Effect of pin arrangement on formed shape with sparse multi-point flexible tool for creep age forming

Self Cite

Accurately predicting the amount of springback has always been a prior focus in metal forming industry, particularly for creep age forming (CAF), for its significant effect on tool cost and forming accuracy. In this study, a closed-form solution for CAF springback prediction covering deformation from elastic to plastic loadings was developed by combining the beam theory and Winkler’s theory, based on which an efficient springback compensation method for CAF was proposed. This developed solution extends the application area beyond the traditional beam theory-based springback prediction methods, maintaining its validity with large loading deflection in plastic range. Finite element (FE) simulation and four-point bending CAF tests adopting a 3rd generation Al-Li alloy were conducted in both elastic and plastic forming regions and the results showed close agreement with the closed-form springback predictions. For the proposed compensation method, an adjustment factor was introduced for complex flexible tool CAF to consider its deviation from the uniform stress loading and can be obtained using the closed-form solution. The flexible tool CAF tests using the Al-Li alloy demonstrated the applicability of the proposed compensation method to obtain the target shape within reasonable iterations, which can be further reduced by combining FE simulation.

Section: Geometric Relation In Caf Of Single Curvature Sheetmentioning

confidence: 99%

An efficient closed-form solution for springback prediction and compensation in elastic–plastic creep age forming

Wang

Rong

Shi

et al. 2023

Self Cite

“…(2) The properties of the sheet yield according to the bilinear yield model. (3) The force exerted by the head on the sheet is evenly distributed on the sheet surface. (4) The middle layer of the sheet coincides with the neutral layer.…”

Section: Fig 5 Finite Element Model Of Mpf-icfd 4 Analysis Of the For...mentioning

confidence: 99%

“…However, the initial investment of stamping equipment is large, and the design and production cycle of the stamping die is long, so the technology only has significant economic benefits for mass production [1,2]. In recent years, with the development of market globalization and product customization, flexible manufacturing technology has received increasing attention [3,4].…”

Section: Introductionmentioning

confidence: 99%

Deformation characteristics and forming force limits of multi-point forming with individually controlled force–displacement

Jia

Chen

Wang

et al. 2022

To solve the problem of springback in traditional multi-point forming (MPF), a new multi-point forming process, namely, multi-point forming with individually controlled force-displacement (MPF-ICFD), was proposed. The core idea of this process is to simultaneously apply a normal force to the upper and lower sides of a sheet during the whole forming process. Therefore, the deformation sequence of the sheet metal is changed from local constraint overall deformation in the traditional MPF process to global constraint local deformation in the MPF-ICFD process, which is beneficial for improving the deformation uniformity and reducing the sheet springback.In this work, the deformation characteristics and forming force limits of MPF-ICFD were studied through mechanical analyses, numerical simulations and experiments. The results show that, compared with the traditional MPF, the springback of sheet metal is 2 significantly reduced, and the uniformities of the strain and wall thickness are significantly improved in the MPF-ICFD. The influence of the sheet thickness on the upper limit of the forming force is more significant than that on the lower limit. For an aluminium alloy sheet with a wall thickness of 1.5-3 mm, the upper and lower limits of forming force of a single head change linearly from 6.3 kN to 12.6 kN and from 0.5 kN to 1 kN, respectively.

“…Multi-point forming is a new flexible forming technology that can quickly adjust the configuration surface of the basic body according to the target shape of the part to construct a forming surface [4], thus realizes mold-less, rapid, and flexible forming. Multipoint forming technology and equipment have been widely used in recent years, mainly used for the three-dimensional forming of sheet metal [5][6][7]. The combining of the multipoint forming technology with the stretch-bending process of aluminum alloy profiles can not only save the time and expense of traditional stretch-bending mold design, manufacturing, and debugging, but also shorten the production cycle of formed parts, and greatly save costs [8].…”

Section: Introductionmentioning

confidence: 99%

Research on ultrasonic-assisted multi-point stretch bending process of aluminum profile

Liang

2021

The tensile and bending process of asymmetric L-shaped aluminum alloy profile is studied by the Abaqus software using the finite element numerical simulation method. The geometric parameters of the ultrasonic-assisted vibration multi-point die (UMPD) and the law of influence on the stress-strain and spring-back of the L-section profile after bending are studied. The results show that the UMPD can reduce the forming stress of the profile during plastic deformation, and the stress-strain distribution of the aluminum profile is more uniform. The changes in the ultrasonic vibration frequency and amplitude of the mold are beneficial to reduce the spring-back of aluminum profiles. The ultrasonic process parameters with a vibration frequency of 20 kHz and an amplitude of 0.02 mm have the best effect on suppressing spring-back, which is reduced by 20.6% compared to the case of no ultrasonic application. Finally, it is verified by experiments that the experimental results are basically consistent with the simulation results, and the changing trend of spring-back deformation is consistent.