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 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.

scholarly journals In-situ observation of lubricant flow on laser textured die surface in sheet metal forming

2017 ◽  
Vol 207 ◽  
pp. 2209-2214 ◽  
Author(s):  
Jochen Vorholt ◽  
Tetsuhide Shimizu ◽  
Hiroyuki Kobayashi ◽  
Lukas Heinrich ◽  
Hendrik Flosky ◽  
...  
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
In Situ Observation ◽  
Lubricant Flow ◽  
Die Surface

scholarly journals Numerical modelling of the gas detonation process of sheet metal forming

2016 ◽  
Vol 734 ◽  
pp. 032099 ◽  
Author(s):  
Sandeep P. Patil ◽  
Madhur Popli ◽  
Vahid Jenkouk ◽  
Bernd Markert
Keyword(s):  
Numerical Modelling ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Gas Detonation ◽  
Detonation Process

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 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.

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.

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.

Optimisation of the Stamping Processes for a Drawn-Part Made of Aluminium

2009 ◽  
Vol 410-411 ◽  
pp. 271-278
Author(s):  
Piotr Lacki
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Frictional Resistance ◽  
Forming Process ◽  
Adhesive Layers ◽  
Simulation Based ◽  
Strip Drawing ◽  
Metal Forming Process ◽  
Dry Conditions

The present work has been undertaken in order to investigate the possibilities of improvements in the production technology of aluminium drawn-parts. Past technology does not guarantee the production of high quality elements. Aluminium is difficult to use in sheet-metal working processes, mainly because of a susceptibility to the formation of aluminium „build-ups” on the tools, i.e. on the punch and die. The “build-ups” can be limited or even completely eliminated by a proper selection of the technological lubricants and proper surface treatment of the tools (e.g. surface coatings). In order to determine the influence of some technological lubricants and anti-adhesive layers on frictional resistance occurring during the sheet-metal forming process a typical “strip-drawing” test has been carried out. 1050A aluminium strips with thickness of 0.5mm have been drawn between two steel die inserts. Tests have been carried out with lubrication and in dry conditions. Additionally, two anti-adhesive coatings - TiN and Cr coatings were tested. Friction coefficients for different frictional pairs have been determined. In order to analyse how friction impacts on the course of sheet-metal forming process a numerical simulation based on the finite element method was performed. A four-stage stamping process of an aluminium cup was analysed. The value of the friction coefficient was changed in order to take into account frictional resistance. Thickness of the cup walls was assumed as one of the parameters determining the usefulness of the drawn-part because it determines its strength.

Sign in / Sign up

Export Citation Format

Share Document