scholarly journals Thickness control in a new flexible hybrid incremental sheet forming process

2017 ◽  
Vol 231 (5) ◽  
pp. 779-791 ◽  
Author(s):  
Huan Zhang ◽  
Bin Lu ◽  
Jun Chen ◽  
Sule Feng ◽  
Zongquan Li ◽  
...  
Keyword(s):  
Production Efficiency ◽  
Thickness Distribution ◽  
Sheet Thickness ◽  
Cost Effective ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Optimization Approach ◽  
Forming Process ◽  
Thickness Prediction ◽  
Flexible Forming Process

Incremental sheet forming is a cost-effective process for rapid manufacturing of sheet metal products. However, incremental sheet forming also has some limitations such as severe sheet thinning and long processing time. These limitations hamper the forming part quality and production efficiency, thus restricting the incremental sheet forming application in industrial practice. To overcome the problem of sheet thinning, a variety of processes, such as multi-step incremental sheet forming, have been proposed to improve the material flow and thickness distribution. In this work, a new process has been developed by introducing multi-point forming as preforming step before conducting incremental sheet forming processing. Employing an established hybrid sheet forming system and the corresponding thickness prediction model, the preform shape can be optimized by employing a two-step optimization approach to improve the sheet thickness distribution. In total, two case study examples, including a hemisphere part and an aerospace cowling part, are fabricated using the developed hybrid flexible process in this study. The experimental results show that the hybrid flexible forming process with the optimal preform design could achieve sheet parts with more uniform thickness distribution and reduced forming time.

Investigation on Wrinkling Deformation in Multi-Pass Incremental Sheet Forming Process

2016 ◽  
Vol 725 ◽  
pp. 578-585 ◽  
Author(s):  
Zhao Bing Liu ◽  
Paul Anthony Meehan
Keyword(s):  
Thickness Distribution ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Final Part ◽  
Optimized Design ◽  
Forming Process ◽  
Element Analysis ◽  
Form Complex

Incremental Sheet Forming (ISF) is a promising rapid prototyping technology used to form complex three-dimensional shapes. For forming a part with severely sloped regions, design of multi-stage deformation passes (intermediate shapes or preforms) before the final part, is widely adopted as a desirable and practical way to control the material flow in order to obtain a more uniform thickness distribution and avoid forming failure. However, a problem sometimes encountered in multi-pass forming is wrinkling deformation between two adjacent deformation passes. This may lead to forming process instability and even fracture. The overall quality of the final part may also deteriorate even if the part is formed successfully. In this paper, the wrinkling phenomenon in multi-pass incremental sheet forming is investigated by means of finite element analysis (FEA) and experimental tests to analyse the wrinkling formation mechanism. This research gives an insight into the optimized design of deformation passes in order to eliminate the unwanted wrinkling deformation in multi-pass incremental forming process.

scholarly journals Accuracy and Sheet Thinning Improvement of Deep Titanium Alloy Part with Warm Incremental Sheet-Forming Process

2021 ◽  
Vol 5 (4) ◽  
pp. 122
Author(s):  
Badreddine Saidi ◽  
Laurence Giraud Moreau ◽  
Abel Cherouat ◽  
Rachid Nasri
Keyword(s):  
Titanium Alloy ◽  
Titanium Alloys ◽  
Thickness Distribution ◽  
Single Point ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Fe Model ◽  
Forming Process ◽  
Shape Accuracy ◽  
Truncated Cone

Incremental forming is a recent forming process that allows a sheet to be locally deformed with a hemispherical tool in order to gradually shape it. Despite good lubrication between the sheet and the tip of the smooth hemisphere tool, ductility often occurs, limiting the formability of titanium alloys due to the geometrical inaccuracy of the parts and the inability to form parts with a large depth and wall angle. Several technical solutions are proposed in the literature to increase the working temperature, allowing improvement in the titanium alloys’ formability and reducing the sheet thinning, plastic instability, and failure localization. An experimental procedure and numerical simulation were performed in this study to improve the warm single-point incremental sheet forming of a deep truncated cone in Ti-6Al-4V titanium alloy based on the use of heating cartridges. The effect of the depth part (two experiments with a truncated cone having a depth of 40 and 60 mm) at hot temperature (440 °C) on the thickness distribution and sheet shape accuracy are performed. Results show that the formability is significantly improved with the heating to produce a deep part. Small errors are observed between experimental and theoretical profiles. Moreover, errors between experimental and numerical displacements are less than 6%, which shows that the Finite Element (FE) model gives accurate predictions for titanium alloy deep truncated cones.

Comparison of some Final Part Geometrical Characteristics of Cylindrical Cups Manufactured by Deep-Drawing and Two-Point Incremental Sheet Forming

2009 ◽  
Vol 410-411 ◽  
pp. 355-363 ◽  
Author(s):  
Babak Taleb Araghi ◽  
Markus Bambach ◽  
Gerhard Hirt
Keyword(s):  
Sheet Metal ◽  
Deep Drawing ◽  
Thickness Distribution ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Surface Strain ◽  
Forming Process ◽  
Sheet Metal Parts ◽  
Part Surface ◽  
Metal Forming Process

Asymmetric incremental sheet forming (AISF) is a new sheet metal forming process in which sheet metal parts are produced by CNC-controlled movements of a simple ball-headed forming tool. Despite its flexibility and successful application in many cases, AISF has not yet been established in an industrial context due to some still existing process limits such as severe thinning, which strongly depends on the inclination of the part surface, as well as a limited geometric accuracy due to springback. Furthermore, there is little knowledge available about the properties of parts produced by AISF, especially in comparison to deep-drawn parts. The aim of the present paper is to compare cylindrical cups manufactured by deep-drawing and AISF regarding the resulting strain and thickness distribution. For AISF, different forming strategies were applied. Comparisons of the wall thickness and surface strain distributions show similar results for the cup produced by deep-drawing and the best cup produced by AISF, but the surface strains and the sheet thinning in the parts formed by AISF were larger than in the deep-drawn part.

An Analytical Model for Deformation Path Design in Multistage Incremental Sheet Forming Process

2014 ◽  
Vol 939 ◽  
pp. 245-252
Author(s):  
Zhao Bing Liu ◽  
Yan Le Li ◽  
W.J.T. Bill Daniel ◽  
Paul Meehan
Keyword(s):  
Analytical Model ◽  
Strain Distribution ◽  
Thickness Distribution ◽  
Technical Problem ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Thickness Variation ◽  
Uniform Thickness ◽  
Forming Process ◽  
Thickness Strain

Incremental sheet forming (ISF) is a new promising technology due to its flexibility and low-cost tooling properties compared with conventional forming processes. However, a common technical problem encountered in ISF is non-uniform thickness variation of formed parts, particularly excessive thinning on severely sloped regions, which may lead to the part fracture and limit the process formability. Design of multistage deformation paths (intermediate shapes or preforms) before the final part is a desirable and practical way to control the material flow in order to obtain more uniform thickness distribution and avoid forming failure. Based on the shear deformation and the strain compensation idea, an analytical model for designing multistage deformation paths and predicting the thickness strain distribution is proposed. The feasibility of the proposed model is validated by the finite element analysis (FEA) and experimental tests in terms of the comparison of prediction, simulation and experimental results on the thickness strain distribution and the process formability.

Theoretical and Numerical Analysis of Incremental Sheet Forming by Using High Pressure Water Jet

2011 ◽  
Author(s):  
B. Lu ◽  
J. Cao ◽  
H. Ou
Keyword(s):  
Sheet Thickness ◽  
Dimensional Accuracy ◽  
Sheet Forming ◽  
Water Jet ◽  
Incremental Sheet Forming ◽  
Forming Process ◽  
Back Plate ◽  
Metal Forming Process ◽  
Plastic Forming ◽  
Part Dimension

Incremental sheet forming using water jet (ISF-WJ) is a new sheet metal forming process proposed in recent years. Few reports can be found on this process and some basic questions are unanswered, i.e., the water jet pressure required for plastic forming and the accuracy of this forming process. In this paper, an analytical model was developed to evaluate the size effect in the ISF-WJ process with respect to some key parameters, such as sheet thickness, part dimension, jet size and jet pressure. Three commonly used engineering sheet materials (aluminum, stainless steel and titanium) are studied in the analysis and the formability of water jet on these materials was evaluated. In addition, comparisons are made between the ISF-WJ and conventional ISF process with rigid tool based on finite element simulations. The result suggests that the dimensional accuracy of ISF-WJ may be controlled by a supporting back plate and ISF-WJ shows a better distribution of strain and thickness reduction than ISF process. It also provides a good reference for future ISF-WJ equipment design and development.

scholarly journals An efficient method for thickness prediction in multi-pass incremental sheet forming

2014 ◽  
Vol 77 (1-4) ◽  
pp. 469-483 ◽  
Author(s):  
Tingting Cao ◽  
Bin Lu ◽  
Dongkai Xu ◽  
Huan Zhang ◽  
Jun Chen ◽  
...  
Keyword(s):  
Efficient Method ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Thickness Prediction

Material Flow Estimation of Deep-Drawn Product by Using Finite-Element Simulation

2011 ◽  
Vol 301-303 ◽  
pp. 452-455 ◽  
Author(s):  
Yuji Kotani ◽  
Hisaki Watari ◽  
Akihiro Watanabe
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Finite Element Simulation ◽  
Material Flow ◽  
Thickness Distribution ◽  
Sheet Thickness ◽  
Original Material ◽  
Element Simulation ◽  
Thickness Prediction ◽  
Simulation And Evaluation

The approach to total weight reduction has been a key issue for car manufacturers as they cope with more and more stringent requirements for fuel economy. In sheet metal forming, local increases in product-sheet thickness effectively contribute to reducing the total product weight. Products could be designed more efficiently if a designer could predict and control the thickness distribution of formed products. This paper describes a numerical simulation and evaluation of the material flow in local thickness increments of products formed by an ironing process. In order to clarify the mechanism of the local increase in sheet thickness, a 3-D numerical simulation of deep drawing and ironing was performed using finite-element simulation. The effects of various types of finite elements that primarily affect thickness changes in original materials and thickness prediction were investigated. It was found that the sheet-thickness distribution could be predicted if the original material was relatively thick and if an appropriate type of finite element is selected.

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.

An approach to eliminate stepped features in multistage incremental sheet forming process: Experimental and FEA analysis

2017 ◽  
Vol 31 (2) ◽  
pp. 599-604 ◽  
Author(s):  
Harish Kumar Nirala ◽  
Prashant K. Jain ◽  
J. J. Roy ◽  
M. K. Samal ◽  
Puneet Tandon
Keyword(s):  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Forming Process ◽  
Fea Analysis
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