Design Of Sheet Metal Parts Research Articles

New sheet metal forming process for springback reduction by continuous stress superposition

The use of ultra-high-strength steels (UHSS) enables a lightweight and resistant design of sheet metal parts in modern car body structures. In terms of manufacturing such dedicated materials, intense springback phenomena reduce the process stability and dimensional quality. In this context, new developments in springback compensation show promising results when superimposing stresses. Therefore, this paper deals with a new approach, which modifies conventional deep drawing of open profiles by substituting the blankholder by L-shaped sliders. This allows an additional application of horizontally acting forces along the edge of the flange and leads to advantageous free buckling and rolling of the material onto lateral punch surfaces. A numerical feasibility study of this new forming method was performed in this work, showing that compressive stresses and alternate bending through buckling in fact does reduce the amount of springback remarkably compared to conventional deep drawing.

Tolerance optimization for sheet metal parts based on joining simulation

In the industrial production process, the tolerance design of product is directly related to the product and production cost. This paper proposes an optimization method for the geometrical tolerance design of sheet metal parts based on joining simulation. Finite Element Method (FEM) is applied to simulate the influence of Body In White (BIW) joining process on the assembly deviation. Because the profile tolerance is widely used in the BIW sheet metal parts as the manufacturing requirements for the single parts as well as the assemblies to ensure the dimensional quality of the product, this type of tolerance on parts are mapped on the FE meshes in this work subjected to the Product Manufacturing Information (PMI). A sensitivity analysis is implemented to rank the tolerances by constructing meta-models. Without compromising the dimensional stability of the assembly, the geometrical tolerances of the single parts are optimized through a two-level optimization system. An automotive reinforcement assembly is studied to illustrate the proposed method. The maximum allowable tolerance ranges of the reinforcement part are adapted with respect to a pre-defined process capability index. The result provides a quantitative tolerance optimization strategy for BIW parts in an early development phase.

Fixture Layout Design of Sheet Metal Parts Based on Global Optimization Algorithms

Fixture layout can affect deformation and dimensional variation of sheet metal assemblies. Conventionally, the assembly dimensions are simulated with a quantity of finite element (FE) analyses, and fixture layout optimization needs significant user intervention and unaffordable iterations of finite element analyses. This paper therefore proposes a fully automated and efficient method of fixture layout optimization based on the combination of 3dcs simulation (for dimensional analyses) and global optimization algorithms. In this paper, two global algorithms are proposed to optimize fixture locator points, which are social radiation algorithm (SRA) and GAOT, a genetic algorithm (GA) in optimization toolbox in matlab. The flowchart of fixture design includes the following steps: (1) The locating points, the key elements of a fixture layout, are selected from a much smaller candidate pool thanks to our proposed manufacturing constraints based filtering methods and thus the computational efficiency is greatly improved. (2) The two global optimization algorithms are edited to be used to optimize fixture schemes based on matlab. (3) Since matlab macrocommands of 3dcs have been developed to calculate assembly dimensions, the optimization process is fully automated. A case study of inner hood is applied to demonstrate the proposed method. The results show that the GAOT algorithm is more suitable than SRA for generating the optimal fixture layout with excellent efficiency for engineering applications.

PREPARATION OF CONSTRUCTION PRODUCTION OF METAL SHEET FOR MEANS OF TRANSPORT

The design of sheet metal parts, pressed, used in the automotive industry is very complicated. Many factors influence the final shape of the part. Contemporary designer does not need to have the knowledge needed to understand the essence of its all requirements that are placed on parts of the body. It is only important that they are aware of their existence and know who in the company can help them in their fulfilment of the construction. Nowadays, only the constructor creates a CAD model geometry, which is assumed to provide the functionality. The rest of the aspects such as the provision of adequate stiffness, manufacturability, assembly features, vibration analysis, etc., are the arena of other specialists. This is the essence of constructing simultaneous, where many cell companies often work on the same element, giving it a set of features impossible to obtain by one expert on everything. Therefore, the role of the designer is often limited to being only a CAD system operator.

A knowledge-based system for strip-layout design for progressive deep drawing dies

Strip-layout design is one of the most critical steps in the design of progressive deep drawing die. It is a skilled and experienced-based activity. This paper presents a Knowledge-Based System KBS for automation of strip-layout design of sheet metal parts produced on progressive deep drawing dies. The proposed system is developed using production rule-based KBS approach of artificial intelligence AI. It comprises eight modules to impart recommendations to the user for selection of proper size of stock strip, identification and sequencing of operations, selection of proper piloting scheme, and number of stations and staging of operations on progressive deep drawing die. Finally, the system models the blank layout and strip-layout automatically in the drawing editor of AutoCAD. The proposed system is flexible, user-interactive and its low cost of implementation makes it affordable for small and medium scale sheet metal industries.

A Retrieval Algorithm of Sheet Metal Parts Based on Relationships of Features

With the rapid increase in the number of three-dimensional (3D) models each year, to quickly and easily find the part desired has become a big challenge of enterprises. Meanwhile, many methods and algorithms have been proposed for part retrieval. However, most of the existing methods are designed for mechanical parts, and can not be well worked for sheet metal part retrieval. An approach to feature-based retrieval of sheet metal parts is presented. Firstly, the features frequently used in sheet metal part design are chosen as the “key words” in retrieval. Based on those features, a relative position model is built to express the different relationships of the features in 3D space. Secondly, a description method of the model is studied. With the description method the relative position of features in sheet metal parts can be expressed by four location description matrices. Thirdly, based on the relative position model and location description matrices, the equivalent definition of relationships of two feature groups is given which is the basis to calculate the similarity of two sheet metal parts. Next, the formula of retrieval algorithm for sheet metal parts is given. Finally, a prototype system is developed to test and verify the effectiveness of the retrieval method suggested. Experiments verify that the new method is able to meet the requirements of searching sheet metal parts and possesses potentials in practical application.

A simplified algorithm for planar development of 3D surface and its application in the blank design of sheet metal forming

This paper introduces a simplified algorithm for generating planar developments of arbitrarily three-dimensional (3D) surface. The 3D surface is first divided into triangular finite elements, the deformation from the curved surface to its planar development is then modeled by in-plane strains of elemental edges. The developed planar shape corresponding to minimum deformation nonuniformity and volume constancy is obtained by solving a constrained nonlinear programming problem. A multi-step scheme of the algorithm is presented and applied to the blank design of sheet metal parts. Based on the assumption that the thickness strain is one of the principal strains, the deformations from the final part to its initial blank are estimated. Numerical and experimental results as well as application examples demonstrate that the present algorithm can predict the blank shape of 3D sheet metal part within a small range of error with low computing time.

Distributed multi-agent system approach for sheet metal forming

In this study, a distributed multi-agent system (DMAS) for sheet metal forming is proposed. The system consists of functional agents such as die design agent, knowledge management agent, validation and verification agent, product description agent, operation planning agent, calculating and dimensioning agent, artificial intelligence agent, assembly and disassembly agent. Also there is a design mediator. Each of the functional agents is enhanced software and can be considered as an expert of the classical die design. This paper provides the theoretical framework for future research. This enhanced system has been implemented on a simple sheet metal part. So, it can be seen that die design of sheet metal parts can successfully be realized using a multi-agent system.

Physical and geometrical data acquiring system for vibration analysis software

The article presents a numerical engineering application CATGEN that integrates two environments—CATIA software and GRAFSIM program. CATIA software is designed specifically for intuitive modelling for Solid, Hybrid and Sheetmetal Part design, Assembly design and integrated Drafting. The GRAFSIM program realizes matrix hybrid graphs (mhg) [J. Świder, Matrix hybrid graphs in description of complex, vibrating mechanical systems, in: Mechanics—book 106, Silesian University of Technology Scientific Books, Gliwice, Poland, 1991 (in Polish) [1]]. Transformation into matrix block diagram [J. Świder, G. Wszołek, Vibration analysis software based on a matrix hybrid graph transformation into a structure of a block diagram method. Proceedings of 11 International Scientific Conference—Achievements in Mechanical & Materials Engineering, Gliwice-Zakopane, 2002, pp. 561–564 [2]]. The program gives possibility for the preparation of comprehensive and complex analysis of two- and three-dimensional mechanical systems with linear couplings.

Automatically extracting sheet-metal features from solid model

With the development of modern industry, sheet-metal parts in mass production have been widely applied in mechanical, communication, electronics, and light industries in recent decades; but the advances in sheet-metal part design and manufacturing remain too slow compared with the increasing importance of sheet-metal parts in modern industry. This paper proposes a method for automatically extracting features from an arbitrary solid model of sheet-metal parts; whose characteristics are used for classification and graph-based representation of the sheet-metal features to extract the features embodied in a sheet-metal part. The extracting feature process can be divided for valid checking of the model geometry, feature matching, and feature relationship. Since the extracted features include abundant geometry and engineering information, they will be effective for downstream application such as feature rebuilding and stamping process planning.

An Information Modelling Framework to Support Intelligent Concurrent Design and Manufacturing of Sheet Metal Parts

Sharing of information is an important issue in supporting integrated and rapid product development. The use of information modelling technology is a promising approach for solving the problems of the intensive sharing of information in a concurrent and rapid product development cycle. This paper explores the definition and the structure of a framework of information modelling for the concurrent design and manufacturing of sheet metal parts. This framework aims to build an information bridge to fill the gap between the sheet metal part design and manufacturing systems. It is based on abstract handling principles of entities called zero thickness and zero bend radius principles. Based on this framework, information models can be built for information sharing by different systems. Knowledge bases that support intelligent concurrent design and manufacturing can also be created. In this paper, a two-branch tree based stepping-structure information modelling methodology for sheet metal parts is described, and a case study is given.

A Feature indexing and Case Retrieval Method of Sheet Metal Parts for CAD.

This paper presents a feature indexing and case retriveal method of machine parts for computer aided design (CAD) based on case-based reasoning (CBR). CBR is a promising method for assisting knowledge acquisition of expert systems. The new method is for standardization and efficient design of sheet metal parts using the CBR. Feature indexing and similarity calculation are key techniques for feasible CBR. A new feature indexing method and a new method of calculating similarities of sheet metal parts are described in this paper. Fuzzy measure is introduced for incorporating human measure of similarities of the parts. Using the indices, case retrieval is carried out.

Stretch flanging of “V”-shaped sheet metal blanks

This paper describes a mathematical model of the stretch flanging of sheet metal blanks which are initially curved in the shape of a “V.” By assuming that all intermediate flange surfaces are developable and the effect of tool friction is negligible, the deformation in the flange is equivalent to that of an in-plane stretching operation. Strain distributions in the latter are shown to be conveniently calculated by elastic-plastic finite element analyses. To assess the applicability of the model, an existing flanging apparatus was used to produce specimens for a variety of flange configurations with AKDQ steel, HSLA-60 steel, and 2036-T4 aluminum. Comparison of the calculated and measured strain distributions along the free edges of these specimens show that the present model is reasonably accurate to be useful in feasibility studies of the design of sheet metal parts.

Practical Application of Stress Strain Theory

THE first and foremost problem in aircraft production is one of proper design and rapid production of sheet metal forming tools. A full understanding of forming properties of various aircraft materials, the limits of each method of forming, and die design and construction, are of vital importance to every tool designer and tool planner. In view of the great variety of parts to be produced, the expensive and time‐consuming trial and error method of die development should be reduced to a minimum. The problems of production, particularly forming problems, will be greatly simplified by the use of this same knowledge and information in the design of sheet metal parts. If the limits to which parts can be formed by the common methods are known and applied, a very large percentage of parts can be designed so that they may be formed readily and economically using as few operations as possible. If parts are designed so that they take advantage of new simplified methods, it is important that tools be made with close cooperation between the pre‐planned, tool planners, and tool designers.