Single Point Incremental Forming Process Research Articles

Optimizing the SPIF parameters for enhancing microhardness and surface quality in Inconel 625 superalloy components

Inconel 625, a high-strength superalloy with excellent corrosion resistance, discovers wide applications in critical sectors such as aerospace, nuclear, marine, and petrochemical. Single-Point Incremental Forming (SPIF) has appeared as an adequate fabricating process for shaping superalloy components. This work used a systematic approach, implementing Response Surface Methodology (RSM) to explore the influence of SPIF process variables, including tool nose diameter, step size, tool spindle speed, and wall angle, on microhardness (MH) and surface roughness (SR). The experimental results have been analyzed to determine the influencing process variables and their optimal settings, which simultaneously enhance MH and reduce SR of Inconel 625 superalloy truncated cones using analysis of variance and the desirability function analysis approach. The most significant parameters that influence MH and SR were TND and SS, respectively. The development of quadratic models for MH and SR has been completed successfully. The maximum MH of 486.8 HV and minimum SR of 0.432 µm have been obtained at the optimal parametric setting of TND = 15 mm, SS = 0.4 mm, TSS = 900 rpm, and WA = 57.5° with the desirability values for MH, SR and combined are 0.832, 0.933, 0.881 respectively. The F-value of the MH model = 109.18 and SR Model = 78.24 implies that both models are significant and both models have excellent prediction strength. The percentage error between predicted and actual values of MH and SR in confirmation run results is less than 5 %.

Experimental analysis of forming forces in incremental forming and its prediction by AI-based methods

Single point incremental forming (SPIF) is an emerging approach to manufacture the user-specific parts of greater strength economically without involving dedicated tools and dies. In this study, peak deforming loads have been measured and estimated in order to determine the size and capacity of forming machinery for manufacturing components, using the SPIF process, for designed process conditions on AA7075-O sheets. Estimation of maximum deforming loads has been accomplished with the help of hybrid artificial neural network (HANN) approach by taking experimental load values as the input dataset. The load values, estimated by HANN approach, have been compared with the load values estimated by two state-of-art regression approaches, that is, Support Vector Machine (SVM) and Gaussian Process Regression (GPR). Results show that the regression methods (SVM and GPR) are outperformed by the HANN model with an accuracy of 99.80%. HANN model estimated force values very close to experimental results. The forming forces were found to be greater when the flat-end tools were used as a forming agent in place of hemispherical-end tool. The proposed study would help the researchers and scientists to assess the capacity the machines used in SPIF process to prepare a particular sheet-part and to prevent the failure of hardware during the SPIF process.

Development of a Compact Incremental Forming Machine

Since the beginning of the 21st century, incremental sheet-metal-forming processes, such as single-point incremental forming (SPIF), have been the subject of extensive research. The SPIF process is highlighted as an efficient and cost-effective solution for producing complex parts with different materials and scales, surpassing conventional methods and being ideal for small series and customized products. Various machines can be used to implement SPIF, such as adapted milling machines, serial robots, and dedicated machines, each with its own advantages. However, although it requires a higher initial investment, a dedicated machine offers superior performance. The objective of this project was the creation of a compact and portable dedicated machine, which included the design of suitable kinematics, a mechanical project, and numerical control. The structural design led to the optimization of the dimensions of the robot arms. Direct and indirect kinematics were analyzed. Finally, the careful selection and adaptation of components were carried out, bearing in mind the support system of the forming punch, including the selection and sizing of motors, reducers, and linear actuators. A functional early prototype was successfully built and tested.

Study of single point incremental forming limits of Al 1050/Mg-AZ31B two-layer sheets fabricated by roll bonding technique: Finite element simulation and experiment

In this work, for the first time, the two-layer Aluminum (Al 1050) and magnesium (AZ31B) sheet were used in the single point incremental forming (SPIF) process. Due to the high strength-to-weight ratio of the Al 1050/Mg-AZ31B sample, today it is used in significant industries such as automotive and aerospace. The finite element simulation process was carried out using the Abaqus Software considering five approaches to determine forming limits. These approaches were forming limit diagram criterion (FLDcrt), effective strain rate (ESR), second derivation of thinning (SDT), Major strain rate (MSR) and Thickness strain rate (TSR) methods. The results showed that the failure prediction in the FLDcrt method was more accurate than other methods. The thickness distribution process was carried out both by simulation and experiment to validate the simulation results. The results show a good agreement between simulation and experimental results. Finally, the results obtained from the SPIF process were compared with the FLD results of the conventional hemispherical punch test, and it was observed that the FLD was higher in the SPIF process. Moreover, the layer arrangement, which affects formability, was investigated. The results showed that the FLD with Mg-AZ31B/Al 1050 arrangement fails in higher strains compared to Al 1050/Mg-AZ31B. After validating the simulation results, the parameter effect of the step-down and tool diameter on the two-layer formability was investigated by the design of experiment. Considering the greater importance of the step-down and tool diameter effect on the created stresses and forming time compared to other parameters, their effect will be investigated. The results showed an optimal condition for the tool diameter, but an opposite relationship with formability was obtained for the step-down.

IMPROVEMENT OF FORMABILITY AND SURFACE FINISH OF CUPRO–NICKEL (70/30) ALLOY DURING SINGLE POINT INCREMENTAL FORMING PROCESS USING CHROME STEEL LASER ABLATED BALL

Cupro–nickel alloy of 70/30 grade was experimented for its formability by SPIF tests, namely straight groove test and wall angle test using a ball attached tool, to emphasize the concern on formability and surface roughness. Two different types of ball were used, one ball was used in polished form and another one was surface-textured using Nd-Yag laser. The cupro–nickel alloy has excellent corrosion resistance and popularly used in marine environments. In this research, an attempt has been made to study the formability when using Chrome steel laser ablated ball. The results concluded that Chrome steel laser ablated ball with oil as lubrication has avoided the occurrence galling and at the same time improved the formability. When experimenting with chrome steel polished ball, the tool and sheet contact is high and the lubricating oil will be less and it is causing the sheet to get heated. The dimples on the ball’s surface made by the laser retain more lubricating oil and thereby decreasing the friction which eventually leads to the delayed fracture. It is found that the formability was increased by 16% in straight groove test, 4.8% for wall angle test and surface roughness values were decreased by 1.4%.

In situ experimental characterization and numerical investigation of Fe-TiB2 Steel Matrix Composite behavior considering fully coupled damage model: Simulation during incremental forming process

The recent and increasing use of Steel Matrix Composites (SMCs) reinforced with titanium particles (TiB2) in engineering applications highlights the need for a deeper understanding of their behavior under various complex loading and forming processes. This paper aims to predict the mechanical behavior related to damage of SMC of reinforced with TiB2 via both experimental techniques and numerical investigations. In situ four-point bending test conducted on Fe-TiB2 SMC highlights a rather heterogeneous plastic deformation accompanied by TiB2 mono and polycrystalline transgranular rupture under bend loading. A fully coupled damage model is considered to simulate the progressive failure and deformation behavior of Fe-TiB2 SMC undergoing plastic deformation and applies it to an incremental forming process. The proposed elastoplastic constitutive equations incorporate a non-linear mixed (isotropic and kinematic) hardening with isotropic damage model. The identified damage parameters obtained provide a satisfactory prediction of composite incremental forming capability and illustrates valuable guide to predict Fe-TiB2 composite sheet's behavior deformation via an SPIF (Single-Point Incremental Forming) process.

THE EVALUATION OF EFFECT OF PARAMETER ON SINGLE POINT INCREMENTAL FORMING OF TITANIUM

Single Point Incremental Forming (SPIF) has emerged as a promising technique for shaping complex geometries in various materials. This study investigates the influence of process parameters, specifically step size and tool diameter, on the SPIF of titanium sheets. The experiment comprises three different step sizes (0.2, 0.4, and 0.6 mm) and three tool diameters (6, 10, and 14 mm), applied to titanium sheets. The research focuses on evaluating the impact of these parameters on three crucial aspects of SPIF: thickness reduction, fracture depth, and forming angle in the fracture zone. Through a series of experiments, the relationship between step size, tool diameter, and these performance indicators is thoroughly examined. Results indicate that smaller step sizes lead to higher thickness reductions and more precise forming angles in the fracture region and smaller tool diameters also increased fracture depths. Understanding the interplay between these parameters is vital for optimizing SPIF processes in titanium sheet forming applications, offering insights for enhanced production efficiency and quality in industries relying on advanced forming techniques. The CNC forming process took about 10 hours.

Influence of single point incremental forming on the low-cycle fatigue performance of AA6061-T6

The current study focuses on the influence of single point incremental forming (SPIF) process on the low-cycle fatigue (LCF) performance of AA6061-T6 sheet. The base material (BM) displays a saturated cyclic response for all strain amplitudes. The SPIF-formed specimens show similar behavior, especially at lower strain amplitudes; however, they exhibit significant cyclic softening at higher strain amplitudes. The LCF life of SPIF specimens (considered in rolling and transverse directions) for all strain amplitudes is slightly reduced due to overlapping/repeated sheet deformation and scallops formed during tool movement. Overlapping affects strain accumulation during SPIF, and scallops affect strain accumulation during cyclic loading and act as a stress concentration site. The texture alteration during the incremental forming also influences the ductility and the subsequent LCF life of the SPIF components.

Investigation of mode-I fracture behavior by essential work of fracture during the single-point incremental forming process

A promising technique for manufacturing low-thickness workpieces with complicated geometries is Incremental Sheet Forming (ISF). Due to its dieless process, ISF is a proper candidate for the production of workpieces at low rates or prototypes of the samples. The mechanical properties of the workpieces produced by ISF are a critical factor in determining their potential applications. Pyramid-shaped samples made of cold rolled steel (DC01) were produced using the single point incremental forming (SPIF) process in this study. To examine how the forming process affects mechanical properties, specimens were obtained from both raw and deformed surfaces. Subsequently, the specimens underwent tensile and fracture tests. The fracture toughness of the specimens was assessed using the essential work of fracture (EWF) technique. Through the use of incremental forming process, the tensile tests revealed a considerable improvement in both ultimate and yield tensile strength, with increases of 33.72% and 90.02%, respectively. However, the forming process led to a reduction of 86.64% in formability compared to the raw specimens. Fracture tests performed on the deformed specimens demonstrated a noteworthy reduction of 59.12% in the amount of energy needed for the initiation of crack growth, compared to the raw specimens. Additionally, we examined how the properties of deformed specimens are affected by the initial rolling direction of the sheets in this study. The study revealed that the mechanical properties and fracture characteristics of the material varied significantly along the transverse direction. The study utilized scanning electron microscopy (SEM) to analyze the fracture mechanisms and found that ductile fracture was the dominant mode of failure. The raw specimens demonstrated more ductile fractured surfaces, which corresponded to higher values of essential work of fracture (EWF).

Experimental Research on Wolfram Inert Gas AA1050 Aluminum Alloy Tailor Welded Blanks Processed by Single Point Incremental Forming Process.

The present paper aims to study the behavior of tailor welded blanks subjected to a single point incremental forming (SPIF) process from an experimental point of view. This process was chosen to deform truncated cone shapes of AA1050 aluminum alloy with different thicknesses. A uniaxial tensile test was performed to determine the mechanical characteristics of the alloy. Initial experimental tests implicated the use of variable wall angle parts which were processed on unwelded sheet blanks for determination of the behavior of the material and the forming forces. Afterwards, the wolfram inert gas (WIG) welding technique was used for joining two sheet blanks with different thicknesses either through one pass on one side, or by one pass on both sides. The conclusion of this paper indicates that one-sided welded blanks cannot be deformed successfully without fracture. In case of two-sided welded blanks, the results showed that the desired depth of 25 mm can be reached successfully. In case of the SPIF process, if welded blanks must be deformed, then the suitable method is to weld the blanks on both sides.

Exploring deformation mechanics of temperature assisted incremental forming with hybrid heating

The single point incremental forming (SPIF) process is a die-less rapid prototyping sheet metal forming method, extensively researched for over two decades. SPIF shows higher formability compared to conventional sheet forming methods. Deformation of materials such as magnesium (Mg) is favored at elevated temperatures due to their poor room temperature formability. Past studies have explored heat-assisted forming techniques to achieve improved formability in SPIF. However, the underlying mechanics of deformation is sparsely explored. The present work explores the mechanism of formability improvement based on thermal gradients for SPIF in hybrid heating. The SPIF experiments are conducted for a combination of local and global heating conditions achieved using tool contact friction and cartridge heaters. The local temperature, stress distributions, and limiting strains are obtained numerically. Fracture-forming limit diagrams (FFL) are developed, and numerical predictions are validated using experimental strain measurements under different forming conditions.

Experimental Investigation of SPIF Process for Conical Frustum

In sheet metal industries, single point incremental forming (SPIF) is a popular technology for quick prototyping and small series manufacturing techniques. In producing specific components with complicated geometries, the technique has become known for its flexibility, effectiveness, and simplicity of usage. The objective of this research work is to carry out the numerical investigation of the SPIF process to study the effect of different parameters on the formability for truncated cone. Al 1060 grade of aluminium is used for this study which is commonly used for kitchenware, reflectors, electronic components etc; where strength is not a major concern. Three dimensional models were developed for different set of parameters using commercial finite element software ABAQUS 6.13 with Dynamic/Explicit solver using solid mechanics model. Taguchi analysis has been carried out to find the effect of parameters (Tool rotational speed, Feed, Step size, Tool diameter and Wall angle) on thickness reduction. Each parameter was varied for three levels and L9 orthogonal array was used. The ANOVA tool has been used to summarize the contribution of each variable. Results have been compared with reported experimental results for validation. The process modelling is concluded with a brief overview of approaches for improving part quality.

Optimization, finite element simulation, fractography and tool wear analysis during SPIF process of perforated stainless steel sheets

The paper deals with an investigation on the single point incremental forming (SPIF) of perforated SS 304 L sheet, to optimize various input parameters, perform the finite element simulation of the SPIF using optimum process setting, conduct fractographic analysis, and to do the wear analysis of the forming tool. The study was conducted with 18 experiments as per Taguchi’s orthogonal array, to evaluate the impact of input parameters on responses. Straight groove and wall angle tests were performed separately, to obtain the maximum sum of strains (Σε)max and maximum wall angle (ϕmax) respectively. The tool wear in terms of reduction in length was measured using a profile projector. The optimization was carried out using the Taguchi grey relational analysis (TGRA). ANOVA was employed to share out the variability brought on by the input parameters. The optimal set of forming parameters was identified, and the confirmation experiment served to confirm it. The effect of all input parameters on the responses were studied referring to the main effect plots. The tool was hardened to bring down the wear and it was confirmed by performing the experiment. FE simulation was done using Abaqus software and the results were in better agreement with that of the experiment. SEM micrographs were taken, analyzed and the fracture mode was identified to be ductile.

Experimental studies of formability in single point incremental forming of Cu-Al bimetallic sheets

In the sheet metal forming industry, single point incremental forming (SPIF) is gaining popularity for producing asymmetrical shapes in small quantities as well as developing rapid prototypes. In the present experimental study, the effect of process variables on the maximum forming wall angle of Cu-Al bimetallic composite sheet using the SPIF process has been investigated. The Cu-Al bimetallic composite sheet was considered for the investigation because of its qualities, including high strength and outstanding thermal and electrical conductivity. The range of step depth, spindle speed, forming speed, layer arrangement, and lubrication type were used as input process variables during the experiments. Formability is evaluated as an output parameter using the maximum forming wall angle. The findings revealed that the Cu-Al layer arrangement produced the greatest forming wall angle with the highest value, 81.5°, when employing 0.6 mm step depth, 1500 rpm spindle speed, 750 mm/min forming speed, and liquid lubrication. Liquid lubrication produced greater forming wall angle values than solid lubrication in all of the experiments. In both lubrication conditions, the Cu-Al layer arrangement exhibited a larger forming wall angle than the Al-Cu layer arrangement.

Determining the influence and correlation for parameters of flexible forming using the random forest method

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.

Influence of Tool Size and Step Depth on the Formability Behavior of AA1050, AA6061-T6, and AA7075-T6 by Single-Point Incremental Forming Process

Influence of Tool Size and Step Depth on the Formability Behavior of AA1050, AA6061-T6, and AA7075-T6 by Single-Point Incremental Forming Process

Electric Hot Single Point Incremental Forming Process of Ti6Al4V Alloy Sheet with Water-Cooled Forming Tool

Electric hot-assisted incremental forming is an effective technique to improve the formability of Ti6Al4V titanium alloy sheets. However, the unstable electric heat can also lead to the unacceptable accuracy and inhomogeneous microstructure. In this study, a water-cooled tool was employed to stable electric-assisted forming temperature. The research results show that the stable forming temperature can significantly improve the forming properties and maintain the consistent microstructure of Ti6Al4V sheets, and the forming force and the degree of springback for the parts also decrease with the increasing temperature. The maximum forming depth is 7.0 mm at 400 °C (forming tool temperature) compared with the forming height of 4.6 mm at room temperature. The microstructure results show that the α phase is refined, and the β phase grains are elongated. The fracture morphologies of the parts at room temperature, 300 °C and 400 °C were compared and analyzed, and the dimples increased in the size and denser at high temperature.

Effect of Ultrasonic Vibration on Forming Force in the Single-Point Incremental Forming Process

Single-point incremental forming (SPIF) has drawn much attention recently due to its flexibility in making parts for rapid prototypes and small samples. Several studies have pointed out the benefits of using ultrasonic vibration (UV) in SPIF experimentally. This study verifies the effect of UV in reducing the forming forces by performing numerical simulations. In addition, the effect of several process parameters, including tool diameters, rotational speeds, step sizes, and ultrasonic vibration amplitudes, is investigated in detail. It is found that an increase in the tool rotational speed and vibrating amplitude decreases forming forces, whereas an increase in the vertical step size increases forming forces.

Deformation Evaluation of A5052 Sheet Metal in SPIF Process

The single point incremental forming (SPIF) process is a high-trend method for forming a metal in a desirable shape. Forming parameters is an important part of deforming metal sheets. So, while reshaping a metal sheet parameters like tools, toolpath, material properties, sheet thickness, and lubricant were considered. Since the Aluminum sheet is used world widely for the body parts of machines for manufacturing parts. So, an A5052 metallic sheet was formed for the improvement of the depth deforming through the SPIF process. While forming an A5052 sheet lubricant was used constantly. After deforming through the SPIF process, further evaluations of the formed part were examined with the nanoprofiling machine to evaluate the deformed areas. Moreover, the deformed part was analyzed for the nana profiling for the deformation occurs on the surface. Likewise, before forming a part, the A5052 design was computer analysis. The simulation part was studied for fixing the maximum depth.

Forming Parameters and Optimization of A5052 in SPIF Process

Forming a metallic sheet along with the consideration of computer simulation and experiment had benefited the milling industry for a long time. The ideal forming, without an error, is a concerning topic. So, the computer simulation had the advantage then direct forming. To observe the results before doing the real experiments simulation comes handy. Which helped to set the parameters for the milling process for the single point incremental forming (SPIF) process. For milling, a CAD design was converted into a 3D model. For this, a conical shape of 3D modeling was made in fusion 360. After onwards, it was simulated for finding the maximum depth for the cracking point. Next for the experimental part, the maximum forming depth was considered, and used lubricant grease for reducing friction. While forming with the grease, the impact of parameters was also changed. Throughout the process, an optimization approach was set to reduce the cracking areas for the G-code. Along with the lubricant use, smooth milling finished surface was observed. To reducing the depth forming errors, an optimization approach was introduced in this research.