Measuring oil thickness to stop machine breakdowns

From a skateboard right up to a jumbo jet, almost every mode of transport we use today needs bearings to keep it going. However, a bearing failure on a production line can mean downtime, lost production and wasted products. What's more, the cost of a single bearing failure in a power station can be more than £100,000.

This is why Professor Rob Dwyer-Joyce of the University of Sheffield's Department of Mechanical Engineering has been working on a solution to the problem. If a lubrication system fails, the oil film between the bearing and the shaft stops working. This causes wear between the two surfaces, vibration, friction, seizure and machine failure.

The problem is that the operation of rotating machines depends on the condition of a lubricant film that is often just a few microns in thickness Professor Dwyer-Joyce has pioneered a novel analytical technique which measures the thickness of lubricating films to predict when a machine's rotating components will fail.

This new technique is the result of research project funded by the Engineering and Physical Sciences Research Council. As part of the project, Professor Dwyer-Joyce developed a new instrument which measures lubricant film thickness in a non-invasive manner.

It has a sensor which emits a special ultrasonic pulse that passes through the bearing shell and reflects back from the lubricated surface. This reflected signal is then recorded and processed to obtain the oil lubricant film thickness to within an accuracy of ±2%.
The device gives localised high resolution readings, provides online rapid measurements and measures films as thin as just 50nm.

This new analytical technique has been commercialised by a spin-out company called Tribosonics. The company is described as the world leader in its field and has developed a set of powerful techniques for monitoring, measuring and investigating film layers in a variety of real world engineering applications.

"Ultrasonics have been used in a wide range of applications. This research is the first time it has been applied to oil films. It will make components work better, machines last longer and ultimately improve people's lives," says Professor Dwyer-Joyce.


For further information, please contact Professor Rob Dwyer-Joyce at:

tel: 0114 222 7736

email : r.dwyer-joyce@sheffield.ac.uk