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Full-scale deep drawing tests using tools featuring multifunctional surfaces are carried out in a production environment. Multifunctional tools display regularly spaced, transversal grooves for lubricant retention obtained by hard-turning, separated by smooth bearing plateaus realized by robot assisted polishing. Advanced methods are employed to characterise the tools’ surface topographies, detecting the surface features and analysing them separately according to their specific function. Four different multifunctional dies as well as two un-textured references are selected for testing. The tests are run using a non-hazardous, environmentally friendly lubricant, and the forming forces are constantly recorded. Multifunctional dies exhibit very good performances, with no galling occurrence and punch forces generally lower than the two references.

In this paper, Bending-Under-Tension, an off-line test method simulating deep-drawing, is chosen for investigating the effectiveness of multifunctional (MUFU) surfaces in metal forming operations. Four different MUFU surfaces, characterized by a plateau bearing area and grooves for lubricant retention, are manufactured, together with two polished references. During the tests, surface texture is the only variable. The results show how MUFU surfaces perform better than the polished references, which produce severe galling, while MUFU surfaces with low bearing area display no clear evidence of galling. Metal-to-metal contact occurs anyway, but the strip material is pulverized and deposited onto the tool instead of cold-welding to it. The pockets create a discontinuity on the texture hindering pick-up propagation.

The effective characterization of textured surfaces presenting a deterministic pattern of lubricant reservoirs is an issue with which many researchers are nowadays struggling. Existing standards are not suitable for the characterization of such surfaces, providing at times values without physical meaning. A new method based on the separation between the plateau and valley regions is hereby presented allowing independent functional analyses of the detected features. The determination of a proper threshold between plateaus and valleys is the first step of a procedure resulting in an efficient division of the two regions, which can be studied separately according to their specific function. The case of a turned multifunctional profile is presented depicting the lacks in efficacy of standardized methods and therefore studied with this new methodology. Limitations of the method are eventually presented, in particular its dependence on a proper leveling of the profile beforehand.

Throughout the years, it has become more and more important to find new methods for reducing friction and wear occurrence in machine elements. A possiblesolution is found in texturing the surfaces under tribological contact, as demonstrated by the development and spread of plateau-honed surface for cylinder liners. To prove the efficacy of a particular textured surface, it is paramount to perform experimental tests under controlled laboratory conditions. In this paper, a new test rig simulating pure sliding conditions is presented, dubbed axial sliding test. It presents four major components: a rod, a sleeve, a housing and a stripwound container. The rod and the sleeve are the two surfaces in relative sliding motion; the stripwound container maintains a constant, but adjustable normal pressure, and the housing serves as interface between the sleeve and the container. For carrying out the test, two machineries are necessary: a press to provide the normal pressure and a tensile machine to perform the axial movements. The test is calibrated so that the correspondence between the normal pressure and the containeradvancement is found. Preliminary tests are carried out involving a multifunctional and a fine-turned rod against a mirror-polished sleeve. Qualitatively, the multifunctional surfaces improve the friction conditions, but a more structured test campaign is required. It is furthermore assessed the repeatability of the test device, in order to rely on the results obtained. Ten repetitions made at the same pressure using the fine-turned rod displayed good repeatability of the force results both in terms of average values and trends.

This chapter deals with functional surfaces in mechanical systems. These surfaces are named in a multitude of ways; therefore, a classification is provided based on how the texture is designed. For a better clarification, a number of practical examples for each category are given. An overview of fabrication methods employed to produce such surfaces is presented. The numerous fabrication methods are classified based on the mechanism they employ for providing a texture. Three main categories (removing, moving, and adding material techniques) are identified, and for each of them, a number of processes are described with examples of the textures they can create. The last section of the chapter deals with surface metrology, a topic of central importance in the design and generation of surfaces for functional purposes. The process of surface characterisation is outlined, reviewing measuring instruments, classical and advanced filtering procedures, quantification methods, and eventually, providing traceability considerations.

In recent years there has been the development of a high number of manufacturing methods for creating textured surfaces which often present deterministic patterns of valley features. Unfortunately, suitable methodologies for characterizing them are lacking. Existing standards cannot in fact properly characterize such surfaces, providing at times unreasonable values. In this paper, a new procedure for characterizing such surfaces is proposed, relying on advanced filtering and feature recognition and separation. Existing advanced filtering methods do not always eliminate all distortions, therefore some modifications are investigated. In particular the robust Gaussian regression filter has been modified providing an envelope first-guess in order to always fit the mean line through the plateau region. Starting from a filtered and aligned profile, the feature thresholds recognition and separation is therefore made possible. In particular the plateau and valley regions can be detected, separated and independently analyzed according to their function. The example of a multifunctional profile is presented. The profile is analyzed using the new procedure, which demonstrates outputting a correctly aligned roughness profile and permitting comprehensive feature analyses.

Throughout the years, it has become more and more important to find new methods for reducing friction and wear occurrence in machine elements. A possible solution is found in texturing the surfaces under tribological contact, hence the development and spread of plateau-honed surface for cylinder liners. To prove the efficacy of a particular textured surface, it is paramount to perform experimental tests under controlled laboratory conditions. In this paper a new test rig simulating pure sliding conditions is presented, dubbed Axial Sliding Test. It presents four major components: a rod, a sleeve, a housing and a stripwound container. The rod and the sleeve are the two surfaces in relative sliding motion; the stripwound container maintains a constant, but adjustable normal pressure and the housing serves as interface between the sleeve and the container. For carrying out the test, two machineries are necessary: a press to provide the normal pressure and a tensile machine to perform the axial movements. The test is calibrated so that the correspondence between the normal pressure and the container advancement is found. Finally, preliminary tests are carried out involving a multifunctional and a fine turned rod against a mirror-polished sleeve. Qualitatively the multifunctional surfaces improve the friction conditions, but a more structured test campaign is required.