Correlating the Features of Topography to Friction by Sliding Experiments

2008 ◽  
Author(s):  
Anirudhan Pottirayil ◽  
Pradeep L. Menezes ◽  
Satish V. Kailas
Keyword(s):  
Sheet Metal ◽  
Coefficient Of Friction ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Work Piece ◽  
Manufacturing Processes ◽  
Experimental Procedure ◽  
The Coefficient Of Friction ◽  
Soft Metal

Friction can influence the quality of the finished product to a large extent in certain manufacturing processes. Sheet metal forming is a particular case, where the friction between the hard-die and the relatively soft work-piece can be extremely important. Under such conditions, topography of the harder surface can influence the resistance to traction at the interface. This paper discusses about the correlation between certain features of the surface topography and coefficient of friction based on experiments involving sliding of a few soft metal pins against a harder material. A brief description of the experimental procedure and the analysis are presented. A hybrid parameter which encapsulates both the amplitude features as well as the relative packing of peaks is shown to correlate well with the coefficient of friction.

scholarly journals Contact pressure and sliding velocity ranges in sheet metal forming simulations

2021 ◽  
Author(s):  
Joseba Cillaurren ◽  
Lander Galdos ◽  
Mario Sanchez ◽  
Alaitz Zabala ◽  
Eneko Saenz de Argandoña ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Contact Pressure ◽  
Sheet Metal ◽  
Coefficient Of Friction ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Sliding Velocity ◽  
Wide Range ◽  
The Coefficient Of Friction ◽  
Friction Models

In the last few years many efforts have been carried out in order to better understand what the real contact between material and tools is. Based on the better understanding new friction models have been developed which have allowed process designers to improve numerical results in terms of component viability and geometrical accuracy. The new models define the coefficient of friction depending on different process parameters such as the contact pressure, the sliding velocity, the material strain, and the tool temperature. Many examples of the improvements achieved, both at laboratory scale and at industrial scale, can be found in the recent literature. However, in each of the examples found in the literature, different ranges of the variables affecting the coefficient of friction are covered depending on the component analysed and the material used to produce such component. The present work statistically analyses the contact pressure and sliding velocity ranges achieved during numerical simulation (FEM) of sheet metal forming processes. Nineteen different industrial components representing a high variety of shapes have been studied to cover a wide range of casuistic. The contact pressure and sliding velocity corresponding to typical areas of the tooling have been analysed though numerical simulation in each case. This study identifies the ranges of contact-pressure and sliding velocities occurring in sheet metal forming aimed to set the characterization range for future friction studies.

scholarly journals Tribological Performance of Environmentally Friendly Bio-Degradable Lubricants Based on a Combination of Boric Acid and Bio-Based Oils

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3892
Author(s):  
Tomasz Trzepieciński
Keyword(s):  
Boric Acid ◽  
Sheet Metal ◽  
Coefficient Of Friction ◽  
Vegetable Oils ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Low Carbon Steel ◽  
Environmentally Friendly ◽  
Low Carbon ◽  
The Coefficient Of Friction

Finding effective and environmentally friendly lubrication to use in sheet metal forming operations presents a substantial environmental and economic challenge to the automotive industry. This paper examines the effectiveness of different lubricants in the reduction of the coefficient of friction (COF) in the process of sheet metal forming of the low carbon steel sheets. These lubricants are based on a combination of boric acid (H3BO3) and edible vegetable oils, both of which are natural and environmentally friendly. To evaluate the friction characteristics of the lubricants in a forming operation, a strip drawing friction test is used. This test consisted in drawing a specimen in the form of a sheet metal strip between two non-rotating counter-samples with radii of 200 and 10 mm. The effectiveness of environmentally friendly lubricants in reducing the COF was compared to the traditional petroleum-based lubricants which are used in sheet metal-forming operations. The effect of lubricant conditions and tool surface roughness on the value of COFs is studied. It was found that palm oil in both configurations of countersample radius, both as pure oil and with the addition of 5 wt.% of H3BO3, was the most effective in lowering the coefficient of friction. In most of the conditions analysed, the addition of boric acid into vegetable oils leads to an increase in the lubrication efficiency by up to 15% compared to pure oils. The effectiveness of lubrication by olive and rapeseed oils in decreasing the frictional resistances clearly depends on the nominal pressure applied.

scholarly journals Methods of determination of frictional resistances in sheet metal forming of car body sheets

2018 ◽  
Vol 19 (6) ◽  
pp. 756-760
Author(s):  
Tomasz Trzepieciński ◽  
Irena Nowotyńska
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Complex Function ◽  
Forming Process ◽  
The Coefficient Of Friction ◽  
Displacement Speed ◽  
Almost All ◽  
Lubrication Conditions

The friction phenomenon existed in almost all plastic working processes, in particular sheet metal forming, is a complex function of the material's properties, parameters of the forming process, surface topography of the sheet and tools, and lubrication conditions. During the stamping of the drawpieces there are zones differentiated in terms of stress and strain state, displacement speed and friction conditions. This article describes the methods for determining the value of the coefficient of friction in selected areas of sheet metal and presents the drawbacks and limitations of these methods.

Surrogate POD Models for Parametrized Sheet Metal Forming Applications

2013 ◽  
Vol 554-557 ◽  
pp. 919-927 ◽  
Author(s):  
Hamdaoui Mohamed ◽  
Guénhaël Le Quilliec ◽  
Piotr Breitkopf ◽  
Pierre Villon
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Optimization Problems ◽  
Strain Tensor ◽  
Forming Limit ◽  
Work Piece ◽  
Displacement Fields ◽  
Lagrange Strain

The aim of this work is to present a POD (Proper Orthogonal Decomposition) based surrogate approach for sheet metal forming parametrized applications. The final displacement field for the stamped work-piece computed using a finite element approach is approximated using the method of snapshots for POD mode determination and kriging for POD coefficients interpolation. An error analysis, performed using a validation set, shows that the accuracy of the surrogate POD model is excellent for the representation of finite element displacement fields. A possible use of the surrogate to assess the quality of the stamped sheet is considered. The Green-Lagrange strain tensor is derived and forming limit diagrams are computed on the fly for any point of the design space. Furthermore, the minimization of a cost function based on the surrogate POD model is performed showing its potential for solving optimization problems.

A Contribution to the Optimisation of a Simple Shear Test

2009 ◽  
Vol 410-411 ◽  
pp. 467-472 ◽  
Author(s):  
Marion Merklein ◽  
M. Biasutti
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Shear Test ◽  
The Finite Element Method ◽  
Simple Shear Test ◽  
Material Parameters

The finite element method is a widely used tool in sheet metal forming. The quality of the results of such an analysis depends largely on the applied constitutive model and its material parameters, which have to be determined experimentally. These data are relevant on the choice of the yield criterion among the wide range of options available in the commercial applications implementing the finite element method. Since the accuracy of material parameters estimation is therefore crucial, investigations were performed with an Al-Mg sheet alloy and a mild steel sheet to optimize a Miyauchi-based simple shear test. This method is one of the basic ways to investigate the plastic properties of a sheet metal up to large strains, which is very important for numerical analysis of sheet metal forming processes. Aim of the test is to determine the shear stress-strain correlation. In order to enhance the quality of the experimental results the detection of the deformation’s field, trough an optical measurement system, and the methodology for its evaluation are focus of the present study.

Numerical Simulation of the Effect of Punch Paths on the Quality of Sheet Metal Stretch Forming

2012 ◽  
Vol 217-219 ◽  
pp. 2002-2005
Author(s):  
Chang Jiang Wang ◽  
Diane J Mynors ◽  
Tarsem Sihra
Keyword(s):  
Numerical Simulation ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Finite Element Modelling ◽  
Metal Strip ◽  
Stretch Forming ◽  
Forming Quality ◽  
Element Modelling

Presented here is the simulation of uniaxial stretch forming using two punches in a sheet metal forming operation. In the finite element modelling, the sheet metal strip was held by two bank holders and two punches are able to move in two directions to stretch the sheet metal. Due to the friction between the punch and sheet metal, it was found that friction affects the sheet metal forming quality, however by adopting an optimal punch path the effect of friction in sheet metal forming can be reduced. The effect of punch paths on the quality of the sheet metal are also reported in this paper.

Study on Parameters for Affecting SCI of Sheet Metal Forming

2010 ◽  
Vol 44-47 ◽  
pp. 2862-2866
Author(s):  
Ji Tao Du
Keyword(s):  
Mechanical Property ◽  
Surface Quality ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Friction Condition ◽  
Experimental Results ◽  
Forming Defect ◽  
Punch Radius

The surface contact impression(SCI) is the neglected forming defect and seriously affects surface quality and mechanical property of stamping parts. The technology parameters and affective degree which alleviate or eliminate SCI are researched , four factors including die radius(DR) , die clearance(DC), punch radius(PR) and friction condition(FC) , which each factor chooses three levels are designed and constitute a L9（34）orthogonal table. The experimental results indicate that the significances order of technology parameters affecting SCI is DR> PR > DC >FC. The analyzed result shows that the superior parameter affecting SCI is DR ,the inferior is FC, adapted DC greatly removes SCI. the research puts forward a reference for improving surface quality of stamping parts.

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