Trace generation of friction stir welding robot for space weld joint on large thin-walled parts

2016 ◽  
Vol 43 (6) ◽  
pp. 617-627 ◽  
Author(s):  
Ruolong Qi ◽  
Weijia Zhou ◽  
Huijie Zhang ◽  
Wei Zhang ◽  
Guangxin Yang
Keyword(s):  
Friction Stir Welding ◽  
Weld Joint ◽  
Plane Curve ◽  
Complex Surface ◽  
Space Curve ◽  
Least Square ◽  
Thin Wall ◽  
Content Type ◽  
Friction Stir ◽  
Thin Walled

Purpose The weld joint of large thin-wall metal parts which deforms in manufacturing and clamping processes is very difficult to manufacture for its shape is different from the initial model; thus, the space normals of the part surface are uncertain. Design/methodology/approach In this paper, an effective method is presented to calculate cutter location points and to estimate the space normals by measuring some sparse discrete points of weld joint. First, a contact-type probe fixed in the end of friction stir welding (FSW) robot is used to measure a series of discrete points on the weld joint. Then, a space curve can be got by fitting the series of points with a quintic spline. Second, a least square plane (LSP) of the measured points is obtained by the least square method. Then, normal vectors of the plane curve, which is the projection of the space curve on the LSP, are used to estimate the space normals of the weld joint curve. After path planning, a post-processing method combing with FSW craft is elaborated. Findings Simulation and real experiment demonstrate that the proposed strategy, which obtains cutter locations of welding and normals without measuring the entire surface, is feasible and effective for the FSW of large thin-walled complex surface parts. Originality/value This paper presents a novel method which makes it possible to accurately weld the large thin-wall complex surface part by the FSW robot. The proposed method might be applied to any multi-axes FSW robot similar to the robot studied in this paper.

Studies of the characterization of weld joint created by using friction stir welding with stellite stir tool

2020 ◽  
Author(s):  
G. Britto Joseph ◽  
T. N. Valarmathi ◽  
A. John Rajan ◽  
K. Pawana Sudeer Kumar ◽  
S. Prasath
Keyword(s):  
Friction Stir Welding ◽  
Weld Joint ◽  
Friction Stir

scholarly journals 3D-Printed Tool Shoulder Design for the Analogue Modelling of Bobbin Friction Stir Weld Joint Quality

2021 ◽  
Vol 21 (1) ◽  
pp. 27-42
Author(s):  
A. Tamadon ◽  
D. J. Pons ◽  
K. Chakradhar ◽  
J. Kamboj ◽  
D. Clucas
Keyword(s):  
Friction Stir Welding ◽  
Cross Sections ◽  
Weld Joint ◽  
Flow Patterns ◽  
Friction Stir Weld ◽  
Butt Weld ◽  
Friction Stir ◽  
Tool Shoulder ◽  
Analogue Modelling ◽  
3D Printed

Abstract A variety of tool shoulder designs comprising three families i.e. blade, spiral and circular shaped scrolls, were produced to improve the material flow and restrictions to avoid the tunnel void. The bobbin tools were manufactured by 3D printing additive manufacturing technology using solid filament. The butt weld joint was produced by each tool using plasticine as the workpiece material. The apparent surface features and bi-colour cross-sections provided a physical flow comparison among the shoulder designs. For the bobbin friction stir welding (BFSW), the tool shoulder with a three-spiral design produced the most stability with the best combination of the flow patterns on surface and cross-sections. The circular family tools showed a suitable intermixing on the surface pattern, while the blade scrolls showed better flow features within the cross-sections. The flow-driven effect of the shoulder features of the bobbin-tool design (inscribed grooves) was replicated by the 3D-printed tools and the analogue modelling of the weld samples. Similar flow patterns were achieved by dissimilar aluminium-copper weld, validating the accuracy of the analogue plasticine for the flow visualization of the bobbin friction stir welding.

Mechanical and Corrosion Behavior of Pure Aluminium Added Friction Stir Weld Joint of Aluminium Alloy

2019 ◽  
Vol 821 ◽  
pp. 327-333
Author(s):  
Sunil Sinhmar ◽  
Dheerendra Kumar Dwivedi
Keyword(s):  
Friction Stir Welding ◽  
Aluminium Alloy ◽  
Corrosion Behavior ◽  
Weld Joint ◽  
Second Phase ◽  
Pure Aluminium ◽  
Nugget Zone ◽  
Friction Stir ◽  
Aluminium Addition ◽  
Aluminium Strip

Friction stir welding (FSW) of AA2014 aluminium alloy was performed by sandwiching pure aluminium (Al) in the form of strip between the abutting surfaces. Mechanical and corrosion behavior of weld joint with and without pure aluminium addition was compared. Friction stir welding was carried out at rotational speed of 931 rpm and traverse speed of 41 mm/min. Pure aluminium strip of 1 mm thickness was used for incorporating Al in weld nugget zone. Microstructure analysis was carried out using optical microscope and FESEM with energy dispersive spectroscopy (EDS). Microhardness and tensile testing were performed on the weld joints. Corrosion behavior was investigated using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (Tafel) test. FESEM analysis was performed before and after corrosion test. Traces of pure aluminium strip were observed in the microstructure. The incorporated strip was found not to be uniformly distributed in the nugget zone. Pure aluminium addition reduced the extent of formation of the second phase particle in the nugget zone as compared to the normal FSW joint i.e. without Al addition. This metallurgical homogeneity resulted in better corrosion resistance of the Al added weld joint than the normal FSW joint.

Optimization of friction stir welding process parameters for AA6063-ETP copper using central composite design

2020 ◽  
Vol 17 (4) ◽  
pp. 491-507 ◽  
Author(s):  
Nitin Panaskar ◽  
Ravi Prakash Terkar
Keyword(s):  
Experimental Data ◽  
Tensile Strength ◽  
Friction Stir Welding ◽  
Process Parameters ◽  
Rotational Speed ◽  
Traverse Speed ◽  
Tool Rotational Speed ◽  
Content Type ◽  
Friction Stir ◽  
Central Composite

Purpose Recently, several studies have been performed on lap welding of aluminum and copper using friction stir welding (FSW). The formation of intermetallic compounds at the weld interface hampers the weld quality. The use of an intermediate layer of a compatible material during welding reduces the formation of intermetallic compounds. The purpose of this paper is to optimize the FSW process parameters for AA6063-ETP copper weld, using a compatible zinc intermediate filler metal. Design/methodology/approach In the present study, a three-level, three-factor central composite design (CCD) has been used to determine the effect of various process parameters, namely, tool rotational speed, tool traverse speed and thickness of inter-filler zinc foil on ultimate tensile strength of the weld. A total of 60 experimental data were fitted in the CCD. The experiments were performed with tool rotational speeds of 1,000, 1,200 and 1,400 rpm each of them with tool traverse speeds of 5, 10 and 15 mm/min. A zinc inter-filler foil of 0.2 and 0.4 mm was also used. The macrograph of the weld surface under different process parameters and the tensile strength of the weld have been investigated. Findings The feasibility of joining 3 mm thick AA6063-ETP copper using zinc inter-filler is established. The regression analysis showed a good fit of the experimental data to the second-order polynomial model with a coefficient of determination (R2) value of 0.9759 and model F-value of 240.33. A good agreement between the prediction model and experimental findings validates the reliability of the developed model. The tool rotational speed, tool traverse speed and thickness of inter-filler zinc foil significantly affected the tensile strength of the weld. The optimal conditions found for the weld were, rotational speed of 1,212.83 rpm and traverse speed of 9.63 mm/min and zinc foil thickness is 0.157 mm; by using optimized values, ultimate tensile strength of 122.87 MPa was achieved, from the desirability function. Originality/value Aluminium and copper sheets could be joined feasibly using a zinc inter-filler. The maximum tensile strength of joints formed by inter-filler (122.87 MPa) was significantly better as compared to those without using inter-filler (83.78 MPa). The optimum process parameters to achieve maximum tensile strength were found by CCD.

scholarly journals An Implicit Algorithm Based on Continuous Moving Least Square to Simulate Material Mixing in Friction Stir Welding Process

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Abdelaziz Timesli ◽  
Bouazza Braikat ◽  
Hassane Lahmam ◽  
Hamid Zahrouni
Keyword(s):  
Friction Stir Welding ◽  
Welding Process ◽  
Least Square ◽  
Implicit Algorithm ◽  
Friction Stir ◽  
Moving Least Square ◽  
Lagrangian Framework ◽  
Strong Formulation ◽  
Implicit Iterative Algorithm ◽  
Material Mixing

An implicit iterative algorithm, based on the continuous moving least square (CMLS), is developed to simulate material mixing in Friction Stir Welding (FSW) process. Strong formulation is chosen for the modeling of the mechanical problem in Lagrangian framework to avoid the drawback of numerical integration. This algorithm is well adapted to large deformations in the mixing zone in the neighborhood of the welding tool. We limit ourselves to bidimensional viscoplastic problem to show the performance of the proposed implicit algorithm. The results show that the proposed algorithm can be employed to simulate FSW.

Effects of welding speeds on the microstructural and mechanical properties of AZ91D Mg alloy by friction stir welding

2020 ◽  
Vol 11 (6) ◽  
pp. 769-782 ◽  
Author(s):  
Nagabhushan Kumar Kadigithala ◽  
Vanitha C
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
Magnesium Alloy ◽  
Welding Speed ◽  
Base Material ◽  
Welding Parameters ◽  
Content Type ◽  
Friction Stir ◽  
Az91d Magnesium Alloy ◽  
Transverse Tensile

PurposeThe main purpose of the present work is to evaluate, the microstructural and mechanical properties of friction stir welded plates of AZ91D magnesium alloy with 3 mm thickness, and to determine the optimum range of welding conditions.Design/methodology/approachMicrostructure and fractographic studies were carried out using scanning electron microscopy (SEM). Vickers micro hardness test was performed to evaluate the hardness profile in the region of the weld area. The phases in the material were confirmed by X-Ray diffraction (XRD) analysis. Transverse tensile tests were conducted using universal testing machine (UTM) to examine the joint strength of the weldments at different parameters.FindingsMetallographic studies revealed that each zone shown different lineaments depending on the mechanical and thermal conditions. Significant improvement in the hardness was observed between the base material and weldments. Transverse tensile test results of weldments had shown almost similar strength that of base material regardless of welding speed. Fractographic examination indicated that the welded specimens failed due to brittle mode fracture. Through these studies it was confirmed that friction stir welding (FSW) can be used for the welding of AZ91D magnesium alloy.Research limitations/implicationsIn the present study, the welding speed varied from 25 mm/min to 75 mm/min, tilt angle varied from 1.5° to 2.5° and constant rotational speed of 500 rpm.Practical implicationsMagnesium and aluminum based alloys which are having high strength and low density, used in automotive and aerospace applications can be successfully joined using FSW technique. The fusion welding defects can be eliminated by adopting this technique.Originality/valueLimited work had been carried out on the FSW of magnesium based alloys over aluminum based alloys. Furthermore, this paper analyses the influence of welding parameters over the microstructural and mechanical properties.

Deflection model for robotic friction stir welding

2014 ◽  
Vol 41 (4) ◽  
pp. 365-372 ◽  
Author(s):  
Jeroen De Backer ◽  
Gunnar Bolmsjö
Keyword(s):  
Friction Stir Welding ◽  
Force Feedback ◽  
Force Sensor ◽  
Industrial Robots ◽  
Positional Accuracy ◽  
Content Type ◽  
Friction Stir ◽  
Robot Controller ◽  
External Forces ◽  
Robotic Friction Stir Welding

Purpose – This paper aims to present a deflection model to improve positional accuracy of industrial robots. Earlier studies have demonstrated the lack of accuracy of heavy-duty robots when exposed to high external forces. One application where the robot is pushed to its limits in terms of forces is friction stir welding (FSW). This process requires the robot to deliver forces of several kilonewtons causing deflections in the robot joints. Especially for robots with serial kinematics, these deflections will result in significant tool deviations, leading to inferior weld quality. Design/methodology/approach – This paper presents a kinematic deflection model, assuming a rigid link and flexible joint serial kinematics robot. As robotic FSW is a process which involves high external loads and a constant welding speed of usually below 50 mm/s, many of the dynamic effects are negligible. The model uses force feedback from a force sensor, embedded on the robot, and predicts the tool deviation, based on the measured external forces. The deviation is fed back to the robot controller and used for online path compensation. Findings – The model is verified by subjecting an FSW tool to an external load and moving it along a path, with and without deviation compensation. The measured tool deviation with compensation was within the allowable tolerance for FSW. Practical implications – The model can be applied to other robots with a force sensor. Originality/value – The presented deflection model is based on force feedback and can predict and compensate tool deviations online.

Computational analysis of inter-material mixing and weld-flaw formation during dissimilar-filler-metal friction stir welding (FSW)

2015 ◽  
Vol 11 (3) ◽  
pp. 322-349 ◽  
Author(s):  
M. Grujicic ◽  
R Yavari ◽  
S. Ramaswami ◽  
J Snipes ◽  
R Galgalikar
Keyword(s):  
Friction Stir Welding ◽  
Computational Analysis ◽  
Filler Metal ◽  
Dissimilar Materials ◽  
Conservation Equation ◽  
Element Analysis ◽  
Content Type ◽  
Metal Insert ◽  
Friction Stir ◽  
Material Mixing

Purpose – Friction stir welding (FSW) butt-joining involving the use of a dissimilar filler metal insert between the retreating and advancing portions of the workpiece is investigated computationally using a combined Eulerian-Lagrangian (CEL) finite element analysis (FEA). The emphasis of the computational analysis was placed on the understanding of the inter-material mixing and weld-flaw formation during a dissimilar-material FSW process. The paper aims to discuss these issues. Design/methodology/approach – The FEA employed is of a two-way thermo-mechanical character (i.e. frictional-sliding/plastic-work dissipation was taken to act as a heat source in the energy conservation equation), while temperature is allowed to affect mechanical aspects of the model through temperature-dependent material properties. Within the analysis, the workpiece and the filler-metal insert are treated as different materials within the Eulerian subdomain, while the tool was treated as a conventional Lagrangian subdomain. The use of the CEL formulation within the workpiece insert helped avoid numerical difficulties associated with excessive Lagrangian element distortion. Findings – The results obtained revealed that, in order to obtain flaw-free FSW joints with properly mixed filler and base materials, process parameters including the location of the tool relative to the centerline of the weld must be selected judiciously. Originality/value – To the authors’ knowledge, the present work is the first reported attempt to simulate FSW of dissimilar materials.

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