Single-point incremental forming (SPIF) enables the forming of fix-clamped sheet metal by moving a relatively small geometrically simple tool along the trajectory, producing the desired shape of the ...final product. Excessive thinning of the sheet results in fracture, determining the limit of formability. This characteristic of the forming process can be improved by upgrading the basic SPIF process to two-step forming, whereby a more even distribution of the sheet thickness can be achieved by pre-bulging with a hemispherical punch. This study focused on analysing the SPIF process and a hybrid two-step forming consisting of sequential bulging and SPIF. The analysis focused on the output parameters of sheet metal thinning and maximum forming force components and was conducted with Abaqus simulation software. An innovative new approach for influence analysis of technological, material and geometrical input parameters and correlation analysis between the mentioned parameters was performed using the random forest (RF) method, which allows the determination of individual parameter influence by analysing tree-shaped models obtained through the training process. The analysis results show a significant influence of the workpiece wall angle and part depth on thinning and initial sheet thickness on values of the forming force components. The results also show a great correlation between the parameters of the bulging depth and the part depth after SPIF and the significant influence of the appropriate choice of the backing plate geometry for the target product geometry.
•Analysis of parameters of SPIF and hybrid two-step forming system.•Focusing on important technological, material, and geometrical parameters.•Forming force and sheet metal thinning predicted by finite element method.•Parameter influence and correlation analysis using random forest method.•Innovative evaluation of parameters on thinning and maximum force.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this paper, an efficient approach for sheet metal thickness measurement is proposed. It is based on the concept of magnetic field effect resonance commonly called as Hall effect. The combination ...of magnet and metal tools generates the DC voltage signal. The magnitude of the generated signal is inversely proportional to the distance between magnet and tool and hence the thickness of the sheet metal. The proposed idea is designed and implemented successfully using suitable hardware. Initially, the designed circuit is tested manually using the Hall-effect sensor and the sheet metal of different thicknesses. Further, the various experimentations are carried out on the complete CNC machine-based incremental sheet metal forming setup to examine the effectuality of the proposed design. Moreover, the evaluation of the manufactured ISF part has been carried out using the image processing technique. It is observed that the proposed approach can be used efficiently in the application such as the incremental sheet metal forming (ISF) process in real-time for thickness measurement.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Incremental Sheet metal Forming (ISF) Process is a suitable process which helps to produce various parts used in automotive sector by rapid prototyping. This method of producing a prototype helps ...industry in reducing the production cost. In ISF process, a final product is evolved through local deformation of the sheet metal made by the tool. Usually better formability is obtained when the tool makes a better contact with the sheet metal throughout the process. Improved formability elevates dimensional accuracy of the product, thus increases the market value of the product. A new tool with multiple ball ends capable of making multiple mating points over sheet metal was used in this research to enhance the efficiency of formability and surface finish. Ability of the new Multi-Point Incremental Forming Tool (MPIF) was investigated and compared to the existing Single Point Forming Tool (SPIF) based on the formability and surface finish. Forming Limit Diagram (FLD), Strain Distribution (SD) and Scanning Electron Microscope (SEM) were used to examine the formability of the sheet metal. The SEM & 3D-Surface roughness profilometer were used to observe the sheet metals surface finish. In addition to these experimental techniques a simulation results were also used to predict the stress and strain rate during forming process. The experimentation and simulation outcome shows that the MPIF provides superior formability and surface finish.
In this paper, we proposed a multiple-tool (MT) modeling method to reduce computational time for finite element simulations of incremental sheet forming (ISF) process. The aim is to investigate the ...computation efficiency and prediction accuracy of thickness reduction and springback of ISF parts using the MT simulation model. The toolpaths required for this method are generated by an in-house code and can be extended to accommodate complex ISF parts geometries. We found that the proposed MT method can significantly reduce CPU time and maintain geometric accuracy in tolerance, although the proposed MT simulation model is physically different from the real forming process of single-tool ISF. To validate the proposed method, the simulation results of the ISF with truncated cone geometry were compared with the experimental results in terms of thickness distribution, forming force, and springback. The comparison results show that the developed multi-tool simulation approach can reduce the CPU time by up to 90% with satisfactory geometric accuracy as compared to traditional FE model. We further designed an asymmetrical ISF parts with multiple curvature changes to verify the adaptability of the MT simulation method. The comparison results show that the method proposed in this study can also greatly reduce the CPU time while maintaining relatively high geometric accuracy for complex ISF part. This study provides an important guideline for the use of FE simulation in the design and fabrication of large industrial-scale ISF parts.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Incremental sheet metal forming can manufacture various sheet metal products without a dedicated punch and die set. In this study, we developed a two-stage incremental forming process to decrease ...shape errors in the conventional incremental forming process. The forming process was classified into the first single point incremental forming (1st SPIF) process for forming a product and the counter single point incremental forming (counter SPIF) process to decrease shape error. The counter SPIF gives bending deformation in the opposite direction. Furthermore, the counter SPIF compensates for shape errors, such as section deflection, skirt spring-back, final forming height, and round. The tool path of the counter SPIF has been optimized through a relatively simple optimization method by modifying the tool path of the previous step. The tool path of the 1st SPIF depends on the geometry of the product. An experiment was performed to form a circular cup shape to verify the proposed tool path of the 1st and counter SPIF. The result confirmed that the shape error decreased when compared to the conventional SPIF. For the application, the ship-hull geometry was adopted. Experimental results demonstrated the feasibility of the two-stage incremental forming process.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Incremental sheet metal forming characterized as increased flexibility and local plastic deformation is well suitable for low-production-run manufacturing and a new sample trial production of complex ...shapes. Thickness thinning is still an obstacle to the application of incremental forming. In this study, a novel mathematical algorithm based on a non-uniform rational B-spline (NURBS) surface was proposed and implemented which focuses on predicting and calculating the final thickness for arbitrary parts in incremental forming. In order to evaluate the validity of the proposed model, the finite element simulation and forming experiments of three kinds of parts, such as truncated cones, truncated pyramids and ellipsoid parts, were conducted. The thickness of theoretical prediction was compared with that of finite element simulation and experiment, and good agreements were obtained. The results show that the proposed model and the method are effective and robust for predicting the thickness of the formed parts in incremental sheet metal forming.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Flexible metal forming processes are novel ways to meet the growing needs for maintaining economic feasibility in mass production and customization. The flexible forming processes inherently have ...more process parameters to control than conventional processes, and thus they may be less economical. However, owing to the rapid development of computing technology over the last two decades, the numerical simulation approach has gained significant attention for optimizing the process parameters. Based on the numerical analysis, sophisticated theories have also been developed to describe the material deformation characteristics during forming processes. In this paper, incremental sheet metal forming, incremental bulk forming, and flexible roll forming are briefly overviewed with regard to innovative techniques for numerical simulations of various flexible metal forming processes.
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CEKLJ, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Incremental sheet metal forming (ISF) is a versatile dieless forming process for manufacturing complex sheet metal components. The toolpath is one of the most critical process parameters, ...significantly influencing the ISF formability. The conventional toolpath strategies, such as spiral and constant z-slice-based tool paths, do not prove helpful for complex asymmetries in part geometry. The approach to toolpath planning in ISF should consider both material behavior and design complexity. This work compares conventional toolpaths with two strategies, namely feature-based and space-filling fractal tool paths. Material thinning and geometric deviations are critical limitations for successful part development. All toolpath strategies were evaluated for material distribution, geometric accuracy, and fracture depth using four carefully designed components with gradually increasing asymmetry. As evident from the results obtained, the material deformation was sensitive to the choice of toolpath strategies. The feature-based tool path captures the part curvatures more uniformly, leading to homogeneous thickness distribution. At the same time, fractal-based strategies lead to lower overall geometric deviation in the region of curved profiles.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In this article, current, application-related investigations in the field of incremental sheet metal forming (ISF) will be presented and discussed. The main focus of the study will be on the chain of ...conceptual design, experimentation and subsequent work processes, right through to the final assembly of car exterior skin parts of a streamlined vintage concept car. This will be accompanied by a comparison and evaluation of different production technologies with regard to their economic efficiency, their real duration times and the specific boundary conditions for the manufacturing of just one part per geometry. The manufacturing processes at the centre of the study were: deep drawing, hydroforming and ISF (Two Point Incremental Forming (TPIF) and rolling). Following the holistic discussion on the procedure and choice of processes, the TPIF is examined in detail using the example of the rear mudguards.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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