequent volume of wear between surfaces. The do so by simulating actual scenarios of moving parts that may include a ball, pin on disc, bouncing ball, block on ring among other simulated arrangements.

Some contact mechanical ...
... environments do not run under normal conditions, some are subjected to high temperatures, which can change the results significantly, hence the specialized high temperature.

Let us look at a typical test of Tribometer. Regardless of the arrangement, the following conditions for any simulated environment holds true.

Two moving parts in contact with each other
Unusual operating conditions, for instance, high temperatures.

To simulate a sample arrangement, the pieces are subjected to the following conditions:

Prescribed rate of oscillation or revolution
Prescribed temperatures
Prescribed contact dimensions

The coefficient of friction is the ratio of the loaded force to the frictional force. This measurement is critical in determining the wear of the material in question and the required contact parameters in delivering the required results that precipitated the contact, for example, a cog and wheel.

The second parameter that is determined is the dimensions of the wear pattern that are determined through measuring the volume of the displaced matter on the surface on which contact was achieved. Through determining this, the efficiency, duty cycle and adversity of the simulated environment can be measured and thereby assisting the design team in modifying the contact area, the materials and maximum force recommended for application.

Factors affecting Accuracy

A good High Temperature Tribometer is designed to work at extreme conditions. Truth be told, it is hard to achieve accurate results in high temperatures, which is why the devices are manufactured to appreciate the temperature changes by scaling up to proximal accuracy. What this means is that the materials used to hold the samples and take the real time measurements are designed to take accurate measurements, despite the effect of heat.

In compensating for the varying measurements due to the adverse temperature conditions, the results are computerized and factors and other coefficients applied in reducing the variables towards the desired results.

There are many other minute details that the tester puts to the test like the frequency of oscillation verses wear and granted that some environments cannot be fully simulated without building customized environments, many manufacturers have put it upon themselves to develop a system of customizing the environments in meeting the most accurate emulation of an arrangement. The best test system that would deliver desired results will ultimately utilize actual materials, masses and operating oscillation or revolution frequency. This is basic elimination of variables that would otherwise affect results and could easily prove inaccurate. Actual environments remain ideal, hence costly to achieve, but many studies, including those done using computerized scaling, have proven their necessity.

Author of this article is associated with Rtec Instruments, a California based company that deals in high temperature tribometer, 3D profilometer, atomic force microscope and other instruments.