Superimposing Ultrasonic Waves on Tube and Wire Drawing

2000 ◽  
Author(s):  
Klaus Siegert ◽  
Jochen Ulmer
Keyword(s):  
Sliding Friction ◽  
Wire Drawing ◽  
Ultrasonic Waves ◽  
Forming Process ◽  
Vibration Direction ◽  
Tube Drawing ◽  
Forming Technology ◽  
The University ◽  
Main Influence

Abstract The drawing forces during wire and tube drawing can be reduced by ultrasonically oscillating dies. A major problem of conventional wire and tube drawing is to introduce high forces into the forming area. Compared to conventional wire and tube drawing, the forming process limits can be extended by superimposing ultrasonic waves due to decreasing drawing forces. Different techniques can be used to exite the die. One possibility is the variation of the vibration mode. In tube and wire drawing, the dies are usually exited longitudinally. If the vibration direction is parallel to the drawing direction, the main influence will be on the friction between workpiece and die. The Institute for Metal Forming Technology of the University of Stuttgart, Germany started a project to investigate the effect of ultrasonic waves on the tribology and on the the formability of the workpiece. The objective of this investigation is to separate the ultrasonic effect on the surface from the volume effects. This paper shows, that the reduction of the sliding friction between a longitudinal oscillating die and the workpiece can be explained by the so called Sliding Friction Vector Effect (SFVE). A statistical evaluation of roughness-measurements makes it possible to show the effect of the ultrasonic vibration on the friction and gives an insight into the operation of the SFVE. The results are compared with wire and tube drawing experiments of copper and Ti-alloys. New tube- and wire-drawing experiments with longitudinally vibrating dies support the theoretical approach. The surface-quality of the manufactured workpieces can be improved and the productivity increases.

Superimposing Ultrasonic Waves on the Dies in Tube and Wire Drawing

2001 ◽  
Vol 123 (4) ◽  
pp. 517-523 ◽  
Author(s):  
Klaus Siegert ◽  
Jochen Ulmer
Keyword(s):  
Sliding Friction ◽  
Wire Drawing ◽  
Ultrasonic Waves ◽  
Forming Process ◽  
Vibration Direction ◽  
Tube Drawing ◽  
Forming Technology ◽  
The University ◽  
Main Influence

The forces during wire and tube drawing can be reduced by ultrasonically oscillating dies. It is a major problem of conventional wire and tube drawing to introduce high forces into the forming area. Compared to conventional wire and tube drawing, the forming process limits can be extended by superimposing ultrasonic waves due to decreasing drawing forces. Different techniques can be used to excite the die. One possibility is the variation of the vibration mode. In tube and wire drawing, the dies are usually excited longitudinally. If the vibration direction is parallel to the drawing direction, the main influence will be on the friction between workpiece and die. The Institute for Metal Forming Technology of the University of Stuttgart, Germany started a project to investigate the effect of ultrasonic waves on the tribology and on the formability of the workpiece. The objective of this investigation is to separate the ultrasonic effect on the surface from the volume effects. This paper shows that the reduction of the sliding friction between a longitudinal oscillating die and the workpiece can be explained by the so-called Sliding Friction Vector Effect (SFVE). A statistical evaluation of roughness-measurements makes it possible to show the effect of the ultrasonic vibration on the friction and gives an insight into the operation of the SFVE. The results are compared with wire and tube drawing experiments of copper and Ti-alloys. New tube- and wire-drawing experiments with longitudinally vibrating dies support the theoretical approach. The surface quality of the manufactured workpieces can be improved and the productivity increased.

Schwingungsüberlagertes Axialformen/Superimposed Oscillated Axial Forming

2020 ◽  
Vol 110 (11-12) ◽  
pp. 838-843
Author(s):  
Philipp Müller ◽  
Bernd-Arno Behrens ◽  
Sven Hübner ◽  
Hendrik Vogt ◽  
Daniel Rosenbusch ◽  
...  
Keyword(s):  
Surface Quality ◽  
Economic Importance ◽  
Combined Effect ◽  
Wird Eine ◽  
Forming Force ◽  
Forming Process ◽  
Forming Technology ◽  
Great Economic Importance ◽  
Gear Geometry

Techniken zur Steigerung der Formgebungsgrenzen in der Umformtechnik sind von hoher wirtschaftlicher Bedeutung. In dieser Arbeit wird eine Schwingungsüberlagerung im Krafthauptfluss eines Axialformprozesses zur Ausprägung einer Verzahnungsgeometrie untersucht. Die Auswirkungen der Schwingung auf die erzielbare Ausfüllung der Zahnkavitäten werden analysiert sowie die Parameter Schmierung und Oberflächengüte der Halbzeuge in ihrer kombinierten Wirkung untersucht. Es konnte eine Reduzierung der mittleren Umformkraft sowie eine Erhöhung der Formfüllung festgestellt werden. Techniques for extending the production limits in forming technology are of great economic importance. In this research, a superimposed oscillation in the main force flow of an axial forming process to form an axial gear geometry is investigated. The effects of the superimposed oscillation on the achievable form-filling of the tooth cavities are analyzed and the parameters lubrication and surface quality of the semi-finished products are investigated in their combined effect. A reduction of the averaged forming force as well as an increase of the form-filling could be achieved.

Fügen von Aluminium- und Kohlenstofffaserstrukturen*/Joining of aluminium and carbon fibre structures - An innovative joining technology based on semi-solid forming strategies

2017 ◽  
Vol 107 (10) ◽  
pp. 743-747
Author(s):  
M. Prof. Liewald ◽  
L. Marx
Keyword(s):  
Carbon Fibre ◽  
Metal Forming ◽  
Carbon Fabric ◽  
Forming Technology ◽  
Joining Technology ◽  
Aluminium Sheets ◽  
Semi Solid ◽  
The University ◽  
The Impact

Das Institut für Umformtechnik (IFU) an der Universität Stuttgart befasst sich derzeit mit der Entwicklung eines neuartigen Verfahrens zum formschlüssigen Fügen von Aluminium- und Carbonstrukturen. Zwei Aluminiumbleche werden dabei lokal auf ein Temperaturniveau knapp oberhalb ihrer Solidustemperatur erwärmt, sodass ein dazwischenliegendes Carbongewebe durch die dann teilflüssige Aluminiummatrix infiltriert werden kann. Dieser Fachartikel befasst sich mit dem Einfluss wichtiger Prozessparameter.   The Institute for Metal Forming Technology (IFU) of the University of Stuttgart aims at the development of a novel joining method for combining aluminium and carbon fibre structures. Two aluminium sheets with carbon fabric in between are conductively heated by two electrodes up to semi-solid state, so the woven carbon fabric is infiltrated with aluminium. This paper focuses on the impact of different process and sample parameters on the quality of the joint.

scholarly journals Comparison of FEM Simulations for the Incremental Forming Process

2005 ◽  
Vol 6-8 ◽  
pp. 533-542 ◽  
Author(s):  
Christophe Henrard ◽  
Anne Marie Habraken ◽  
Alexander Szekeres ◽  
Joost R. Duflou ◽  
S. He ◽  
...  
Keyword(s):  
Complex Shape ◽  
Incremental Forming ◽  
Mesh Size ◽  
Strain History ◽  
Forming Process ◽  
Wall Angle ◽  
Fem Simulations ◽  
Forming Technology ◽  
Reaction Forces ◽  
The University

Incremental forming is an innovative and highly flexible sheet metal forming technology for small batch production and prototyping that does not require any adapted dies or punches to form a complex shape. The purpose of this article is to perform FEM simulations of the forming of a cone with a 50-degree wall angle by incremental forming and to investigate the influence of some crucial computational parameters on the simulation. The influence of several parameters will be discussed: the FEM code used (Abaqus or Lagamine, a code developed at the University of Liège), the mesh size, the potential simplification due to the symmetry of the part and the friction coefficient. The output is given in terms of final geometry (which depends on the springback), strain history and distribution during the deformation, as well as reaction forces. It will be shown that the deformation is localized around the tool and that the deformations constantly remain close to a plane strain state for this geometry. Moreover, the tool reaction clearly depends on the way the contact is taken into account.

Change Law Research and Characteristic Analysis of Urban Pavement Runoff Pollution

2012 ◽  
Vol 518-523 ◽  
pp. 2418-2422
Author(s):  
Gui Xia Ji ◽  
Chun Lei Xu ◽  
Huan Zhang ◽  
Da Wei Si ◽  
Yi Cheng Lu
Keyword(s):  
Water Quality ◽  
Influence Factors ◽  
Pollution Index ◽  
Suspended Solid ◽  
Characteristic Analysis ◽  
Runoff Water ◽  
Exponential Change ◽  
The University ◽  
Main Influence

Through the pavement runoff monitoring of USST（the University of Shanghai for Science and Technology） courtyard pavement runoff and JunGong road runoff, the analysis of main influence factors and pollution degree, this article indicate that underling surface, rainfall duration, rainfall intensity and rainfall are important influencing factors of initial runoff water quality. Organic and suspended solid are the main pollutants of urban runoff. COD, SS and turbidity are the main pollution index, and they present exponential change law and finally achieved stability along with the delay of rainfall. The more heavily it rains, the more quickly water quality become stabilization. Stable water quality are influenced by rainfall character and pavement character. The more heavily it rains, the better stable water quality is. The more dust pavement contain, the worse stable water quality is. Stable water quality of courtyard pavement runoff are better than street runoff.

Production of Titanium Alloy Components by Semi-Solid Forming

2012 ◽  
Vol 192-193 ◽  
pp. 515-520 ◽  
Author(s):  
Levente Kertesz ◽  
Mathias Liewald
Keyword(s):  
Mechanical Properties ◽  
Metal Forming ◽  
Medical Engineering ◽  
High Variability ◽  
Development Work ◽  
Forming Process ◽  
Forming Technology ◽  
Semi Solid ◽  
New Research ◽  
The University

The relatively high costs of processing titanium alloys and the high variability in the products' quality currently represent the major economic obstacles to using such materials in either production or medical engineering. For this reason, new research and development work at the Institute for Metal Forming Technology of the University of Stuttgart is pursuing the objective of improving and enhancing pre-existing processes for these types of materials. In doing this, aspects are considered which specify definite mechanical properties during and after the forming process as well as reduce the costs by means of cutting the manufacturing times, increase the use of semi-finished products and minimise finishing operations.

scholarly journals Experimental Modeling of Pressure in the Hydrostatic Formation of a Cylindrical Cup with Different Materials

2021 ◽  
Vol 11 (13) ◽  
pp. 5814
Author(s):  
Trung-Kien Le ◽  
Thi-Thu Nguyen ◽  
Ngoc-Tam Bui
Keyword(s):  
Fluid Pressure ◽  
Regression Method ◽  
Mathematical Equation ◽  
Forming Process ◽  
Forming Technology ◽  
Input Parameters ◽  
Sheet Products ◽  
Cylindrical Cup ◽  
The Relationship

Forming complex sheet products using hydrostatic forming technology is currently a focus of the majority of forming processes. However, in order to increase stability during the forming process, it is necessary to identify and analyze the dependency of the forming pressure and the quality of a product on input parameters. For the purpose of modeling the forming pressure, this paper presents empirical research on the product of a cylindrical cup made of various materials, including carbon steel (DC04), copper (CDA260), and stainless steel (SUS 304) with different thicknesses (0.8 mm, 1.0 mm, and 1.2 mm), under a defined range of binder pressures. The regression method is selected to formulate an equation that shows the relationship between the input parameters, including the materials (ultimate strength and yield stress), workpiece thickness, binder pressure and the output parameter, and the formation of fluid pressure. The mathematical equation allows us to determine the extent of the effect of each input on the forming pressure. The experimental results can be used for the easier planning and forecasting of the process and product quality in hydrostatic forming.

Numerical Simulation and Experimental Study on the Weld-Line Movement of Tailor-Welded Blank

2010 ◽  
Vol 97-101 ◽  
pp. 357-360 ◽  
Author(s):  
Xiu Li Hu ◽  
Hao Zhao ◽  
Zhong Wen Xing
Keyword(s):  
Numerical Simulation ◽  
Influence Factors ◽  
Weld Line ◽  
Forming Process ◽  
Forming Technology ◽  
Element Simulation ◽  
Tailor Welded Blank ◽  
Weld Line Movement ◽  
Line Movement ◽  
Main Influence

TWB and its forming technology play important role in lightweight manufacturing for the automobile parts. The weld-line movement during TWB forming process affects the product quality greatly. In this paper, two main influence factors of the movement, BHF and the blank thickness at the both sides of the weld-line, were studied by both the experiments and finite element simulation. The results showed that BHF has significant impact on the weld-line movement, especially when the thickness difference of the blanks in TWB is beyond a certain range. Besides, suitable BHF and thickness of the blanks can not only control the weld-line movement, but also improve the formability of TWB.

Epistemic and relational conflicts in sharing identical vs. complementary information during cooperative learning

2002 ◽  
Vol 61 (3) ◽  
pp. 139-151 ◽  
Author(s):  
Céline Darnon ◽  
Céline Buchs ◽  
Fabrizio Butera
Keyword(s):  
Cooperative Learning ◽  
Social Comparison ◽  
Positive Relationship ◽  
Learning Task ◽  
Control Group ◽  
Complementary Information ◽  
Relational Conflict ◽  
The Social ◽  
The University

When interacting on a learning task, which is typical of several academic situations, individuals may experience two different motives: Understanding the problem, or showing their competences. When a conflict (confrontation of divergent propositions) emerges from this interaction, it can be solved either in an epistemic way (focused on the task) or in a relational way (focused on the social comparison of competences). The latter is believed to be detrimental for learning. Moreover, research on cooperative learning shows that when they share identical information, partners are led to compare to each other, and are less encouraged to cooperate than when they share complementary information. An epistemic vs. relational conflict vs. no conflict was provoked in dyads composed by a participant and a confederate, working either on identical or on complementary information (N = 122). Results showed that, if relational and epistemic conflicts both entailed more perceived interactions and divergence than the control group, only relational conflict entailed more perceived comparison activities and a less positive relationship than the control group. Epistemic conflict resulted in a more positive perceived relationship than the control group. As far as performance is concerned, relational conflict led to a worse learning than epistemic conflict, and - after a delay - than the control group. An interaction between the two variables on delayed performance showed that epistemic and relational conflicts were different only when working with complementary information. This study shows the importance of the quality of relationship when sharing information during cooperative learning, a crucial factor to be taken into account when planning educational settings at the university.

Evaluation of the Academic Setting in Spain 1This study was financed by the University of Oviedo.

1995 ◽  
Vol 11 (2) ◽  
pp. 133-137 ◽  
Author(s):  
Juan Fernández ◽  
Miguel A. Mateo ◽  
José Muñiz
Keyword(s):  
Higher Education ◽  
Decision Making ◽  
Social Climate ◽  
Three Dimensions ◽  
Academic Setting ◽  
Teaching And Research ◽  
Evaluation Questionnaire ◽  
University Teachers ◽  
The University

The conditions are investigated in which Spanish university teachers carry out their teaching and research functions. 655 teachers from the University of Oviedo took part in this study by completing the Academic Setting Evaluation Questionnaire (ASEQ). Of the three dimensions assessed in the ASEQ, Satisfaction received the lowest ratings, Social Climate was rated higher, and Relations with students was rated the highest. These results are similar to those found in two studies carried out in the academic years 1986/87 and 1989/90. Their relevance for higher education is twofold because these data can be used as a complement of those obtained by means of students' opinions, and the crossing of both types of data can facilitate decision making in order to improve the quality of the work (teaching and research) of the university institutions.

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