The Effect of Multi-Point Electrical Paths on Global Springback Elimination in Single Point Incremental Forming

2017 ◽  
Author(s):  
Jacklyn Niebauer ◽  
Derek Shaffer ◽  
Ihab Ragai ◽  
John T. Roth
Keyword(s):  
Sheet Metal ◽  
Incremental Forming ◽  
Single Point ◽  
High Stress ◽  
High Stress Concentration ◽  
Part Geometry ◽  
Electrically Assisted ◽  
Electrically Assisted Manufacturing ◽  
Future Work ◽  
Springback Reduction

Automotive and aerospace industries are interested in implementing die-less forming processes in order to reduce part costs and the required forming energy. One method of die-less forming is incremental forming, in which a sheet metal part is formed; typically with a hemispherical tool that deforms material as it pushes into the material and passes along the surface to create the desired part geometry. One problem with incremental forming is global springback, which occurs after the part has been formed and is released from the forming fixture. This effect is caused by residual stresses that are created during part deformation and result in geometric inaccuracies after the clamping force has been released. In this paper, the effect of post-deformation applied direct current on the springback of pre-formed sheet metal will be investigated. This is a process is a type of electrically assisted manufacturing (EAM). This paper is a continuation of previous works presented at MSEC 2015–2016. The initial feasibility study described herein already achieves a springback reduction of 26.3% and is dependent on the regions of high stress concentration as well as current density. Future work will extend this reduction through further testing of complex configurations.

Effect of Toolpath on the Springback of 2024-T3 Aluminum During Single Point Incremental Forming

2015 ◽  
Author(s):  
Zachary C. Reese ◽  
Brandt J. Ruszkiewicz ◽  
Chetan P. Nikhare ◽  
John T. Roth
Keyword(s):  
Residual Stresses ◽  
Sheet Metal ◽  
Tool Path ◽  
Incremental Forming ◽  
Single Point ◽  
Final Part ◽  
Cnc Milling ◽  
Forming Process ◽  
Step Size ◽  
Part Geometry

Incremental forming is a nontraditional forming method in which a spherical tool is used to asymmetrically deform sheet metal without the need for expensive allocated dies. Incremental forming employs a tool path similar to that used when CNC milling. Hence, when forming a part, the forming tool makes a series of passes circumferentially around the workpiece, gradually spirally stepping down in the z-axis on each sequential pass. This tool path deforms the sheet metal stock into the final, desired shape. These passes can start from the outer radius of the part and work in (Out to In, OI forming) or they can start from the center of the shape and work outward (In to Out, IO forming). As with many sheet metal operations, springback is a big concern during the incremental forming process. During the deformation process, residual stresses are created within the workpiece causing the final formed shape to springback when it is unclamped, sometimes very significantly. The more complex the geometry of the final part and the more total deformation that occurs when forming the geometry, the greater the residual stresses that are generated within the part. The residual stresses that have built up in the piece cause more significant distortion to the part when it is released from the retaining fixturing. This paper examines how the step size (in the z direction), OI vs. IO forming, and final part geometry affect the total springback in a finished piece. For all of these tests 0.5 mm thick sheets of 2024-T3 aluminum were used to form both the truncated pyramid and truncated cone shape. From this investigation it was found that smaller step sizes result in greater springback, IO is significantly less effective in forming the part (due to workpiece tearing), and final part geometry plays an important role due to the creation of residual stresses that exist in corners.

Electrically Assisted Global Springback Elimination in AMS-T-9046 Titanium After Single Point Incremental Forming

2016 ◽  
Author(s):  
Tyler J. Grimm ◽  
John T. Roth ◽  
Ihab Ragai
Keyword(s):  
Sheet Metal ◽  
Manufacturing Industry ◽  
Incremental Forming ◽  
Single Point ◽  
Electrical Current ◽  
Stress Concentrations ◽  
Wall Angle ◽  
Element Analysis ◽  
New Type ◽  
Springback Reduction

Incremental Forming (IF) is a new type of sheet metal forming method being investigated by many because of its great potential in the manufacturing industry. The IF method forms sheet metal by use of a hemispherically shaped tool which follows a specified path that gradually forms the material as it traverses across the material. No dies are needed for this process, which is where the potential lies. IF is currently being researched in order to reduce the drawbacks of the process. These drawbacks include a maximum formable wall angle, degraded surface finish, low part accuracy, and local and global springback. This research focuses on the reduction of global springback, which arises from the stresses induced in the workpiece. This research approaches the problem with the use of electrical paths ran through the residual stress concentrations. The stress concentrations were mapped using Finite Element Analysis (FEA) and multiple tests were done to see which path had the greatest effect on springback. It was concluded that the best paths to apply electrical current through in order to reduce springback in an incrementally formed truncated pyramid are: along the formed corners from top to bottom, across the upper section of the formed corner, and along each side of the inner formed square. In addition, it was found that the path the electricity takes has a greater effect on the amount of springback reduction than the amount of paths applied. It is hypothesized that this is due to the stiffening effects of certain stresses.

The Effects of Polarity and Current Path in Electrically Assisted Single Point Incremental Forming of 2024-T3 Aluminum

2017 ◽  
Author(s):  
Tyler J. Grimm ◽  
Ihab Ragai ◽  
John T. Roth
Keyword(s):  
Incremental Forming ◽  
Single Point ◽  
Negative Electrode ◽  
Electrical Current ◽  
Single Point Incremental Forming ◽  
Direct Electrical Current ◽  
Electrically Assisted ◽  
Current Path ◽  
Two Parameters ◽  
Springback Reduction

Electrically assisted incremental sheet forming (EAIF) is a novel addition to the incremental forming (IF) method. One variation of this approach applies direct electrical current during forming. Many improvements over tradition IF can be seen by utilizing this method, to include greater part accuracy, reduced forming force, and greater formability. In order to maximize the effects of electrically assisted incremental forming, all parameters of the method must be investigated, including the polarity of the current passing through the part and the path that the applied current takes. The effects of altering these two parameters is the primary investigation in this research. It was determined that, in order to optimize springback reduction and formability during electrically assisted single point incremental forming, the tool should be assigned the positive electrode and the center of the workpiece should be assigned the negative electrode. Additionally, the mechanism behind the spalling effect inherent to EAIF is discussed.

Asymmetric Single Point Incremental Forming of Sheet Metal

CIRP Annals ◽  
2005 ◽  
Vol 54 (2) ◽  
pp. 88-114 ◽  
Author(s):  
J. Jeswiet ◽  
F. Micari ◽  
G. Hirt ◽  
A. Bramley ◽  
J. Duflou ◽  
...  
Keyword(s):  
Sheet Metal ◽  
Incremental Forming ◽  
Single Point ◽  
Single Point Incremental Forming

Effects of Tool Deflection in Accumulated Double-Sided Incremental Forming Regarding Part Geometry

2016 ◽  
Author(s):  
Huaqing Ren ◽  
Newell Moser ◽  
Zixuan Zhang ◽  
Kornel F. Ehmann ◽  
Jian Cao
Keyword(s):  
Sheet Metal ◽  
Relative Position ◽  
Capital Investment ◽  
Incremental Forming ◽  
Position Angle ◽  
Tool Deflection ◽  
Geometric Accuracy ◽  
Localized Deformation ◽  
Forming Process ◽  
Part Geometry

Incremental forming is a flexible dieless forming process. In incremental forming, the metal sheet is clamped around its periphery. One or multiple generic stylus-type tools move along a predefined toolpath, incrementally deforming the sheet metal into a final, freeform shape. Compared with the traditional sheet metal forming process, the incremental forming process is more flexible, energy efficient and cost effective due to lower capital investment related to tooling. However, maintaining tight geometric tolerances in incremental formed parts can be a challenge. Specifically, undesired global bending is usually induced near the region between the tools and fixture resulting in a compromise in geometric accuracy. To address this issue, Accumulated Double-Sided Incremental Forming (ADSIF) is proposed, which utilizes two tools on both sides of the metal to better achieve localized deformation while simultaneously constraining global bending outside the forming area. Moreover, in ADSIF, the two tools are moving from inward to outward, and thus the tools are always forming virgin material and so as to limit forces on the already-formed part. Thus, ADSIF has a higher potential to achieve the desired geometry. Nevertheless, tool deflection due to machine compliance is still an issue that can have a considerable effect on geometric accuracy. In this work, the effect of tool deflection related to part geometry is studied for the ADSIF process. The nature of using two tools, rather than one, in ADSIF inherently implies that relative tool position is a critical process parameter. It is the region near these two tools where local squeezing and bending of the sheet occurs, the primary modes of deformation found in ADSIF. The change of relative tool positions (i.e., tool gap and relative position angle) are studied in detail by first developing an analytical model. It is concluded that the tool gap will be enlarged under the influence of tool compliance while the relative position angle is less affected. Additionally, a finite element simulation capable of modeling tool deflection is established. The comparison between the simulation results using rigid tools and deformable ones clearly demonstrated the significant influence of tool compliance on part geometry. Lastly, an axisymmetric part with varying wall angles was formed, and it was confirmed that ADSIF demonstrates improved geometry accuracy compared with conventional Double-Sided Incremental Forming.

Finite Element Analysis of Incremental Sheet Forming for Metal Sheet

2018 ◽  
Vol 783 ◽  
pp. 148-153
Author(s):  
Muhammad Sajjad ◽  
Jithin Ambarayil Joy ◽  
Dong Won Jung
Keyword(s):  
Mechanical Properties ◽  
Sheet Metal ◽  
Tool Path ◽  
Incremental Forming ◽  
Single Point ◽  
Machining Process ◽  
Machining Parameters ◽  
Forming Process ◽  
Element Analysis ◽  
Tool Diameter

Incremental sheet metal forming, is a non-conventional machining process which offers higher formability, flexibility and low cost of production than the traditional conventional forming process. Punch or tool used in this forming process consecutively forces the sheet to deform locally and ultimately gives the target profile. Various machining parameters, such as type of tool, tool path, tool size, feed rate and mechanical properties of sheet metal, like strength co-efficient, strain hardening index and ultimate tensile strength, effects the forming process and the formability of final product. In this research paper, Single Point Incremental Forming was simulated using Dassault system’s Abaqus 6.12-1 and results are obtained. Results of sheet profile and there change in thickness is investigated. For this paper, we simulated the process in abaqus. The tool diameter and rotational speed is find out for the production of parts through incremental forming. The simulation is done for two type of material with different mechanical properties. Various research papers were used to understand the process of incremental forming and its simulation.

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.

Springback Evaluation of Parts Made by Single-Point Incremental Sheet Forming

2011 ◽  
Author(s):  
Paolo Bosetti ◽  
Stefania Bruschi
Keyword(s):  
Process Parameters ◽  
Incremental Forming ◽  
Elastic Recovery ◽  
Single Point ◽  
Industrial Applications ◽  
Geometrical Parameters ◽  
Forming Process ◽  
Part Geometry ◽  
Before And After ◽  
Measuring Machine

One of the major drawbacks of single-point incremental forming process for sheet metal (SPIF) consists in the poor geometrical accuracy of formed parts. This limits the use of SPIF technology and has pushed the development of alternative incremental processes—such as the two-points incremental forming—aimed at improving the forming accuracy. However, these processes require the use of supporting dies and they therefore reduce the competitive advantage of SPIF process. The possibility to compensate for part springback, in order to have the part geometry as close as possible to the nominal one, represents one of the major challenges to make SPIF process suitable for real industrial applications. However, any possible approach in springback compensation must pass through the comprehension of the springback phenomenon. The objective of the paper is to analyze the springback of parts made by SPIF, by evaluating the influence that elastic recovery before and after the part unclamping has on the final part geometry. A SPIF experimental campaign was carried out on a truncated pyramid as case study, by varying both the part geometrical parameters (the wall angle and the height), and the process parameters (the tool step-down size and the feed rate). The material used in this study was the duplex steel DP600 provided in 0.8 mm thick sheets. After forming—but before unclamping—the part geometry was measured by means of of an electronic touch probe mounted on the machine tool-holder, in order to investigate the elastic recovery due to the successive tool laps. After unclamping, the part geometry was measured on a coordinate measuring machine. The influence of geometrical and process parameters was analyzed and the contribution of elastic recovery before and after the part unclamping was assessed.

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