Study on Forming Behaviour of Friction Stir Welded Blanks During Single Point Incremental Forming (SPIF) Process

Author(s):  
Shalin Marathe ◽  
Harit Raval

Abstract The automobile, transportation and shipbuilding industries are aiming at fuel efficient products. In order to enhance the fuel efficiency, the overall weight of the product should be brought down. This requirement has increased the use of material like aluminium and its alloys. But, it is difficult to weld aluminium using conventional welding processes. This problem can be solved by inventions like friction stir welding (FSW) process. During fabrication of product, FSW joints are subjected to many different processes and forming is one of them. During conventional forming, the formability of the welded blanks is found to be lower than the formability of the parent blank involved in it. One of the major reasons for reduction in formability is the global deformation provided on the blank during forming process. In order to improve the formability of homogeneous blanks, Single Point Incremental Forming (SPIF) is found to be giving excellent results. So, in this work formability of the welded blanks is investigated during the SPIF process. Friction Stir Welding is used to fabricate the welded blanks using AA 6061 T6 as base material. Welded blanks are formed in to truncated cone through SPIF process. CNC milling machine is used as SPIF machine tool to perform the experimental work. In order to avoid direct contact between weld seam and forming tool, a dummy sheet was used between them. As responses forming limit curve (FLC), surface roughness, and thinning are investigated. It was found that use of dummy sheet leads to improve the surface finish of the formed blank. The formability of the blank was found less in comparison to the parent metal involved in it. Uneven distribution of mechanical properties in the welded blanks leads to decrease the formability of the welded blanks.

2011 ◽  
Vol 264-265 ◽  
pp. 188-193 ◽  
Author(s):  
G. Palumbo ◽  
Marco Brandizzi ◽  
G. Cervelli ◽  
M. Fracchiolla

The present work focuses the attention on the Single Point Incremental Forming (SPIF) of the Titanium (Ti) alloy Ti-6Al-4V. Tensile tests were carried out using the optical strain measurement system Aramis3D, in order to determine the mechanical behaviour of the alloy and to investigate the anisotropy of such alloy. Finite Element (FE) simulations of the SPIF process (using ABAQUS/explicit) were performed using a simple but non-axialsymmetric shape (truncated pyramid) with the aim of investigating the effect of both the tool/pitch ratio (D/p) and the draw angle (α), taking into account the anisotropic behaviour. The analysis of plastic strains and thinning maps, together with the evaluation of shape errors originated by the forming process, highlighted that the parameter D/p plays a key role in the SPIF. Results from the preliminary FE analysis were used for investigating the production by SPIF of an automotive component (car door shell). A specific subroutine was created by the authors for automatically generating the tool path to be used in both the FE simulations and the manufacturing of parts by SPIF on a CNC milling machine.


Author(s):  
Chetan P. Nikhare

Abstract A substantial increase in demand on the sheet metal part usage in aerospace and automotive industries is due to the increase in the sale of these products to ease the transportation. However, due to the increase in fuel prices and further environmental regulation had left no choice but to manufacture more fuel efficient and inexpensive vehicles. These heavy demands force researchers to think outside the box. Many innovative research projects came to replace the conventional sheet metal forming of which single point incremental forming is one of them. SPIF is the emerging die-less sheet metal forming process in which the single point tool incrementally forces any single point of sheet metal at any processing time to undergo plastic deformation. It has several advantages over the conventional process like high process flexibility, elimination of die, complex shape and better formability. Previous literature provides enormous research on formability of metal during this process, process with various metals and hybrid metals, the influence of various process parameter, but residual formability after this process is untouched. Thus, the aim of this paper is to investigate the residual formability of the formed parts using single point incremental forming and then restrike with a conventional tool. The common process parameters of single point incremental forming were varied, and residual formability was studied through the conventional process. The strain and thickness distribution were measured and analyzed. In addition, the forming limit of the part was plotted and compared.


2013 ◽  
Vol 554-557 ◽  
pp. 2221-2229 ◽  
Author(s):  
João B.S. Farias ◽  
Miguel A.B.E. Martins ◽  
Daniel G. Afonso ◽  
Sonia R.H. Marabuto ◽  
Jorge A. Ferreira ◽  
...  

Single point incremental forming has attracted the interest of researchers in the last decade for the production of prototypes and small batch production of sheet-based parts [1, 2]. This technique allows the manufacture of parts without using expensive die sets. The SPIF (Single point incremental forming) process can be performed on different equipments such as adapted CNC milling machines, serial robots and built proposed machines [3]. Every solution has advantages and disadvantages. This work presents the CAD/CAM strategies for a parallel kinematics SPIF machine, designed and built at the University of Aveiro [3]. This machine brings a new approach to the SPIF industry. The machinery used to perform SPIF operations has limitations in their work volume with limited movements and in the magnitude of applicable forces. With that in mind, this machine was projected to overcome that obstacle, and was provided with a system with 6 degrees of freedom, while maintaining the ability to apply high loads. The disadvantage is the increase in volume occupied by the kinematic system. The manufacture of new parts could be reached out with more flexibility on the chosen tool path. The first step is the product design in the commercial CAD system. Next step is generating the tool path of the forming tool. This step is very important to achieve the desired part shape. It is used a commercial CAM system (EdgeCAM 2012®), which has resources from three up to five axis strategies. The last step is to send the information to the machine’s control system, based on real-time software. This paper will describe each step with more details.


Author(s):  
Senthil Kumar Velukkudi Santhanam ◽  
Vigneshwaran Ganesan ◽  
Subramanian Pillappan Shanmuganatan

In the recent manufacturing trend and, in particular, in sheet metal forming, the requirement of customized production is still growing. Incremental forming is a special technique requiring no high capacity presses or set of dies, thus meeting the increasing demand for low volume production and rapid prototyping. The complex three dimensional parts of sheet metals are formed by the computer numerical control (CNC) movement of a simple generative hemispherical tool. In this paper, the single point incremental forming process is performed on friction stir processed AA 6063-O alloy. The process parameters for the experiment are taken based on L9 Orthogonal array. In this paper the maximum wall angle or the formability is investigated on a formed pyramid frusta. It is inferred that Friction stir process has improved the ductility of the aluminium alloy thus contributing to enhanced formability.


2017 ◽  
Vol 890 ◽  
pp. 362-366 ◽  
Author(s):  
Amar Al-Obaidi ◽  
Verena Kräusel ◽  
Dirk Landgrebe

The strategy in manufacturing hardened parts used in car bodies is to tailor the mechanical properties. This is done by combining together a high-strength region and a high-toughness region to ensure the crash performance required. Other successive secondary operations such as trimming, joining and welding can be improved as a result of the tailoring process. In this work, the mechanical properties of 22MnB5 alloy sheet material produced by single-point incremental forming have been tailored. For this purpose, the sheets were locally heated by induction during the forming process and subsequently cooled. The sheet temperature was controlled by the CNC milling machine feed rate and induction power. As a result, the produced tailored parts consist of three different regions: ductile, transition and hardened regions. The Vickers hardness values were 583 HV1 and 175 HV1 for the hardened and ductile regions, respectively. The proposed application allows forming and quenching at the same time without transfer and to reduce the process time.


2019 ◽  
Vol 821 ◽  
pp. 256-262 ◽  
Author(s):  
Ramil Kesvarakul ◽  
Khompee Limpadapun

Single Point Incremental Forming (SPIF) is a die-less forming process with advantages of high-flexibility, low-cost and short lead time. The high local strains that are applied to the metal sheet, often exceeding the conventional formability limit. This paper is focused on comparison of predicted forming limit curves with measured experimental data on Hot-Dip Zinc-Coated Cold-Rolled sheet, with 0.20 mm thick is studied in single point incremental forming. Truncated square pyramid and cone are formed to study the formability of blank sheets at room temperature. It was found that both Formulation of plastic instability criteria and Keeler’s formula gives the lowest FLC. FLDs have predicted failures in forming process consistently with the real experiments. The experimentally obtained cracking limit differ from analytical one and empirical one by about 3.398 and 2.135 true strain respectively at FLD0, the corresponding plane strain values.


2010 ◽  
Vol 97-101 ◽  
pp. 126-129 ◽  
Author(s):  
Ghulam Hussain ◽  
Gao Lin ◽  
Nasir Hayat ◽  
Nameem Ullah Dar ◽  
Asif Iqbal

Straight groove test is a widely-used formability test in Single Point Incremental Forming (SPIF). This test does not cover all the forming aspects of SPIF process, however. In order to ascertain its legitimacy, two new tests covering necessary SPIF aspects are devised. The FLC of an aluminum sheet is determined using the newly proposed and straight groove tests. It is found that the straight groove test shows much lower formability than the new tests. Therefore, the employment of newly devised test(s) is proposed for the determination of precise formability limits.


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