Investigation of forming accuracy in multipoint forming with composite elastic pads

The uniformity of temperature field distribution in creep aging process is very important to the forming accuracy of components. In this paper, the temperature field distribution of 2219 aluminum alloy tank cover during aging forming is simulated by using the finite element software FLUENT, and a two-stage heating process is proposed to reduce the temperature field distribution heterogeneity. The results show that the temperature difference of the tank cover is large in the single-stage heating process, and the maximum temperature difference is above 27°C,which seriously affects the forming accuracy of the tank cover. With two-stage heating process, the temperature difference in the first stage has almost no direct impact on the forming accuracy of the top cover. In the second stage, the temperature difference of the tank cover is controlled within 10°C, compared with the single-stage heating, the maximum temperature difference is reduced by more than 17°C. The two-stage heating effectively reduces the heterogeneity of the temperature field of the top cover. The research provides technical support for the precise thermal mechanical coupling of large-scale creep aging forming components.

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Multi-point Forming with Wrinkle Resistance Function and Its Forming Accuracy

Journal of Mechanical Engineering ◽

10.3901/jme.2012.12.056 ◽

2012 ◽

Vol 48 (12) ◽

pp. 56 ◽

Cited By ~ 6

Author(s):

Zhiwei LIU

Keyword(s):

Wrinkle Resistance ◽

Forming Accuracy ◽

Resistance Function

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Deformation behavior in multi-point forming using a strip steel pad

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406219898233 ◽

2020 ◽

Vol 234 (9) ◽

pp. 1775-1785 ◽

Cited By ~ 1

Author(s):

Erhu Qu ◽

Mingzhe Li ◽

Rui Li

Keyword(s):

Numerical Simulation ◽

Deformation Behavior ◽

Sandwich Structure ◽

Deformation Behaviour ◽

Deformation Resistance ◽

Spring Back ◽

Strip Steel ◽

Forming Accuracy ◽

Sheet Bending ◽

Formed Part

The blank is prone to wrinkles and spring-back in multi-point forming, seriously affecting the quality and forming accuracy of the formed part. To improve this state, a sandwich structure constructed from a strip steel pad and blank was presented. The deformation behaviour and forming accuracy using three forming processes, namely, without a cushion, using a polyurethane elastic pad and using a strip steel pad, were analysed by numerical simulation and experimentation. The results showed that the use of the strip steel pad in multi-point forming can effectively increase the deformation resistance of the sheet bending; make the material evenly thinned during forming; suppress defects such as wrinkles, spring-back, dimples and straight edges; and improve the forming accuracy.

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Reconfigurable Multipoint Forming Using Waffle-Type Elastic Cushion and Variable Loading Profile

Materials ◽

10.3390/ma13204506 ◽

2020 ◽

Vol 13 (20) ◽

pp. 4506

Author(s):

Mohammed Moheen ◽

Adel Abdel-Wahab ◽

Hany Hassanin ◽

Khamis Essa

Keyword(s):

Process Parameters ◽

Fem Analysis ◽

Thickness Variation ◽

Variable Loading ◽

Shape Deviation ◽

Multipoint Forming ◽

Base Radius ◽

Manufacturing Techniques ◽

Elastic Cushion ◽

Reconfigurable Die

There is an increasing demand for flexible, relatively inexpensive manufacturing techniques that can accommodate frequent changes to part design and production technologies, especially when limited batch sizes are required. Reconfigurable multi-point forming (MPF) is an advanced manufacturing technique which uses a reconfigurable die consisting of a set of moveable pins to shape sheet metal parts easily. This study investigates the use of a novel variable thickness waffle-type elastic cushion and a variable punch-loading profile to either eliminate or minimise defects associated with MPF, namely wrinkling, thickness variation, shape deviation, and dimpling. Finite element modelling (FEM), analysis of variance (ANOVA), and the response surface methodology (RSM) were used to investigate the effect of process parameters pertaining to the cushion dimensions and type of loading profile on the aforementioned defects. The results of this study indicate that the most significant process parameters were maximum cushion thickness, cushion cut-out base radius, and cushion cut-out profile radius. The type of loading profile was found to be insignificant in all responses, but further investigation is required as the rate, and the thermal effects were not considered in the material modelling. Optimal process parameters were found to be a maximum cushion thickness of 3.01 mm, cushion cut-out base radius of 2.37 mm, cushion cut-out profile radius of 10 mm, and a “linear” loading profile. This yielded 0.50 mm, 0.00515 mm, 0.425 mm for peak shape deviation, thickness variation, and wrinkling, respectively.

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Study on the Forming Accuracy and Density of Eucalyptus/PES Fabricated by Laser Sintering

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.667.200 ◽

2015 ◽

Vol 667 ◽

pp. 200-205

Author(s):

Yan Ling Guo ◽

Yue Qiang Yu ◽

Kai Yi Jiang

Keyword(s):

Layer Thickness ◽

Laser Power ◽

Dimensional Accuracy ◽

Processing Parameters ◽

Variable Density ◽

Laser Sintering ◽

Powder Size ◽

Forming Accuracy ◽

Preheating Temperature ◽

Forming Precision

. Based on orthogonal test, the forming accuracy and density of laser sintering eucalyptus/PES blend is studied in this paper. It mainly analysed the effect of the powder size and process parameters (such as laser power, layer thickness, preheating temperature, etc) on the forming precision and density of sintered eucalyptus/PES parts, also the correlation analysis of molding error caused by the powder’s physical properties and machine is performed. By measuring the parts’ dimensions, the results show that the laser power and powder size are two main factors influencing parts’ density, and variable density, layer thickness and preheating temperature jointly affect the dimensional accuracy. The optimized processing parameters are obtained. The powder size, laser power, scanning rate, layers thickness and preheating temperature are 300 mesh, 43W, 2000mm/s, 0.1mm, 60°C respectively.

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Forming 3D Sheet Metals by Means of Continuous Rolling Method

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.16-19.570 ◽

2009 ◽

Vol 16-19 ◽

pp. 570-574 ◽

Cited By ~ 1

Author(s):

Zhi Qing Hu ◽

Ming Zhe Li ◽

Xue Peng Gong ◽

Zeng Ming Feng

Keyword(s):

Sheet Metal ◽

Three Dimensional ◽

Sheet Metals ◽

Continuous Rolling ◽

The Core ◽

3D Surface ◽

Multipoint Forming ◽

Rolling Method ◽

Novel Method

In this paper, we present a novel method of using the continuous rolling to fabricate three-dimensional sheet metal. The core bendable roller is composed of the flexible axis and the controllable equipment. The transversal shape of the sheet metal can be realized by regulating the controllable equipment to make the axis of bendable roller bent; the longitudinal shape is formed by driving the three bendable rollers rotated and the top roller making a displacement synchronously. Some experiments were performed and typical 3D surface parts were formed. Based on the results of the experiments, the effects of the thickness and the rolling times are discussed. The results of the research will be beneficial to define the parameters and perfect the theory of continuous multipoint forming of multiform 3D parts.

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Comparison of the Geometric Accuracy by DSIF Toolpath with SPIF Toolpath

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.494-495.497 ◽

2014 ◽

Vol 494-495 ◽

pp. 497-501 ◽

Cited By ~ 1

Author(s):

Jin Han Wu ◽

Qiu Cheng Wang

Keyword(s):

Incremental Forming ◽

Single Point ◽

Metal Sheet ◽

Single Point Incremental Forming ◽

Geometric Accuracy ◽

Forming Process ◽

Forming Accuracy ◽

Finite Method

As there is no sufficient support between the single moving tool and fixture, the formed metal sheet is easy to bend in single point incremental forming (SPIF). Double sided incremental forming (DSIF) is proposed in which two tools are used on each side of the sheet to improve the components forming accuracy. Element finite method is introduced to simulate the forming process with both DSIF and SPIF toolpaths and the component geometric accuracies are compared. The simulation result shows the DSIF toolpaths can obtain better geometric accuracy than SPIF.

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High Frequency Ultrasonic Elliptical Vibration Turning Studty for Weak Rigidity Precision Workpiece

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.467-469.236 ◽

2011 ◽

Vol 467-469 ◽

pp. 236-240 ◽

Cited By ~ 1

Author(s):

Wen Li ◽

De Yuan Zhang

Keyword(s):

Surface Roughness ◽

High Frequency ◽

Critical Speed ◽

Machining Efficiency ◽

Elliptical Vibration Cutting ◽

Vibration Cutting ◽

Elliptical Vibration ◽

Forming Accuracy ◽

Ultrasonic Elliptical Vibration ◽

Cutting Direction

Based on analysis of the micro-surface and kinematical formulas of elliptical vibration cutting(EVC), the paper presents that frequency and amplitude of vibration parameter affect surface roughness, forming accuracy and machining efficiency of weak rigidity workpiece: increase vibration frequency are result in lower vibration cutting duty cycle , lower cutting force, advancer critical speed, so advance forming accuracy and machining efficiency; decrease amplitude are result in reduce the height of vibration ripples in cutting direction , so improve surface roughness. Experiences of cutting the weak rigidity workpiece by the designed double bending hybrid vibration high transducer, verified that the high frequency elliptical vibration cutting are proved more conducive to machining weak rigidity workpiece.

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