Three-Dimensional Tube Geometry Control for Rotary Draw Tube Bending, Part 2: Statistical Tube Tolerance Analysis and Adaptive Bend Correction

2000 ◽  
Vol 123 (2) ◽  
pp. 266-271 ◽  
Author(s):  
Huazhou Lou ◽  
Kim A. Stelson
Keyword(s):  
Three Dimensional ◽  
Tolerance Analysis ◽  
Bend Angle ◽  
Tube Bending ◽  
Process Error ◽  
Process Tolerance ◽  
Bending Process ◽  
Angle Bend ◽  
Geometry Error ◽  
Tube Geometry

The control of each individual bend and overall process is presented in Part 1 of the paper. In Part 2 of the paper, statistical methods are used to analyze and improve 3-D tube bending accuracy. The relationship between bending process error and tube geometry error is obtained with Monte Carlo simulation. For the same tube tolerance requirement, the required process tolerance varies in a large range based on tube geometry. Among the three bending errors: bend angle, bend plane and distance between bends, bend angle error has the largest influence on tube error. For a tube with multiple bends, the overall tube geometry error can be minimized by intentionally modifying the nominal values of the bends to be made based on the errors in the existing bends. The required modification of the bending commands is calculated with an adaptive bend correction algorithm.

Three-Dimensional Tube Geometry Control for Rotary Draw Tube Bending: Part 2—Statistical Tube Tolerance Analysis and Adaptive Bend Correction

2000 ◽  
Author(s):  
Huazhou Lou ◽  
Kim A. Stelson
Keyword(s):  
Three Dimensional ◽  
Tolerance Analysis ◽  
Bend Angle ◽  
Tube Bending ◽  
Process Error ◽  
Process Tolerance ◽  
Bending Process ◽  
Angle Bend ◽  
Geometry Error ◽  
Tube Geometry

Abstract The control of each individual bend and overall process is presented in part 1 of the paper. In part 2 of the paper, statistical methods are used to analyze and improve 3-D tube bending accuracy. The relationship between bending process error and tube geometry error is obtained with Monte Carlo simulation. For the same tube tolerance requirement, the required process tolerance varies in a large range based on tube geometry. Among the three bending errors: bend angle, bend plane and distance between bends, bend angle error has the largest influence on tube error. For a tube with multiple bends, the overall tube geometry error can be minimized by intentionally modify the nominal values of the bends to be made based on the errors in the existing bends. The required modification of the bending commands is calculated with an adaptive bend correction algorithm.

Innovative Machine Concepts for 3D Bending of Tubes and Profiles

2011 ◽  
Vol 473 ◽  
pp. 37-42 ◽  
Author(s):  
Matthias Hermes ◽  
Daniel Staupendahl ◽  
Christoph Becker ◽  
A. Erman Tekkaya
Keyword(s):  
Cross Sections ◽  
Cost Efficiency ◽  
Three Dimensional ◽  
Free Form ◽  
Tube Bending ◽  
Stretch Bending ◽  
Bending Process ◽  
New Process ◽  
Spinning Process ◽  
Springback Reduction

The paper deals with two new processes and developed special machines for profile and tube bending. The first process is a new roll-based machine for three-dimensional bending of profiles with symmetrical and asymmetrical cross-sections that has been developed. Compared to conventional processes like stretch bending, the advantage of Torque Superposed Spatial (TSS) Bending is the kinematic adjustment of the bending contour, leading to higher flexibility and cost efficiency especially in small batch production. The second process is the new process of Incremental Tube Forming (ITF). This process is based on a combination of a spinning process and kinematic free form bending of tubular semi-finished products. It is suitable for bending tubes two- and three-dimensionally to arbitrary contours and for manufacturing tailored tubes. The combined spinning and bending process leads to low bending forces with the possibility of a significant springback reduction.

Geometrical Phenomena in Tube Bending with Local Induction Heating

2014 ◽  
Vol 622-623 ◽  
pp. 717-724 ◽  
Author(s):  
Janusz Tomczak ◽  
Zbigniew Pater ◽  
Andrzej Gontarz ◽  
Eugeniusz Hadasik ◽  
Marek Cieśla ◽  
...  
Keyword(s):  
Induction Heating ◽  
Three Dimensional ◽  
Geometrical Parameters ◽  
Tube Bending ◽  
Heat Induction ◽  
Bending Process ◽  
Axis Position ◽  
Commercial Software Package ◽  
The Stability ◽  
Thermal Phenomena

A theoretical and experimental analysis of heat induction bending for tubes used in the power industry is performed. First, the design of the heat induction bending process for tubes is described and industrial application areas for this technology are presented. Next, the main methods for tube bending with local induction heating are discussed and the effect of the technology on geometrical parameters of bends formed is presented. Then, the heat induction bending process for tubes is modeled using numerical techniques (FEM). The simulations are performed in a three-dimensional strain state, where thermal phenomena are taken into account, using the commercial software package Simufact Forming v. 11.0. In the simulations, the changes in workpiece geometry in the region of the bend being made (cross section ovalization, darkening and thickening of walls, neutral axis position) are examined. Also, potential phenomena that could limit the stability of the bending process and cause shape defects are predicted. The results of the numerical modeling are then compared to those obtained under industrial conditions.

Three-Dimensional Tube Geometry Control for Rotary Draw Tube Bending, Part 1: Bend Angle and Overall Tube Geometry Control

2000 ◽  
Vol 123 (2) ◽  
pp. 258-265 ◽  
Author(s):  
Huazhou Lou ◽  
Kim A. Stelson
Keyword(s):  
Process Control ◽  
Control Strategy ◽  
Control Method ◽  
Three Dimensional ◽  
Bend Angle ◽  
Trial And Error ◽  
Operator Experience ◽  
Low Efficiency ◽  
Optimal Process Control ◽  
Tube Geometry

Traditional trial-and-error springback compensation methods have the problems of high scrap rate, low efficiency, high cost of fixtures and operator experience dependency. The method presented in this paper uses on-line measured springback data from the same batch to predict and compensate for springback. Because there are no springback data for the first bend, bend-rebend control is used to make the first bend to eliminate trial tubes. In addition to springback, relaxation and radial growth are also estimated and compensated for to make a bend more accurate. A process control method is developed to optimize the overall control strategy such that the overall tube error is minimized without increasing the required hardware accuracy. The optimal process control strategy has significantly higher accuracy than the traditional trial-and-error method. The details of statistical analysis of tube tolerance and adaptive bend correction algorithm are presented in Part 2 of the paper.

scholarly journals Optimization of Bending Process Parameters for Seamless Tubes Using Taguchi Method and Finite Element Method

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Jui-Chang Lin ◽  
Kingsun Lee
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Taguchi Method ◽  
Raw Materials ◽  
Three Dimensional ◽  
Fem Simulation ◽  
Optimal Parameters ◽  
Tube Bending ◽  
Bending Process ◽  
Element Method

The three-dimensional tube (or pipe) is manufactured by CNC tube bending machine. The key techniques are determined by tube diameter, wall thickness, material, and bending radius. The obtained technique through experience and the trial and error method is unreliable. Finite element method (FEM) simulation for the tube bending process before production can avoid wasting manpower and raw materials. The computer-aided engineering (CAE) software ABAQUS 6.12 is applied to simulate bending characteristics and to explore the maximum stress and strain conditions. The Taguchi method is used to find the optimal parameters of bending. The confirmation experiment is performed according to optimal parameters. Results indicate that the strain error between CAE simulation and bending experiments is within 6.39%.

Three-Dimensional Tube Geometry Control for Rotary Draw Tube Bending: Part 1—Bend Angle and Overall Tube Geometry Control

2000 ◽  
Author(s):  
Huazhou Lou ◽  
Kim A. Stelson
Keyword(s):  
Process Control ◽  
Control Strategy ◽  
Control Method ◽  
Three Dimensional ◽  
Bend Angle ◽  
Trial And Error ◽  
Operator Experience ◽  
Low Efficiency ◽  
Optimal Process Control ◽  
Tube Geometry

Abstract Traditional trial-and-error springback compensation methods have the problems of high scrap rate, low efficiency, high cost of fixtures and operator experience dependency. The method presented in this paper uses on-line measured springback data from the same batch to predict and compensate for springback. Because there are no springback data for the first bend, bend-rebend control is used to make the first bend to eliminate trial tubes. In addition to springback, relaxation and radial growth are also estimated and compensated for to make a bend more accurate. A process control method is developed to optimize the overall control strategy such that the overall tube error is minimized without increasing the required hardware accuracy. The optimal process control strategy has significantly higher accuracy than the traditional trial-and-error method. The details of statistical analysis of tube tolerance and adaptive bend correction algorithm are presented in part 2 of the paper.

scholarly journals Experimental Investigation of the Effects of Irradiating Schemes in Laser Tube Bending Process

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1123
Author(s):  
Mehdi Safari ◽  
Ricardo J. Alves de Sousa ◽  
Jalal Joudaki
Keyword(s):  
Laser Beam ◽  
Contact Process ◽  
Steel Tube ◽  
Thickness Variation ◽  
Tube Bending ◽  
Lateral Bending ◽  
Bending Angle ◽  
Laser Tube ◽  
Bending Process ◽  
Thickness Variations

The laser tube bending process (LTBP) process is a thermal non-contact process for bending tubes with less springback and less thinning of the tube. In this paper, the laser tube bending process will be studied experimentally. The length of irradiation and irradiation scheme are two main affecting process parameters in the LTBP process. For this purpose, different samples according to two main irradiation schemes (Circular irradiating scheme (CIS) and axial irradiating scheme (AIS)) and different lengths of laser beam irradiation (from 4.7 to 28.2 mm) are fabricated. The main bending angle of laser-bent tube, lateral bending angle, ovality, and thickness variations is measured experimentally, and the effects of the irradiating scheme and the length of irradiation are investigated. An 18 mm diameter, 1 mm thick mild steel tube was bent with 1100 Watts laser beam. The results show that for both irradiating schemes, by increasing the irradiating length of the main and lateral bending angle, the ovality and thickness variation ratio of the bent tube are increased. In addition, for a similar irradiating length, the main bending angle with AIS is considerably higher than CIS. The lateral bending angle by AIS is much less than the lateral bending angle with CIS. The results demonstrate that the ovality percentage and the thickness variation ratio for the laser-bent tube obtained by CIS are much more than the values associated with by AIS laser-bent tube.

Computer Aided Tolerance Analysis of Parts and Assemblies

1989 ◽  
Author(s):  
R. T. Scott ◽  
G. A. Gabriele
Keyword(s):  
Real World ◽  
Probability Distributions ◽  
Three Dimensional ◽  
Tolerance Analysis ◽  
The Real ◽  
Assembly Tolerance ◽  
Computer Aided ◽  
Probability Information ◽  
Exact Constraint

Abstract An exact constraint scheme based on the physical contacting constraints of real part mating features is used to represent the process of assembling the parts. To provide useful probability information about how assembly dimensions are distributed when the parts are assembled as intended, the real world constraints that would prevent interference are ignored. This work addresses some limitations in the area of three dimensional assembly tolerance analysis. As a result of this work, the following were demonstrated: 1. Assembly of parts whose assembly mating features are subjected to variation; 2. Assemble parts using a real world set of exact constraints; 3. Provide probability distributions of assembly dimensions.

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