A Novel Incremental Sheet Bending Process of Complex Curved Steel Plate

Author(s):  
Qiyang Zuo ◽  
Kai He ◽  
Xiaobing Dang ◽  
Wei Feng ◽  
Ruxu Du

Bending complex curved steel plates for constructing ship hull has long been a challenge in shipbuilding industry. This paper presents a novel incremental bending process to obtain complicated curved steel plates by a series of sequential and layered punches. Taking advantage of this process, the blank plate that is fixed and held by a flexible supporting system can incrementally be bent into the target shape by a press tool along a planned tool path step by step and layer by layer. Acting as a “lower die,” the flexible supporting system can provide flexible and multifunctional supports for the work piece during the forming process, whose four general motion modes are demonstrated in this paper. Meanwhile, the procedures of tool path planning and forming layering are also explained in detail. In addition, aiming at different motion modes of the flexible supporting system, two springback compensation methods are given. Furthermore, according to the forming principle presented in this paper, an original incremental prototype equipment was designed and manufactured, which is mainly composed of a three-axis computer numerical control (CNC) machine, a flexible supporting system, and a three-dimensional (3D) scanning feedback system. A series of forming experiments focusing on a gradual curvature shape were carried out using this prototype to investigate the feasibility and validity of this forming process.

Author(s):  
Qiyang Zuo ◽  
Kai He ◽  
Zhigang Sun ◽  
Hui Xu ◽  
Wei Li ◽  
...  

The bending of complex curved sheet metals of ship hull has long been a challenge in shipbuilding yard on account of some inherent defects of the traditional forming processes such as the line heating. This paper presents a novel incremental bending process based on punching to obtain complex curved steel plates in order to take the place of those inefficient traditional forming processes of ship hull. The presented incremental bending process is carried out by a series of stepping punches, so it is also defined as incremental punching in this work. By means of this process, the blank plate that is fixed and held by a flexible supporting system can incrementally be bent to the target shape by a press tool with a planned tool trajectory one step after another. Meanwhile, in order to improve geometric accuracy of the formed work-piece, a 3D scanning feedback system is applied to measure the deformation of the work-piece during the forming process. Three dimensional shape of the formed work-piece can be imaged and rebuilt with a large amount of point cloud data by the 3D scanning feedback system. Then the difference between the rebuilt model of the formed work-piece and the target CAD-model can be acquired, which can be used for feedback control of the forming accuracy if necessary. To validate the presented forming process, an original incremental punching prototype was designed and manufactured, which is mainly composed of a 3-axis CNC machine, a flexible supporting system and a 3D scanning feedback system. A forming experiment of a gradual curvature steel plate was carried out using this prototype and is discussed in detail in this paper in order to demonstrate the feasibility of the proposed incremental bending process of complex curved steel plate.


Author(s):  
Hossein Ghorbani-Menghari ◽  
Mehrdad Azadipour ◽  
Mehran Ghasempour-Mouziraji ◽  
Young Hoon Moon ◽  
Ji Hoon Kim

The deformation machining process (DMP) involves machining and incremental forming of thin structures. It can be applied for manufacturing products such as curved-surface blades without using 5-axis computerised numerical control machines. This work presents the effect of tool diameter and forming temperature on spring-back and dimensional accuracy of a simple fabricated part. The results of the first phase of the study are utilised to design the fabrication process of a curved surface blade. A feature-based algorithm is used to design the tool path for the forming process. The dimensional accuracy of the final product is improved through warm forming, two-point incremental forming, and extension of the bending zone to the outside of the product edges. The results show that DMP can be used to fabricate complex curved-surface workpieces with acceptable dimensional accuracy.


2001 ◽  
Vol 17 (02) ◽  
pp. 52-61
Author(s):  
H.C. Kuo ◽  
L.J. Wu

The increasing use of thin steel plates in manufacturing and the shipbuilding industry has given rise to several issues: massive deformation problems, the need for many skilled workers, and the expense of costs for straightening in on-line processes. This study explains the results of experiments and predicts techniques for the control of deformation in thin panels. The objective of this paper is to explain the use of the G(1,1) Grey method to predict deformation. Bending and buckling are usually the dominant modes of deformation in heat working. It follows angular deformation. De- formation due to different heat sources is discussed. In this paper, laser and torch are used in different constraints, for example, free-free beam and cantilever beam. Many important factors include tiny adjustments during the heat forming process, such as changing the moment speed, intensity of input heating, plate thickness and heating path, to improve manufacture techniques and to predict deformation by data series. For the prediction of deformation, a method to estimate input heating of laser and torch is introduced. The proposed prediction method can be used during the forming process simply and efficiently.


2017 ◽  
Vol 899 ◽  
pp. 272-277
Author(s):  
Hugo Dutra Gomes ◽  
Maria Carolina dos Santos Freitas ◽  
Luciano Pessanha Moreira ◽  
Flavia de Paula Vitoretti ◽  
Jose Adilson de Castro

The present study is primarily engaged in the implementation of the incremental stamping process in a computerized numeric control This paper presents two different approaches to this forming process, an experimental and other numerical. Experimental used by the computer numerical control to perform the printing process and performs numerical simulations of the process using the finite element method. Some parameters are analyzed in both approaches, such as product geometry effects, tool geometry, tool speed, tool path, contact conditions and mechanical properties of the materials.


2015 ◽  
Vol 809-810 ◽  
pp. 277-282
Author(s):  
Khalil Ibrahim Abass

The Single Point Incremental Forming Process (SPIF) is a forming technique of sheet material based on layered manufacturing principles. The forming tool is moved along the tool path while the edges of sheet material are clamped. The finished part is manufactured by the CNC machine. SPIF involves extensive plastic deformation and the description of the process is more complicated by highly nonlinear boundary conditions, namely contact and frictional effects have been accomplished. However, due to the complex nature of these models, numerical approaches dominated by the FEA are now in widespread use. The paper presents the data and main results of a study on effect of using cover blank in SPIF through FEA. The considered SPIF has been studied under certain process conditions referring to the test work piece, tool, etc., applying ANSYS 11.0. The results show that the simulation model can predict an ideal profile of processing track, spring back error of SPIF, the behavior of contact tool-work piece, the product accuracy by evaluation its thickness and strain distributions, the contact status and chattering among surface interface tool-work piece.


2012 ◽  
Vol 472-475 ◽  
pp. 1586-1591 ◽  
Author(s):  
S.H. Wu ◽  
Ana Reis ◽  
F.M. Andrade Pires ◽  
Abel D. Santos ◽  
A. Barata da Rocha

Single point incremental forming (SPIF) is an innovative flexible sheet metal forming process which can be used to produce complex shapes from various materials. Due to its flexibility, it attracts a more and more attention in the recent decades. Several studies show that besides the major operating parameters, namely feed rate, tool radius, and forming speed etc., tool path is also an important processing parameter to affect the final forming component. In view of that, the present paper studies the influence of tool paths on the work piece quality by the finite element method coupled with the Continuum Damage Mechanics (CDM) model. The formability of incremental forming in different tool paths is also analyzed.


2016 ◽  
Vol 40 (4) ◽  
pp. 433-443 ◽  
Author(s):  
Jiuhua Li ◽  
Xiaobing Dang ◽  
Kai He ◽  
Qiyang Zuo ◽  
Ruxu Du

A new type of incremental bending process for complicated curved sheet metal is proposed in the paper. The blank sheet is bended incrementally step by step. To validate the forming process, an incremental bending prototype is designed and manufactured, which was composed of a 3-DOF working table, a flexible supporting system and a 3D scanning system. The forming trajectory based on the theory of the minimum energy is planned according to the designed model of the sheet metal. Several experiments are carried out and the designed part is manufactured, which validated the proposed incremental forming method was successful.


2007 ◽  
Vol 344 ◽  
pp. 583-590 ◽  
Author(s):  
M. Skjoedt ◽  
M.H. Hancock ◽  
N. Bay

Single point incremental forming (SPIF) is a relatively new sheet forming process. A sheet is clamped in a rig and formed incrementally using a rotating single point tool in the form of a rod with a spherical end. The process is often performed on a CNC milling machine and the tool movement is programed using CAM software intended for surface milling. Often the function called profile milling or contour milling is applied. Using this milling function the tool only has a continuous feed rate in two directions X and Y, which is the plane of the undeformed sheet. The feed in the vertical Z direction is done in the same angular position in the XY plane along a line down the side of the work piece. This causes a scarring of the side and also results in a peak in the axial force when the tool is moved down. The present paper offers a solution to this problem. A dedicated program uses the coordinates from the profile milling code and converts them into a helical tool path with continuous feed in all three directions. Using the helical tool path the scarring is removed, the part is otherwise unchanged and a major disadvantage of using milling software for SPIF is removed. The solution is demonstrated by SPIF of three different geometries: a pyramid, a cone and a complex part.


2013 ◽  
Vol 549 ◽  
pp. 100-107 ◽  
Author(s):  
Wiriyakorn Phanitwong ◽  
Arkarapon Sontamino ◽  
Sutasn Thipprakmas

The U-bending process is a common sheet-metal forming process widely employed to fabricate sheet parts like channels, beams, and frames of various sizes applied in almost all industrial fields. In recent years, the precision requirements are increased on the U-bent parts. To achieve these requirements, in this study, the effects of part geometry on the spring-back/spring-go feature including work piece length, U-channel width, punch and die radii, and work piece thickness, were investigated by using the finite element method (FEM) and laboratory experiments. The FEM simulation results clearly revealed the influence of part geometry on spring-back/spring-go feature via the changes of stress distribution analyses on the bending allowance zone, the bottom of bent part, and the U-leg of bent part. Specifically, the part geometry affected on the bending characteristic on the bending allowance zone, as well as it affected on the spring-back feature. In addition, the part geometry also affected on the formation of reversed bending characteristic on the bottom and U-leg of bent parts, as well as it affected on the spring-go feature. The bending angle could be achieved by compensating these bending and reversed bending characteristics. Therefore, to meet the required bending angle, the suitable design of part geometry was strongly considered to maintain the balancing of the bending and reversed bending characteristics. The laboratory experiments were carried out to validate the accuracy of the FEM simulation results. The FEM simulation results showed good agreement with the experimental results with reference to the bending angle and bending force.


Author(s):  
Mandeep Dhanda ◽  
Aman Kukreja ◽  
SS Pande

This paper reports a novel method to generate adaptive spiral tool path for the CNC machining of complex sculptured surface represented in the form of cloud of points without the need for surface fitting. The algorithm initially uses uniform 2 D circular mesh-grid to compute the cutter location (CL) points by applying the tool inverse offset method (IOM). These CL points are refined adaptively till the surface form errors converge below the prescribed tolerance limits in both circumferential and radial directions. They are further refined to eliminate the redundancy in machining and generate optimum region wise tool path to minimize the tool lifts. The NC part programs generated by our algorithm were widely tested for different case studies using the commercial CNC simulator as well as by the actual machining trial. Finally, a comparative study was done between our developed system and the commercial CAM software. The results showed that our system is more efficient and robust in terms of the obtained surface quality, productivity, and memory requirement.


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