Optimization of Fixture and Joint Positions in Sheet Metal Assembly: The Effect of Fixture Numbers and Constraints

2011 ◽  
Author(s):  
Kambiz Haji Hajikolaei ◽  
G. Gary Wang
Keyword(s):  
Sheet Metal ◽  
Metal Forming ◽  
Optimization Method ◽  
Stochastic Methods ◽  
Objective Functions ◽  
Variation Analysis ◽  
Spring Back ◽  
Final Assembly ◽  
Deterministic Methods ◽  
Sheet Metal Assembly

Assembly process is widely used in the manufacturing processes. Fabrication processes such as machining, casting and metal forming are not perfect and introduce variation in the components. Variations of components and tools accumulate and cause the assembly variation. In this paper, after reviewing the literature and presenting sheet metal assembly variation analysis, an optimization method is used to minimize the assembly variation by optimizing the location of joints and fixtures. The model is constructed in ANSYS with three fixtures and two joints. When a black-box function calculated numerically in software is used as the objective function, using deterministic methods for optimization is not suitable because the deterministic methods need knowledge of the objective functions. Also, using stochastic methods such as genetic algorithm is not suitable because of the large number of function evaluations they normally need. In this paper, an optimization algorithm based on mode-pursuing sampling (MPS) method is used to minimize the assembly variation. The optimization method is explained and after implementing the method, results are presented. It is learned that, in addition to the number of fixtures, the constraints on neighboring fixture locations also affect the optimal fixture layout, as well as the final assembly stiffness and spring-back.

A Genetic Algorithm Approach to Weld Pattern Optimization in Sheet Metal Assembly

2003 ◽  
Author(s):  
Gene Y. Liao
Keyword(s):  
Genetic Algorithm ◽  
Sheet Metal ◽  
Optimization Method ◽  
Structural Deformation ◽  
Assembly Process ◽  
Sheet Metal Parts ◽  
Final Assembly ◽  
Welding Operation ◽  
Genetic Algorithm Approach ◽  
Sheet Metal Assembly

In sheet metal assembly process, welding operation joins two or more sheet metal parts together. Since sheet metals are subject to dimensional variation resulted from manufacturing randomness, gap may be generated at each weld pair prior to welding. These gaps are forced to close during a welding operation and accordingly undesirable structural deformation results. Optimizing the welding pattern (the number and locations of weld pairs) of an assembly process was proven to significantly improve the quality of final assembly. This paper presents a Genetic Algorithm (GA)-based optimization method to automatically search for the optimal weld pattern so that the assembly deformation is minimized. Application result of a real industrial part demonstrated that the proposed algorithm effectively achieve the objective.

Variation Analysis for Compliant Assembly

2000 ◽  
Author(s):  
S. Jack Hu ◽  
Yufeng Long ◽  
Jaime Camelio
Keyword(s):  
Sheet Metal ◽  
Assembly Line ◽  
Assembly Process ◽  
Variation Analysis ◽  
Assembly Lines ◽  
Compliant Assembly ◽  
Single Station ◽  
Dimensional Variation ◽  
Sheet Metal Assembly

Abstract Assembly processes for compliant non-rigid parts are widely used in manufacturing automobiles, furniture, and electronic appliances. One of the major issues in the sheet metal assembly process is to control the dimensional variation of assemblies throughout the assembly line. This paper provides an overview of the recent development in variation analysis for compliant assembly. First, the unique characteristics of compliant assemblies are discussed. Then, various approaches to variation modeling for compliant assemblies are presented for single station and multi-station assembly lines. Finally, examples are given to demonstrate the applications of compliant assembly variation models.

Experimental Study on Electromagnetic Forming of Copper Sheets

2013 ◽  
Author(s):  
Shanmuga Sundaram Karibeeran ◽  
Rajiv Selvam
Keyword(s):  
Sheet Metal ◽  
Metal Forming ◽  
Weight Ratio ◽  
Cost Effective ◽  
Electromagnetic Forming ◽  
Light Weight ◽  
Thin Sheets ◽  
Spring Back ◽  
Aerospace Applications ◽  
Copper Aluminum

The sheet metal forming of copper, aluminum alloys using conventional stamping processes posses various problems, because of the lower formability limits, spring back and the tendency to wrinkle compared to steel. The principle of electromagnetism using attractive force is adopted to modify the conventional stamping process, to form thin sheets of 0.05 mm thickness. Further, this process can be used to form many sheet metal components with less expensive tooling and lesser number of operations. This process ultimately leads to light weight, cost effective and better strength-to-weight ratio components required for aerospace applications. In this study, a maximum of 30.77 % reduction in diameter was observed at 2.75A using electromagnetic forming which leads to the absence of spring back.

The Effect of Anisotropy on Spring-Back of CK67 Steel Sheet in L-Dies Bending Processes

2011 ◽  
Vol 291-294 ◽  
pp. 672-675
Author(s):  
Jafar Bazrafshan ◽  
A. Gorji ◽  
A. Taghizadeh Armaky
Keyword(s):  
Numerical Simulations ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Steel Sheet ◽  
Elastic Recovery ◽  
Sheet Thickness ◽  
Bend Angle ◽  
Spring Back ◽  
Geometric Changes

One of the most sensitive features of sheet metal forming processes is the elastic recovery during unloading, called spring-back, which leads to some geometric changes in the product. This phenomenon will affect bend angle and bend curvature, and can be influenced by various factors. In this research, the effects of sheet thickness and die radiuses an sheet anisotropy on spring-back in L-die bending of CK67 steel sheet were studied by experiments and numerical simulations.

scholarly journals The Performance of 3D Printed Polymer Tools in Sheet Metal Forming

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1256
Author(s):  
Fabio Tondini ◽  
Alberto Basso ◽  
Ulfar Arinbjarnar ◽  
Chris Valentin Nielsen
Keyword(s):  
Sheet Metal ◽  
Metal Forming ◽  
Spring Back ◽  
Bend Radius ◽  
Nose Radius ◽  
Aluminum Sheets ◽  
3D Printed ◽  
Small Production ◽  
Back Angle ◽  
Bulk Part

Additively manufactured polymer tools are evaluated for use in metal forming as prototype tools and in the attempt to make sheet metal more attractive to small production volumes. Printing materials, strategies and accuracies are presented before the tools and tested in V-bending and groove pressing of 1 mm aluminum sheets. The V-bending shows that the tools change surface topography during forming until a steady state is reached at around five strokes. The geometrical accuracy obtained in V-bending is evaluated by the spring-back angle and the resulting bend radius, while bending to 90° with three different punch nose radii. The spring-back shows additional effects from the elastic deflection of the tools, and the influence from the punch nose radius is found to be influenced by the printing strategy due to the ratio between tool radius and the printed solid shell thickness enclosing the otherwise less dense bulk part of the tool. Groove pressing shows the combined effect of groove heights and angular changes due to spring-back. In all cases, the repeatability is discussed to show the potential of tool corrections for obtaining formed parts closer to nominal values.

Optimization of Stamping Parameters Using Stochastic Focusing Search Algorithm

2012 ◽  
Vol 479-481 ◽  
pp. 1963-1967
Author(s):  
Ling Long ◽  
Chao Song ◽  
Guo Fu Yin
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Optimization Design ◽  
Search Algorithm ◽  
Optimization Procedure ◽  
Optimization Method ◽  
Forming Process ◽  
Metal Forming Process ◽  
Optimization Function

A new kind of swarm intelligence algorithm called stochastic focusing search(SFS) is proposed and applied to optimize sheet metal forming process in this paper. The steps of the optimization procedure include combining numerical simulation technology with orthogonal experiments to provide training samples for BP net, and producing the fitted function as optimization function for SFS algorithm. The validation of the final optimization results by a rectangular box part stamping case shows that this kind of optimization methodology is correct and reliable for the design of deep drawing process. Advantages of the SFS algorithm are demonstrated that SFS has good global searching ability and fast convergence speed in finding optimal solutions, which means the optimization method using SFS algorithm can provide a competitive way of solving the optimization design problems in sheet metal forming.

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