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MIT World Peace University

Single-point incremental forming is a versatile process. It is being studied by many researchers and industries because of its ability to form various geometric shapes without the need for specific tooling. In the current research work, numerical and experimental investigation on thinning in parts formed using the incremental forming process is done. The influence of three-process parameters specifically pitch, tool diameter, and feed on thinning (minimum thickness) is investigated. A hemispherical-ended forming tool with an 8 mm tool diameter made of high-speed steel and aluminum blank Al-6061 with 0.8 mm thickness is used for experimental work. Results show that all the process parameters have a major influence on the minimum sheet thickness of formed surfaces. It is observed that small tool and high feed result in improved thickness, whereas the medium value of pitch results in less thinning.

School of Mechanical Engineering

Engineering and Technology

Soft Computing in Materials Development and its Sustainability in the Manufacturing Sector

Numerical and Experimental Investigation on Thinning in Single-Point Incremental Sheet Forming

In the present research work, parts are formed using two-step hybrid incremental sheet forming (HISF) process. The effect of process parameters such as preform tool size, tool diameter, and preforming depth on thinning in the formed part is studied. A simulation model is developed and simulation results are compared with the experimental results. Also, results of HISF process are compared with the results of single point incremental sheet forming. The simulation results are in good agreement with the experimental results. It is observed that HISF process results in lower thinning as compared to SPIF process. Further, it is found that preform tool size has considerable influence on the minimum thickness of formed part. Large preform tools result in relatively lower thinning.

Engineering Research Express

Experimental and simulation studies on hybrid incremental sheet forming

Erosion wear is a severe issue in different industrial applications results in economic costs and operational failure. In most of the industry pipelines are used to handle the slurry during industrial process, the slurry handling pipeline is failure due to erosion wear. The slurry pot test rig is developed and fabricated for investigating the erosion wear rate of different material and solid particles used in the slurry pipeline with various working conditions. The various influencing parameters such as solid particle flow velocity, impact angle, solid particle size, and concentration are responsible for the rate of material loss and erosion wear mechanisms. The present study is based on experimental work and its validation of results of slurry erosion wear for slurry handling pipeline using slurry pot test rig and CFD simulation. For experimentation, mild steel is used as pipeline material and coal bottom ash is used as solid particles for simulating slurry handling pipeline use in a thermal power plant. The experimentation is performed on the slurry pot test rig. The computational fluid dynamics (CFD) tool is used to predict and simulate the experimental results of the slurry pot test rig. The simulation results compared with experimental results and check the percentage of errors with both the results. The simulation results show a similar kind of trend for erosion wear behavior of mild steel as per the experimental results. Simulation results show the average error up to±21% variation with the experimental result. The simulation results give the position of erosion wear over the sample surface. © 2022, Walailak University. All rights reserved.

World University root node

Trends in Sciences

CFD Simulation and Experimental Results Validation of Slurry Erosion Wear using Slurry Pot Test Rig

Single point incremental forming (SPIF) process is an advanced dieless sheet metal forming process in which the requirement of a dedicated punch-die setup is eliminated. The dedicated punch-die setup is replaced by a universal blank holding fixture, a punch (or tool), and a backing plate. It has a variety of applications ranging from automotive to biomedical fields. But its limitations such as inability to form steeper wall angle and high geometric error in single-stage restricts its application in sheet metal industries. To overcome this, multistage SPIF process is an alternative to achieve larger wall angles. Formability in multistage SPIF process is increased by providing intermediate stages. Various methodologies have been suggested to enhance the profile accuracy, however, it still remains the major issue. In the present paper influence of process variables namely feed rate, number of forming stages and pitch size on geometric accuracy and surface roughness of formed part is investigated. Taguchi L18 orthogonal array is used for design of the experiments. From the analysis of variance (ANOVA), it is found that the number of stages and pitch size have a significant influence on geometric accuracy and surface roughness. Since feed rate is an insignificant parameter. So a higher feed rate can be used to reduce forming time. Further, a mathematical model is developed to predict the geometrical accuracy and surface roughness of the formed part. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd 2021.

Lecture Notes in Mechanical Engineering

Experimental investigation on geometric accuracy and surface roughness of formed part in multistage single point incremental forming (spif) process

Single-point incremental forming (SPIF) process is an emerging sheet metal forming process in which constraint of using dedicated press tools is eliminated. Some process limitations like poor surface finish, longer forming time, higher geometrical error, and uneven wall thickness distribution restrict its applicability in sheet metal industry. But SPIF process with dummy sheet has the capability to overcome some of the prevailing limitations of SPIF process. In the present paper, influence of dummy sheet thickness, step size, wall angle, and feed rate on geometrical error in terms of root-mean-squared error (RMSE) of formed part is investigated. Box Behnken design is used to design the experiments. From the analysis of experimental result, it is found that dummy sheet thickness, step size, and wall angle are significant process parameters influencing RMSE. No significant influence of feed rate on RMSE is observed. RMSE increases with increase in dummy sheet thickness and wall angle, while it decreases with increases in step size. As feed rate increases, there is nominal decrease in RMSE which is desirable. So higher feed rate is recommended to reduce forming time. Further, empirical model is developed to predict RMSE. Also, optimization of process parameters is performed to minimize RMSE. Confirmation experiments were performed in order to check the accuracy of developed predictive model and it is found that predicted results are in good agreement with experimental results. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd 2021.

Experimental investigation on geometric error in single-point incremental forming with dummy sheet

In the present experimental work, hybrid incremental sheet forming (HISF) process comprising stretch forming followed by single point incremental sheet forming (SPIF) is developed for forming conical frustum. Experimental investigation is done to find the influence of process parameters on thickness distribution and localized thinning in the formed parts. Experimental result reveals that stretching has a substantial effect on localized thinning in formed parts. Small improvement in the thickness distribution and localized thinning is found in formed parts. Experimental investigation on the influence of preform tool shape is also done to further improve thickness distribution. It is observed that the geometry of preform tool and amount of stretching has a great influence on thinning and thickness distribution. It is found that intermediate preform tool size and small amount of preforming results in forming conical frustum having uniform thickness distribution. Also, a considerable reduction in forming time using developed HISF process is observed as compared to SPIF process alone. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd 2021.

Hybrid incremental forming: Investigation on localized thinning and thickness distribution in formed parts

In this paper, experimental investigation of hybrid forming process which combines stretching and single point incremental sheet forming (SPIF) process is done. The process combination has many advantages such as higher formability, short forming time, uniform material distribution etc. as compared to SPIF process alone. The process comprises of partial forming of part shape using stretching in first step, followed by forming of complete part shape using SPIF process in second step. Effect of three parameters namely stretching amount, pitch and tool diameter is investigated on response characteristics namely wall thickness and geometric accuracy of formed parts. Taguchi's L25orthogonal arrays (OA) is used to design the experimental plan. It is observed from the experimental results that, stretching amount and pitch has considerable influence on wall thickness. Also, pitch and tool size significantly affect part accuracy. Grey relational analysis (GRA) is used for multi-performance optimization of most affecting parameters to optimize the wall thickness and geometric accuracy. Validation of optimization process is done by carrying out experiments using optimized values of process parameters. It is observed that the optimum set of process parameters results in optimum wall thickness and geometric accuracy of formed parts. © 2020 Elsevier Ltd. All rights reserved.

Materials Today: Proceedings

Optimization of wall thickness and geometric accuracy in stretch forming combined with incremental sheet forming using grey relational analysis (GRA)

This article describes a comparative study of surfaces of lead zirconate titanate ceramic and carbon fiber reinforced polymer composite materials. In the present study, abrasive water jet machining technique is used to machine ceramic and composite materials. Major process parameters namely stand-off distance, water pressure and traverse speed are considered. The experiments are designed by using response surface methodology. After machining, surface roughness of the machined samples is measured by surface roughness tester. The significance and influence of process parameters are studied by performing analysis of variance. It is observed that water pressure, stand-off distance and traverse speed are significant parameters in machining of lead zirconate titanate ceramic and water pressure and traverse speed are significant parameters in machining of carbon fiber reinforced polymer composite material. It is observed that increase in water pressure and decrease in stand-off distance decreases surface roughness in machining of ceramic material. The surface roughness is reduced from 3.189 to 2.010 μm. Increase in water pressure and decrease in traverse speed results in decrease in surface roughness in machining of composite material. The surface roughness varies between 2.392 and 3.998 μm. Further, the machined surfaces of ceramic and composite materials are examined by using scanning electron microscope to study the microscopic features of the machined surfaces. It is observed that machined surfaces of ceramic and composite material reveal three distinct regions of surface roughness. © 2020 Elsevier Ltd. All rights reserved.

Comparative study of lead zirconate titanate ceramic and carbon fiber reinforced polymer composite surfaces machined by abrasive water jet

In the present experimental study, influence of process parameters in hybrid incremental sheet forming (HISF) is studied. Stretch forming combined with ISF is used for forming of conical parts. Stretch forming or preforming is done in order to get the intermediate shape and thickness distribution. On the same setup final part shape is obtained using the conventional ISF process. A low cost hemispherical-ended wooden preforming tool is used for the preforming purpose. Tools used for ISF process are also hemispherical-ended in shape but having smaller diameters and are made up of stainless steel SS-305. Experiments are designed according to design of experiment (DOE) Taguchi method. Analysis of variance (ANOVA) is used to analyse the effect of process parameters namely preforming depth, tool diameter and pitch on response geometric accuracy. It is found that there is considerable effect of tool diameter on geometric accuracy of the formed part. Also, forming time is reduced considerably due to the preforming operation.

Advances in Materials and Processing Technologies

An Experimental Study on Geometric Accuracy in Hybrid Incremental Sheet Forming

In the present experimental study incremental sheet forming is combined with stretch forming in order to obtain uniform thickness distribution, minimise thinning and to improve geometric accuracy of formed part. Preforming or stretch forming is initially done in order to obtain initial thickness distribution. Incremental sheet forming is then employed to obtain final part shape and thickness distribution. Forming time is also minimised considerably because of initial stretch forming process. The experiments are designed using central composite design (CCD) of response surface methodology. From the results, it is observed that preforming and preform tool shape have significant influence on sheet thinning. Also the combination of ISF and stretch forming processes yields in reduced thinning and uniform thickness distribution. Multi-performance optimisation using desirability function is also performed to improve thinning and geometric accuracy. Further mathematical models are developed which are in good agreement with the experimental results.

Fulltext

International Journal of Materials Engineering Innovation

Optimisation and modelling of thinning and geometric accuracy in incremental sheet forming combined with stretch forming

Single point incremental forming (SPIF) has several advantages over conventional sheet forming process, but due to its inherent drawbacks such as localized thinning, poor formability of parts having steep walls and long processing time make it unsuitable in many industrial applications. In present experimental investigation, two-step hybrid incremental sheet forming (HISF) process is proposed which combines stretch forming (SF) and SPIF process. Stretch forming or preforming is done in order to get intermediate shape and desired thickness distribution. On the same setup final part shape is obtained using SPIF process. From the literature review it is found that sophisticated tooling is used for stretching process. In present experimental investigation simple tooling comprising wooden preforming tool is used for stretching followed by SPIF process to form final part shape. Full factorial design of experiments is used to quantify influence of wall angle, preforming and preform tool radius on minimum thickness. From the experimental results it is observed that wall angle has significant influence on thinning which is in good agreement with the previous literature. Further, from the same set of experiments, the influence of preforming depth and preform tool radius on minimum thickness is studied keeping wall angle as constant. It is found that preforming has significant influence on minimum thickness and formability. For conical frustum of 30o and 50o wall angle, 70 mm preform tool radius and 10 mm preforming results in minimum thinning. Also, improvement of 18% in minimum thickness is observed while forming parts with 50o wall angle. Using preform tool radius 70 mm and preforming depth 18 mm, an improvement of around 40 % in forming depth of part having 70o wall angle is achieved in HISF process as compared to SPIF process.

Procedia Manufacturing

An Experimental Investigation on Thinning and Formability in Hybrid Incremental Sheet Forming Process

Poor geometric accuracy of formed parts is one of the key drawbacks in incremental sheet forming (ISF) process. In present experimental study, ISF is combined with stretch forming (SF) to improve the accuracy of formed parts. Influence of process parameters namely preforming, preform tool radius, wall angle, and tool offset on the geometric accuracy of parts formed in ISF process is investigated. A hemispherical ended forming tool of stainless steel (SS-304) is used to form frustum of cones with wall angle from 30° to 70°. Experiments are designed according to Taguchi’s orthogonal array (OA). From the experimental results, it is found that there is considerable influence of wall angle, preforming, and tool offset on the geometric accuracy of formed part. As the wall angle increases, geometric error reduces considerably resulting in accurate part shapes. The results obtained in present study will certainly be helpful to improve geometric accuracy of sheet metal parts formed using ISF in industries. © Springer Nature Singapore Pte Ltd. 2019.

Incremental sheet forming: An experimental study on the geometric accuracy of formed parts

Incremental forming process has become more and more popular because of its ease of forming and capability to produce different part shapes using same machine set-up. This article describes an experimental study on the influence of process parameters in single point incremental forming (SPIF) on the surface roughness and thickness of formed part. Experiments are performed on aluminium alloy (Al-1050) sheet on a 3-axis CNC milling machine. Hemispherical-headed tool of stainless steel (SS-304) is used to study the effect of tool path, tool diameter and pitch on the surface roughness (R a ) and thickness (t) of formed part. Design of experiment (DOE) full factorial plan is used, and results are plotted using ANOVA. Considerable effect of tool diameter is found on the surface quality of formed part. © 2016, © 2016 Taylor & Francis.