scholarly journals A Review on Part Geometric Precision Improvement Strategies in Double-Sided Incremental Forming

Metals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 103
Author(s):  
Sattar Ullah ◽  
Peng Xu ◽  
Xiaoqiang Li ◽  
Yanle Li ◽  
Kai Han ◽  
...  
Keyword(s):  
Incremental Forming ◽  
Sheet Thickness ◽  
Adaptation Strategy ◽  
Geometric Error ◽  
Thickness Variation ◽  
Geometric Accuracy ◽  
Support Tool ◽  
Additional Equipment ◽  
Geometric Precision ◽  
Future Work

Low geometric accuracy is one of the main limitations in double-sided incremental forming (DSIF) with a rough surface finish, long forming time, and excessive sheet thinning. The lost contact between the support tool and the sheet is considered the main reason for the geometric error. Researchers presented different solutions for geometric accuracy improvement, such as toolpath compensation, adaptation, material redistribution, and heat-assisted processes. Toolpath compensations strategies improve geometric precision without adding extra tooling to the setup. It relies on formulas, simulation, and algorithm-based studies to enhance the part accuracy. Toolpath adaptation improves the part accuracy by adding additional equipment such as pneumatically or spring-loaded support tools or changing the conventional toolpath sequence such as accumulative-DSIF (ADSIF) and its variants. It also includes forming multi-region parts with various arrangements. Toolpath adaptation mostly requires experimental trial-and-error experiments to adjust parameters to obtain the desired shape with precision. Material redistribution strategies are effective for high-wall-angle parts. It is the less studied area in the geometric precision context in the DSIF. The heat-assisted process mainly concentrates on hard-to-form material. It can align itself to any toolpath compensation or adaptation strategy. This work aims to provide DSIF variants and studies, which focus on improving geometric accuracy using various methodologies. It includes a brief survey of tool force requirements for different strategies, sheet thickness variation in DSIF, and support tool role on deformation and fracture mechanism. Finally, a brief discussion and future work are suggested based on the insights from several articles.

A Mixed Toolpath Strategy for Improved Geometric Accuracy and Higher Throughput in Double-Sided Incremental Forming

2014 ◽  
Author(s):  
Rui Xu ◽  
Huaqing Ren ◽  
Zixuan Zhang ◽  
Rajiv Malhotra ◽  
Jian Cao
Keyword(s):  
Incremental Forming ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Geometric Accuracy ◽  
Recent Past ◽  
Forming Process ◽  
Process Flexibility ◽  
Formed Part ◽  
Future Work

Incremental sheet forming has attracted considerable attention in the recent past due to advantages that include high process flexibility and higher formability as compared to conventional forming processes. However, attaining required geometric accuracy of the formed part is one of the major issues plaguing this process. The Double-Sided Incremental Forming process has emerged as a potential process variant which can preserve the process flexibility while maintaining required geometric accuracy. This paper investigates a mixed toolpath for Double-Sided Incremental Forming which is able to simultaneously achieve good geometric accuracy and higher throughput than is currently possible. The geometries of parts formed using the mixed toolpath strategy are compared to the desired geometry. Furthermore, an examination of the forming forces is used to uncover the reasons for experimentally observed trends. Future work in this area is also discussed.

Deflection Compensations for Tool Path to Enhance Accuracy During Double-Sided Incremental Forming

2016 ◽  
Vol 138 (9) ◽  
Author(s):  
Lingam Rakesh ◽  
Srivastava Amit ◽  
N. V. Reddy
Keyword(s):  
Deformation Zone ◽  
Tool Path ◽  
Incremental Forming ◽  
Single Point ◽  
Three Dimensional ◽  
Geometric Accuracy ◽  
Forming Process ◽  
Sheet Plane ◽  
Support Tool ◽  
Metal Forming Process

Incremental sheet forming (ISF) is a flexible sheet metal forming process that enables forming of complex three-dimensional components by successive local deformations without using component-specific tooling. ISF is also regarded as a die-less manufacturing process in the absence of part-specific die. Geometric accuracy of formed components is inferior to that of their conventional counterparts. In single-point incremental forming (SPIF), the simplest variant of ISF, bending near component opening region is unavoidable due to lack of support. The bending in the component opening region can be reduced to a larger extent by another variant of ISF, namely, double-sided incremental forming (DSIF) in which a moving tool is used to support the sheet locally at the deformation zone. However, the overall geometry of formed components still has unacceptable deviation from the desired geometry. Experimental observation and literature indicate that the supporting tool loses contact with the sheet after forming certain depth. This work demonstrates a methodology to enhance geometric accuracy of formed components by compensating for tool and sheet deflections due to forming forces. Forming forces necessary to predict compensations are obtained using force equilibrium method along with thickness calculation methodology developed using overlap of deformation zone that occurs during forming (instead of using sine law). A number of examples are presented to show that the proposed methodology works for a variety of geometries (axisymmetric, varying wall angle, free-forms, features above and below initial sheet plane, and multiple features). Results indicate that there is significant improvement in accuracy of the components produced using compensated tool paths using DSIF, and support tool maintains contact with sheet throughout the forming process.

scholarly journals Parameter optimization for deformation energy and forming quality in single point incremental forming process using response surface methodology

2017 ◽  
Vol 9 (7) ◽  
pp. 168781401771011 ◽  
Author(s):  
Zimeng Yao ◽  
Yan Li ◽  
Mingshun Yang ◽  
Qilong Yuan ◽  
Pengtao Shi
Keyword(s):  
Surface Roughness ◽  
Incremental Forming ◽  
Single Point ◽  
Sheet Thickness ◽  
Deformation Energy ◽  
Geometric Error ◽  
Forming Process ◽  
Wall Angle ◽  
Forming Quality ◽  
Step Down

The deformation energy in single point incremental forming has an immediate impact on the processing cost, the heat and the wear effects between the tool and the formed material. Meanwhile, poor forming quality is still one of the largest challenges for the development and commercialization of this method. Therefore, the goal of this study is to search for the optimal working condition for lower energy consumption with better forming quality during the forming process. A Box–Behnken design for a cone parts forming process has been performed. The effects of four input parameters (step down, tool diameter, wall angle, and initial sheet thickness) on three outputs—deformation energy, surface roughness, and geometric error—have been investigated. With the target of minimal synchronization of deformation energy consumption, surface roughness, and geometric error, which are 1522.4 J, 0.97 µm, and 1.939 mm, respectively, in this case, four processing parameters were optimized with tool diameters as 16 mm, step down as 0.5 mm, sheet thickness as 0.57 mm, and wall angle as 65°. With optimization of deformation energy and surface roughness, in conjunction with geometric error compensation, an increased accuracy of the resulting parts can be obtained with minimum deformation energy and surface roughness.

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.

Controlling the Thickness Uniformity in Equal Channel Angular Rolling (ECAR)

2007 ◽  
Vol 539-543 ◽  
pp. 2872-2877 ◽  
Author(s):  
Young Hoon Chung ◽  
Jong Woo Park ◽  
Kyong Hwan Lee
Keyword(s):  
Shear Strain ◽  
Shear Deformation ◽  
Control Mechanism ◽  
Sheet Thickness ◽  
Surface Friction ◽  
Metal Sheet ◽  
Thickness Variation ◽  
Thickness Control ◽  
Thickness Uniformity ◽  
Elastic Unit

As the surface friction between feeding rolls and metal sheet generates the feeding power of ECAR, the generated feeding power is low, and the friction between the metal sheet and ECAR die should be minimized. However, for obtaining a large shear deformation by ECAR, the metal sheet should be tightly contacted with the wall of ECAR die. In this condition, the thickness of the metal sheet is continuously increased during ECAR. A new ECAR apparatus is developed for maximizing the shear deformation and obtaining sheet thickness uniformity, and succeeding continuous ECAR with such a limited feeding power. By controlling the outlet gap of the ECAR die with elastic unit, the thickness of the metal sheet is kept uniform. Detailed thickness control mechanism during the new ECAR process is analyzed. A sheet of Al 6063 alloy that is 1-pass deformed with the new ECAR apparatus shows below ±0.037 mm of thickness variation and 0.61 of shear strain.

Analysis of the Strain Distribution and Texture Measurements in Asymmetric Rolling (AR) and Asymmetric Accumulative Roll Bonding (AARB)

2021 ◽  
Vol 1016 ◽  
pp. 715-724
Author(s):  
Renan P. Godoi ◽  
Bianca D. Zanquetta ◽  
José Benaque Rubert ◽  
Raul E. Bolmaro ◽  
Martina C. Avalos ◽  
...  
Keyword(s):  
Accumulative Roll Bonding ◽  
Sheet Thickness ◽  
Thickness Reduction ◽  
Thickness Variation ◽  
Asymmetric Rolling ◽  
Roll Bonding ◽  
Bonding Condition ◽  
Shear Component ◽  
Strong Shear ◽  
Metallic Composites

Severe plastic deformation (SPD) with strong shear component is required to promote both grain refinement and texture randomization. When Asymmetric rolling (AR) is applied as asymmetric accumulative roll bonding (AARB), it enables the production of architectured microstructures and metallic composites. Finite element (FE) simulations of AR and AARB were employed to understand the influence of pass thickness reduction (PTR) on the through thickness variation of the velocity gradient. The influence of the PTR up to a total thickness reduction of 50% and the effect of a single 50% reduction step in a bi-layer bonding condition was analyzed. The influence of these process parameters on the strain and rigid body rotation components was compared with the experimental data obtained on an AA1050 aluminum. A better shear to compression ratio across the sheet thickness is achieved by PTRs lower than 30%; at a PTR of 50% the texture is dominated by the frictional shear generated at the roll-sheet interface and the process has a stronger compressive character. This indicates that simple ARB followed by AR with smaller PTRs should generate a better shear distribution than AARB alone.

Comparison of the Geometric Accuracy by DSIF Toolpath with SPIF Toolpath

2014 ◽  
Vol 494-495 ◽  
pp. 497-501 ◽  
Author(s):  
Jin Han Wu ◽  
Qiu Cheng Wang
Keyword(s):  
Incremental Forming ◽  
Single Point ◽  
Metal Sheet ◽  
Single Point Incremental Forming ◽  
Geometric Accuracy ◽  
Forming Process ◽  
Forming Accuracy ◽  
Finite Method

As there is no sufficient support between the single moving tool and fixture, the formed metal sheet is easy to bend in single point incremental forming (SPIF). Double sided incremental forming (DSIF) is proposed in which two tools are used on each side of the sheet to improve the components forming accuracy. Element finite method is introduced to simulate the forming process with both DSIF and SPIF toolpaths and the component geometric accuracies are compared. The simulation result shows the DSIF toolpaths can obtain better geometric accuracy than SPIF.

scholarly journals Study on Thickness Thinning Ratio of the Forming Parts in Single Point Incremental Forming Process

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Mingshun Yang ◽  
Zimeng Yao ◽  
Yan Li ◽  
Pengyang Li ◽  
Fengkui Cui ◽  
...  
Keyword(s):  
Deformation Zone ◽  
Incremental Forming ◽  
Single Point ◽  
Sheet Thickness ◽  
Single Point Incremental Forming ◽  
Forming Process ◽  
Feeding Speed ◽  
Forming Angle ◽  
Tool Diameter ◽  
Thinning Rate

An excessive thickness-reducing ratio of the deformation zone in single point incremental forming of the metal sheet process has an important influence on the forming limit. Prediction of the deformation zone thickness is an important approach to control the thinning ratio. Taking the 1060 aluminum as the research object, the principle of thickness deformation in the single point incremental forming process was analyzed; the finite element model was established using ABAQUS. A formula with high accuracy to predict the deformation zone thickness was fitted with the simulation results, and the influences of process parameters, such as tool diameter, step down, feeding speed, sheet thickness, and forming angle, on thinning ratio were analyzed. The accuracy of the finite element simulation was verified by experiment. A method to control the thinning rate by changing the forming trajectory was proposed. The results showed that the obtained value by using the fitted formula is closer to the experimental results than that obtained by the sine theorem. The thinning rate of the deformation zone increases with the increase of tool diameter, forming angle, and sheet thickness and decreases with the increase of step down, while the feeding speed had no significant effect on the thinning ratio. The most important factor of the thinning ratio is the forming angle, and the thinning ratio can be effectively reduced by using the forming trajectory with a uniformly distributed pressing point.

Incremental Forming of Friction Stir Welded Taylored Sheets

2006 ◽  
Author(s):  
G. Ambrogio ◽  
L. Fratini ◽  
F. Micari
Keyword(s):  
Metal Forming ◽  
Cost Reduction ◽  
Large Scale ◽  
Incremental Forming ◽  
Research Work ◽  
Sheet Thickness ◽  
Friction Stir ◽  
Tailored Blanks ◽  
Metal Stamping ◽  
Light Components

In the last decade sheet metal forming market has undergone substantial mutations since the development of more efficient strategies in terms of flexibility and cost reduction is strictly due. Such requirements are not consistent with traditional metal stamping processes which are characterized by complex equipment, capital and tooling costs; thus the industrial application of such processes is economically convenient just for large scale productions. For this reason most of the research work developed in the last years has been focused on the development of new sheet forming processes able to achieve the above discussed goals. Contemporary, with particular reference to the automotive industries the requirement of light components and the engineering of the outer skin parts of the vehicles have determined the growing utilization of tailored blanks characterized by either different material or different sheet thickness. In the paper SPIF processes of FS welded aluminium blanks are investigated in order to analyse the product properties in terms of strength and formability. A proper experimental investigation has been carried out and interesting guidelines have been highlighted in the next paragraphs.

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