A New Theoretical Method for Analysis the Material Flow Pattern in Forward Extrusion

2012 ◽  
Vol 622-623 ◽  
pp. 452-456
Author(s):  
Babak Saghafi ◽  
Karen Abrinia
Keyword(s):  
Conformal Mapping ◽  
Flow Pattern ◽  
Material Flow ◽  
Circular Cross Section ◽  
Physical Modelling ◽  
Model Material ◽  
Optimum Shape ◽  
Forming Process ◽  
Theoretical Formulation ◽  
Forward Extrusion

Material flow pattern in extrusion is an important part of the forming process. Understanding and formulating the material flow helps to determine the optimum shape of the die and important details of the process. In this paper, physical modelling of forward extrusion of non-symmetric L-shape section has been carried out to obtain an experimental understanding of the material flow pattern. A theoretical formulation using the conformal mapping theory has also been presented to predict the material flow pattern. The conformal mapping function was set up to translate the non-circular cross-section region of special-shaped products into unit dish. The results for the material flow pattern for the forward extrusion of L shaped profile from circular billets are presented here. In the physical modelling tests plasticine was used as the model material and different coloured layers of plasticine were used to build up the billet. Experimental and theoretical results were compared and good agreements were observed.

Back-Pressure Forging Using a Servo Die Cushion

2015 ◽  
Vol 9 (2) ◽  
pp. 184-192 ◽  
Author(s):  
Kiichiro Kawamoto ◽  
◽  
Takeshi Yoneyama ◽  
Masato Okada ◽  
Keyword(s):  
Material Flow ◽  
Back Pressure ◽  
Low Back ◽  
Excellent Performance ◽  
Forming Process ◽  
Shape Accuracy ◽  
Forging Process ◽  
Forward Extrusion ◽  
High Responsiveness ◽  
Forged Parts

The application of a servo die cushion to the back-pressure forging process improves the shape accuracy of forged parts. Servo die cushions have excellent performance in precise motion control and high responsiveness to set loads. To use a servo die cushion to obtain these features, back pressure is applied to the bottom outer punch during forward extrusion-type forging. Without back pressure, material flow delay around the central counter punch corner results in an unfilled corner at the bottom outer punch. Applying back pressure to the outer punch reduces the area of the unfilled corner. However, extensive back pressure at the beginning of the forming process causes burrs at the bottom because of the clearance between the counter punch and the outer punch; variable back-pressure settings along the punch stroke effectively remove burrs while also providing a smaller unfilled area by allowing for low back pressure at the beginning of the forming process and high back pressure during the forming process. Furthermore, using the flexible slide motion of the servo press to vary the punch motion leads to even further reduction in the unfilled area.

scholarly journals Possibilities of Using Physical Modeling With Soft Materials to Analyze and Optimize Metal Forming Processes

2020 ◽  
Author(s):  
Marek Hawryluk ◽  
Maciej Suliga ◽  
Mateusz Więclaw
Keyword(s):  
Numerical Modelling ◽  
Metal Forming ◽  
Material Flow ◽  
Physical Simulation ◽  
Dead Zone ◽  
Physical Modelling ◽  
Soft Materials ◽  
Extrusion Process ◽  
Model Material ◽  
Real Process

Abstract The study presents the concept of physical modelling together with the characterization of the modelling materials as well as the possibilities of applying this type of physical simulation methods for the analysis, design and optimization of industrial metal forming processes. The paper discusses the crucial similarity conditions between the physical model and the real process necessary to transform the results into industrial processes. Physical modelling is one of the most popular as well as cheapest methods of analyzing metal plastic forming processes and it can constitute an easy independent verifying tool. It can also be a competitive alternative or supplementation, or a quick verification, of the popular yet relatively expensive methods based on a broadly understood mathematical apparatus, e.g. the finite element method or various types of computer science techniques. The method provides the possibility to define the stress and deformation distribution, estimate the force parameters of the given process as well as localize the dead zones and material flow errors. On the example of a forward extrusion process, the study demonstrates the effect of matching the model material to two metallic materials: annealed aluminum and reinforced aluminum. Additionally, for reinforced aluminum, numerical modelling was performed, which made it possible to determine e.g.: the force parameters and the material flow manner. Next, based on physical modelling, verification through numerical modelling was made of the boundary and tribological conditions, as physical modelling revealed a so-called dead zone in the corner of the die, which had not been recorded in numerical modelling.

scholarly journals Cold Forging Effect on the Microstructure of Motorbike Shock Absorbers Fabricated by Tube Forming in a Closed Die

2021 ◽  
Vol 11 (5) ◽  
pp. 2142
Author(s):  
Trung-Kien Le ◽  
Tuan-Anh Bui
Keyword(s):  
Material Flow ◽  
Cold Forging ◽  
Technological Parameters ◽  
Forming Process ◽  
Tube Forming ◽  
Shock Absorbers ◽  
Thin Walled Tube ◽  
Thin Walled ◽  
Quality Of Products ◽  
Forming Defects

Motorbike shock absorbers made with a closed die employ a tube-forming process that is more sensitive than that of a solid billet, because the tube is usually too thin-walled to conserve material. During tube forming, defects such as folding and cracking occur due to unstable tube forming and abnormal material flow. It is therefore essential to understand the relationship between the appearance of defects and the number of forming steps to optimize technological parameters. Based on both finite element method (FEM) simulations and microstructural observations, we demonstrate the important role of the number and methodology of the forming steps on the material flow, defects, and metal fiber anisotropy of motorbike shock absorbers formed from a thin-walled tube. We find limits of the thickness and height ratios of the tube that must be held in order to avoid defects. Our study provides an important guide to workpiece and processing design that can improve the forming quality of products using tube forming.

scholarly journals Material flow control in sheet-bulk metal forming processes using blasted tool surfaces

2018 ◽  
Vol 190 ◽  
pp. 13003 ◽  
Author(s):  
Marion Merklein ◽  
Maria Löffler ◽  
Daniel Gröbel ◽  
Johannes Henneberg
Keyword(s):  
Metal Forming ◽  
Material Flow ◽  
Simultaneous Occurrence ◽  
Tribological Behaviour ◽  
Forming Process ◽  
Functional Elements ◽  
Bulk Metal ◽  
Bulk Metal Forming ◽  
Main Challenge ◽  
Functional Components

Highly-integrated and closely-tolerated functional components can be produced by sheet-bulk metal forming which is the application of bulk forming operations on sheet metals. These processes are characterized by a successive and/or simultaneous occurrence of different load conditions such as stress and strain states which reduce the geometrical accuracy of the functional elements. Thus, one main challenge within sheet-bulk metal forming is the identification of methods to control the material flow and thus to improve the product quality. One suitable approach is to control the material flow by local modifications of the tribological conditions. Within this study requirements regarding the needed adaption of the tribological conditions for a specific sheet-bulk metal forming process were defined by numerical investigations. The results reveal that a local increase of the friction leads to an improved die filling of the functional elements. Based on these results abrasive blasting as a method to modify the tool surface and thus influencing the tribological behaviour was investigated. For the determination of the tribological mechanism of blasted tool surfaces, the influence of different blasting media as well as blasting pressures on the surface integrity and the friction were determined. The correlations between surface properties and friction conditions were used to derive the mechanisms of blasted tool surfaces.

scholarly journals A Comparative Analysis of the Physical Modelling of Two Methods of Balls Separation

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7126
Author(s):  
Łukasz Wójcik ◽  
Zbigniew Pater ◽  
Tomasz Bulzak ◽  
Janusz Tomczak ◽  
Konrad Lis
Keyword(s):  
Comparative Analysis ◽  
Physical Modelling ◽  
Rolling Process ◽  
Model Material ◽  
Physical Analysis ◽  
Real Process ◽  
Radial Forces ◽  
3D Printed ◽  
Torque Values ◽  
Skew Rolling

The article presents the results of model tests with which a comparative analysis of two methods of ball separation during the skew rolling process was carried out. A verification of the results obtained in the physical modelling process with the results obtained in the real process of skew ball rolling was also carried out. During the physical modelling, the effect of changing the ball separation method on the quality of the products obtained, variations in maximum torque values and maximum radial forces were analyzed. In the case of real tests, the results were verified with the results of physical modelling, in which the surface quality and torque values for one of the tool sets were compared. Physical modelling was used to verify the differences between the two methods of ball separation. Commercial plasticine based on synthetic wax from the manufacturer PRIMO was used as a model material for physical analysis. The plasticine used for testing was cooled to 0 °C and the cooling process took 24 h. The tools used for the physical modelling were 3D printed and the material used was ABS. The method of physical modelling using plasticine as a model material allows for a correct analysis of hot metal forming processes.

scholarly journals High productivity micro rotary swaging

2018 ◽  
Vol 190 ◽  
pp. 15002 ◽  
Author(s):  
Eric Moumi ◽  
Marius Herrmann ◽  
Christian Schenck ◽  
Bernd Kuhfuss
Keyword(s):  
Material Flow ◽  
Process Variations ◽  
Main Process ◽  
Forming Process ◽  
Workpiece Material ◽  
High Productivity ◽  
Rotary Swaging ◽  
Micro Parts ◽  
Intensive Investigation ◽  
Clamping Device

Rotary swaging is an incremental forming process with two main process variations plunge and infeed rotary swaging. With plunge rotary swaging, the diameter is reduced within a limited section whereas the infeed rotary swaging enables a diameter reduction over the entire workpiece length. The process is now subject to intensive investigation for manufacturing of micro parts. By increasing the process speed, failures occur particularly due to inappropriate material flow. In plunge rotary swaging, the workpiece material can flow radially into the gap between the dies and thus the workpiece quality suffers. In infeed rotary swaging the workpiece material flows against the feeding direction and can provoke bending or braking of the workpiece. Therefore, additional measures to control both the radial and the axial material flow to enable high productivity micro rotary swaging are investigated. The radial material flow during plunge rotary swaging can be controlled by elastic intermediate elements that enable an increase of productivity by factor three. A spring-loaded clamping device that enables an increase of the productivity by factor four can temporarily buffer the axial material flow in infeed rotary swaging against the feeding direction.

scholarly journals Physical Modelling of the Ball-Rolling Processes

Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 35 ◽  
Author(s):  
Zbigniew Pater ◽  
Janusz Tomczak ◽  
Łukasz Wójcik ◽  
Tomasz Bulzak
Keyword(s):  
Acrylonitrile Butadiene Styrene ◽  
Physical Modelling ◽  
Model Material ◽  
Helical Rolling ◽  
Rolling Mills ◽  
Cross Rolling ◽  
Plastic Forming ◽  
3D Printed ◽  
Manufacturing Accuracy ◽  
Steel Balls

The objective of the article was to present the state of the problem of physical modelling of the hot-working processes with plasticine as the model material. It was stated that the aforementioned method can prove helpful in analyzing complex plastic forming processes such as cross rolling and helical rolling of balls. In order to confirm this hypothesis, an attempt at forming steel balls with diameters of 40 mm (cross rolling) and 57 mm (helical rolling) under laboratory conditions was made. Further on, these processes were conducted in model form using special model rolling mills and 3D printed acrylonitrile butadiene styrene (ABS) tools. The comparison of the test results regarding shape and manufacturing accuracy, as well as force parameters, confirmed the validity of using physical modelling in the investigation of the process of cross rolling and helical rolling of balls.

scholarly journals Plastometric tests for plasticine as physical modelling material

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Łukasz Wójcik ◽  
Konrad Lis ◽  
Zbigniew Pater
Keyword(s):  
Strain Rate ◽  
Temperature Change ◽  
Compression Test ◽  
Constitutive Equations ◽  
Metal Forming ◽  
Material Flow ◽  
Physical Modelling ◽  
Flow Curves ◽  
Black And White ◽  
White Colour

Abstract This paper presents results of plastometric tests for plasticine, used as material for physical modelling of metal forming processes. The test was conducted by means of compressing by flat dies of cylindrical billets at various temperatures. The aim of the conducted research was comparison of yield stresses and course of material flow curves. Tests were made for plasticine in black and white colour. On the basis of the obtained experimental results, the influence of forming parameters change on flow curves course was determined. Sensitivity of yield stresses change in function of material deformation, caused by forging temperature change within the scope of 0&C ÷ 20&C and differentiation of strain rate for ˙ɛ = 0.563; ˙ɛ = 0.0563; ˙ɛ = 0.0056s−1,was evaluated. Experimental curves obtained in compression test were described by constitutive equations. On the basis of the obtained results the function which most favourably describes flow curves was chosen.

Improved Sheet Bulk Metal Forming Processes by Local Adjustment of Tribological Properties

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
H. Hetzner ◽  
J. Koch ◽  
S. Tremmel ◽  
S. Wartzack ◽  
M. Merklein
Keyword(s):  
Contact Pressure ◽  
Metal Forming ◽  
Material Flow ◽  
System Analysis ◽  
Sheet Thickness ◽  
Fe Model ◽  
Forming Process ◽  
Bulk Metal ◽  
Bulk Metal Forming ◽  
Functional Features

This paper is focused on a combined deep drawing and extrusion process dedicated to the new process class of sheet bulk metal forming (SBMF). Exemplified by the forming of gearings, combined sheet and bulk forming operations are applied to sheet metal in order to form local functional features through an intended and controlled change of the sheet thickness. For investigations on the form filling and the identification of significant influencing factors on the material flow, a FE simulation model has been built. The FE model is validated by the results of manufacturing experiments using DC04 with a thickness of 2.0 mm as blank material. Due to the fact that the workpiece is in extensive contact to the tool surface and that the pressure reaches locally up to 2500 MPa, the tribological conditions are a determining factor of the process. Thus, their influence is discussed in detail in this paper. In the first instance, different frictional zones having a distinct effect on the resulting material flow are identified and their effect on improved form filling is demonstrated. Subsequently, a more comprehensive methodology is developed to define tribological zones of forming tools. For this, a system analysis of the digital mock-up of the forming process is performed. Besides friction, other relevant aspects of forming tool tribology like contact pressure, sliding velocity, and surface magnification are considered. The gathered information is employed to partition the tools into tribological zones. This is done by systematically intersecting and re-merging zones identified for each of the criterion. The so-called load-scanning test allows the investigation of the friction coefficient in dependence of the contact pressure and possible loading limits of tribological pairings. It provides an appropriate tribological model test to evaluate tribological measures like coatings, surface textures and lubricants with respect to their targeted application in particular zones. The obtained results can be employed in the layout of further forming processes to reach the desired process behavior. This can be, for example, an improved form filling, less abrasive wear and adhesive damage or lower forming forces, respectively tool load for an improved durability of the die.

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