Study On The Single Point Incremental Sheet Forming of AISI 321 Variable Wall Angle Geometry

Afzal, Muhammad Jawad; Israr, Asif; Akram, Muhammad Soban; Muqeet, Abdul

doi:10.21203/rs.3.rs-836822/v1

Cited by 2 publications

(2 citation statements)

References 11 publications

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“…In addition, the pillow grows significantly with an increase in the forming depth, but not continuously; hence the pillow reduces at a specific depth due to the property of the hardening exponent. Afzal [170], however, stated that the formed part shows a pillow effect because the base of the sheet remains in the elastic state, while the rest of the sheet is in the plastic state. Essa and Hartley [171] examined different ways to increase the geometric accuracy of implementing FE in SPIF on the Al-5251-H22 aluminium alloy.…”

Section: Pillow Effectmentioning

confidence: 99%

Recent Developments and Future Challenges in Incremental Sheet Forming of Aluminium and Aluminium Alloy Sheets

Trzepieciński

Najm

Oleksik

et al. 2022

Metals

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Due to a favourable strength-to-density ratio, aluminium and its alloys are increasingly used in the automotive, aviation and space industries for the fabrication of skins and other structural elements. This article explores the opportunities for and limitations of using Single- and Two Point Incremental Sheet Forming techniques to form sheets from aluminium and its alloys. Incremental Sheet Forming (ISF) methods are designed to increase the efficiency of processing in low- and medium-batch production because (i) it does not require the production of a matrix and (ii) the forming time is much higher than in conventional methods of sheet metal forming. The tool in the form of a rotating mandrel gradually sinks into the sheet, thus leading to an increase in the degree of deformation of the material. This article provides an overview of the published results of research on the influence of the parameters of the ISF process (feed rate, tool rotational speed, step size), tool path strategy, friction conditions and process temperature on the formability and surface quality of the workpieces. This study summarises the latest development trends in experimental research on, and computer simulation using, the finite element method of ISF processes conducted in cold forming conditions and at elevated temperature. Possible directions for further research are also identified.

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Section: Pillow Effectmentioning

confidence: 99%

Recent Developments and Future Challenges in Incremental Sheet Forming of Aluminium and Aluminium Alloy Sheets

Trzepieciński

Najm

Oleksik

et al. 2022

Metals

View full text Add to dashboard Cite

show abstract

“…Furthermore, higher forming depth leads to bigger billowing but not in a linear way: certain specified depths relieve the pillow effect because of the property of the hardening expo-nent. Afzal (2021) sees this differently: he claims that the pillow effect sets in because of two different states in the formed sheet: the unformed base is in an elastic state, while the formed wall is in a plastic state. Isidore et al (Isidore, 2014;Isidore et al, 2016) found that parts formed with the help of a hemispherical tool caused more oversized pillows because strains and compressive stresses were generated due to the compression of the material.…”

Section: Introductionmentioning

confidence: 99%

Investigation and machine learning-based prediction of parametric effects of single point incremental forming on pillow effect and wall profile of AlMn1Mg1 aluminum alloy sheets

Najm

Paniti

2022

J Intell Manuf

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Today the topic of incremental sheet forming (ISF) is one of the most active areas of sheet metal forming research. ISF can be an essential alternative to conventional sheet forming for prototypes or non-mass products. Single point incremental forming (SPIF) is one of the most innovative and widely used fields in ISF with the potential to form sheet products. The formed components by SPIF lack geometric accuracy, which is one of the obstacles that prevents SPIF from being adopted as a sheet forming process in the industry. Pillow effect and wall displacement are influential contributors to manufacturing defects. Thus, optimal process parameters should be selected to produce a SPIF component with sufficient quality and without defects. In this context, this study presents an insight into the effects of the different materials and shapes of forming tools, tool head diameters, tool corner radiuses, and tool surface roughness (Ra and Rz). The studied factors include the pillow effect and wall diameter of SPIF components of AlMn1Mg1 aluminum alloy blank sheets. In order to produce a well-established study of process parameters, in the scope of this paper different modeling tools were used to predict the outcomes of the process. For that purpose, actual data collected from 108 experimentally formed parts under different process conditions of SPIF were used. Neuron by Neuron (NBN), Gradient Boosting Regression (GBR), CatBoost, and two different structures of Multilayer Perceptron were used and analyzed for studying the effect of parameters on the factors under scrutiny. Different validation metrics were adopted to determine the quality of each model and to predict the impact of the pillow effect and wall diameter. For the calculation of the pillow effect and wall diameter, two equations were developed based on the research parameters. As opposed to the experimental approach, analytical equations help researchers to estimate results values relatively speedily and in a feasible way. Different partitioning weight methods have been used to determine the relative importance (RI) and individual feature importance of SPIF parameters for the expected pillow effect and wall diameter. A close relationship has been identified to exist between the actual and predicted results. For the first time in the field of incremental forming study, through the construction of Catboost models, SHapley Additive exPlanations (SHAP) was used to ascertain the impact of individual parameters on pillow effect and wall diameter predictions. CatBoost was able to predict the wall diameter with R2 values between the range of 0.9714 and 0.8947 in the case of the training and testing dataset, and between the range of 0.6062 and 0.6406 when predicting pillow effect. It was discovered that, depending on different validation metrics, the Levenberg–Marquardt training algorithm performed the most effectively in predicting the wall diameter and pillow effect with R2 values in the range of 0.9645 and 0.9082 for wall diameter and in the range of 0.7506 and 0.7129 in the case of the pillow effect. NBN has no results worthy of mentioning, and GBR yields good prediction only of the wall diameter.

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Study On The Single Point Incremental Sheet Forming of AISI 321 Variable Wall Angle Geometry

Cited by 2 publications

References 11 publications

Recent Developments and Future Challenges in Incremental Sheet Forming of Aluminium and Aluminium Alloy Sheets

Recent Developments and Future Challenges in Incremental Sheet Forming of Aluminium and Aluminium Alloy Sheets

Investigation and machine learning-based prediction of parametric effects of single point incremental forming on pillow effect and wall profile of AlMn1Mg1 aluminum alloy sheets

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