Experimental investigations on the incremental sheet forming of commercial steel ASTM A653 CS-A G90 to predict maximum bending effort

Author(s):  
Pablo D. Valle ◽  
Fred Lacerda Amorim ◽  
Dalberto D. Da Costa ◽  
Paulo V. P. Marcondes
Author(s):  
Harish K. Nirala ◽  
Anupam Agrawal

Single-point incremental sheet forming (SPISF) is a promising die-less forming technique. It has a variety of applications in many industries, viz., automobile, aerospace, and bone transplants. In SPISF, a sheet of metal is deformed by using numerically controlled single-point, hemispherical end-shaped forming tool, which incrementally deforms the sheet with highly localized plastic deformation. SPISF is a flexible yet relatively slow process when compared with conventional forming techniques like deep drawing and spinning. Since the beginning of die-less forming technology, researchers are recommending it for small batch production system or for customized fabrication. Being a slow process, it still has not achieved wide industrial acceptability. Among several key parameters dictating the process speed, the sheet clamping mechanism is one of the significant parameters of SPISF. Clamping mechanism plays a vital role in its manufacturing lead time. However, research efforts in this direction have been largely neglected. In this investigation, to improve the process speed, a novel electromagnetic clamping mechanism for SPISF is proposed. Detailed numerical and experimental investigations have been carried out to set up its applicability for the SPISF process. From the available literature, it has been found that this type of clamping mechanism in SPISF has not been studied or investigated. The proposed electromagnetic clamping makes the process of sheet clamping faster and convenient, and provides one-click clamping solution. This concept can take the process of incremental sheet forming toward better industrial acceptability. Furthermore, SPISF of symmetric and asymmetric components is conducted to test the feasibility of the concept.


2009 ◽  
Vol 623 ◽  
pp. 37-48 ◽  
Author(s):  
Steeve Dejardin ◽  
Jean Claude Gelin ◽  
Sebastien Thibaud

The paper is related to the analysis of shape distortions and springback effects arising in Single Point Incremental Forming. An experimental set up has been designed and manufactured to carry single point incremental forming on small size sheet metal parts. The experimental set up is mounted on 3-axes CNC milling machine tool and the forming tool is attached and move with the spindle. Experiments have been carried out on sheet metal parts to obtain tronconical shapes. The forming strategy associated to the movement of the forming tool has been also investigated. The experiments indicate that shape distortions arising in the corners of the tronconical shape are clearly related to forming strategy. The springback of rings cut in the tronconical parts have been also investigated. It is shown that positive or negative springback could be also related to forming strategy. In order to enhance experimental investigations, Finite Element simulations of the incremental sheet forming have been performed. Results obtained from the simulations prove that if boundary conditions and forming strategy carefully are taking into account, the finite elements results are in good agreement with experiments. So it is then possible to use FEM as a design tool for incremental sheet forming.


Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1862
Author(s):  
Harshal Y. Shahare ◽  
Abhay Kumar Dubey ◽  
Pavan Kumar ◽  
Hailiang Yu ◽  
Alexander Pesin ◽  
...  

Incremental Sheet Forming (ISF) is emerging as one of the popular dieless forming processes for the small-sized batch production of sheet metal components. However, the parts formed by the ISF process suffer from poor surface finish, geometric inaccuracy, and non-uniform thinning, which leads to poor part characteristics. Hammering, on the other hand, plays an important role in relieving residual stresses, and thus enhances the material properties through a change in grain structure. A few studies based on shot peening, one of the types of hammering operation, revealed that shot peening can produce nanostructure surfaces with different characteristics. This paper introduces a novel process, named the Incremental Sheet Hammering (ISH) process, i.e., integration of incremental sheet forming (ISF) process and hammering to improve the efficacy of the ISF process. Controlled hammering in the ISF process causes an alternating motion at the tool-sheet interface in the local deformation zone. This motion leads to enhanced material flow and subsequent improvement in the surface finish. Typical toolpath strategies are incorporated to impart the tool movement. The mechanics of the process is further explored through explicit-dynamic numerical models and experimental investigations on 1 mm thick AA1050 sheets. The varying wall angle truncated cone (VWATC) and constant wall angle truncated cone (CWATC) test geometries are identified to compare the ISF and ISH processes. The results indicate that the formability is improved in terms of wall angle, forming depth and forming limits. Further, ISF and ISH processes are compared based on the numerical and experimental results. The indicative statistical analysis is performed which shows that the ISH process would lead to an overall 10.99% improvement in the quality of the parts primarily in the surface finish and forming forces.


Author(s):  
Pavan Kumar ◽  
Satwik Priyadarshi ◽  
J. J. Roy ◽  
M. K. Samal ◽  
P. K. Jain ◽  
...  

This work explores the effect of tool geometry on surface finish in incremental sheet forming (ISF) process. In the present work, two different tool geometries i.e. hemispherical shaped tool and ellipsoidal shaped tool are considered. Area at tool-sheet contact and scallop height were calculated for both the tool geometries. To assess the effect of tool geometry on the surface finish of the formed components, both analytical and experimental approaches have been used. A test geometry having the shape of frustum of pyramid was considered for the proposed investigation and four surface roughness parameters i.e. arithmetic mean surface roughness (Ra), root mean square surface roughness (Rq), maximum peak-to-valley height (Rt) and average peak-to-valley height (Rz) have been selected as response parameters. Based on the analytical model and experimental investigations, both qualitative and quantitative comparisons had been made among the effects of hemispherical and ellipsoidal tool geometries on surface finish. The investigation deduces that better surface finish of the formed component can be achieved by using ellipsoidal shaped tool rather than the hemispherical shaped tool.


Author(s):  
Abdulmajeed Dabwan ◽  
Adham E Ragab ◽  
Mohamed A Saleh ◽  
Atef M Ghaleb ◽  
Mohamed Z Ramadan ◽  
...  

Incremental sheet forming is a specific group of sheet forming methods that enable the manufacture of complex parts utilizing computer numerical control instead of specialized tools. It is an incredibly adaptable operation that involves minimal usage of sophisticated tools, dies, and forming presses. Besides its main application in the field of rapid prototyping, incremental sheet forming processes can be used for the manufacture of unique parts in small batches. The goal of this study is to broaden the knowledge of the deformation process in single-point incremental forming. This work studies the deformation behavior in single-point incremental forming by experimentally investigating the principal stresses, principal strains, and thinning of single-point incremental forming products. Conical-shaped components are fabricated using AA1050-H14 aluminum alloy at various combinations of fundamental variables. The factorial design is employed to plan the experimental study and analysis of variance is conducted to analyze the results. The grey relational analysis approach coupled with entropy weights is also implemented to identify optimum process variables for single-point incremental forming. The results show that the tool diameter has the greatest effect on the thinning of the SPIF product, followed by the sheet thickness, step size, and feed rate.


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