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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.

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.

The tool surface topography is often a key parameter in the tribological performance of modern metal forming tools. A new generation of multifunctional surfaces is achieved by combination of conventional tool manufacturing processes with a novel Robot Assisted Polishing process. This novel surface texturing method allows for a large degree of freedom in specifying surface characteristics and facilitates a high degree of reproducibility between samples surfaces. A series of strip reduction tests, equivalent to a metal forming ironing process, are conducted to benchmark the tribological performance of 15 generated tool surfaces.

Among the technical tasks that have to be fulfilled in order to carry out economically feasible small quantity production in cold forging, low tool costs, short design lead time and quick tool change systems are some of the most important issues. The present paper describes a flexible tool system, which makes it possible to operate with the eight basic cold forging processes; forward rod extrusion, backward can extrusion, forward tube extrusion, open die reduction, ironing, coining, upsetting and heading by changing only a few component specific tool parts like punch, die and ejector, whereas all other tool parts are standard, applicable for many different tool set-ups, thus minimizing the tool costs and the design lead time. The tool exchange time has been minimized by developing special quick tool change systems for punches and dies and a tool positioning system of the hard stop type.

The employment of surface texturing for improved tribological contacts has spread over the years. The possibilities of designing and manufacturing textured surfaces with predetermined geometries have multiplied as well as the need of performing experimental laboratory tests before applying the surfaces in an industrial context. In this paper, a number of experimental tests were performed using a novel test rig, called axial sliding test, simulating the contact of surfaces under pure sliding conditions. The aim of the experiments is to evaluate the frictional behavior of a new typology of textured surfaces, the so-called multifunctional surfaces, characterized by a plateau area able to bear loads and a deterministic pattern of lubricant pockets. Six surface typologies, namely three multifunctional and three machined using classical processes, were chosen to slide against a mirror-polished counterpart. A number of experiments were carried out at different normal pressures employing for all specimens the same reciprocating movement and the same lubrication. The measured friction forces were plotted against the incremental normal pressure, and the friction coefficients were calculated. The results comparison showed clearly how employing multifunctional surfaces can reduce friction forces up to 50 % at high normal loads compared to regularly ground or turned surfaces. Friction coefficients approximately equal to 0.12 were found for classically machined surfaces, whereas the values were 0.06 for multifunctional ones. All the specimens were characterized before and after testing. Wear occurrence was not detected on the tested surfaces except for the mirror-polished one which underwent all the experiments.

During the last five years the industrial application of stripwound cold-forging tools has had its real break through. The basic advantages of stripwound prestressed containers — higher pressure loadability and smaller dimensions — are today fully utilized in the manufacture of high quality cold forgings with a higher degree of deformation and/or more complex features. Die inserts prestressed by stripwound prestressed containers show a 2–10 times increase in die life, resulting in reduced tooling costs.

Based on the steps used in establishing a conceptual model for a theoretical analysis of a problem in metal forming, analogous steps are suggested when the use of a physical model is contemplated. Two lists of the types of information useful in the design of a process are given: the aims of synthesis, and the aims of analysis. Based on this the necessary idealizations must be made, whereupon a method of measurement is selected. Suitable model materials for the specimen and the tool can then be selected, as can friction conditions. Idealizations for facilitating measuring techniques and for the selection of a model material are discussed. Measuring techniques for determination of flow, strains, stresses, normal pressures in the specimen, and strains and stresses in the tool are described. Equipment for measuring constancy of volume, stress-strain curves and creep properties is shown and some results given.