Surface texturing has emerged in the last decade as a viable option of surface engineering resulting in significant improvement in load capacity, wear resistance, friction coefficient etc. of tribological mechanical components. Various techniques can be employed for surface texturing but Laser Surface Texturing (LST) is probably the most advanced so far. LST produces a very large number of micro-dimples on the surface and each of these micro-dimples can serve either as a micro-hydrodynamic bearing in cases of full or mixed lubrication, a micro-reservoir for lubricant in cases of starved lubrication conditions, or a micro-trap for wear debris in either lubricated or dry sliding. The present paper reviews the current effort being made world wide on surface texturing in general and on laser surface texturing in particular. It presents the state of the art in LST and the potential of this technology in various lubricated applications like mechanical seals, piston rings and thrust bearings. The paper also describes some fundamental on going research around the world with LST.

State of the art in Laser Surface Texturing

Overview no. 55 Wear-Mechanism maps

Surface texturing has emerged in the last decade as a viable option of surface engineering resulting in significant improvement in load capacity, wear resistance, friction coefficient etc. of tribological mechanical components. Various techniques can be employed for surface texturing but Laser Surface Texturing (LST) is probably the most advanced so far. LST produces a very large number of micro-dimples on the surface and each of these micro- dimples can serve either as a micro-hydrodynamic bearing in cases of full or mixed lubrication, a micro-reservoir for lubricant in cases of starved lubrication conditions, or a micro-trap for wear debris in either lubricated or dry sliding. The paper reviews the current effort being made world wide on laser surface texturing in particular. It presents the state of the art in LST and the potential of this technology in various lubricated applications like mechanical seals, piston rings, thrust bearings, magnetic recording etc. The paper also describes some fundamental on-going research around the world with LST.

State of the Art in Laser Surface Texturing

https://cyberleninka.org/article/n/544115.pdf

Hydrodynamic lubrication of textured surfaces: A review of modeling techniques and key findings

Texture and mouthfeel arising from the consumption of food and beverages are critical to consumer choice and acceptability. While the food structure design rules for many existing products have been well established, although not necessarily understood, the current drive to produce healthy consumer acceptable food and beverages is pushing products into a formulation space whereby these design rules no longer apply. Both subtle and large scale alterations to formulations can result in significant changes in texture and mouthfeel, even when measurable texture-related quantities such as rheology are the same. However, we are only able to predict sensations at the initial stages of consumption from knowledge of material properties of intact food. Research is now on going to develop strategies to capture the dynamic aspects of oral processing, including: from a sensory perspective, the recent development of Temporal Dominance Sensation; from a material science perspective, development of new in vitro techniques in thin film rheology and tribology as well as consideration of the multifaceted effect of saliva. While in vivo, ex vivo, imitative and empirical approaches to studying oral processing are very insightful, they either do not lend themselves to routine use or are too complex to be able to ascertain the mechanism for an observed behaviour or correlation with sensory. For these reasons, we consider that fundamental in vitro techniques are vital for rational design of food, provided they are designed appropriately to capture the important physics taking place during oral processing. We map the oral breakdown trajectory through 6 stages and suggest a dynamic multi-scale approach to capture underlying physics. The ultimate goal is to use fundamental insights and techniques to design new food and beverages that are healthy yet acceptable to consumers.

Oral processing, texture and mouthfeel: from rheology to tribology and beyond

Real area of contact and boundary friction in metal forming

A Thermal Elastohydrodynamic Inlet Zone Analysis

Surface asperity deformation during sheet forming

An analytical model for strip rolling operating in the mixed regime is developed. The model combines analysis for the influence of bulk plastic deformation on the effective hardness of the strip asperities with an approach to allow for the influence of roughness on lubricant flow. An approximate correction for thermal effects is also included. The predictions of the model are compared with experimental measurements of film thickness and slip. Presented as a Society of Tribologists and Lubrication Engineers paper at the STLE/ASME Tribology Conference in New Orleans, Louisiana, October 24–27, 1993

Mixed Lubrication of Strip Rolling

In the past, many different modes of vibration and causes of rolling chatter have been presented, yet no complete and clear picture of the basic mechanics emerged. In order to control chatter in cold rolling operations, a much better understanding of the basic mechanics of the problem is required. To provide, therefore, a ground work for developing such a basic understanding, in this paper, existing models of a mill stand as well as of the rolling process in the open literature are presented. In addition, existing chatter models, which are formulated to investigate chatter as the consequence of the interaction between the structural dynamics of the mills and the dynamics of the rolling process, are also reviewed.

William R. D. Wilson

Papers

Real area of contact and boundary friction in metal forming

A Thermal Elastohydrodynamic Inlet Zone Analysis

Surface asperity deformation during sheet forming

Mixed Lubrication of Strip Rolling

Review of chatter studies in cold rolling