Tribological Size Effects in Sheet Metal Forming Measured by a Strip Drawing Test

CIRP Annals ◽  
2006 ◽  
Vol 55 (1) ◽  
pp. 291-294 ◽  
Author(s):  
F. Vollertsen ◽  
Z. Hu
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Size Effects ◽  
Metal Forming ◽  
Drawing Test ◽  
Strip Drawing

scholarly journals Temperature induced friction increase in friction test and forming demonstrator for sheet metal forming

2021 ◽  
Author(s):  
Jan Filzek ◽  
Daniel Keil ◽  
Holger Schröder
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Transient Effects ◽  
Friction Test ◽  
Drawing Test ◽  
Machine Operators ◽  
Strip Drawing ◽  
Flat Strip ◽  
The Individual

High process stability is needed in sheet metal forming industry. This can be achieved by predicting and controlling the transient process and temperature variation, especially at start of production. In this connection, the temperature induced friction changing plays a significant role because it leads to product failures. The handling of the transient friction effects is currently done reactively, based on the individual experience of the machine operators. In future, those transient effects need to be controlled. This paper shows initially an analysis of the temperature induced friction increase in a well-known and proven flat strip drawing test. Different tribological systems were tested at tool temperatures between 20 and 80 °C. The temperature increase results in a higher friction of up to 77 %. Several influences on friction increase will be presented. These friction influences were verified afterwards with a heated forming demonstrator under laboratory conditions.

Effects of Rolling Direction and Lubricant on Friction in Sheet Metal Forming

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Xiaojun Liu ◽  
Mathias Liewald ◽  
Dina Becker
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Rolling Direction ◽  
Alloy Sheet ◽  
Friction Behavior ◽  
Drawing Test ◽  
Strip Drawing ◽  
The Coefficient Of Friction ◽  
Surface Microstructures

Lubrication and friction at workpiece-tool interface play an important role in product quality control of sheet metal forming process. Surface microstructures of sheets have a great influence on the development of lubrication films. In order to investigate the effects of the rolling direction of aluminum alloy sheet and lubricant on the friction behavior in sheet metal forming, strip drawing test was used. The sample used was electric discharge texturing (EDT) surface. Lubricants, both with and without additives, were used. The strip drawing tests were performed at angles between the sliding and rolling directions of 0–90 deg. Variations in the sheet surface topography were analyzed by comparing the sheet surface microstructures and its 3D surface parameters before and after the strip drawing test. Results of the strip drawing tests indicate that the kind and amount of lubricant have great influences on friction at the interface, and the lubricant with additives benefits improving the friction behavior between the sheet and the tool. The EDT surface of the aluminum alloy sheet has an anisotropic frictional property during deep drawing process due to different angles between the sliding and rolling directions. When the sliding direction is parallel to the rolling direction, the coefficient of friction has the highest value. When the angle between the sliding and rolling directions increases, the coefficient of friction decreases. The surface microstructure of the sheets after the strip drawing test at different angles between the sliding and rolling directions has been modified, and its 3D surface parameters decrease significantly to a different degree.

scholarly journals Numerical modelling of microscopic lubricant flow in sheet metal forming. Application to plane strip drawing

2017 ◽  
Vol 112 (3) ◽  
pp. 203-237 ◽  
Author(s):  
Y. Carretta ◽  
R. Boman ◽  
J. Bech ◽  
N. Legrand ◽  
M. Laugier ◽  
...  
Keyword(s):  
Numerical Modelling ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Lubricant Flow ◽  
Strip Drawing

scholarly journals Experimental identification of essential features of micro strip drawing with double deflection

2018 ◽  
Vol 43 (2) ◽  
pp. 1-5
Author(s):  
Lewin Rathmann ◽  
Frank Vollertsen
Keyword(s):  
Experimental Evidence ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Maximum Distance ◽  
Contact Zones ◽  
Experimental Identification ◽  
Optical Projection ◽  
Strip Drawing ◽  
The Moment

In sheet metal forming contact between blank and die edge is reduced to local contact zones. For micro range, they can easily be found during a simulation, but an experimental evidence is difficult. Therefore, an optical projection of strip drawing with double deflection is presented and it is demonstrated that the contact zones can be identified using this method. These results are compared to those from simulation and it is shown that they reflect the simulative results. The results are presented on the basis of using a die with a die radius of r = 0.6 mm. The height of the gap between die edge and blank at the moment of their maximum distance is determined in the experiment to d = 18 ± 9 μm while it is d = 2 μm in the simulation.

Size Effects on Sheet-Metal Formability for Miniature Parts

2006 ◽  
Vol 505-507 ◽  
pp. 721-726
Author(s):  
Quang Cherng Hsu
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Size Effects ◽  
Metal Forming ◽  
Industrial Development ◽  
Surface Condition ◽  
Rapid Progress ◽  
Hydraulic Bulge ◽  
Rectangular Grids ◽  
Microstructure Of Material

Due to the rapid progress of industrial development, the formation of lightweight and small-size parts is becoming increasingly important. Especially in the IC and 3C industry, the sheet metal forming of miniature parts is especially interesting. Size effects such as specimen dimension, blank thickness, punch corner dimension, grain size, and grid dimension (for strain measurement), as well as the microstructure of material and surface condition all seriously influence the forming of miniature parts. In this paper, systematic experiments including Erichsen stretch forming and hydraulic bulge, and strain analyzers including for circular and rectangular grids are described for establishing the relationships of sheet metal formability to process parameters. The details of the experimental procedures and results are presented and discussed.

Simulation of Dynamic Lubricant Effects in Sheet Metal Forming Processes

2010 ◽  
Vol 438 ◽  
pp. 171-178 ◽  
Author(s):  
Manuel Ludwig ◽  
Cecile Müller ◽  
Peter Groche
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Viscous Effects ◽  
Fluid Films ◽  
Surface Evolution ◽  
Tribological System ◽  
Strip Drawing ◽  
Mixed Lubrication Regime ◽  
Local Pressures

Tribology plays an important role in sheet metal forming processes relating to near net shape production processes and achievable surface qualities. Nearly every process is realized by using characteristic lubricants affecting the tribological system to achieve the desired results. Deterministic structures on sheet surfaces can result in less friction and higher drawing ratios. This is caused by hydrostatic pressures build up in closed lubricant areas and hydrodynamic pressures due to the lubricant motion especially in thin fluid films [1, 2, 3]. Friction mechanisms in the mixed lubrication regime are not fully understood till today. The numerical simulation of flows in lubricant pockets and their influence on surface evolution are promising ways to gain more knowledge of the lubricant behavior in tribological systems. Therefore, this paper shows results of combined numerical and experimental approaches. The described simulations of closed lubricant pockets on surfaces identify influencing parameters. Strip drawing experiments are done to verify the simulations. The influence and the importance of local pressures due to viscous effects in the lubricant are considered as well as the necessity to use fluid-structure-interactions to simulate the behavior of lubricants in the tribological system.

A new approach for evaluating sheet metal forming based on sheet drawing test. Application to TRIP 700 steel

2013 ◽  
Vol 213 (10) ◽  
pp. 1703-1710 ◽  
Author(s):  
V. Miguel ◽  
A. Martínez ◽  
J. Coello ◽  
F.J. Avellaneda ◽  
A. Calatayud
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
New Approach ◽  
Drawing Test ◽  
Test Application

scholarly journals The Effect of the Use of Technological Lubricants Based on Vegetable Oils on the Process of Titanium Sheet Metal Forming

2017 ◽  
Vol 62 (2) ◽  
pp. 489-494 ◽  
Author(s):  
W. Więckowski ◽  
K. Dyja
Keyword(s):  
Sheet Metal ◽  
Vegetable Oils ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Strength Properties ◽  
Forming Process ◽  
Titanium Sheet ◽  
Plastic Properties ◽  
Strip Drawing ◽  
Metal Forming Process

Abstract The paper evaluates the drawability of titanium sheet metal Grade 2, with the focus on friction conditions that are present in the sheet metal forming process. The study aims to present the results of the examinations of the friction coefficient during a strip drawing test. The focus of the experiment was on lubricants based on vegetable oils i.e. rapeseed oil, sunflower oil and olive oil. Boric acid was used to improve the lubricating properties of vegetable oils. The results of numerical simulations of the process of forming a cover with stiffening components made of grade 2 titanium sheet metal was also presented. The numerical simulation was carried out using the FEM method with PAMStamp 2G software. The effect of conditions of friction between the sheet metal and tool parts and pressure force of the blank holder on the forming process were investigated. Numerical calculations were performed with consideration for the phenomenon of material strain hardening and anisotropy of plastic properties of the sheet metal formed. The analysis of the deformations and reduction in wall thickness of the drawn parts can be used for determination of the effect of changes in selected parameters on the process of drawn part forming. The quality of drawn parts was assessed based on the shape inaccuracy determined during simulation of forming. The inaccuracy depended on the conditions of the process and strength properties of the titanium sheet metal.

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