Measurement of Forming Stresses in Plain Spherical Bearings Using Neutron Diffraction

2014 ◽  
Vol 777 ◽  
pp. 58-64
Author(s):  
Johnpaul Woodhead ◽  
Julian D. Booker ◽  
Christopher E. Truman ◽  
Vadim Davydov
Keyword(s):  
Neutron Diffraction ◽  
Metal Forming ◽  
Material Behaviour ◽  
Forming Process ◽  
Measurement Results ◽  
Metal Forming Process ◽  
Bearing Race ◽  
Cold Metal ◽  
Inner Race ◽  
Related Process

Nosing is a cold metal-forming process used in the manufacture of plain spherical bearings. This process ensures the outer bearing race conforms to the shape of the inner race (a ball), with a composite liner in-between to provide a low frictional moment. These bearings must be precision engineered due to the large forces and demanding environments they operate within in service. The manufacture of these bearings and related process settings is very much an experiential route, although increasingly Finite Element simulations are used to predict and characterise complex material behaviour. It is imperative the numerical nosing models are validated against experimental measurements due to uncertainties in material properties, process variables and part manufacture variations. In this paper, neutron diffraction is used to determine the residual stresses in a large nosed bearing. Measurements were made on the POLDI instrument at PSI, Switzerland. This paper compares the predicted stresses with measurement results, and draws conclusions concerning the validity and usability of the models.

scholarly journals Common defects of parts manufactured through single point incremental forming

2021 ◽  
Vol 343 ◽  
pp. 04007
Author(s):  
Mihai Popp ◽  
Gabriela Rusu ◽  
Sever-Gabriel Racz ◽  
Valentin Oleksik
Keyword(s):  
Sheet Metal ◽  
Metal Forming ◽  
Incremental Forming ◽  
Single Point ◽  
Single Point Incremental Forming ◽  
Forming Process ◽  
Metal Forming Process ◽  
Serial Robot ◽  
The Many ◽  
Cold Metal

Single point incremental forming is one of the most intensely researched die-less manufacturing process. This process implies the usage of a CNC equipment or a serial robot which deforms a sheet metal with the help of a relatively simple tool that follows an imposed toolpath. As every cold metal forming process, besides the many given advantages it has also some drawbacks. One big drawback in comparison with other cold metal forming processes is the low accuracy of the deformed parts. The aim of this research is to investigate the sheet metal bending mechanism through finite element method analysis. The results shows that the shape of the retaining rings has a big influence over the final geometrical accuracy of the parts manufactured through single point incremental forming.

scholarly journals Numerical and Experimental Study of Producing Two-Step Flanges by Extrusion with a Movable Sleeve

2017 ◽  
Vol 62 (2) ◽  
pp. 495-499 ◽  
Author(s):  
G. Winiarski ◽  
A. Gontarz
Keyword(s):  
Metal Forming ◽  
Tube Wall ◽  
Metal Flow ◽  
Experimental Tests ◽  
External Diameter ◽  
Technological Parameters ◽  
Forming Process ◽  
Metal Forming Process ◽  
Tubular Billet ◽  
Cold Metal

Abstract The paper presents a new metal forming process for producing two-step external flanges on hollow parts. With this method, the flange is extruded by a movable sleeve, which moves in the opposite direction to the punch. This reduces the phenomenon of buckling of the tube wall, which allows extruding flanges with relatively large volumes. The new method was applied to produce a two-step flange on the end of a tubular billet made of 6060 aluminum alloy. This cold metal forming process was designed based on numerical simulations and experimental tests. The effect of the basic technological parameters on metal flow was investigated and limitations of the process were identified. The experimental results confirmed the possibility of forming a two-step flange with a diameter that is approximately twice as big as the external diameter of the tubular billet.

scholarly journals Laser Welding of High-strength Aluminium Alloys for the Sheet Metal Forming Process

Procedia CIRP ◽  
2014 ◽  
Vol 18 ◽  
pp. 203-208 ◽  
Author(s):  
J. Enz ◽  
S. Riekehr ◽  
V. Ventzke ◽  
N. Sotirov ◽  
N. Kashaev
Keyword(s):  
Laser Welding ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Aluminium Alloys ◽  
High Strength ◽  
Forming Process ◽  
Metal Forming Process

Application of the Radial Return Method to Compute Stress Increments From Mroz’s Hardening Rule

2000 ◽  
Vol 123 (4) ◽  
pp. 398-402 ◽  
Author(s):  
Sing C. Tang ◽  
Z. Cedric Xia ◽  
Feng Ren
Keyword(s):  
Metal Forming ◽  
Computing Time ◽  
Isotropic Hardening ◽  
Stress Increment ◽  
Anisotropic Hardening ◽  
Forming Process ◽  
Shell Elements ◽  
Hardening Rule ◽  
Metal Forming Process ◽  
Return Method

It is well known in the literature that the isotropic hardening rule in plasticity is not realistic for handling plastic deformation in a simulation of a full sheet-metal forming process including springback. An anisotropic hardening rule proposed by Mroz is more realistic. For an accurate computation of the stress increment for a given strain increment by using Mroz’s rule, the conventional subinterval integration takes excessive computing time. This paper proposes the radial return method to compute such stress increment for saving computing time. Two numerical examples show the efficiency of the proposed method. Even for a sheet model with more than 10,000 thin shell elements, the radial return method takes only 40 percent of the overall computing time by the subinterval integration.

Numerical and Experimental Investigations of Multistage Sheet-Bulk Metal Forming Process with Compound Press Tools

2015 ◽  
Vol 651-653 ◽  
pp. 1153-1158 ◽  
Author(s):  
Bernd Arno Behrens ◽  
Anas Bouguecha ◽  
Milan Vucetic ◽  
Sven Hübner ◽  
Daniel Rosenbusch ◽  
...  
Keyword(s):  
Metal Forming ◽  
Solid Metal ◽  
Experimental Investigations ◽  
Metal Component ◽  
Forming Process ◽  
Bulk Metal ◽  
Bulk Metal Forming ◽  
Process Sequence ◽  
Metal Forming Process ◽  
Flange Forming

Sheet-bulk metal forming is a manufacturing technology, which allows to produce a solid metal component out of a flat sheet. This paper focuses on numerical and experimental investigations of a new multistage forming process with compound press tools. The complete process sequence for the production of this solid metal component consists of three forming stages, which include a total of six production techniques. The first forming stage includes deep drawing, simultaneous cutting and following wall upsetting. In the second forming stage, flange forming combined with cup bottom ironing takes place. In the last stage of the process sequence, the component is sized. To investigate and to improve process parameters such as plastic strain distribution, resulting dimensions and process forces, FEA is performed. Based on these results the developed process is designed.

Optimization of Deep Drawing Processes Using Statistical Design of Experiments

1996 ◽  
Author(s):  
Dietrich Bauer ◽  
Regine Krebs
Keyword(s):  
Mathematical Model ◽  
Analysis Of Variance ◽  
Orthogonal Array ◽  
Deep Drawing ◽  
Metal Forming ◽  
Drawing Process ◽  
Drawing Force ◽  
Forming Process ◽  
Deep Drawing Process ◽  
Metal Forming Process

Abstract For a deep drawing process some important controllable variables (factors) upon the maximum drawing force are analyzed to find a setting adjustment for these process factors that provides a very low force for the metal forming process. For this investigation an orthogonal array L18 with three-fold replication is used. To find the optimum of the process, the experimental results are analyzed in accordance with the robust-design-method according to Taguchi (Liesegang et. al., 1990). For this purpose, so-called Signal-to-Noise-ratios are calculated. The analysis of variance for this S/N-ratios leads to a mathematical model for the deep drawing process. This model allows to find the pressumed optimal settings of the investigated factors. In the following, a confirmation experiment is carried out by using these optimal settings. The maximum drawing force of the confirmation experiment does not correspond with the confidence interval, which was calculated by analysis of variance techniques. So the predicted optimum of the process does not lead to a metal forming process with very low deep drawing force. The comparison with a full factorial plan shows that there are interactions between the investigated factors. These interactions could not be discovered by the used orthogonal array. Thus the established mathematical model does not describe the relation between the factors and deep drawing force in accordance with the practical deep drawing conditions.

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