Materials

Development of ambient temperature cured metal and ceramic matrix composites
Use of composite material is increasing due to economical processing of complicated shapes in large quantities. Addition of fiber/particulates improves the composite strength. In the current study, the tribological characterisations of polymer based particulate composites which are processed at room temperature are investigated. The friction and wear behaviour of styrene reinforced with metal and ceramic powders are being investigated under different operating conditions using a pin-on-disc tribometer.

Pin on Disc Tribometer

Wear of cryo treated materials
Problems inherent with conventional heat treatment process significantly affect the performance of components.  Deep Cryogenic Treatment can be utilised as a tool to enhance the properties of a vast majority of the components. Although the enhancement in performance can be explained for steel, the same cannot be explained for other materials in a clear way. For most of the materials cryotreatment is done at 77K. Even though the studies have shown the improvement in wear resistance properties, the physics behind it are not understood very clearly. Recent studies have revealed that the cryotreated racing parts perform very well. Thus Cryogenic treatment is one of the important processes to enhance the wear properties of the material. The project attempts to understand the physics behind the improvement in wear resistance properties of cryotreated materials.  This also involves the detailed study of tribological properties of cryotreated materials and correlation amongst them.

Study of stick-slip phenomena in machine tool slide ways
Linear motion guideways are one of the most critical parts of any machine tool. The main factor affecting the performance of guideways is friction. In the sliding contact guideways, the relative motion between the elements is sliding, thus giving rise to sliding friction. Reduction of friction, either through improved design, or through the use of more suitable contacting materials, or again through the application of better lubricating substances, is thus an extremely important problem of modern technology.

Lubricants and coolants being the mainstay of the automotive and machine tool industry for reducing friction and wear become important from both the operational and manufacturing point of view. Generally speaking, the smoothness of movement is improved by reducing friction. Though frictional force is reduced by the application of lubricant it is also important to keep the frictional force steady. Unsteady or variation in frictional force leads to jerky motion or stick slip in machine tool slideways. Thus, stick slip, in tribology, is a cyclic fluctuation in the magnitudes of friction force and relative velocity between two elements in sliding contact, usually associated with a decrease of the coefficient of friction with onset of sliding or with increase of sliding velocity. In most practical sliding systems these fluctuations of the sliding velocity are considered a serious nuisance, and measures are normally taken to eliminate, or at any rate to reduce the amplitude of the fluctuations.

Linear Reciprocating Tribometer

The requirements of linear guideways and industrial lubricants are rising, especially for machine tools which have to meet various demands such as high positioning exactness, good compatibility with coolants, stick slip free with low coefficient of friction over a wide speed range and good demulsifying behaviour on metallic slideways. The above requirements can be achieved by employing different slideway materials and design of lubricants by the addition of different additives like Boron Nitride etc.

The tribological efficiency of these lubricants with regard to linear guideways is tested using a reciprocating tribometer. The research work envisages investigation of tribological efficiency of lubricant governed by a number of parameters. These include the sliding speed of the mating members, physical and chemical properties of the lubricant, demulsifying behaviour, oil groove design and geometry and the material of the sliding members involved. It is also proposed to investigate some of the tribological issues by replacing the liquid with a solid lubricant such as Molybdenum di-sulphide or Boron Nitride or Graphite impregnated into a polymer. The other aspects of study include possible oil and wear particle analysis.

Linear Reciprocating Tribometer

Slideway Oil Groove Design