Basic investigations on boundary lubrication in metal forming processes by in situ observation of the real contact area

Weidel, S.; Engel, Ulf; Merklein, Marion; Geiger, Manfred

doi:10.1007/s11740-009-0198-5

Cited by 23 publications

(9 citation statements)

References 16 publications

(19 reference statements)

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“…This effect appears clearly when flattening model asperities with a flank angle of 5°. For idealised asperities with a flank angle of 28°, this effect occurs only at higher normal pressures [42][43][44].…”

Section: Effect Of Surface Characteristics On Tribological Behavioursmentioning

confidence: 99%

Friction related size-effect in microforming – a review

2014

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This paper presents a thorough literature review of the size effects of friction in microforming. During miniaturization, the size effects of friction occur clearly. The paper first introduces experimental research progress on size effects of friction in both micro bulk and sheet forming. The effects of several parameters are discussed. Based on the experimental results, several approaches have been performed to develop a model or functions to analyse the mechanism of size effects of friction, and simulate the micro deep drawing process by integrating them into an FE program. Following this, surface modification, e.g. a DLC film and a micro structure/textured surface, as a method to reduce friction are presented. Finally, the outlook for the size effect of friction in the future is assessed, based on the understanding of the current research progress.

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Section: Effect Of Surface Characteristics On Tribological Behavioursmentioning

confidence: 99%

Friction related size-effect in microforming – a review

2014

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“…The lubricant, when applied to the surface of a deformed material or tool, forms a thin layer that partially or completely separates the surfaces in contact. The basic properties of the lubricant include viscosity and surface free energy, which determine the performance of the lubricant under high unit pressures [18]. Due to the large variety of conditions of plastic working processes, there are no universal lubricants.…”

Section: Introductionmentioning

confidence: 99%

Assessment of the effectiveness of lubrication of Ti-6Al-4V titanium alloy sheets using radial basis function neural networks

Trzepieciński

Szpunar

2021

Acta Polytech

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The aim of the research presented in this article was to determine the value of the friction coefficient using a simple tribological test and to build an empirical model of friction with the use of radial basis function artifi-cial neural networks. The friction tests were carried out on a specially designed friction simulator that allows a sheet metal strip to be drawn between two fixed dies. The test materials were sheets of Ti-6Al-4V titanium alloy with a thickness of 0.5 mm. The friction tests were carried out with variable contact forces of counter-samples with rounded surfaces and in various lubrication conditions. Mineral oils and bio-degradable oils with the addition of boric acid (5 wt %) were tested. Based on the results of friction investigations, neural models of friction were built using RBF artificial neural networks. The good properties of the RBF network 2:2-35-1:1 were confirmed by a high value of the determination coefficient R2 = 0.9984 and a low value of the S.D. ratio equal to 0.0557. It was found that the COF value was the highest for the average values of both the nominal pressure and kinematic viscosity. Over the entire range of nominal pressures applied, SAE10W-40 engine oil ensured the most effective reduction of the COF. The COF value was the highest for the average values of both the nominal pressure and kinematic viscosity.

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“…The quality of the products manufactured by these methods is directly affected by the type of lubrication and lubricant. In addition, lubricants affect the formability of sheet metal and the fracture that occurs during forming [1,2].…”

Section: Introductionmentioning

confidence: 99%

The effect of nanoparticle-added solid lubricant on the formability of sheet metal

et al. 2019

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In sheet metal forming processes, formation without fracture is related to sheet metal formability. Parameters such as tool geometry, blank holder force, and lubricant are changed in order to push the formability of material to its maximum capacity. Lubricants play an important role in sheet metal forming processes. Depending on the type of lubricant, the formability of the sheet metal can be increased, the surface quality of the product can be improved, and the tool life can be extended. In this study, nanoparticles were added to solid lubricants, and the effect of nanolubricants on sheet metal formability was investigated with Erichsen test. Test specimens were observed by SEM, and the nanoparticle effect was investigated by EDX mapping. In addition, the optimum nanoparticle concentration was determined, and the effects of the nanoparticle on solid lubricants were compared with other lubricants which were used in sheet metal forming. As a result of the study, it was observed that the nanoparticle additive increased the formability by 13%. Results showed that the formability of the sheet metal increased up to certain nanoparticle concentrations, but it decreased above this limit.

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Basic investigations on boundary lubrication in metal forming processes by in situ observation of the real contact area

Cited by 23 publications

References 16 publications

Friction related size-effect in microforming – a review

Friction related size-effect in microforming – a review

Assessment of the effectiveness of lubrication of Ti-6Al-4V titanium alloy sheets using radial basis function neural networks

The effect of nanoparticle-added solid lubricant on the formability of sheet metal

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