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

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.

Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 35 ◽  
Author(s):  
Zbigniew Pater ◽  
Janusz Tomczak ◽  
Łukasz Wójcik ◽  
Tomasz Bulzak

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.


Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 867 ◽  
Author(s):  
Łukasz Wójcik ◽  
Zbigniew Pater ◽  
Tomasz Bulzak ◽  
Janusz Tomczak

This article presents the results of model tests aiming to verify the possibility of applying commercial plasticine as a model material for modelling the limits to the cross-wedge rolling process. This study presents a comparison of the results of laboratory testing and physical modelling of cross-wedge rolling (CWR) processes. Commercial plasticine was the model material used in the research to model 50HS grade steel formed in 1150 °C. The model material was cooled to 0 °C, 5 °C, 10 °C, 12,5 °C, and 15 °C. Physical modelling of neckings and slippages is only possible when the plasticine is heated to 12.5 °C prior to forming. Commercial plasticine does not enable one to model the cracking process inside the rolled element.


Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3084
Author(s):  
Zbigniew Pater

The paper presents a comparative analysis of skew rolling in 3- and 4-roll CNC rolling mills. The analysis is performed using the FEM-based commercial simulation software Simufact.Forming. The formation of both solid and hollow railway axles is analyzed. Distributions of effective strain, temperature and damage criterion in rolled axles are determined, and loads and torques acting on the tools during rolling are estimated. An innovative concept of calibrating hollow axles by the rotary compression technique developed at the Lublin University of Technology is presented. Experimental tests of rolling solid axles in a 3-roll rolling mill (in a scale of 1:5) are performed, and basic force parameters of the rolling process are measured. Numerical and experimental loads and torques show a high agreement in terms of both quality and quantity.


2020 ◽  
Author(s):  
Marek Hawryluk ◽  
Maciej Suliga ◽  
Mateusz Więclaw

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.


Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 764
Author(s):  
Jarosław Bartnicki ◽  
Yingxiang Xia ◽  
Xuedao Shu

The paper presents chosen aspects of the skew rolling process of hollow stepped products with the use of a skew rolling mill designed and manufactured at the Lublin University of Technology. This machine is characterized by the numerical control of spacing between the working rolls and the sequence of the gripper axial movement, which allows for the individual programming of the obtained shapes of parts such as stepped axles and shafts. The length of these zones and the values of possibly realizable cross-section reduction and obtained outlines are the subject of this research paper. The chosen results regarding the influence of the technological parameters used on the course of the process are shown in the present study. Numerical modelling using the finite element method in Simufact Forming, as well as the results of experimental tests performed in a skew rolling mill, were applied in the conducted research. The work takes into account the influence of cross-section reduction of the hollow parts and the feed rate per rotation on the metal flow mechanisms in the skew rolling process. The presented results concern the obtained dimensional deviations and changes in the wall thickness determining the proper choice of technological parameters for hollow parts formed by the skew rolling method. Knowledge about the cause of the occurrence of these limitations is very important for the development of this technology and the choice of the process parameters.


Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2125 ◽  
Author(s):  
Janusz Tomczak ◽  
Zbigniew Pater ◽  
Tomasz Bulzak

This paper presents selected numerical and experimental results of a skew rolling process for producing balls using helical tools. The study investigates the effect of the billet’s initial temperature on the quality of produced balls and the rolling process itself. In addition, the effect of billet diameter on the quality of produced balls is investigated. Experimental tests were performed using a helical rolling mill available at the Lublin University of Technology. The experiments consisted of rolling 40 mm diameter balls with the use of two helical tools. To determine optimal rolling parameters ensuring the highest quality of produced balls, numerical modelling was performed using the finite element method in the Forge software. The numerical analysis involved the determination of metal flow kinematics, temperature and damage criterion distributions, as well as the measurement of variations in the force parameters. The results demonstrate that the highest quality balls are produced from billet preheated to approximately 1000 °C.


2016 ◽  
Vol 716 ◽  
pp. 864-870
Author(s):  
Andrzej Stefanik ◽  
Piotr Szota ◽  
Sebastian Mróz ◽  
Teresa Bajor ◽  
Sonia Boczkal

This paper presents the research results of the microstructure changes of the round rods of AZ31 magnesium alloy in the hot rolling processes. The rolling was conducted in duo mill and a three-high skew rolling mill. Numerical modelling of the AZ31 magnesium alloy round rods rolling process was conducted using a computer program Forge 2011®. The verification of the results of numerical modelling was carried out during laboratory tests in a two-high rolling mill D150 and a three-high skew rolling mill RSP 40/14. Distributions of the total effective strain and temperature during AZ31 rods rolling process were determined on the basis of the theoretical analysis. Microstructure and texture changes during both analysed processes were studied.


Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2970 ◽  
Author(s):  
Tomczak ◽  
Pater ◽  
Bulzak

This paper presents the results of theoretical and experimental investigations of a new process of rolling rods from scrap rail heads. First, the industrial applications of scrap railway rails and methods of their recycling are discussed, and then the concept of two-stage rolling of rods from heads cut off from scrap rails is proposed. In the first stage of the process, a rail head preform was rolled in a hexagonal pass of a longitudinal rolling mill. Then in the second stage, the hexagonal bar was skew rolled into a rod in a helical roll pass. Theoretical considerations were based on finite element numerical modelling. The rolling process was simulated under 3D deformation using Forge NxT v.1.1 software developed by Transvalor Company. Calculations were carried out to determine the material flow kinematics, strength, and thermal parameters of the process and to identify the phenomena that might constrain its implementation. The numerical results were verified in experimental tests, during which preforms and rods were formed from scrap rail heads. The tests were conducted in longitudinal and skew rolling mills. The results indicate that rods can be effectively formed from scrap rail heads in just two steps. Rods obtained using the proposed method can be used as full-featured, semifinished products for the manufacture of various types of machine parts.


2019 ◽  
Vol 11 (1) ◽  
pp. 14-23 ◽  
Author(s):  
W. H. Ho ◽  
I. J. Tshimanga ◽  
M. N. Ngoepe ◽  
M. C. Jermy ◽  
P. H. Geoghegan

Abstract Purpose Fabrication of a suitable flow model or phantom is critical to the study of biomedical fluid dynamics using optical flow visualization and measurement methods. The main difficulties arise from the optical properties of the model material, accuracy of the geometry and ease of fabrication. Methods Conventionally an investment casting method has been used, but recently advancements in additive manufacturing techniques such as 3D printing have allowed the flow model to be printed directly with minimal post-processing steps. This study presents results of an investigation into the feasibility of fabrication of such models suitable for particle image velocimetry (PIV) using a common 3D printing Stereolithography process and photopolymer resin. Results An idealised geometry of a cerebral aneurysm was printed to demonstrate its applicability for PIV experimentation. The material was shown to have a refractive index of 1.51, which can be refractive matched with a mixture of de-ionised water with ammonium thiocyanate (NH4SCN). The images were of a quality that after applying common PIV pre-processing techniques and a PIV cross-correlation algorithm, the results produced were consistent within the aneurysm when compared to previous studies. Conclusions This study presents an alternative low-cost option for 3D printing of a flow phantom suitable for flow visualization simulations. The use of 3D printed flow phantoms reduces the complexity, time and effort required compared to conventional investment casting methods by removing the necessity of a multi-part process required with investment casting techniques.


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